Commit Graph

991 Commits (7c78c599bb9b51e5cbdae3e7dc1d723eefcf7c61)

Author SHA1 Message Date
Taylor Blau e87a229d57 Merge branch 'en/sparse-checkout-design'
Design doc.

* en/sparse-checkout-design:
  sparse-checkout.txt: new document with sparse-checkout directions
2022-11-18 18:44:01 -05:00
Kousik Sanagavarapu 29c550f0af repository-version.txt: partialClone casing change
Remotes are considered "promisor" if extensions.partialClone and some
other configuration variables are set. The casing for this in
Documentation/technical/repository-version.txt is not proper and may
cause confusion. This change corrects this casing.

Signed-off-by: Kousik Sanagavarapu <five231003@gmail.com>
Signed-off-by: Taylor Blau <me@ttaylorr.com>
2022-11-11 17:23:12 -05:00
Taylor Blau 4b6302c72f Merge branch 'po/glossary-around-traversal'
The glossary entries for "commit-graph file" and "reachability
bitmap" have been added.

* po/glossary-around-traversal:
  glossary: add reachability bitmap description
  glossary: add "commit graph" description
  doc: use 'object database' not ODB or abbreviation
  doc: use "commit-graph" hyphenation consistently
2022-11-08 17:14:51 -05:00
Elijah Newren 20d87d3291 sparse-checkout.txt: new document with sparse-checkout directions
Once upon a time, Matheus wrote some patches to make
   git grep [--cached | <REVISION>] ...
restrict its output to the sparsity specification when working in a
sparse checkout[1].  That effort got derailed by two things:

  (1) The --sparse-index work just beginning which we wanted to avoid
      creating conflicts for
  (2) Never deciding on flag and config names and planned high level
      behavior for all commands.

More recently, Shaoxuan implemented a more limited form of Matheus'
patches that only affected --cached, using a different flag name,
but also changing the default behavior in line with what Matheus did.
This again highlighted the fact that we never decided on command line
flag names, config option names, and the big picture path forward.

The --sparse-index work has been mostly complete (or at least released
into production even if some small edges remain) for quite some time
now.  We have also had several discussions on flag and config names,
though we never came to solid conclusions.  Stolee once upon a time
suggested putting all these into some document in
Documentation/technical[3], which Victoria recently also requested[4].
I'm behind the times, but here's a patch attempting to finally do that.

[1] https://lore.kernel.org/git/5f3f7ac77039d41d1692ceae4b0c5df3bb45b74a.1612901326.git.matheus.bernardino@usp.br/
    (See his second link in that email in particular)
[2] https://lore.kernel.org/git/20220908001854.206789-2-shaoxuan.yuan02@gmail.com/
[3] https://lore.kernel.org/git/CABPp-BHwNoVnooqDFPAsZxBT9aR5Dwk5D9sDRCvYSb8akxAJgA@mail.gmail.com/
    (Scroll to the very end for the final few paragraphs)
[4] https://lore.kernel.org/git/cafcedba-96a2-cb85-d593-ef47c8c8397c@github.com/

Signed-off-by: Elijah Newren <newren@gmail.com>
Signed-off-by: Taylor Blau <me@ttaylorr.com>
2022-11-07 18:15:45 -05:00
Philip Oakley fa8e8d5b31 doc: use 'object database' not ODB or abbreviation
The abbreviation 'ODB' is used in the technical documentation
sections for commit-graph and parallel-checkout, along with an
'odb' option in `git-pack-redundant`, without expansion.

Use 'object database' in full, in those entries. The text has not
been reflowed to keep the changes minimal.

While in the glossary for `object` terms, add the common`oid`
abbreviation to its entry.

Signed-off-by: Philip Oakley <philipoakley@iee.email>
Signed-off-by: Taylor Blau <me@ttaylorr.com>
2022-10-30 19:58:46 -04:00
Philip Oakley 776ba91a5e doc: use "commit-graph" hyphenation consistently
Note, historical release notes have not been updated.

Signed-off-by: Philip Oakley <philipoakley@iee.email>
Signed-off-by: Taylor Blau <me@ttaylorr.com>
2022-10-30 19:58:40 -04:00
Jeff Hostetler 81071626ba trace2: add global counter mechanism
Add global counters mechanism to Trace2.

The Trace2 counters mechanism adds the ability to create a set of
global counter variables and an API to increment them efficiently.
Counters can optionally report per-thread usage in addition to the sum
across all threads.

Counter events are emitted to the Trace2 logs when a thread exits and
at process exit.

Counters are an alternative to `data` and `data_json` events.

Counters are useful when you want to measure something across the life
of the process, when you don't want per-measurement events for
performance reasons, when the data does not fit conveniently within a
region, or when your control flow does not easily let you write the
final total.  For example, you might use this to report the number of
calls to unzip() or the number of de-delta steps during a checkout.

Signed-off-by: Jeff Hostetler <jeffhost@microsoft.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2022-10-24 12:45:26 -07:00
Jeff Hostetler 8ad575646c trace2: add stopwatch timers
Add stopwatch timer mechanism to Trace2.

Timers are an alternative to Trace2 Regions.  Regions are useful for
measuring the time spent in various computation phases, such as the
time to read the index, time to scan for unstaged files, time to scan
for untracked files, and etc.

However, regions are not appropriate in all places.  For example,
during a checkout, it would be very inefficient to use regions to
measure the total time spent inflating objects from the ODB from
across the entire lifetime of the process; a per-unzip() region would
flood the output and significantly slow the command; and some form of
post-processing would be requried to compute the time spent in unzip().

Timers can be used to measure a series of timer intervals and emit
a single summary event (at thread and/or process exit).

Signed-off-by: Jeff Hostetler <jeffhost@microsoft.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2022-10-24 12:45:26 -07:00
Jeff Hostetler 8e8c5ad27a api-trace2.txt: elminate section describing the public trace2 API
Eliminate the mostly obsolete `Public API` sub-section from the
`Trace2 API` section in the documentation.  Strengthen the referral
to `trace2.h`.

Most of the technical information in this sub-section was moved to
`trace2.h` in 6c51cb525d (trace2: move doc to trace2.h, 2019-11-17) to
be adjacent to the function prototypes.  The remaining text wasn't
that useful by itself.

Furthermore, the text would need a bit of overhaul to add routines
that do not immediately generate a message, such as stopwatch timers.
So it seemed simpler to just get rid of it.

Signed-off-by: Jeff Hostetler <jeffhost@microsoft.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2022-10-24 12:45:25 -07:00
Jeff Hostetler 5bbb925137 tr2tls: clarify TLS terminology
Reduce or eliminate use of the term "TLS" in the Trace2 code.

