Commit Graph

145 Commits (main)

Author SHA1 Message Date
Karthik Nayak 7e873eb390 meson: rename 'third_party_sources' to 'third_party_excludes'
The 'third_party_sources' variable was moved to the root 'meson.build'
file in the previous commit. The variable is actually used to exclude
third party sources, so rename it accordingly to 'third_party_excludes'
to avoid confusion. While here, remove a duplicate from the list.

Signed-off-by: Karthik Nayak <karthik.188@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2025-04-23 10:36:18 -07:00
Karthik Nayak 1597b6e86e meson: move headers definition from 'contrib/coccinelle'
The Meson build for coccinelle static analysis lists all headers to
analyse. Due to the way Meson exports variables between subdirs, this
variable is also available in the root Meson build.

An upcoming commit, will add a new check complimenting 'hdr-check' in
the Makefile. This would require the list of headers. So move the
'coccinelle_headers' to the root Meson build and rename it to 'headers',
remove the root path being appended to each header and retain that in
the coccinelle Meson build since it is specific to the coccinelle build.

Also move the 'third_party_sources' variable to the root Meson build
since it is also a dependency for the 'headers' variable. This also
makes it easier to understand as the variable is now propagated from the
top level to the bottom.

While 'headers_to_check' is only computed when we have a repository and
the 'git' executable is present, the variable itself is exposed as an
empty array. This allows dependencies in upcoming commits to simply
check for length of the array and not worry about dependencies required
to actually populate the array.

Signed-off-by: Karthik Nayak <karthik.188@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2025-04-23 10:36:18 -07:00
Junio C Hamano c3ebf18eb2 Merge branch 'en/merge-recursive-debug'
Remove remnants of the recursive merge strategy backend, which was
superseded by the ort merge strategy.

* en/merge-recursive-debug:
  builtin/{merge,rebase,revert}: remove GIT_TEST_MERGE_ALGORITHM
  tests: remove GIT_TEST_MERGE_ALGORITHM and test_expect_merge_algorithm
  merge-recursive.[ch]: thoroughly debug these
  merge, sequencer: switch recursive merges over to ort
  sequencer: switch non-recursive merges over to ort
  merge-ort: enable diff-algorithms other than histogram
  builtin/merge-recursive: switch to using merge_ort_generic()
  checkout: replace merge_trees() with merge_ort_nonrecursive()
2025-04-17 10:28:18 -07:00
Ramsay Jones 214e2c6856 meson.build: set default help format to html on windows
The build variable DEFAULT_HELP_FORMAT has an appropriate default
('man') set in the code, so there is no need to pass the -Define on
the compiler command-line, unless the build requires a non-standard
value.

In addition, on windows the make build overrides the default help
format to 'html', rather than 'man', in the 'config.mak.uname' file.

In order to suppress the -Define on the C compiler command-line, only
add the -Define to the 'libgit_c_args' variable when the requested
value is not the standard 'man'. In order to override the default value
on windows, add a 'platform' value to the 'default_help_format' combo
option and set it as the default choice. When this option is set to
'platform', use the 'host_machine.system()' method call to determine the
appropriate default value for the host system.

Signed-off-by: Ramsay Jones <ramsay@ramsayjones.plus.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2025-04-16 20:43:43 -07:00
Ramsay Jones 65e3757c24 meson.build: only set build variables for non-default values
Some preprocessor -Defines have defaults set in the source code when
they have not been provided to the C compiler. In this case, there is
no need to pass them on the command-line, unless the build requires a
non-standard value.

The build variables for DEFAULT_EDITOR and DEFAULT_PAGER have appropriate
defaults ('vi' and 'less') set in the code. Add the preprocessor -Defines
to the 'libgit_c_args' only if the values set with the corresponding
'options' are different to these standard values.

Also, the 'git-var' documentation contains some conditional text which
documents the chosen compiled in value, which would not read well for
the standard values. Similar to the above, only add the corresponding
'-a' attribute arguments to the 'asciidoc_common_options' variable, if
the values set in the 'options' are different to these standard values.

Signed-off-by: Ramsay Jones <ramsay@ramsayjones.plus.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2025-04-16 20:43:43 -07:00
Ramsay Jones 0d07e0617c meson.build: remove -DCURL_DISABLE_TYPECHECK
Commit 9371322a60 ("sparse: suppress some \"using sizeof on a function\"
warnings", 2013-10-06) used target-specific variable assignments to add
-DCURL_DISABLE_TYPECHECK to SPARSE_FLAGS for each of the files affected
by the "typecheck-gcc.h" warnings. (http-push.c, http.c, http-walker.c
and remote-curl.c).

These warnings are only issued by sparse, and not by gcc, so we do not
want to disable the 'type checking' for non-sparse targets. The meson
build does not provide any sparse targets, so there is no need to use
the CURL_DISABLE_TYPECHECK preprocessor flag with the c compiler.

In order to re-enable the curl 'type checking' in the meson build, remove
the assignment of -DCURL_DISABLE_TYPECHECK to libgit_c_args.

Signed-off-by: Ramsay Jones <ramsay@ramsayjones.plus.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2025-04-16 20:43:43 -07:00
Junio C Hamano 9bdd7ecf7e Merge branch 'ps/test-wo-perl-prereq'
"make test" used to have a hard dependency on (basic) Perl; tests
have been rewritten help environment with NO_PERL test the build as
much as possible.

* ps/test-wo-perl-prereq:
  t5703: refactor test to not depend on Perl
  t5316: refactor `max_chain()` to not depend on Perl
  t0210: refactor trace2 scrubbing to not use Perl
  t0021: refactor `generate_random_characters()` to not depend on Perl
  t/lib-httpd: refactor "one-time-perl" CGI script to not depend on Perl
  t/lib-t6000: refactor `name_from_description()` to not depend on Perl
  t/lib-gpg: refactor `sanitize_pgp()` to not depend on Perl
  t: refactor tests depending on Perl for textconv scripts
  t: refactor tests depending on Perl to print data
  t: refactor tests depending on Perl substitution operator
  t: refactor tests depending on Perl transliteration operator
  Makefile: stop requiring Perl when running tests
  meson: stop requiring Perl when tests are enabled
  t: adapt existing PERL prerequisites
  t: introduce PERL_TEST_HELPERS prerequisite
  t: adapt `test_readlink()` to not use Perl
  t: adapt `test_copy_bytes()` to not use Perl
  t: adapt character translation helpers to not use Perl
  t: refactor environment sanitization to not use Perl
  t: skip chain lint when PERL_PATH is unset
2025-04-16 13:54:20 -07:00
Junio C Hamano 7cfdb0abc6 Merge branch 'ps/misc-build-fixes'
Random build fixes.

* ps/misc-build-fixes:
  ci: use Visual Studio for win+meson job on GitHub Workflows
  meson: distinguish build and target host binaries
  meson: respect 'tests' build option in contrib
  gitweb: fix generation of "gitweb.js"
  meson: fix handling of '-Dcurl=auto'
2025-04-16 13:54:18 -07:00
Patrick Steinhardt a7fa5b2f0c Documentation: stop depending on Perl to generate command list
The "cmd-list.perl" script is used to extract the list of commands part
of a specific category and extracts the description of each command from
its respective manpage. The generated output is then included in git(1)
to list all Git commands.

The script is written in Perl. Refactor it to use shell scripting
exclusively so that we can get rid of the mandatory dependency on Perl
to build our documentation.

The converted script is slower compared to its Perl implementation. But
by being careful and not spawning external commands in `format_one ()`
we can mitigate the performance hit to a reasonable level:

    Benchmark 1: Perl
      Time (mean ± σ):      10.3 ms ±   0.2 ms    [User: 7.0 ms, System: 3.3 ms]
      Range (min … max):    10.0 ms …  11.1 ms    200 runs

    Benchmark 2: Shell
      Time (mean ± σ):      74.4 ms ±   0.4 ms    [User: 48.6 ms, System: 24.7 ms]
      Range (min … max):    73.1 ms …  75.5 ms    200 runs

    Summary
      Perl ran
        7.23 ± 0.13 times faster than Shell

While a sevenfold slowdown is significant, the benefit of not requiring
Perl for a fully-functioning Git installation outweighs waiting a couple
of milliseconds longer during the build process.

Signed-off-by: Patrick Steinhardt <ps@pks.im>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2025-04-16 07:30:30 -07:00
Junio C Hamano 7b03646f85 Merge branch 'js/comma-semicolon-confusion'
Code clean-up.

* js/comma-semicolon-confusion:
  detect-compiler: detect clang even if it found CUDA
  clang: warn when the comma operator is used
  compat/regex: explicitly mark intentional use of the comma operator
  wildmatch: avoid using of the comma operator
  diff-delta: avoid using the comma operator
  xdiff: avoid using the comma operator unnecessarily
  clar: avoid using the comma operator unnecessarily
  kwset: avoid using the comma operator unnecessarily
  rebase: avoid using the comma operator unnecessarily
  remote-curl: avoid using the comma operator unnecessarily
2025-04-15 13:50:17 -07:00
Junio C Hamano d5baf636a4 Merge branch 'ps/mingw-creat-excl-fix'
Fix lockfile contention in reftable code on Windows.

* ps/mingw-creat-excl-fix:
  compat/mingw: fix EACCESS when opening files with `O_CREAT | O_EXCL`
  meson: fix compat sources when compiling with MSVC
2025-04-15 13:50:15 -07:00
Junio C Hamano ee847e0034 Merge branch 'ps/object-wo-the-repository'
The object layer has been updated to take an explicit repository
instance as a parameter in more code paths.

* ps/object-wo-the-repository:
  hash: stop depending on `the_repository` in `null_oid()`
  hash: fix "-Wsign-compare" warnings
  object-file: split out logic regarding hash algorithms
  delta-islands: stop depending on `the_repository`
  object-file-convert: stop depending on `the_repository`
  pack-bitmap-write: stop depending on `the_repository`
  pack-revindex: stop depending on `the_repository`
  pack-check: stop depending on `the_repository`
  environment: move access to "core.bigFileThreshold" into repo settings
  pack-write: stop depending on `the_repository` and `the_hash_algo`
  object: stop depending on `the_repository`
  csum-file: stop depending on `the_repository`
2025-04-15 13:50:15 -07:00
Junio C Hamano 55f7879f57 Merge branch 'ps/test-wo-perl-prereq' into ps/fewer-perl
* ps/test-wo-perl-prereq:
  t5703: refactor test to not depend on Perl
  t5316: refactor `max_chain()` to not depend on Perl
  t0210: refactor trace2 scrubbing to not use Perl
  t0021: refactor `generate_random_characters()` to not depend on Perl
  t/lib-httpd: refactor "one-time-perl" CGI script to not depend on Perl
  t/lib-t6000: refactor `name_from_description()` to not depend on Perl
  t/lib-gpg: refactor `sanitize_pgp()` to not depend on Perl
  t: refactor tests depending on Perl for textconv scripts
  t: refactor tests depending on Perl to print data
  t: refactor tests depending on Perl substitution operator
  t: refactor tests depending on Perl transliteration operator
  Makefile: stop requiring Perl when running tests
  meson: stop requiring Perl when tests are enabled
  t: adapt existing PERL prerequisites
  t: introduce PERL_TEST_HELPERS prerequisite
  t: adapt `test_readlink()` to not use Perl
  t: adapt `test_copy_bytes()` to not use Perl
  t: adapt character translation helpers to not use Perl
  t: refactor environment sanitization to not use Perl
  t: skip chain lint when PERL_PATH is unset
2025-04-15 08:28:51 -07:00
Patrick Steinhardt d9f517d051 object-file: split out functions relating to object store subsystem
While we have the "object-store.h" header, most of the functionality for
object stores is actually hosted in "object-file.c". This makes it hard
to find relevant functions and causes us to mix up concerns.

Split out functions relating to the object store subsystem into a new
"object-store.c" file.

Signed-off-by: Patrick Steinhardt <ps@pks.im>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2025-04-15 08:24:36 -07:00
Patrick Steinhardt 97dc141fd6 object-file: move `git_open_cloexec()` to "compat/open.c"
The `git_open_cloexec()` wrapper function provides the ability to open a
file with `O_CLOEXEC` in a platform-agnostic way. This function is
provided by "object-file.c" even though it is not specific to the object
subsystem at all.

Move the file into "compat/open.c". This file already exists before this
commit, but has only been compiled conditionally depending on whether or
not open(3p) may return EINTR. With this change we now unconditionally
compile the object, but wrap `git_open_with_retry()` in an ifdef.

Signed-off-by: Patrick Steinhardt <ps@pks.im>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2025-04-15 08:24:35 -07:00
Junio C Hamano 0dfca98881 Merge branch 'ps/object-wo-the-repository' into ps/object-file-cleanup
* ps/object-wo-the-repository:
  hash: stop depending on `the_repository` in `null_oid()`
  hash: fix "-Wsign-compare" warnings
  object-file: split out logic regarding hash algorithms
  delta-islands: stop depending on `the_repository`
  object-file-convert: stop depending on `the_repository`
  pack-bitmap-write: stop depending on `the_repository`
  pack-revindex: stop depending on `the_repository`
  pack-check: stop depending on `the_repository`
  environment: move access to "core.bigFileThreshold" into repo settings
  pack-write: stop depending on `the_repository` and `the_hash_algo`
  object: stop depending on `the_repository`
  csum-file: stop depending on `the_repository`
2025-04-08 14:28:17 -07:00
Elijah Newren ad45b327c0 merge-recursive.[ch]: thoroughly debug these
As a wise man once told me, "Deleted code is debugged code!"  So, move
the functions that are shared between merge-recursive and merge-ort from
the former to the latter, and then debug the remainder of
merge-recursive.[ch].

Joking aside, merge-ort was always intended to replace merge-recursive.
It has numerous advantages over merge-recursive (operates much faster,
can operate without a worktree or index, and fixes a number of known
bugs and suboptimal merges).  Since we have now replaced all callers of
merge-recursive with equivalent functions from merge-ort, move the
shared functions from the former to the latter, and delete the remainder
of merge-recursive.[ch].

Signed-off-by: Elijah Newren <newren@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2025-04-08 13:59:13 -07:00
Patrick Steinhardt b648bd6549 reftable/reader: rename data structure to "table"
The `struct reftable_reader` subsystem encapsulates a table that has
been read from the disk. As such, the current name of that structure is
somewhat hard to understand as it only talks about the fact that we read
something from disk, without really giving an indicator _what_ that is.

Furthermore, this naming schema doesn't really fit well into how the
other structures are named: `reftable_merged_table`, `reftable_stack`,
`reftable_block` and `reftable_record` are all named after what they
encapsulate.

Rename the subsystem to `reftable_table`, which directly gives a hint
that the data structure is about handling the individual tables part of
the stack.

While this change results in a lot of churn, it prepares for us exposing
the APIs to third-party callers now that the reftable library is a
standalone library that can be linked against by other projects.

Signed-off-by: Patrick Steinhardt <ps@pks.im>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2025-04-07 14:53:09 -07:00
Patrick Steinhardt 267143f286 meson: stop requiring Perl when tests are enabled
The Perl interpreter used to be a strict dependency for running our test
suite. This requirement is explicit in the Meson build system, where we
require Perl to be present unless tests have been disabled.

With the preceding commits we have loosened this restriction so that it
is now possible to run tests when Perl is unavailable. Loosen the above
requirement accordingly.

Signed-off-by: Patrick Steinhardt <ps@pks.im>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2025-04-07 14:47:38 -07:00
Patrick Steinhardt 23633466df meson: distinguish build and target host binaries
Almost all of the tools we discover during the build process need to be
native programs. There are only a handful of exceptions, which typically
are programs whose paths we need to embed into the resulting executable
so that they can be found on the target system when Git executes. While
this distinction typically doesn't matter, it does start to matter when
considering cross-compilation where the build and target machines are
different.

Meson supports cross-compilation via so-called machine files. These
machine files allow the user to override parameters for the build
machine, but also for the target machine when cross-compiling. Part of
the machine file is a section that allows the user to override the
location where binaries are to be found in the target system. The
following machine file would for example override the path of the POSIX
shell:

    [binaries]
    sh = '/usr/xpg4/bin/sh'

It can be handed over to Meson via `meson setup --cross-file`.

We do not handle this correctly right now though because we don't know
to distinguish binaries for the build and target hosts at all. Address
this by explicitly passing the `native:` parameter to `find_program()`:

  - When set to `true`, we get binaries discovered on the build host.

  - When set to `false`, we get either the path specified in the
    machine file. Or, if no machine file exists or it doesn't specify
    the binary path, then we fall back to the binary discovered on the
    build host.

As mentioned, only a handful of binaries are not native: only the system
shell, Python and Perl need to be treated specially here.

Reported-by: Peter Seiderer <ps.report@gmx.net>
Signed-off-by: Patrick Steinhardt <ps@pks.im>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2025-04-01 02:20:44 -07:00
Patrick Steinhardt 5a69234b86 meson: fix handling of '-Dcurl=auto'
The "curl" option controls whether or not a couple of features that
depend on curl shall be included. Most importantly, these features
include the HTTP remote helpers, which are rather quintessential for a
well-functioning Git installation. So while the dependency can in theory
be dropped, most users wouldn't consider the resulting installation to
be fully functional.

The "curl" option is defined as a feature, which means that it can be
"enabled", "disabled" or "auto", which has the effect that the feature
will be enabled if the dependency itself has been found. While most of
the other features have "auto" as default value, the "curl" option is
set to "enabled" by default due to it being so important. Consequently,
autoconfiguration of Git will fail by default if the library cannot be
found.

There is a bug though with how we handle the option in case the user
overrides the feature with `meson setup -Dcurl=auto`: while we will try
to find the library in that case, we won't ever use it because we later
on check for `get_option('curl').enabled()` when deciding whether or not
we want to build dependent sources. But `enabled()` only returns true if
the option has the value "enabled", for "auto" it will return false.

Fix the issue by instead checking for `curl.found()`, which is only true
if the library has been found. And as we only try to find the library
when `get_option('curl')` returns "true" or "auto" this is exactly what
we want.