The term "TLS" has two popular meanings: "thread-local storage" and
"transport layer security".  In the Trace2 source, the term is associated
with the former.  There was concern on the mailing list about it refering
to the latter.

Update the source and documentation to eliminate the use of the "TLS" term
or replace it with the phrase "thread-local storage" to reduce ambiguity.

Signed-off-by: Jeff Hostetler <jeffhost@microsoft.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2022-10-24 12:45:25 -07:00
Derrick Stolee 7190b7ebf9 bundle-uri: fix technical doc issues
Two documentation issues exist in the technical docs for the bundle URI
feature.

First, there is an extraneous "the" across a linebreak, making the
nonsensical phrase "the bundle the list" which should just be "the
bundle list".

Secondly, the asciidoc update treats the string "`have`s" as starting a
"<code>" block, but the second tick is interpreted as an apostrophe
instead of a closing "</code>" tag. This causes entire sentences to be
formatted as code until the next one comes along. Simply adding a space
here does not work properly as the rendered HTML keeps that space.
Instead, restructure the sentence slightly to avoid using a plural,
allowing the HTML to render correctly.

Reported-by: Philip Oakley <philipoakley@iee.email>
Signed-off-by: Derrick Stolee <derrickstolee@github.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2022-10-07 11:00:21 -07:00
Junio C Hamano 4140830d25 Merge branch 'js/typofix'
* js/typofix:
  Documentation: clean up various typos in technical docs
  Documentation: clean up a few misspelled word typos
2022-09-21 15:27:02 -07:00
Junio C Hamano 8c88f75909 Merge branch 'tz/tech-docs-to-help-fix'
Docfix for topic already in -rc0.

* tz/tech-docs-to-help-fix:
  api docs: link to html version of api-trace2
  docs: fix a few recently broken links
2022-09-21 14:23:14 -07:00
Jacob Stopak bbb0c357b8 Documentation: clean up various typos in technical docs
Used GNU "aspell check <filename>" to review various technical
documentation files with the default aspell dictionary. Ignored
false-positives between american and british english.

Signed-off-by: Jacob Stopak <jacob@initialcommit.io>
Reviewed-by: Eric Sunshine <sunshine@sunshineco.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2022-09-21 10:28:36 -07:00
Junio C Hamano 42bf77c7d0 Merge branch 'vd/scalar-to-main'
Hoist the remainder of "scalar" out of contrib/ to the main part of
the codebase.

* vd/scalar-to-main:
  Documentation/technical: include Scalar technical doc
  t/perf: add 'GIT_PERF_USE_SCALAR' run option
  t/perf: add Scalar performance tests
  scalar-clone: add test coverage
  scalar: add to 'git help -a' command list
  scalar: implement the `help` subcommand
  git help: special-case `scalar`
  scalar: include in standard Git build & installation
  scalar: fix command documentation section header
2022-09-19 14:35:25 -07:00
Todd Zullinger 4945f046c7 api docs: link to html version of api-trace2
In f6d25d7878 (api docs: document that BUG() emits a trace2 error event,
2021-04-13), a link to the plain text version of api-trace2 was added in
`technical/api-error-handling.txt`.

All of our other `link:`s point to the html versions.  Do the same here.

Signed-off-by: Todd Zullinger <tmz@pobox.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2022-09-16 08:39:11 -07:00
Todd Zullinger 086eaab8da docs: fix a few recently broken links
Some links were broken in the recent move of various technical docs
c0f6dd49f1 (Merge branch 'ab/tech-docs-to-help', 2022-08-14).

Fix them.

Signed-off-by: Todd Zullinger <tmz@pobox.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2022-09-16 08:38:03 -07:00
Jacob Stopak c9dba103dd Documentation: fix various repeat word typos
Inspired by 24966cd982 ("doc: fix repeated words", 08-09-2019),
I ran "egrep -R "\<([a-zA-Z]+)\> \<\1\>" ./Documentation/*" to
find current cases of repeated words such as "the the" that were
quite clearly typos.

There were many false positives reported, such as "really really"
or valid uses of "that that" which I left alone.

Signed-off-by: Jacob Stopak <jacob@initialcommit.io>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2022-09-12 11:04:55 -07:00
Junio C Hamano 3fe0121479 Merge branch 'ac/bitmap-lookup-table'
The pack bitmap file gained a bitmap-lookup table to speed up
locating the necessary bitmap for a given commit.

* ac/bitmap-lookup-table:
  pack-bitmap-write: drop unused pack_idx_entry parameters
  bitmap-lookup-table: add performance tests for lookup table
  pack-bitmap: prepare to read lookup table extension
  pack-bitmap-write: learn pack.writeBitmapLookupTable and add tests
  pack-bitmap-write.c: write lookup table extension
  bitmap: move `get commit positions` code to `bitmap_writer_finish`
  Documentation/technical: describe bitmap lookup table extension
2022-09-05 18:33:39 -07:00
Victoria Dye 9eb7a73158 Documentation/technical: include Scalar technical doc
Include 'Documentation/technical/scalar.txt' alongside the other HTML
technical docs when installing them.

Now that the document is intended as a widely-accessible reference, remove
the internal work-in-progress roadmap from the document. Those details
should no longer be needed to guide Scalar's development and, if they were
left, they could fall out-of-date and be misleading to readers.

Signed-off-by: Victoria Dye <vdye@github.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2022-09-02 10:02:56 -07:00
Junio C Hamano d528044c83 Merge branch 'sg/parse-options-subcommand'
Introduce the "subcommand" mode to parse-options API and update the
command line parser of Git commands with subcommands.

* sg/parse-options-subcommand: (23 commits)
  remote: run "remote rm" argv through parse_options()
  maintenance: add parse-options boilerplate for subcommands
  pass subcommand "prefix" arguments to parse_options()
  builtin/worktree.c: let parse-options parse subcommands
  builtin/stash.c: let parse-options parse subcommands
  builtin/sparse-checkout.c: let parse-options parse subcommands
  builtin/remote.c: let parse-options parse subcommands
  builtin/reflog.c: let parse-options parse subcommands
  builtin/notes.c: let parse-options parse subcommands
  builtin/multi-pack-index.c: let parse-options parse subcommands
  builtin/hook.c: let parse-options parse subcommands
  builtin/gc.c: let parse-options parse 'git maintenance's subcommands
  builtin/commit-graph.c: let parse-options parse subcommands
  builtin/bundle.c: let parse-options parse subcommands
  parse-options: add support for parsing subcommands
  parse-options: drop leading space from '--git-completion-helper' output
  parse-options: clarify the limitations of PARSE_OPT_NODASH
  parse-options: PARSE_OPT_KEEP_UNKNOWN only applies to --options
  api-parse-options.txt: fix description of OPT_CMDMODE
  t0040-parse-options: test parse_options() with various 'parse_opt_flags'
  ...
2022-09-01 13:40:18 -07:00
Junio C Hamano 10ccb50b16 Merge branch 'tl/trace2-config-scope'
Tweak trace2 output about configuration variables.