Signed-off-by: Patrick Steinhardt <ps@pks.im>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2025-04-01 02:20:43 -07:00
Junio C Hamano 81d8747cea Merge branch 'es/meson-building-docs-requires-perl'
Build update.

* es/meson-building-docs-requires-perl:
  meson: fix perl detection when docs are enabled, but perl bindings aren't
2025-03-29 16:39:11 +09:00
Junio C Hamano f76fe4ab06 Merge branch 'jk/use-wunreachable-code-for-devs'
Enable -Wunreachable-code for developer builds.

* jk/use-wunreachable-code-for-devs:
  config.mak.dev: enable -Wunreachable-code
  git-compat-util: add NOT_CONSTANT macro and use it in atfork_prepare()
  run-command: use errno to check for sigfillset() error
2025-03-29 16:39:10 +09:00
Junio C Hamano 64aef9217f Merge branch 'ps/meson-with-breaking-changes'
Update meson based build procedure for breaking changes support.

* ps/meson-with-breaking-changes:
  meson: don't install git-pack-redundant(1) docs with breaking changes
  meson: don't compile git-pack-redundant(1) with breaking changes
  meson: define WITH_BREAKING_CHANGES when enabling breaking changes
2025-03-29 16:39:08 +09:00
Johannes Schindelin 3db4cb987f clang: warn when the comma operator is used
When compiling Git using `clang`, the `-Wcomma` option can be used to
warn about code using the comma operator (because it is typically
unintentional and wants to use the semicolon instead).

Helped-by: Patrick Steinhardt <ps@pks.im>
Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
Acked-by: Phillip Wood <phillip.wood@dunelm.org.uk>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2025-03-28 17:38:12 -07:00
Junio C Hamano f50df872a4 Merge branch 'jt/diff-pairs'
A post-processing filter for "diff --raw" output has been
introduced.

* jt/diff-pairs:
  builtin/diff-pairs: allow explicit diff queue flush
  builtin: introduce diff-pairs command
  diff: add option to skip resolving diff statuses
  diff: return diff_filepair from diff queue helpers
2025-03-26 16:26:09 +09:00
Patrick Steinhardt 871491f7ad meson: fix compat sources when compiling with MSVC
In our compat library we have both "msvc.c" and "mingw.c". The former is
mostly a thin wrapper around the latter as it directly includes it, but
it has a couple of extra headers that aren't included in "mingw.c" and
is expected to be used with the Visual Studio compiler toolchain.

While our Makefile knows to pick up the correct file depending on
whether or not the Visual Studio toolchain is used, we don't do the same
with Meson. Fix this.

Signed-off-by: Patrick Steinhardt <ps@pks.im>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2025-03-21 04:11:15 -07:00
Jeff King 16f5d967e2 config.mak.dev: enable -Wunreachable-code
Having the compiler point out unreachable code can help avoid bugs, like
the one discussed in:

  https://lore.kernel.org/git/20250307195057.GA3675279@coredump.intra.peff.net/

In that case it was found by Coverity, but finding it earlier saves
everybody time and effort.

We can use -Wunreachable-code to get some help from the compiler here.
Interestingly, this is a noop in gcc. It was a real warning up until gcc
4.x, when it was removed for being too flaky, but they left the
command-line option to avoid breaking users. See:

  https://stackoverflow.com/questions/17249934/why-does-gcc-not-warn-for-unreachable-code

However, clang does implement this option, and it finds the case
mentioned above (and no other cases within the code base). And since we
run clang in several of our CI jobs, that's enough to get an early
warning of breakage.

We could enable it only for clang, but since gcc is happy to ignore it,
it's simpler to just turn it on for all developer builds.

Signed-off-by: Jeff King <peff@peff.net>
[jc: squashed meson.build change sent by Patrick]
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2025-03-17 17:31:28 -07:00
Junio C Hamano 82e79c6364 git-compat-util: add NOT_CONSTANT macro and use it in atfork_prepare()
Our hope is that the number of code paths that falsely trigger
warnings with the -Wunreachable-code compilation option are small,
and they can be worked around case-by-case basis, like we just did
in the previous commit.  If we need such a workaround a bit more
often, however, we may benefit from a more generic and descriptive
facility that helps document the cases we need such workarounds.

    Side note: if we need the workaround all over the place, it
    simply means -Wunreachable-code is not a good tool for us to
    save engineering effort to catch mistakes.  We are still
    exploring if it helps us, so let's assume that it is not the
    case.

Introduce NOT_CONSTANT() macro, with which, the developer can tell
the compiler:

    Do not optimize this expression out, because, despite whatever
    you are told by the system headers, this expression should *not*
    be treated as a constant.

and use it as a replacement for the workaround we used that was
somewhat specific to the sigfillset case.  If the compiler already
knows that the call to sigfillset() cannot fail on a particular
platform it is compiling for and declares that the if() condition
would not hold, it is plausible that the next version of the
compiler may learn that sigfillset() that never fails would not
touch errno and decide that in this sequence:

	errno = 0;
	sigfillset(&all)
	if (errno)
		die_errno("sigfillset");

the if() statement will never trigger.  Marking that the value
returned by sigfillset() cannot be a constant would document our
intention better and would not break with such a new version of
compiler that is even more "clever".  With the marco, the above
sequence can be rewritten:

	if (NOT_CONSTANT(sigfillset(&all)))
		die_errno("sigfillset");

which looks almost like other innocuous annotations we have,
e.g. UNUSED.

Signed-off-by: Junio C Hamano <gitster@pobox.com>
2025-03-17 17:30:49 -07:00
Eli Schwartz 7c8cd9c158 meson: fix perl detection when docs are enabled, but perl bindings aren't
The `perl` variable in meson.build is assigned to a program lookup,
which may have the value "not-found object" if configuring with
`-Dperl=disabled`.

There is already a list of other cases where we do need a perl command,
even when not building perl bindings. Building documentation should be
one of those cases, but was missing from the list. Add it.

Fixes:

```
$ meson setup builddir/ -Ddocs=man -Dperl=disabled -Dtests=false
[...]
Documentation/meson.build:308:22: ERROR: Tried to use not-found external program in "command"
```

Bug: https://bugs.gentoo.org/949247
Signed-off-by: Eli Schwartz <eschwartz@gentoo.org>
Acked-by: Patrick Steinhardt <ps@pks.im>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2025-03-17 15:25:42 -07:00
Patrick Steinhardt 24a3f30c0d meson: don't compile git-pack-redundant(1) with breaking changes
We continue to compile the git-pack-redundant(1) builtin with Meson when
breaking changes are enabled even though we ultimately don't expose this
command at all. This is mostly harmless, but given that the intent of
the build option is to be as close as possible to the state where the
breaking change has been fully implemented this isn't optimal either.

Improve the situation by not compiling the builtin when breaking changes
are enabled.

Based-on-patch-by: Phillip Wood <phillip.wood123@gmail.com>
Signed-off-by: Patrick Steinhardt <ps@pks.im>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2025-03-12 09:20:21 -07:00
Patrick Steinhardt 7208d84305 meson: define WITH_BREAKING_CHANGES when enabling breaking changes
While Meson already supports the `-Dbreaking_changes=true` option, it
only wires up the build option that propagates into the tests. The build
option is only used for our tests to enable the `WITH_BREAKING_CHANGES`
prerequisite though, and does not influence the code that is actually
being built.

The omission went unnoticed because we only have tests right now that
get disabled when breaking changes are enabled, but not the other way
round. In other words, we don't have any tests that verify that breaking
changes behave as expected.

Fix the build issue by setting the `WITH_BREAKING_CHANGES` preprocessor
macro when breaking changes are enabled. Note that the `libgit_c_args`
array is defined after the current spot where we handle the option, so
to not have multiple sites where we handle it we instead move it after
the array has been defined.

Based-on-patch-by: Phillip Wood <phillip.wood123@gmail.com>
Signed-off-by: Patrick Steinhardt <ps@pks.im>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2025-03-12 09:20:20 -07:00
Patrick Steinhardt 172d0f686b object-file: split out logic regarding hash algorithms
While we have a "hash.h" header, the actual implementation of the
subsystem is hosted by "object-file.c". This makes it harder than
necessary to find the actual implementation of the hash subsystem and
intermingles the different concerns with one another.

Split out the implementation of hash algorithms into a new, separate
"hash.c" file.

Signed-off-by: Patrick Steinhardt <ps@pks.im>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2025-03-10 13:16:20 -07:00
Johannes Schindelin 31761f3911 meson: fix sorting
In 904339edbd (Introduce support for the Meson build system,
2024-12-06) the `meson.build` file was introduced, adding also a
Windows-specific list of source files. This list was obviously meant to
be sorted alphabetically, but there is one mistake. Let's fix that.

Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2025-03-06 08:35:07 -08:00
Junio C Hamano ca39da6997 Merge branch 'ps/meson-contrib-bits'
Update meson-based build procedure to cover contrib/ and other
places as well.