* tl/trace2-config-scope:
  tr2: shows scope unconditionally in addition to key-value pair
  api-trace2.txt: print config key-value pair
2022-08-29 14:55:13 -07:00
Junio C Hamano bc820cf9e6 Merge branch 'vd/scalar-enables-fsmonitor'
"scalar" now enables built-in fsmonitor on enlisted repositories,
when able.

* vd/scalar-enables-fsmonitor:
  scalar: update technical doc roadmap with FSMonitor support
  scalar unregister: stop FSMonitor daemon
  scalar: enable built-in FSMonitor on `register`
  scalar: move config setting logic into its own function
  scalar-delete: do not 'die()' in 'delete_enlistment()'
  scalar-[un]register: clearly indicate source of error
  scalar-unregister: handle error codes greater than 0
  scalar: constrain enlistment search
2022-08-29 14:55:12 -07:00
Abhradeep Chakraborty e9977b12fd Documentation/technical: describe bitmap lookup table extension
When reading bitmap file, Git loads each and every bitmap one by one
even if all the bitmaps are not required. A "bitmap lookup table"
extension to the bitmap format can reduce the overhead of loading
bitmaps which stores a list of bitmapped commit id pos (in the midx
or pack, along with their offset and xor offset. This way Git can
load only the necessary bitmaps without loading the previous bitmaps.

Older versions of Git ignore the lookup table extension and don't
throw any kind of warning or error while parsing the bitmap file.

Add some information for the new "bitmap lookup table" extension in the
bitmap-format documentation.

Mentored-by: Taylor Blau <me@ttaylorr.com>
Co-Mentored-by: Kaartic Sivaraam <kaartic.sivaraam@gmail.com>
Co-Authored-by: Taylor Blau <me@ttaylorr.com>
Signed-off-by: Abhradeep Chakraborty <chakrabortyabhradeep79@gmail.com>
Reviewed-by: Taylor Blau <me@ttaylorr.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2022-08-26 10:13:33 -07:00
Junio C Hamano f00ddc9f48 Merge branch 'vd/scalar-generalize-diagnose'
The "diagnose" feature to create a zip archive for diagnostic
material has been lifted from "scalar" and made into a feature of
"git bugreport".

* vd/scalar-generalize-diagnose:
  scalar: update technical doc roadmap
  scalar-diagnose: use 'git diagnose --mode=all'
  builtin/bugreport.c: create '--diagnose' option
  builtin/diagnose.c: add '--mode' option
  builtin/diagnose.c: create 'git diagnose' builtin
  diagnose.c: add option to configure archive contents
  scalar-diagnose: move functionality to common location
  scalar-diagnose: move 'get_disk_info()' to 'compat/'
  scalar-diagnose: add directory to archiver more gently
  scalar-diagnose: avoid 32-bit overflow of size_t
  scalar-diagnose: use "$GIT_UNZIP" in test
2022-08-25 14:42:32 -07:00
SZEDER Gábor fa83cc834d parse-options: add support for parsing subcommands
Several Git commands have subcommands to implement mutually exclusive
"operation modes", and they usually parse their subcommand argument
with a bunch of if-else if statements.

Teach parse-options to handle subcommands as well, which will result
in shorter and simpler code with consistent error handling and error
messages on unknown or missing subcommand, and it will also make
possible for our Bash completion script to handle subcommands
programmatically.

The approach is guided by the following observations:

  - Most subcommands [1] are implemented in dedicated functions, and
    most of those functions [2] either have a signature matching the
    'int cmd_foo(int argc, const char **argc, const char *prefix)'
    signature of builtin commands or can be trivially converted to
    that signature, because they miss only that last prefix parameter
    or have no parameters at all.

  - Subcommand arguments only have long form, and they have no double
    dash prefix, no negated form, and no description, and they don't
    take any arguments, and can't be abbreviated.

  - There must be exactly one subcommand among the arguments, or zero
    if the command has a default operation mode.

  - All arguments following the subcommand are considered to be
    arguments of the subcommand, and, conversely, arguments meant for
    the subcommand may not preceed the subcommand.

So in the end subcommand declaration and parsing would look something
like this:

    parse_opt_subcommand_fn *fn = NULL;
    struct option builtin_commit_graph_options[] = {
        OPT_STRING(0, "object-dir", &opts.obj_dir, N_("dir"),
                   N_("the object directory to store the graph")),
        OPT_SUBCOMMAND("verify", &fn, graph_verify),
        OPT_SUBCOMMAND("write", &fn, graph_write),
        OPT_END(),
    };
    argc = parse_options(argc, argv, prefix, options,
                         builtin_commit_graph_usage, 0);
    return fn(argc, argv, prefix);

Here each OPT_SUBCOMMAND specifies the name of the subcommand and the
function implementing it, and the address of the same 'fn' subcommand
function pointer.  parse_options() then processes the arguments until
it finds the first argument matching one of the subcommands, sets 'fn'
to the function associated with that subcommand, and returns, leaving
the rest of the arguments unprocessed.  If none of the listed
subcommands is found among the arguments, parse_options() will show
usage and abort.

If a command has a default operation mode, 'fn' should be initialized
to the function implementing that mode, and parse_options() should be
invoked with the PARSE_OPT_SUBCOMMAND_OPTIONAL flag.  In this case
parse_options() won't error out when not finding any subcommands, but
will return leaving 'fn' unchanged.  Note that if that default
operation mode has any --options, then the PARSE_OPT_KEEP_UNKNOWN_OPT
flag is necessary as well (otherwise parse_options() would error out
upon seeing the unknown option meant to the default operation mode).

Some thoughts about the implementation:

  - The same pointer to 'fn' must be specified as 'value' for each
    OPT_SUBCOMMAND, because there can be only one set of mutually
    exclusive subcommands; parse_options() will BUG() otherwise.

    There are other ways to tell parse_options() where to put the
    function associated with the subcommand given on the command line,
    but I didn't like them:

      - Change parse_options()'s signature by adding a pointer to
        subcommand function to be set to the function associated with
        the given subcommand, affecting all callsites, even those that
        don't have subcommands.

      - Introduce a specific parse_options_and_subcommand() variant
        with that extra funcion parameter.

  - I decided against automatically calling the subcommand function
    from within parse_options(), because:

      - There are commands that have to perform additional actions
        after option parsing but before calling the function
        implementing the specified subcommand.

      - The return code of the subcommand is usually the return code
        of the git command, but preserving the return code of the
        automatically called subcommand function would have made the
        API awkward.