* ps/meson-contrib-bits:
  ci: exercise credential helpers
  ci: fix propagating UTF-8 test locale in musl-based Meson job
  meson: wire up static analysis via Coccinelle
  meson: wire up git-contacts(1)
  meson: wire up credential helpers
  contrib/credential: fix compilation of "osxkeychain" helper
  contrib/credential: fix compiling "libsecret" helper
  contrib/credential: fix compilation of wincred helper with MSVC
  contrib/credential: fix "netrc" tests with out-of-tree builds
  GIT-BUILD-OPTIONS: propagate project's source directory
2025-03-03 08:53:03 -08:00
Junio C Hamano ab09eddf60 Merge branch 'ps/build-meson-fixes-0130'
Assorted fixes and improvements to the build procedure based on
meson.

* ps/build-meson-fixes-0130:
  gitlab-ci: restrict maximum number of link jobs on Windows
  meson: consistently use custom program paths to resolve programs
  meson: fix overwritten `git` variable
  meson: prevent finding sed(1) in a loop
  meson: improve handling of `sane_tool_path` option
  meson: improve PATH handling
  meson: drop separate version library
  meson: stop linking libcurl into all executables
  meson: introduce `libgit_curl` dependency
  meson: simplify use of the common-main library
  meson: inline the static 'git' library
  meson: fix OpenSSL fallback when not explicitly required
  meson: fix exec path with enabled runtime prefix
2025-03-03 08:53:02 -08:00
Justin Tobler 5bd10b2adc builtin: introduce diff-pairs command
Through git-diff(1), a single diff can be generated from a pair of blob
revisions directly. Unfortunately, there is not a mechanism to compute
batches of specific file pair diffs in a single process. Such a feature
is particularly useful on the server-side where diffing between a large
set of changes is not feasible all at once due to timeout concerns.

To facilitate this, introduce git-diff-pairs(1) which acts as a backend
passing its NUL-terminated raw diff format input from stdin through diff
machinery to produce various forms of output such as patch or raw.

The raw format was originally designed as an interchange format and
represents the contents of the diff_queued_diff list making it possible
to break the diff pipeline into separate stages. For example,
git-diff-tree(1) can be used as a frontend to compute file pairs to
queue and feed its raw output to git-diff-pairs(1) to compute patches.
With this, batches of diffs can be progressively generated without
having to recompute renames or retrieve object context. Something like
the following:

	git diff-tree -r -z -M $old $new |
	git diff-pairs -p -z

should generate the same output as `git diff-tree -p -M`. Furthermore,
each line of raw diff formatted input can also be individually fed to a
separate git-diff-pairs(1) process and still produce the same output.

Based-on-patch-by: Jeff King <peff@peff.net>
Signed-off-by: Justin Tobler <jltobler@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2025-03-03 08:17:47 -08:00
Patrick Steinhardt 3ee3a6eb52 meson: fix overwritten `git` variable
We're assigning the `git` variable in three places:

  - In "meson.build" to store the external Git executable.

  - In "meson.build" to store the compiled Git executable.

  - In "Documentation/meson.build" to store the external Git executable,
    a second time.

The last case is only needed because we overwrite the original variable
with the built version. Rename the variable used for the built Git
executable so that we don't have to resolve the external Git executable
multiple times.

Signed-off-by: Patrick Steinhardt <ps@pks.im>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2025-02-26 09:09:37 -08:00
Patrick Steinhardt 16c89dcf80 meson: prevent finding sed(1) in a loop
We're searching for the sed(1) executable in a loop, which will make us
try to find it multiple times. Starting with the preceding commit we
already declare a variable for that program in the top-level build file.
Use it so that we only need to search for the program once.

Signed-off-by: Patrick Steinhardt <ps@pks.im>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2025-02-26 09:09:36 -08:00
Patrick Steinhardt 42846efc3b meson: improve handling of `sane_tool_path` option
The `sane_tool_path` option can be used to override the PATH variable
from which the build process, tests and ultimately Git will end up
picking programs from. It is currently lacking though because we only
use it to populate the PATH environment variable for executed scripts
and for the `BROKEN_PATH_FIX` mechanism, but we don't use it to find
programs used in the build process itself.

Fix this issue by treating it similar to the Windows-specific paths,
which will make us use it both to find programs and to populate the PATH
environment variable.

To help with this fix, change the type of the option to be an array of
paths, which makes the handling a bit easier for us. It's also the
correct thing to do as the input indeed is a list of paths.

Furthermore, the option now overrides the default behaviour on Windows,
which si to pick up tools from Git for Windows. This is done so that it
becomes easier to override that default behaviour in case it's not
desired.

Signed-off-by: Patrick Steinhardt <ps@pks.im>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2025-02-26 09:09:36 -08:00
Patrick Steinhardt 454d79b61b meson: improve PATH handling
When locating programs required for the build we give some special
treatment to Windows systems so that we know to also look up tools
provided by a Git for Windows installation. This ensures that the build
doesn't have any prerequisites other than Microsoft Visual Studio, Meson
and Git for Windows.

Consequently, some of the programs returned by `find_program()` may not
be found via PATH, but via these extra directories. But while Meson can
use these tools directly without any special treatment, any scripts that
we execute may not be able to find those programs. To help them we thus
prepend the directories of a subset of the found programs to PATH.

This doesn't make much sense though: we don't need to prepend PATH for
any program that was found via PATH, but we really only need to do so
for programs located via the extraneous Windows-specific paths. So
instead of prepending all programs paths, we really only need to prepend
the Windows-specific paths.

Adapt the code accordingly by only prepeding Windows-specific paths to
PATH, which both simplifies the code and clarifies intent.

Signed-off-by: Patrick Steinhardt <ps@pks.im>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2025-02-26 09:09:36 -08:00
Patrick Steinhardt eee25bbd84 meson: drop separate version library
When building `libgit.a` we link it against a `libgit_version.a` library
that contains the version information that we inject at build time. The
intent of this is to avoid rebuilding all of `libgit.a` whenever the
version changes. But that wouldn't happen in the first place, as we know
to just rebuild the files that depend on the generated "version-def.h"
file.

This is an artifact of an earlier version of the Meson build infra that
didn't ultimately land. We didn't yet have "version-def.h", and instead
injected the version via preprocessor directives. And here we would have
rebuilt all of `libgit.a` indeed in case the version changes, because
the preprocessor directive applied to all files.

Stop building the separate library and instead add "version-def.h" to
the list of source files directly.

Signed-off-by: Patrick Steinhardt <ps@pks.im>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2025-02-26 09:09:36 -08:00
Patrick Steinhardt f5fac42e07 meson: stop linking libcurl into all executables
We set up libcurl via the `libgit_dependencies` variable, which gets
propagated into every user of the `libgit` dependency. This is not
necessary though, as most of our executables aren't even supposed to
link against libcurl.

Fix this by only propagating include directories as a libgit dependency
and propagating the full curl dependency via `libgit_curl`.

Signed-off-by: Patrick Steinhardt <ps@pks.im>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2025-02-26 09:09:35 -08:00
Patrick Steinhardt dfc88bd647 meson: introduce `libgit_curl` dependency
We've got a set of common source files that we use for those executables
that link against libcurl. The setup is somewhat repetitive though.
Simplify it by declaring a `libgit_curl` dependency that bundles all of
it together.

Note that we don't include curl itself as a dependency. This is because
we already pull it in transitively via the libgit dependency, which is
unfortunate because libgit itself shouldn't actually link against curl
in the first place. This will get fixed in the next commit.

Signed-off-by: Patrick Steinhardt <ps@pks.im>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2025-02-26 09:09:35 -08:00
Patrick Steinhardt ebb35369f1 meson: simplify use of the common-main library
The "common-main.c" file is used by multiple executables. In order to
make it easy to set it up we have created a separate library that these
executables can link against. All of these executables also want to link
against `libgit.a` though, which makes it necessary to specify both of
these as dependencies for every executable.

Simplify this a bit by declaring the library as a source dependency:
instead of creating a static library, we now instead compile the common
set of files into each executable separately.

Signed-off-by: Patrick Steinhardt <ps@pks.im>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2025-02-26 09:09:35 -08:00
Patrick Steinhardt ce9432889c meson: inline the static 'git' library
When setting up `libgit.a` we first create the static library itself,
and then declare it as part of a dependency such that compile arguments,
include directories and transitive dependencies get propagated to the
users of that library. As such, the static library isn't expected to be
used by anything but the declared dependency.

Inline the static library so that we don't even use a separate variable
for it. This avoids any kind of confusion that may arise and clarifies
how the library is supposed to be used.

Signed-off-by: Patrick Steinhardt <ps@pks.im>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2025-02-26 09:09:35 -08:00
Patrick Steinhardt 6128301075 meson: fix OpenSSL fallback when not explicitly required
When OpenSSL isn't provided by the system we know to fall back to the
subproject wrapper. This is especially helpful on Windows systems, where
you typically don't have OpenSSL available, in order to reduce the
number of required dependencies.

The fallback is broken though when the OpenSSL backend is set to 'auto'
as we end up calling `dependency('openssl', required: false)` in that
case, which implicitly disables falling back to the wrapper.

Fix the issue by re-allowing the fallback in case either OpenSSL is
required or in case the backend is set to 'auto'. While at it, fix
reporting of the backend in case the user asked us to pick no HTTPS
backend at all.

Signed-off-by: Patrick Steinhardt <ps@pks.im>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2025-02-26 09:09:35 -08:00
Patrick Steinhardt bd262d07b6 meson: fix exec path with enabled runtime prefix
When the runtime prefix option is enabled, Git is built such that it
knows to locate its binaries relative to the directory a binary is being
executed from. This requires us to figure out relative paths, which is
handled in `system_prefix()` by trying to strip a couple of well-known
paths.

One of these paths, GIT_EXEC_PATH, is expected to be absolute when
runtime prefixes are enabled, but relative otherwise. And while our
Makefile gets this correctly, in Meson we always wire up the absolute
path, which may result in us not being able to find binaries.

Fix this by conditionally injecting the paths depending on whether or
not the `runtime_prefix` option is enabled.

Signed-off-by: Patrick Steinhardt <ps@pks.im>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2025-02-26 09:09:34 -08:00
Junio C Hamano f65d9cfd3f Merge branch 'po/meson-perl-fix'
Upgrade the minimum Perl version enforced by meson-based build to
match what Makefile-based build uses.

* po/meson-perl-fix:
  meson: fix Perl version check for Meson versions before 1.7.0
  meson: bump minimum required Perl version to 5.26.0
2025-02-25 14:19:37 -08:00
Peter Oliver 0bf8d1b395 meson: fix Perl version check for Meson versions before 1.7.0
Command `perl --version` says, e.g., “This is perl 5, version 26,
subversion 0 (v5.26.0)”, which older versions of Meson interpret as
version 26.

This will be fixed in Meson 1.7.0, but at the time of writing that isn’t
yet released.

If we run `perl -V:version` we get the unambiguous response
“version='5.26.0';”, but we need at least Meson 1.5.0 to be able to do that.

Note that Perl are seriously considering dropping the leading 5 entirely
in the near future (https://perl.github.io/PPCs/ppc0025-perl-version/),
but that shouldn’t affect us.

Signed-off-by: Peter Oliver <git@mavit.org.uk>
Co-authored-by: Patrick Steinhardt <ps@pks.im>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2025-02-19 08:04:26 -08:00
Peter Oliver d874d37837 meson: bump minimum required Perl version to 5.26.0
Commit 702d8c1f3b (Require Perl 5.26.0, 2024-10-23) dropped support
for Perl versions older than 5.26.0. The Meson build system, which
has been developed in parallel to that commit, hasn't been bumped
accordingly and thus still requires Perl 5.8.1 or newer.

Fix this by requiring Perl 5.26.0 or newer with Meson.

Signed-off-by: Peter Oliver <git@mavit.org.uk>
Reviewed-by: Patrick Steinhardt <ps@pks.im>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2025-02-19 08:04:11 -08:00
Junio C Hamano e565f37553 Merge branch 'ds/backfill'
Lazy-loading missing files in a blobless clone on demand is costly
as it tends to be one-blob-at-a-time.  "git backfill" is introduced
to help bulk-download necessary files beforehand.

* ds/backfill:
  backfill: assume --sparse when sparse-checkout is enabled
  backfill: add --sparse option
  backfill: add --min-batch-size=<n> option
  backfill: basic functionality and tests
  backfill: add builtin boilerplate
2025-02-18 15:30:31 -08:00
Patrick Steinhardt 1cee22ebff meson: wire up credential helpers
We've got a couple of credential helpers in "contrib/credential", all
of which aren't yet wired up via Meson. Do so.

Note that ideally, we'd also wire up t0303 to be executed with each of
the credential helpers to verify their functionality. Unfortunately
though, none of them pass the test suite right now, so this is left for
a future change.

Signed-off-by: Patrick Steinhardt <ps@pks.im>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2025-02-18 11:40:03 -08:00
Patrick Steinhardt c5823641a6 GIT-BUILD-OPTIONS: propagate project's source directory
A couple of our tests require knowledge around where to find the
project's source directory in order to locate files required for the
test itself. Until now we have been wiring these up ad-hoc via new,
specialized variables catered to the specific usecase. This is quite
awkward though, as every test that potentially needs to locate paths
relative to the source directory needs to grow another variable.

Introduce a new "GIT_SOURCE_DIR" variable into GIT-BUILD-OPTIONS to stop
this proliferation. Remove existing variables that can be derived from
it.

Signed-off-by: Patrick Steinhardt <ps@pks.im>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2025-02-18 11:40:02 -08:00
Junio C Hamano 0cc13007e5 Merge branch 'bc/doc-adoc-not-txt'
All the documentation .txt files have been renamed to .adoc to help
content aware editors.

* bc/doc-adoc-not-txt:
  Remove obsolete ".txt" extensions for AsciiDoc files
  doc: use .adoc extension for AsciiDoc files
  gitattributes: mark AsciiDoc files as LF-only
  editorconfig: add .adoc extension
  doc: update gitignore for .adoc extension
2025-02-14 17:53:47 -08:00
Junio C Hamano a4af0b6288 Merge branch 'js/libgit-rust'
Foreign language interface for Rust into our code base has been added.

* js/libgit-rust:
  libgit: add higher-level libgit crate
  libgit-sys: also export some config_set functions
  libgit-sys: introduce Rust wrapper for libgit.a
  common-main: split init and exit code into new files
2025-02-12 10:08:53 -08:00
Junio C Hamano 9d0e81e2ae Merge branch 'ps/zlib-ng'
The code paths to interact with zlib has been cleaned up in
preparation for building with zlib-ng.

* ps/zlib-ng:
  ci: make "linux-musl" job use zlib-ng
  ci: switch linux-musl to use Meson
  compat/zlib: allow use of zlib-ng as backend
  git-zlib: cast away potential constness of `next_in` pointer
  compat/zlib: provide stubs for `deflateSetHeader()`
  compat/zlib: provide `deflateBound()` shim centrally
  git-compat-util: move include of "compat/zlib.h" into "git-zlib.h"
  compat: introduce new "zlib.h" header
  git-compat-util: drop `z_const` define
  compat: drop `uncompress2()` compatibility shim
2025-02-06 14:56:45 -08:00
Derrick Stolee a3f79e9abd backfill: add builtin boilerplate
In anticipation of implementing 'git backfill', populate the necessary files
with the boilerplate of a new builtin. Mark the builtin as experimental at
this time, allowing breaking changes in the near future, if necessary.

Signed-off-by: Derrick Stolee <stolee@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2025-02-03 16:12:41 -08:00
Junio C Hamano f49905d47d Merge branch 'ps/build-meson-fixes'
More build fixes and enhancements on meson based build procedure.

* ps/build-meson-fixes:
  ci: wire up Visual Studio build with Meson
  ci: raise error when Meson generates warnings
  meson: fix compilation with Visual Studio
  meson: make the CSPRNG backend configurable
  meson: wire up fuzzers
  meson: wire up generation of distribution archive
  meson: wire up development environments
  meson: fix dependencies for generated headers
  meson: populate project version via GIT-VERSION-GEN
  GIT-VERSION-GEN: allow running without input and output files
  GIT-VERSION-GEN: simplify computing the dirty marker
2025-02-03 10:23:34 -08:00
Junio C Hamano 803b5acaa7 Merge branch 'ps/3.0-remote-deprecation'
Following the procedure we established to introduce breaking
changes for Git 3.0, allow an early opt-in for removing support of
$GIT_DIR/branches/ and $GIT_DIR/remotes/ directories to configure
remotes.

* ps/3.0-remote-deprecation:
  remote: announce removal of "branches/" and "remotes/"
  builtin/pack-redundant: remove subcommand with breaking changes
  ci: repurpose "linux-gcc" job for deprecations
  ci: merge linux-gcc-default into linux-gcc
  Makefile: wire up build option for deprecated features
2025-02-03 10:23:33 -08:00
Junio C Hamano 72f1ddfbc9 Merge branch 'ps/build-meson-fixes' into ps/build-meson-fixes-0130
* ps/build-meson-fixes:
  ci: wire up Visual Studio build with Meson
  ci: raise error when Meson generates warnings
  meson: fix compilation with Visual Studio
  meson: make the CSPRNG backend configurable
  meson: wire up fuzzers
  meson: wire up generation of distribution archive
  meson: wire up development environments
  meson: fix dependencies for generated headers
  meson: populate project version via GIT-VERSION-GEN
  GIT-VERSION-GEN: allow running without input and output files
  GIT-VERSION-GEN: simplify computing the dirty marker
2025-01-30 14:53:50 -08:00
Junio C Hamano f046ab2dd4 Merge branch 'ds/path-walk-1'
Introduce a new API to visit objects in batches based on a common
path, or by type.

* ds/path-walk-1:
  path-walk: drop redundant parse_tree() call
  path-walk: reorder object visits
  path-walk: mark trees and blobs as UNINTERESTING
  path-walk: visit tags and cached objects
  path-walk: allow consumer to specify object types
  t6601: add helper for testing path-walk API
  test-lib-functions: add test_cmp_sorted
  path-walk: introduce an object walk by path
2025-01-29 14:05:09 -08:00
Josh Steadmon 3f8f2abe05 common-main: split init and exit code into new files
Currently, object files in libgit.a reference common_exit(), which is
contained in common-main.o. However, common-main.o also includes main(),
which references cmd_main() in git.o, which in turn depends on all the
builtin/*.o objects.