  - Also add a OPT_SUBCOMMAND_F() variant to allow specifying an
    option flag: we have two subcommands that are purposefully
    excluded from completion ('git remote rm' and 'git stash save'),
    so they'll have to be specified with the PARSE_OPT_NOCOMPLETE
    flag.

  - Some of the 'parse_opt_flags' don't make sense with subcommands,
    and using them is probably just an oversight or misunderstanding.
    Therefore parse_options() will BUG() when invoked with any of the
    following flags while the options array contains at least one
    OPT_SUBCOMMAND:

      - PARSE_OPT_KEEP_DASHDASH: parse_options() stops parsing
        arguments when encountering a "--" argument, so it doesn't
        make sense to expect and keep one before a subcommand, because
        it would prevent the parsing of the subcommand.

        However, this flag is allowed in combination with the
        PARSE_OPT_SUBCOMMAND_OPTIONAL flag, because the double dash
        might be meaningful for the command's default operation mode,
        e.g. to disambiguate refs and pathspecs.

      - PARSE_OPT_STOP_AT_NON_OPTION: As its name suggests, this flag
        tells parse_options() to stop as soon as it encouners a
        non-option argument, but subcommands are by definition not
        options...  so how could they be parsed, then?!

      - PARSE_OPT_KEEP_UNKNOWN: This flag can be used to collect any
        unknown --options and then pass them to a different command or
        subsystem.  Surely if a command has subcommands, then this
        functionality should rather be delegated to one of those
        subcommands, and not performed by the command itself.

        However, this flag is allowed in combination with the
        PARSE_OPT_SUBCOMMAND_OPTIONAL flag, making possible to pass
        --options to the default operation mode.

  - If the command with subcommands has a default operation mode, then
    all arguments to the command must preceed the arguments of the
    subcommand.

    AFAICT we don't have any commands where this makes a difference,
    because in those commands either only the command accepts any
    arguments ('notes' and 'remote'), or only the default subcommand
    ('reflog' and 'stash'), but never both.

  - The 'argv' array passed to subcommand functions currently starts
    with the name of the subcommand.  Keep this behavior.  AFAICT no
    subcommand functions depend on the actual content of 'argv[0]',
    but the parse_options() call handling their options expects that
    the options start at argv[1].

  - To support handling subcommands programmatically in our Bash
    completion script, 'git cmd --git-completion-helper' will now list
    both subcommands and regular --options, if any.  This means that
    the completion script will have to separate subcommands (i.e.
    words without a double dash prefix) from --options on its own, but
    that's rather easy to do, and it's not much work either, because
    the number of subcommands a command might have is rather low, and
    those commands accept only a single --option or none at all.  An
    alternative would be to introduce a separate option that lists
    only subcommands, but then the completion script would need not
    one but two git invocations and command substitutions for commands
    with subcommands.

    Note that this change doesn't affect the behavior of our Bash
    completion script, because when completing the --option of a
    command with subcommands, e.g. for 'git notes --<TAB>', then all
    subcommands will be filtered out anyway, as none of them will
    match the word to be completed starting with that double dash
    prefix.

[1] Except 'git rerere', because many of its subcommands are
    implemented in the bodies of the if-else if statements parsing the
    command's subcommand argument.

[2] Except 'credential', 'credential-store' and 'fsmonitor--daemon',
    because some of the functions implementing their subcommands take
    special parameters.

Signed-off-by: SZEDER Gábor <szeder.dev@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2022-08-19 11:13:14 -07:00
SZEDER Gábor 99d86d60e5 parse-options: PARSE_OPT_KEEP_UNKNOWN only applies to --options
The description of 'PARSE_OPT_KEEP_UNKNOWN' starts with "Keep unknown
arguments instead of erroring out".  This is a bit misleading, as this
flag only applies to unknown --options, while non-option arguments are
kept even without this flag.

Update the description to clarify this, and rename the flag to
PARSE_OPTIONS_KEEP_UNKNOWN_OPT to make this obvious just by looking at
the flag name.

Signed-off-by: SZEDER Gábor <szeder.dev@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2022-08-19 11:13:14 -07:00
SZEDER Gábor 80882bc5e7 api-parse-options.txt: fix description of OPT_CMDMODE
The description of the 'OPT_CMDMODE' macro states that "enum_val is
set to int_var when ...", but it's the other way around, 'int_var' is
set to 'enum_val'.  Fix this.

Signed-off-by: SZEDER Gábor <szeder.dev@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2022-08-19 11:13:14 -07:00
Victoria Dye 8e2841890a scalar: update technical doc roadmap with FSMonitor support
Update the Scalar roadmap to reflect completion of enabling the built-in
FSMonitor in Scalar.

Note that implementation of 'scalar help' was moved to the final set of
changes to move Scalar out of 'contrib/'. This is due to a dependency on
changes to 'git help', as all changes to the main Git tree *exclusively*
implemented to support Scalar are part of that series.

Signed-off-by: Victoria Dye <vdye@github.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2022-08-18 21:35:32 -07:00
Junio C Hamano 0d133a3dcf Merge branch 'ds/bundle-uri-more'
The "bundle URI" design gets documented.

* ds/bundle-uri-more:
  bundle-uri: add example bundle organization
  docs: document bundle URI standard
2022-08-18 13:07:04 -07:00
Junio C Hamano c0f6dd49f1 Merge branch 'ab/tech-docs-to-help'
Expose a lot of "tech docs" via "git help" interface.

* ab/tech-docs-to-help:
  docs: move http-protocol docs to man section 5
  docs: move cruft pack docs to gitformat-pack
  docs: move pack format docs to man section 5
  docs: move signature docs to man section 5
  docs: move index format docs to man section 5
  docs: move protocol-related docs to man section 5
  docs: move commit-graph format docs to man section 5
  git docs: add a category for file formats, protocols and interfaces
  git docs: add a category for user-facing file, repo and command UX
  git help doc: use "<doc>" instead of "<guide>"
  help.c: remove common category behavior from drop_prefix() behavior
  help.c: refactor drop_prefix() to use a "switch" statement"
2022-08-14 23:19:28 -07:00
Victoria Dye 43370b1e91 scalar: update technical doc roadmap
Update the Scalar roadmap to reflect the completion of generalizing 'scalar
diagnose' into 'git diagnose' and 'git bugreport --diagnose'.

Signed-off-by: Victoria Dye <vdye@github.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2022-08-12 13:20:03 -07:00
Teng Long 35ae40ead3 tr2: shows scope unconditionally in addition to key-value pair
When we specify GIT_TRACE2_CONFIG_PARAMS or trace2.configparams,
trace2 will prints "interesting" config values to log. Sometimes,
when a config set in multiple scope files, the following output
looks like (the irrelevant fields are omitted here as "..."):

...| def_param    |  ...  | core.multipackindex:false
...| def_param    |  ...  | core.multipackindex:false
...| def_param    |  ...  | core.multipackindex:false

As the log shows, even each config in different scope is dumped, but
we don't know which scope it comes from. Therefore, it's better to
add the scope names as well to make them be more recognizable. For
example, when execute:

    $ GIT_TRACE2_PERF=1 \
    > GIT_TRACE2_CONFIG_PARAMS=core.multipackIndex \
    > git rev-list --test-bitmap HEAD"

The following is the ouput (the irrelevant fields are omitted here
as "..."):

Format normal:
... git.c:461 ... def_param scope:system core.multipackindex=false
... git.c:461 ... def_param scope:global core.multipackindex=false
... git.c:461 ... def_param scope:local core.multipackindex=false

Format perf:

... | def_param    | ... | scope:system | core.multipackindex:false
... | def_param    | ... | scope:global | core.multipackindex:false
... | def_param    | ... | scope:local  | core.multipackindex:false

Format event:

{"event":"def_param", ... ,"scope":"system","param":"core.multipackindex","value":"false"}
{"event":"def_param", ... ,"scope":"global","param":"core.multipackindex","value":"false"}
{"event":"def_param", ... ,"scope":"local","param":"core.multipackindex","value":"false"}

Signed-off-by: Teng Long <dyroneteng@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2022-08-11 21:05:00 -07:00
Teng Long 050d0dc241 api-trace2.txt: print config key-value pair
It's supported to print "interesting" config key-value paire
to tr2 log by setting "GIT_TRACE2_CONFIG_PARAMS" environment
variable and the "trace2.configparam" config, let's add the
related docs in Documentaion/technical/api-trace2.txt.

Signed-off-by: Teng Long <dyroneteng@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2022-08-11 21:05:00 -07:00
Derrick Stolee d06ed85dcb bundle-uri: add example bundle organization
The previous change introduced the bundle URI design document. It
creates a flexible set of options that allow bundle providers many ways
to organize Git object data and speed up clones and fetches. It is
particularly important that we have flexibility so we can apply future
advancements as new ideas for efficiently organizing Git data are
discovered.

However, the design document does not provide even an example of how
bundles could be organized, and that makes it difficult to envision how
the feature should work at the end of the implementation plan.

Add a section that details how a bundle provider could work, including
using the Git server advertisement for multiple geo-distributed servers.
This organization is based on the GVFS Cache Servers which have
successfully used similar ideas to provide fast object access and
reduced server load for very large repositories.

Signed-off-by: Derrick Stolee <derrickstolee@github.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2022-08-10 14:03:17 -07:00
Derrick Stolee 2da14fad8f docs: document bundle URI standard
Introduce the idea of bundle URIs to the Git codebase through an
aspirational design document. This document includes the full design
intended to include the feature in its fully-implemented form. This will
take several steps as detailed in the Implementation Plan section.

By committing this document now, it can be used to motivate changes
necessary to reach these final goals. The design can still be altered as
new information is discovered.

Signed-off-by: Derrick Stolee <derrickstolee@github.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2022-08-10 14:03:11 -07:00
Ævar Arnfjörð Bjarmason 1e2320161d docs: move http-protocol docs to man section 5
Continue the move of existing Documentation/technical/* protocol and
file-format documentation into our main documentation space by moving
the http-protocol.txt documentation over. I'm renaming it to
"protocol-http" to be consistent with other things in the new
gitformat-protocol-* namespace.

Signed-off-by: Ævar Arnfjörð Bjarmason <avarab@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2022-08-04 14:12:24 -07:00
Ævar Arnfjörð Bjarmason 6b6029dd1d docs: move cruft pack docs to gitformat-pack
Integrate the cruft packs documentation initially added in
3d89a8c118 (Documentation/technical: add cruft-packs.txt, 2022-05-20)
to the newly created "gitformat-pack" documentation.

Like the "bitmap-format" added before it in
0d4455a3ab (documentation: add documentation for the bitmap format,
2013-11-14) the "cruft-packs" were documented in their own file.

As the diff move detection will show there is no change to
"Documentation/technical/cruft-packs.txt" here except to move it, and
to "indent" the existing sections by adding an extra "=" to them.

We could similarly convert the "bitmap-format.txt", but let's leave it
for now due to a conflict with the in-flight ac/bitmap-lookup-table
series.

Signed-off-by: Ævar Arnfjörð Bjarmason <avarab@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2022-08-04 14:12:24 -07:00
Ævar Arnfjörð Bjarmason 977c47b46d docs: move pack format docs to man section 5
Continue the move of existing Documentation/technical/* protocol and
file-format documentation into our main documentation space by moving
the various documentation pertaining to the *.pack format and related
files, and updating things that refer to it to link to the new
location.

By moving these we can properly link from the newly created
gitformat-commit-graph to a gitformat-chunk-format page.

Integrating "Documentation/technical/bitmap-format.txt" and
"Documentation/technical/cruft-packs.txt" might logically be part of
this change, but as those cover parts of the wider "pack
format" (including associated files) that's documented outside of
"Documentation/technical/pack-format.txt" let's leave those for now,
subsequent commit(s) will address those.

Signed-off-by: Ævar Arnfjörð Bjarmason <avarab@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2022-08-04 14:12:24 -07:00
Ævar Arnfjörð Bjarmason 20516890dc docs: move signature docs to man section 5
Continue the move of existing Documentation/technical/* protocol and
file-format documentation into our main documentation space by moving
the signature format documentation.

Signed-off-by: Ævar Arnfjörð Bjarmason <avarab@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2022-08-04 14:12:24 -07:00
Ævar Arnfjörð Bjarmason 00d3e8d7dd docs: move index format docs to man section 5
Continue the move of existing Documentation/technical/* protocol and
file-format documentation into our main documentation space by moving
the index format documentation.

Signed-off-by: Ævar Arnfjörð Bjarmason <avarab@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2022-08-04 14:12:23 -07:00
Ævar Arnfjörð Bjarmason 5db921054e docs: move protocol-related docs to man section 5
Continue the move of existing Documentation/technical/* protocol and
file-format documentation into our main documentation space. By moving
the things that discuss the protocol we can properly link from
e.g. lsrefs.unborn and protocol.version documentation to a manpage we
build by default.

So far we have been using the "gitformat-" prefix for the
documentation we've been moving over from Documentation/technical/*,
but for protocol documentation let's use "gitprotocol-*".