We would like to allow external users to link libgit.a without needing
to include so many extra objects. Enable this by splitting common_exit()
and check_bug_if_BUG() into a new file common-exit.c, and add
common-exit.o to LIB_OBJS so that these are included in libgit.a.

This split has previously been proposed ([1], [2]) to support fuzz tests
and unit tests by avoiding conflicting definitions for main(). However,
both of those issues were resolved by other methods of avoiding symbol
conflicts. Now we are trying to make libgit.a more self-contained, so
hopefully we can revisit this approach.

Additionally, move the initialization code out of main() into a new
init_git() function in its own file. Include this in libgit.a as well,
so that external users can share our setup code without calling our
main().

[1] https://lore.kernel.org/git/Yp+wjCPhqieTku3X@google.com/
[2] https://lore.kernel.org/git/20230517-unit-tests-v2-v2-1-21b5b60f4b32@google.com/

Signed-off-by: Josh Steadmon <steadmon@google.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2025-01-28 14:39:16 -08:00
Patrick Steinhardt 84bb5eeace ci: switch linux-musl to use Meson
Switch over the "linux-musl" job to use Meson instead of Makefiles. This
is done due to multiple reasons:

  - It simplifies our CI infrastructure a bit as we don't have to
    manually specify a couple of build options anymore.

  - It verifies that Meson detects and sets those build options
    automatically.

  - It makes it easier for us to wire up a new CI job using zlib-ng as
    backend.

One platform compatibility that Meson cannot easily detect automatically
is the `GIT_TEST_UTF8_LOCALE` variable used in tests. Wire up a build
option for it, which we set via a new "MESONFLAGS" environment variable.

Note that we also drop the CC variable, which is set to "gcc". We
already default to GCC when CC is unset in "ci/lib.sh", so this is not
needed.

Signed-off-by: Patrick Steinhardt <ps@pks.im>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2025-01-28 13:03:23 -08:00
Patrick Steinhardt b9d6f64393 compat/zlib: allow use of zlib-ng as backend
The zlib-ng library is a hard fork of the old and venerable zlib
library. It describes itself as zlib replacement with optimizations for
"next generation" systems. As such, it contains several implementations
of central algorithms using for example SSE2, AVX2 and other vectorized
CPU intrinsics that supposedly speed up in- and deflating data.

And indeed, compiling Git against zlib-ng leads to a significant speedup
when reading objects. The following benchmark uses git-cat-file(1) with
`--batch --batch-all-objects` in the Git repository:

    Benchmark 1: zlib
      Time (mean ± σ):     52.085 s ±  0.141 s    [User: 51.500 s, System: 0.456 s]
      Range (min … max):   52.004 s … 52.335 s    5 runs

    Benchmark 2: zlib-ng
      Time (mean ± σ):     40.324 s ±  0.134 s    [User: 39.731 s, System: 0.490 s]
      Range (min … max):   40.135 s … 40.484 s    5 runs

    Summary
      zlib-ng ran
        1.29 ± 0.01 times faster than zlib

So we're looking at a ~25% speedup compared to zlib. This is of course
an extreme example, as it makes us read through all objects in the
repository. But regardless, it should be possible to see some sort of
speedup in most commands that end up accessing the object database.

The zlib-ng library provides a compatibility layer that makes it a
proper drop-in replacement for zlib: nothing needs to change in the
build system to support it. Unfortunately though, this mode isn't easy
to use on most systems because distributions do not allow you to install
zlib-ng in that way, as that would mean that the zlib library would be
globally replaced. Instead, many distributions provide a package that
installs zlib-ng without the compatibility layer. This version does
provide effectively the same APIs like zlib does, but all of the symbols
are prefixed with `zng_` to avoid symbol collisions.

Implement a new build option that allows us to link against zlib-ng
directly. If set, we redefine zlib symbols so that we use the `zng_`
prefixed versions thereof provided by that library. Like this, it
becomes possible to install both zlib and zlib-ng (without the compat
layer) and then pick whichever library one wants to link against for
Git.

Signed-off-by: Patrick Steinhardt <ps@pks.im>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2025-01-28 13:03:23 -08:00
Patrick Steinhardt 3656d57bbf compat: drop `uncompress2()` compatibility shim
Our compat library has an implementation of zlib's `uncompress2()`
function that gets used when linking against an old version of zlib
that doesn't yet have it. The last user of `uncompress2()` got removed
in 15a60b747e (reftable/block: open-code call to `uncompress2()`,
2024-04-08), so the compatibility code is not required anymore. Drop it.

Signed-off-by: Patrick Steinhardt <ps@pks.im>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2025-01-28 13:03:22 -08:00
Junio C Hamano a17fd7dd3a Merge branch 'ps/reftable-sign-compare'
The reftable/ library code has been made -Wsign-compare clean.

* ps/reftable-sign-compare:
  reftable: address trivial -Wsign-compare warnings
  reftable/blocksource: adjust `read_block()` to return `ssize_t`
  reftable/blocksource: adjust type of the block length
  reftable/block: adjust type of the restart length
  reftable/block: adapt header and footer size to return a `size_t`
  reftable/basics: adjust `hash_size()` to return `uint32_t`
  reftable/basics: adjust `common_prefix_size()` to return `size_t`
  reftable/record: handle overflows when decoding varints
  reftable/record: drop unused `print` function pointer
  meson: stop disabling -Wsign-compare
2025-01-28 13:02:24 -08:00
Junio C Hamano 3ddeb7f337 Merge branch 'ps/build-meson-subtree'
The meson-driven build is now aware of "git-subtree" housed in
contrib/subtree hierarchy.

* ps/build-meson-subtree:
  meson: wire up the git-subtree(1) command
  meson: introduce build option for contrib
  contrib/subtree: fix building docs
2025-01-28 13:02:23 -08:00
Junio C Hamano d8093fd6c1 Merge branch 'tc/meson-use-our-version-def-h'
The meson build procedure looked for the 'version-def.h' file in a
wrong directory, which has been corrected.

* tc/meson-use-our-version-def-h:
  meson: ensure correct version-def.h is used
2025-01-23 15:07:01 -08:00
Patrick Steinhardt 13cb20fc46 meson: fix compilation with Visual Studio
The Visual Studio compiler defaults to C89 unless explicitly asked to
use a different version of the C standard. We don't specify any C
standard at all though in our Meson build, and consequently compiling
Git fails:

    ...\git\git-compat-util.h(14): fatal error C1189: #error:  "Required C99 support is in a test phase.  Please see git-compat-util.h for more details."

Fix the issue by specifying the project's C standard. Funny enough,
specifying C99 does not work because apparently, `__STDC_VERSION__` is
not getting defined in that version at all. Instead, we have to specify
C11 as the project's C standard, which is also done in our CMake build
instructions.

We don't want to generally enforce C11 though, as our requiremets only
state that a C99 compiler is required. In fact, we don't even require
plain C99, but rather the GNU variant thereof.

Meson allows us to handle this case rather easily by specifying
"gnu99,c11", which will cause it to fall back to C11 in case GNU C99 is
unsupported. This feature has only been introduced with Meson 1.3.0
though, and we support 0.61.0 and newer. In case we use such an oldish
version though we fall back to requiring GNU99 unconditionally. This
means that Windows essentially requires Meson 1.3.0 and newer when using
Visual Studio, but I doubt that this is ever going to be a real problem.

Tested-by: M Hickford <mirth.hickford@gmail.com>
Signed-off-by: Patrick Steinhardt <ps@pks.im>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2025-01-22 12:37:34 -08:00
Patrick Steinhardt ef8c3a1b8a meson: make the CSPRNG backend configurable
The CSPRNG backend is not configurable in Meson and isn't quite
discoverable, either. Make it configurable and add the actual backend
used to the summary.

Signed-off-by: Patrick Steinhardt <ps@pks.im>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2025-01-22 12:37:34 -08:00
Patrick Steinhardt 28911f7dca meson: wire up fuzzers
Meson does not yet know to build our fuzzers. Introduce a new build
option "fuzzers" and wire up the fuzzers in case it is enabled. Adapt
our CI jobs so that they build the fuzzers by default.

Signed-off-by: Patrick Steinhardt <ps@pks.im>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2025-01-22 12:37:33 -08:00
Patrick Steinhardt 88d4bff8c3 meson: wire up generation of distribution archive
Meson knows to generate distribution archives via `meson dist`. In
addition to generating the archive itself, this target also knows to
compile and execute tests from that archive, which helps to ensure that
the result is an adequate drop-in replacement for the versioned project.

While this already works as-is, one omission is that we don't propagate
the commit that this is built from into the resulting archive. This can
be fixed though by adding a distribution script that propagates the
version into the "version" file, which GIT-VERSION-GEN knows to read if
present.

Use GIT-VERSION-GEN to populate that file. As the script is executed in
the build directory, not in the directory where we generate the archive,
we have to use a shell to resolve the "MESON_DIST_ROOT" environment
variable.

Signed-off-by: Patrick Steinhardt <ps@pks.im>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2025-01-22 12:37:33 -08:00
Patrick Steinhardt 5d0cf6bb3a meson: wire up development environments
The Meson build system is able to wire up development environments. The
intent is to make build artifacts of the project available. This is
typically used to export e.g. paths to linkable libraries, which isn't
all that interesting in our context given that we don't have an official
library interface.

But what we can use this mechanism for is to expose the built Git
executables as well as the build directory. This allows users to play
around with the built Git version in the devenv, and allows them to
execute our test scripts directly with the built distribution.

Wire up this feature, which can then be used via `meson devenv` in the
build directory.

Signed-off-by: Patrick Steinhardt <ps@pks.im>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2025-01-22 12:37:33 -08:00
Patrick Steinhardt 53d75bd3e4 meson: fix dependencies for generated headers
We generate a couple of headers from our documentation. These headers
are added to the libgit sources, but two of them aren't used by the
library, but instead by our builtins. This can cause parallel builds to
fail because the builtin object may be compiled before the header was
generated.

Fix the issue by adding both "config-list.h" and "hook-list.h" to the
list of builtin sources. While "command-list.h" is generated similarly,
it is used by "help.c" and thus part of the libgit sources indeed.

Reported-by: Evan Martin <evan.martin@gmail.com>
Signed-off-by: Patrick Steinhardt <ps@pks.im>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2025-01-22 12:37:33 -08:00
Patrick Steinhardt 6ff99174d1 meson: populate project version via GIT-VERSION-GEN
The Git version for Meson is currently wired up manually. It can thus
grow (and already has grown) stale quite easily, as having multiple
sources of truth is never a good idea. This issue is mostly of cosmetic
nature as we don't use the project version anywhere, and instead use the
GIT-VERSION-GEN script to propagate the correct version into our build.
But it is somewhat puzzling when `meson setup` announces to build an old
Git release.

There are a couple of alternatives for how to solve this:

  - We can keep the version undefined, but this makes Meson output
    "undefined" for the version, as well.

  - We can use GIT-VERSION-GEN to generate the version for us. At the
    point of configuring the project we haven't yet figured out host
    details though, and thus we didn't yet set up the shell environment.
    While not an issue for Unix-based systems, this would be an issue in
    Windows, where the shell typically gets provided via Git for Windows
    and thus requires some special setup.

  - We can pull the default version out of GIT-VERSION-GEN and move it
    into its own file. This likely requires some adjustments for scripts
    that bump the version, but allows Meson to read the version from
    that file trivially.

Pick the second option and use GIT-VERSION-GEN as it gives us the most
accurate version. In order to fix the bootstrapping issue on Windows
systems we simply set the version to 'unknown' in case no shell was
found. As the version is only of cosmetic value this isn't really much
of an issue.

Signed-off-by: Patrick Steinhardt <ps@pks.im>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2025-01-22 12:37:32 -08:00
Patrick Steinhardt c5bc9a7f94 Makefile: wire up build option for deprecated features
With 57ec9254eb (docs: introduce document to announce breaking changes,
2024-06-14), we have introduced a new document that tracks upcoming
breaking changes in the Git project. In 2454970930 (BreakingChanges:
early adopter option, 2024-10-11) we have amended the document a bit to
mention that any introduced breaking changes must be accompanied by
logic that allows us to enable the breaking change at compile-time.
While we already have two breaking changes lined up, neither of them has
such a switch because they predate those instructions.

Introduce the proposed `WITH_BREAKING_CHANGES` preprocessor macro and
wire it up with both our Makefiles and Meson. This does not yet wire up
the build flag for existing deprecations.

Signed-off-by: Patrick Steinhardt <ps@pks.im>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2025-01-22 12:28:27 -08:00
Patrick Steinhardt eb8728d88a meson: stop disabling -Wsign-compare
In 4f9264b0cd (config.mak.dev: drop `-Wno-sign-compare`, 2024-12-06) we
have started an effort to make our codebase compile with -Wsign-compare.
But while we removed the -Wno-sign-compare flag from "config.mak.dev",
we didn't adjust the Meson build instructions in the same way.

Fix this.

Signed-off-by: Patrick Steinhardt <ps@pks.im>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2025-01-21 14:20:28 -08:00
brian m. carlson 1f010d6bdf doc: use .adoc extension for AsciiDoc files
We presently use the ".txt" extension for our AsciiDoc files.  While not
wrong, most editors do not associate this extension with AsciiDoc,
meaning that contributors don't get automatic editor functionality that
could be useful, such as syntax highlighting and prose linting.

It is much more common to use the ".adoc" extension for AsciiDoc files,
since this helps editors automatically detect files and also allows
various forges to provide rich (HTML-like) rendering.  Let's do that
here, renaming all of the files and updating the includes where
relevant.  Adjust the various build scripts and makefiles to use the new
extension as well.

Note that this should not result in any user-visible changes to the
documentation.

Signed-off-by: brian m. carlson <sandals@crustytoothpaste.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2025-01-21 12:56:06 -08:00
Patrick Steinhardt 8454b42f94 meson: wire up the git-subtree(1) command
Wire up the git-subtree(1) command, which is part of "contrib/". Note
that we have to move around the exact location where we include the
"contrib/" subdirectory so that it comes after building the docs so that
we have access to some of the common functionality.

Signed-off-by: Patrick Steinhardt <ps@pks.im>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2025-01-17 09:56:38 -08:00
Toon Claes 4771501c0a meson: ensure correct version-def.h is used
To build the libgit-version library, Meson first generates
`version-def.h` in the build directory. Then it compiles `version.c`
into a library. During compilation, Meson tells to include both the
build directory and the project root directory.

However, when the user previously has compiled Git using Make, they will
have a `version-def.h` file in project root directory as well. Because
`version-def.h` is included in `version.c` using the #include directive
with double quotes, some preprocessors will look for the header file in
the same directory as the source file. This will cause compilation of
`version.c` ran by Meson to include `version-def.h` previously made by
Make, which might be out of date.

To explicitly tell the preprocessor which `version-def.h` to use, pass
the absolute path of this file as macro GIT_VERSION_H to the
preprocessor using option `-D` and have `version.c` `#include
GIT_VERSION_H`. To remain working with other build systems than Meson,
include "version-def.h" if that macro is not defined.

Co-authored-by: Patrick Steinhardt <ps@pks.im>
Signed-off-by: Toon Claes <toon@iotcl.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2025-01-14 11:14:54 -08:00
Patrick Steinhardt 6a0ee54f9a meson: provide a summary of configured backends
There are a couple of backends from which the user can choose for HTTPS,
SHA1, its unsafe variant as well as SHA256. Provide a summary of the
configured values to make these more discoverable.

Signed-off-by: Patrick Steinhardt <ps@pks.im>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2024-12-30 06:50:49 -08:00
Patrick Steinhardt d2c0b6a86c meson: wire up unsafe SHA1 backend
In 06c92dafb8 (Makefile: allow specifying a SHA-1 for non-cryptographic
uses, 2024-09-26), we have introduced a cryptographically-insecure
backend for SHA1 that can optionally be used in some contexts where the
processed data is not security relevant. This effort was in-flight with
the effort to introduce Meson, so we don't have an equivalent here.

Wire up a new build option that lets users pick an unsafe SHA1 backend.

Note that for simplicity's sake we have to drop the error condition
around an unhandled SHA1 backend. This should be fine though given that
Meson verifies the value for combo-options for us.

Signed-off-by: Patrick Steinhardt <ps@pks.im>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2024-12-30 06:50:49 -08:00
Patrick Steinhardt 6d8aa2aec8 meson: simplify conditions for HTTPS and SHA1 dependencies
The conditions used to figure out whteher the Security framework or
OpenSSL library is required are a bit convoluted because they can be
pulled in via the HTTPS, SHA1 or SHA256 backends. Refactor them to be
easier to read.

Signed-off-by: Patrick Steinhardt <ps@pks.im>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2024-12-30 06:50:46 -08:00
Patrick Steinhardt d6787d9751 meson: require SecurityFramework when it's used as SHA1 backend
The Security framework is required when we use CommonCrypto either as
HTTPS or SHA1 backend, but we only require it in case it is set up as
HTTPS backend. Fix this.

Signed-off-by: Patrick Steinhardt <ps@pks.im>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2024-12-30 06:50:45 -08:00
Patrick Steinhardt 31eb6d7cf0 meson: deduplicate access to SHA1/SHA256 backend options
We've got a couple of repeated calls to `get_option()` for the SHA1 and
SHA256 backend options. While not an issue, it makes the code needlessly
verbose.

Fix this by consistently using a local variable.

Signed-off-by: Patrick Steinhardt <ps@pks.im>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2024-12-30 06:50:45 -08:00
Patrick Steinhardt 8214e27d27 meson: consistenlty spell 'CommonCrypto'
The 'CommonCrypto' backend can be specified as HTTPS and SHA1 backends,
but the value that one needs to use is inconsistent across those two
build options. Unify it to 'CommonCrypto'.