Signed-off-by: Ævar Arnfjörð Bjarmason <avarab@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2022-08-04 14:12:23 -07:00
Ævar Arnfjörð Bjarmason 8cbace93d2 docs: move commit-graph format docs to man section 5
Continue the move of existing Documentation/technical/* protocol and
file-format documentation into our main documentation space.

By moving the documentation for the commit-graph format into man
section 5 and the new "developerinterfaces" category. This change is
split from subsequent commits due to the relatively large amount of
ASCIIDOC formatting changes that are required.

Signed-off-by: Ævar Arnfjörð Bjarmason <avarab@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2022-08-04 14:12:23 -07:00
Ævar Arnfjörð Bjarmason 844739ba27 git docs: add a category for file formats, protocols and interfaces
Create a new "File formats, protocols and other developer interfaces"
section in the main "git help git" manual page and start moving the
documentation that now lives in "Documentation/technical/*.git" over
to it. This complements the newly added and adjacent "Repository,
command and file interfaces" section.

This makes the technical documentation more accessible and
discoverable. Before this we wouldn't install it by default, and had
no ability to build man page versions of them. The links to them from
our existing documentation link to the generated HTML version of these
docs.

So let's start moving those over, starting with just the
"bundle-format.txt" documentation added in 7378ec90e1 (doc: describe
Git bundle format, 2020-02-07). We'll now have a new
gitformat-bundle(5) man page. Subsequent commits will move more git
internal format documentation over.

Unfortunately the syntax of the current Documentation/technical/*.txt
is not the same (when it comes to section headings etc.) as our
Documentation/*.txt documentation, so change the relevant bits of
syntax as we're moving this over.

Signed-off-by: Ævar Arnfjörð Bjarmason <avarab@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2022-08-04 14:12:23 -07:00
Junio C Hamano 3a03633812 Merge branch 'vd/scalar-doc'
Doc update.

* vd/scalar-doc:
  scalar: convert README.md into a technical design doc
  scalar: reword command documentation to clarify purpose
2022-07-27 09:16:54 -07:00
Junio C Hamano a88527203f Merge branch 'sg/index-format-doc-update'
Docfix.

* sg/index-format-doc-update:
  index-format.txt: remove outdated list of supported extensions
2022-07-27 09:16:53 -07:00
Victoria Dye 72d3a5da32 scalar: convert README.md into a technical design doc
Adapt the content from 'contrib/scalar/README.md' into a design document in
'Documentation/technical/'. In addition to reformatting for asciidoc,
elaborate on the background, purpose, and design choices that went into
Scalar.

Most of this document will persist in the 'Documentation/technical/' after
Scalar has been moved out of 'contrib/' and into the root of Git. Until that
time, it will also contain a temporary "Roadmap" section detailing the
remaining series needed to finish the initial version of Scalar. The section
will be removed once Scalar is moved to the repo root, but in the meantime
serves as a guide for readers to keep up with progress on the feature.

Signed-off-by: Victoria Dye <vdye@github.com>
Acked-by: Derrick Stolee <derrickstolee@github.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2022-07-18 11:03:56 -07:00
SZEDER Gábor a10f6e2bda index-format.txt: remove outdated list of supported extensions
The first section of 'Documentation/technical/index-format.txt'
mentions that "Git currently supports cache tree and resolve undo
extensions", but then goes on, and in the "Extensions" section
describes not only these two, but six other extensions [1].

Remove this sentence, as it's misleading about the status of all those
other extensions.

Alternatively we could keep that sentence and update the list of
extensions, but that might well lead to a recurring issue, because
apparently this list is never updated when a new index extension is
added.

[1] Split index, untracked cache, FS monitor cache, end of index
    entry, index entry offset table and sparse directory entries.

Signed-off-by: SZEDER Gábor <szeder.dev@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2022-07-18 09:24:43 -07:00
Junio C Hamano 5dbbdaac79 Merge branch 'ac/bitmap-format-doc'
Adjust technical/bitmap-format to be formatted by AsciiDoc, and
add some missing information to the documentation.

* ac/bitmap-format-doc:
  bitmap-format.txt: add information for trailing checksum
  bitmap-format.txt: fix some formatting issues
  bitmap-format.txt: feed the file to asciidoc to generate html
2022-07-11 15:38:50 -07:00
Abhradeep Chakraborty ac7667bd44 bitmap-format.txt: add information for trailing checksum
Bitmap file has a trailing checksum at the end of the file. However
there is no information in the bitmap-format documentation about it.

Add a trailer section to include the trailing checksum info in the
`Documentation/technical/bitmap-format.txt` file.

Signed-off-by: Abhradeep Chakraborty <chakrabortyabhradeep79@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2022-06-16 11:48:50 -07:00
Abhradeep Chakraborty caea900272 bitmap-format.txt: fix some formatting issues
The asciidoc generated html for `Documentation/technical/bitmap-
format.txt` is broken. This is mainly because `-` is used for nested
lists (which is not allowed in asciidoc) instead of `*`.

Fix these and also reformat it for better readability of the html page.

Signed-off-by: Abhradeep Chakraborty <chakrabortyabhradeep79@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2022-06-16 11:48:50 -07:00
Junio C Hamano 4da14b574f Merge branch 'ab/bug-if-bug'
A new bug() and BUG_if_bug() API is introduced to make it easier to
uniformly log "detect multiple bugs and abort in the end" pattern.

* ab/bug-if-bug:
  cache-tree.c: use bug() and BUG_if_bug()
  receive-pack: use bug() and BUG_if_bug()
  parse-options.c: use optbug() instead of BUG() "opts" check
  parse-options.c: use new bug() API for optbug()
  usage.c: add a non-fatal bug() function to go with BUG()
  common-main.c: move non-trace2 exit() behavior out of trace2.c
2022-06-10 15:04:15 -07:00
Junio C Hamano a50036da1a Merge branch 'tb/cruft-packs'
A mechanism to pack unreachable objects into a "cruft pack",
instead of ejecting them into loose form to be reclaimed later, has
been introduced.

* tb/cruft-packs:
  sha1-file.c: don't freshen cruft packs
  builtin/gc.c: conditionally avoid pruning objects via loose
  builtin/repack.c: add cruft packs to MIDX during geometric repack
  builtin/repack.c: use named flags for existing_packs
  builtin/repack.c: allow configuring cruft pack generation
  builtin/repack.c: support generating a cruft pack
  builtin/pack-objects.c: --cruft with expiration
  reachable: report precise timestamps from objects in cruft packs
  reachable: add options to add_unseen_recent_objects_to_traversal
  builtin/pack-objects.c: --cruft without expiration
  builtin/pack-objects.c: return from create_object_entry()
  t/helper: add 'pack-mtimes' test-tool
  pack-mtimes: support writing pack .mtimes files
  chunk-format.h: extract oid_version()
  pack-write: pass 'struct packing_data' to 'stage_tmp_packfiles'
  pack-mtimes: support reading .mtimes files
  Documentation/technical: add cruft-packs.txt
2022-06-03 14:30:37 -07:00
Ævar Arnfjörð Bjarmason 0cc05b044f usage.c: add a non-fatal bug() function to go with BUG()
Add a bug() function to use in cases where we'd like to indicate a
runtime BUG(), but would like to defer the BUG() call because we're
possibly accumulating more bug() callers to exhaustively indicate what
went wrong.