Signed-off-by: Patrick Steinhardt <ps@pks.im>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2024-12-30 06:50:45 -08:00
Patrick Steinhardt d963ac98ec meson: enable auto-discovered "gitweb"
In 7d549fe317 (meson: skip gitweb build when Perl is disabled,
2024-12-20) we have started to conditionally enable "gitweb" based on
whether or not Perl is enabled. By accident though that change causes us
to not build gitweb in case its feature flag is set to "auto" even if
autoconfiguration determines that it could be built. This is because we
use "gitweb_option.enabled()", which only checks whether the feature has
been explicitly enabled.

Fix the issue by using `gitweb_option.allowed()` instead, which returns
true in case it is either explicitly enabled or set to "auto". This also
works for the case where the feature becomes auto-disabled due to Perl
not being present because we use `disable_auto_if(not perl.found())`.

Signed-off-by: Patrick Steinhardt <ps@pks.im>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2024-12-27 08:17:19 -08:00
Patrick Steinhardt cbcc2f7911 GIT-BUILD-OPTIONS: wire up NO_GITWEB option
Building our "gitweb" interface is optional in our Makefile and in Meson
and not wired up at all with CMake, but disabling it causes a couple of
tests in the t950* range that pull in "t/lib-gitweb.sh". This is because
the test library knows to execute gitweb-tests based on whether or not
Perl is available, but we may have Perl available and still end up not
building gitweb e.g. with `make test NO_GITWEB=YesPlease`.

Fix this issue by wiring up a new "NO_GITWEB" build option so that we
can skip these tests in case gitweb is not built.

Note that this new build option requires us to move the configuration of
GIT-BUILD-OPTIONS to a later point in our Meson build instructions. But
as that file is only consumed by our tests at runtime this change does
not cause any issues.

Signed-off-by: Patrick Steinhardt <ps@pks.im>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2024-12-27 08:17:19 -08:00
Junio C Hamano f074cdea46 Merge branch 'ps/build-hotfix'
A topic to optionally build with meson, which has graduated to
'master' recently, has regressed the normal Makefile build, which
is being corrected.

* ps/build-hotfix:
  meson: add options to override build information
  GIT-VERSION-GEN: fix overriding GIT_BUILT_FROM_COMMIT and GIT_DATE
  GIT-VERSION-GEN: fix overriding GIT_VERSION
  Makefile: introduce template for GIT-VERSION-GEN
  Makefile: drop unneeded indirection for GIT-VERSION-GEN outputs
  Makefile: stop including "GIT-VERSION-FILE" in docs
2024-12-23 09:32:26 -08:00
Junio C Hamano 83c8f76235 Merge branch 'ps/ci-meson'
The meson-build procedure is integrated into CI to catch and
prevent bitrotting.

* ps/ci-meson:
  ci: wire up Meson builds
  t: introduce compatibility options to clar-based tests
  t: fix out-of-tree tests for some git-p4 tests
  Makefile: detect missing Meson tests
  meson: detect missing tests at configure time
  t/unit-tests: rename clar-based unit tests to have a common prefix
  Makefile: drop -DSUPPRESS_ANNOTATED_LEAKS
  ci/lib: support custom output directories when creating test artifacts
2024-12-23 09:32:25 -08:00
Patrick Steinhardt 1bc815c3d0 meson: add options to override build information
We inject various different kinds of build information into build
artifacts, like the version string or the commit from which Git was
built. Add options to let users explicitly override this information
with Meson.

Signed-off-by: Patrick Steinhardt <ps@pks.im>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2024-12-20 12:36:46 -08:00
Patrick Steinhardt 7d549fe317 meson: skip gitweb build when Perl is disabled
It is possible to configure a Git build without Perl when disabling both
our test suite and all Perl-based features. In Meson, this can be
achieved with `meson setup -Dperl=disabled -Dtests=false`.

It was reported by a user that this breaks the Meson build because
gitweb gets built even if Perl was not discovered in such a build:

    $ meson setup .. -Dtests=false -Dperl=disabled
    ...
    ../gitweb/meson.build:2:43: ERROR: Unable to get the path of a not-found external program

Fix this issue by introducing a new feature-option that allows the user
to configure whether or not to build Gitweb. The feature is set to
'auto' by default and will be disabled automatically in case Perl was
not found on the system.

Reported-by: Daniel Engberg <daniel.engberg.lists@pyret.net>
Signed-off-by: Patrick Steinhardt <ps@pks.im>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2024-12-20 08:39:20 -08:00
Patrick Steinhardt 23eeee08d6 Makefile: drop -DSUPPRESS_ANNOTATED_LEAKS
The -DSUPPRESS_ANNOTATED_LEAKS preprocessor directive was used to enable
our `UNLEAK()` macro in the past, which marks memory as still-reachable
so that the leak sanitizer does not complain. Starting with 52c7dbd036
(git-compat-util: drop now-unused `UNLEAK()` macro, 2024-11-20) this
macro has been removed, and thus the preprocessor directive is not
required anymore, either.

Drop it.

Signed-off-by: Patrick Steinhardt <ps@pks.im>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2024-12-13 06:48:45 -08:00
Patrick Steinhardt 904339edbd Introduce support for the Meson build system
Introduce support for the Meson build system, a "modern" meta build
system that supports many different platforms, including Linux, macOS,
Windows and BSDs. Meson supports different backends, including Ninja,
Xcode and Microsoft Visual Studio. Several common IDEs provide an
integration with it.

The biggest contender compared to Meson is probably CMake as outlined in
our "Documentation/technical/build-systems.txt" file. Based on my own
personal experience from working with both build systems extensively I
strongly favor Meson over CMake. In my opinion, it feels significantly
easier to use with a syntax that feels more like a "real" programming
language. The second big reason is that Meson supports Rust natively,
which may prove to be important given that the project may pick up Rust
as another language eventually.

Using Meson is rather straight-forward. An example:

    ```
    # Meson uses out-of-tree builds. You can set up multiple build
    # directories, how you name them is completely up to you.
    $ mkdir build
    $ cd build
    $ meson setup .. -Dprefix=/tmp/git-installation

    # Build the project. This also provides several other targets like
    e.g. `install` or `test`.
    $ ninja

    # Meson has been wired up to support execution of our test suites.
    # Both our unit tests and our integration tests are supported.
    # Running `meson test` without any arguments will execute all tests,
    # but the syntax supports globbing to select only some tests.
    $ meson test 't-*'
    # Execute single test interactively to allow for debugging.
    $ meson test 't0000-*' --interactive --test-args=-ix
    ```

The build instructions have been successfully tested on the following
systems, tests are passing:

  - Apple macOS 10.15.

  - FreeBSD 14.1.

  - NixOS 24.11.

  - OpenBSD 7.6.

  - Ubuntu 24.04.

  - Windows 10 with Cygwin.

  - Windows 10 with MinGW64, except for t9700, which is also broken with
    our Makefile.

  - Windows 10 with Visual Studio 2022 toolchain, using the Native Tools
    Command Prompt with `meson setup --vsenv`. Tests pass, except for
    t9700.

  - Windows 10 with Visual Studio 2022 solution, using the Native Tools
    Command Prompt with `meson setup --backend vs2022`. Tests pass,
    except for t9700.

  - Windows 10 with VS Code, using the Meson plug-in.

It is expected that there will still be rough edges in the current
version. If this patch lands the expectation is that it will coexist
with our other build systems for a while. Like this, distributions can
slowly migrate over to Meson and report any findings they have to us
such that we can continue to iterate. A potential cutoff date for other
build systems may be Git 3.0.

Some notes:

  - The installed distribution is structured somewhat differently than
    how it used to be the case. All of our binaries are installed into
    `$libexec/git-core`, while all binaries part of `$bindir` are now
    symbolic links pointing to the former. This rule is consistent in
    itself and thus easier to reason about.

  - We do not install dashed binaries into `$libexec/git-core` anymore,
    so there won't e.g. be a symlink for git-add(1). These are not
    required by modern Git and there isn't really much of a use case for
    those anymore. By not installing those symlinks we thus start the
    deprecation of this layout.

  - We're targeting Meson 1.3.0, which has been released relatively
    recently November 2023. The only feature we use from that version is
    `fs.relative_to()`, which we could replace if necessary. If so, we
    could start to target Meson 1.0.0 and newer, released in December
    2022.

  - The whole build instructions count around 3300 lines, half of which
    is listing all of our code and test files. Our Makefiles are around
    5000 lines, autoconf adds another 1300 lines. CMake in comparison
    has only 1200 linescode, but it avoids listing individual files and
    does not wire up auto-configuration as extensively as the Meson
    instructions do.

  - We bundle a set of subproject wrappers for curl, expat, openssl,
    pcre2 and zlib. This allows developers to build Git without these
    dependencies preinstalled, and Meson will fetch and build them
    automatically. This is especially helpful on Windows.

Helped-by: Eli Schwartz <eschwartz@gentoo.org>
Signed-off-by: Patrick Steinhardt <ps@pks.im>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2024-12-07 07:52:14 +09:00