We already have this sort of facility in various parts of the
codebase, just in the form of ad-hoc re-inventions of the
functionality that this new API provides. E.g. this will be used to
replace optbug() in parse-options.c, and the 'error("BUG:[...]' we do
in a loop in builtin/receive-pack.c.

Unlike the code this replaces we'll log to trace2 with this new bug()
function (as with other usage.c functions, including BUG()), we'll
also be able to avoid calls to xstrfmt() in some cases, as the bug()
function itself accepts variadic sprintf()-like arguments.

Any caller to bug() can follow up such calls with BUG_if_bug(),
which will BUG() out (i.e. abort()) if there were any preceding calls
to bug(), callers can also decide not to call BUG_if_bug() and leave
the resulting BUG() invocation until exit() time. There are currently
no bug() API users that don't call BUG_if_bug() themselves after a
for-loop, but allowing for not calling BUG_if_bug() keeps the API
flexible. As the tests and documentation here show we'll catch missing
BUG_if_bug() invocations in our exit() wrapper.

Signed-off-by: Ævar Arnfjörð Bjarmason <avarab@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2022-06-02 12:51:35 -07:00
Taylor Blau f9825d1cf7 builtin/repack.c: support generating a cruft pack
Expose a way to split the contents of a repository into a main and cruft
pack when doing an all-into-one repack with `git repack --cruft -d`, and
a complementary configuration variable.

Signed-off-by: Taylor Blau <me@ttaylorr.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2022-05-26 15:48:26 -07:00
Taylor Blau 94cd775a6c pack-mtimes: support reading .mtimes files
To store the individual mtimes of objects in a cruft pack, introduce a
new `.mtimes` format that can optionally accompany a single pack in the
repository.

The format is defined in Documentation/technical/pack-format.txt, and
stores a 4-byte network order timestamp for each object in name (index)
order.

This patch prepares for cruft packs by defining the `.mtimes` format,
and introducing a basic API that callers can use to read out individual
mtimes.

Signed-off-by: Taylor Blau <me@ttaylorr.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2022-05-26 15:48:26 -07:00
Taylor Blau 3d89a8c118 Documentation/technical: add cruft-packs.txt
Create a technical document to explain cruft packs. It contains a brief
overview of the problem, some background, details on the implementation,
and a couple of alternative approaches not considered here.

Signed-off-by: Taylor Blau <me@ttaylorr.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2022-05-20 22:31:21 -07:00
Johannes Schindelin a6c80c313c trace2 docs: add missing full stop
Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2022-05-04 10:31:05 -07:00
Johannes Schindelin 236d1177ba trace2 docs: clarify what `varargs` is all about
Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2022-05-04 10:31:05 -07:00
Johannes Schindelin c4667b17fb trace2 docs: fix a JSON formatted example
The example was not in valid JSON format due to a duplicate key "sid".

Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2022-05-04 10:31:04 -07:00
Johannes Schindelin 1c538b951f trace2 docs: surround more terms in backticks
Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2022-05-04 10:31:04 -07:00
Johannes Schindelin c191b9188b trace2 docs: "printf" is not an English word
We append an ellipsis and enclose it in backticks to indicate that it is
a function elsewhere, let's also use that here.

While at it, ensure the same for `waitpid()`.

Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2022-05-04 10:31:04 -07:00
Johannes Schindelin 3188d3c0b9 trace2 docs: a couple of grammar fixes
Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2022-05-04 10:31:04 -07:00
Junio C Hamano 0f5e885173 Merge branch 'rc/fetch-refetch'
"git fetch --refetch" learned to fetch everything without telling
the other side what we already have, which is useful when you
cannot trust what you have in the local object store.

* rc/fetch-refetch:
  docs: mention --refetch fetch option
  fetch: after refetch, encourage auto gc repacking
  t5615-partial-clone: add test for fetch --refetch
  fetch: add --refetch option
  builtin/fetch-pack: add --refetch option
  fetch-pack: add refetch
  fetch-negotiator: add specific noop initializer
2022-04-04 10:56:23 -07:00
Robert Coup 4963d3e41f docs: mention --refetch fetch option
Document it for partial clones as a means to apply a new filter, and
reference it from the remote.<name>.partialclonefilter config parameter.

Signed-off-by: Robert Coup <robert@coup.net.nz>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2022-03-28 10:25:53 -07:00
Junio C Hamano 7391ecd338 Merge branch 'ds/partial-bundles'
Bundle file format gets extended to allow a partial bundle,
filtered by similar criteria you would give when making a
partial/lazy clone.

* ds/partial-bundles:
  clone: fail gracefully when cloning filtered bundle
  bundle: unbundle promisor packs
  bundle: create filtered bundles
  rev-list: move --filter parsing into revision.c
  bundle: parse filter capability
  list-objects: handle NULL function pointers
  MyFirstObjectWalk: update recommended usage
  list-objects: consolidate traverse_commit_list[_filtered]
  pack-bitmap: drop filter in prepare_bitmap_walk()
  pack-objects: use rev.filter when possible
  revision: put object filter into struct rev_info
  list-objects-filter-options: create copy helper
  index-pack: document and test the --promisor option
2022-03-21 15:14:24 -07:00
Junio C Hamano a54cc523ad Merge branch 'ds/commit-graph-gen-v2-fixes'
Fixes to the way generation number v2 in the commit-graph files are
(not) handled.

* ds/commit-graph-gen-v2-fixes:
  commit-graph: declare bankruptcy on GDAT chunks
  commit-graph: fix generation number v2 overflow values
  commit-graph: start parsing generation v2 (again)
  commit-graph: fix ordering bug in generation numbers
  t5318: extract helpers to lib-commit-graph.sh
  test-read-graph: include extra post-parse info
2022-03-16 17:53:09 -07:00
Derrick Stolee 105c6f14ad bundle: parse filter capability
The v3 bundle format has capabilities, allowing newer versions of Git to
create bundles with newer features. Older versions that do not
understand these new capabilities will fail with a helpful warning.

Create a new capability allowing Git to understand that the contained
pack-file is filtered according to some object filter. Typically, this
filter will be "blob:none" for a blobless partial clone.

This change teaches Git to parse this capability, place its value in the
bundle header, and demonstrate this understanding by adding a message to
'git bundle verify'.

Since we will use gently_parse_list_objects_filter() outside of
list-objects-filter-options.c, make it an external method and move its
API documentation to before its declaration.

Signed-off-by: Derrick Stolee <derrickstolee@github.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2022-03-09 10:25:27 -08:00
Derrick Stolee 6dbf4b8172 commit-graph: declare bankruptcy on GDAT chunks
The Generation Data (GDAT) and Generation Data Overflow (GDOV) chunks
store corrected commit date offsets, used for generation number v2.
Recent changes have demonstrated that previous versions of Git were
incorrectly parsing data from these chunks, but might have also been
writing them incorrectly.

I asserted [1] that the previous fixes were sufficient because the known
reasons for incorrectly writing generation number v2 data relied on
parsing the information incorrectly out of a commit-graph file, but the
previous versions of Git were not reading the generation number v2 data.

However, Patrick demonstrated [2] a case where in split commit-graphs
across an alternate boundary (and possibly some other special
conditions) it was possible to have a commit-graph that was generated by
a previous version of Git have incorrect generation number v2 data which
results in errors like the following:

  commit-graph generation for commit <oid> is 1623273624 < 1623273710

[1] https://lore.kernel.org/git/f50e74f0-9ffa-f4f2-4663-269801495ed3@github.com/
[2] https://lore.kernel.org/git/Yh93vOkt2DkrGPh2@ncase/

Clearly, there is something else going on. The situation is not
completely understood, but the errors do not reproduce if the
commit-graphs are all generated by a Git version including these recent
fixes.

If we cannot trust the existing data in the GDAT and GDOV chunks, then
we can alter the format to change the chunk IDs for these chunks. This
causes the new version of Git to silently ignore the older chunks (and
disabling generation number v2 in the process) while writing new
commit-graph files with correct data in the GDA2 and GDO2 chunks.

Update commit-graph-format.txt including a historical note about these
deprecated chunks.

Reported-by: Patrick Steinhardt <ps@pks.im>
Signed-off-by: Derrick Stolee <derrickstolee@github.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2022-03-07 09:17:03 -08:00
Han-Wen Nienhuys fa48de62ac Documentation: object_id_len goes up to 31
The value is stored in a 5-bit field, so we can't support more without
a format version upgrade.

Signed-off-by: Han-Wen Nienhuys <hanwen@google.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2022-02-23 13:36:26 -08:00
Taylor Blau 95e8383bac midx.c: make changing the preferred pack safe
The previous patch demonstrates a bug where a MIDX's auxiliary object
order can become out of sync with a MIDX bitmap.

This is because of two confounding factors:

  - First, the object order is stored in a file which is named according
    to the multi-pack index's checksum, and the MIDX does not store the
    object order. This means that the object order can change without
    altering the checksum.

  - But the .rev file is moved into place with finalize_object_file(),
    which link(2)'s the file into place instead of renaming it. For us,
    that means that a modified .rev file will not be moved into place if
    MIDX's checksum was unchanged.

This fix is to force the MIDX's checksum to change when the preferred
pack changes but the set of packs contained in the MIDX does not. In
other words, when the object order changes, the MIDX's checksum needs to
change with it (regardless of whether the MIDX is tracking the same or
different packs).

This prevents a race whereby changing the object order (but not the
packs themselves) enables a reader to see the new .rev file with the old
MIDX, or similarly seeing the new bitmap with the old object order.

But why can't we just stop hardlinking the .rev into place instead
adding additional data to the MIDX? Suppose that's what we did. Then
when we go to generate the new bitmap, we'll load the old MIDX bitmap,
along with the MIDX that it references. That's fine, since the new MIDX
isn't moved into place until after the new bitmap is generated. But the
new object order *has* been moved into place. So we'll read the old
bitmaps in the new order when generating the new bitmap file, meaning
that without this secondary change, bitmap generation itself would
become a victim of the race described here.

This can all be prevented by forcing the MIDX's checksum to change when
the object order does. By embedding the entire object order into the
MIDX, we do just that. That is, the MIDX's checksum will change in
response to any perturbation of the underlying object order. In t5326,
this will cause the MIDX's checksum to update (even without changing the
set of packs in the MIDX), preventing the stale read problem.

Note that this makes it safe to continue to link(2) the MIDX .rev file
into place, since it is now impossible to have a .rev file that is
out-of-sync with the MIDX whose checksum it references. (But we will do
away with MIDX .rev files later in this series anyway, so this is
somewhat of a moot point).

In theory, it is possible to store a "fingerprint" of the full object
order here, so long as that fingerprint changes at least as often as the
full object order does. Some possibilities here include storing the
identity of the preferred pack, along with the mtimes of the
non-preferred packs in a consistent order. But storing a limited part of
the information makes it difficult to reason about whether or not there
are gaps between the two that would cause us to get bitten by this bug
again.

Signed-off-by: Taylor Blau <me@ttaylorr.com>
Reviewed-by: Derrick Stolee <dstolee@microsoft.com>
Reviewed-by: Jonathan Tan <jonathantanmy@google.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2022-01-27 12:07:52 -08:00
Junio C Hamano 4ce498baa3 Merge branch 'en/zdiff3'
"Zealous diff3" style of merge conflict presentation has been added.

* en/zdiff3:
  update documentation for new zdiff3 conflictStyle
  xdiff: implement a zealous diff3, or "zdiff3"
2021-12-15 09:39:47 -08:00
Junio C Hamano cdac0caddd Merge branch 'jt/midx-doc-fix'
Docfix.

* jt/midx-doc-fix:
  Doc: no midx and partial clone relation
2021-12-10 14:35:13 -08:00
Junio C Hamano 4ee5cacc16 Merge branch 'tl/midx-docfix'
Doc mark-up fix.

* tl/midx-docfix:
  midx: fix a formatting issue in "multi-pack-index.txt"
2021-12-10 14:35:11 -08:00
Junio C Hamano 83113c4268 Merge branch 'cw/protocol-v2-doc-fix'
Doc update.

* cw/protocol-v2-doc-fix:
  protocol-v2.txt: align delim-pkt spec with usage
2021-12-10 14:35:00 -08:00
Elijah Newren ddfc44a898 update documentation for new zdiff3 conflictStyle
Signed-off-by: Elijah Newren <newren@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2021-12-01 14:45:59 -08:00
Jonathan Tan 7d3fc7df70 Doc: no midx and partial clone relation
The multi-pack index treats promisor packfiles (that is, packfiles that
have an accompanying .promisor file) the same as other packfiles. Remove
a section in the documentation that seems to indicate otherwise.

Signed-off-by: Jonathan Tan <jonathantanmy@google.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2021-11-22 12:46:33 -08:00
Teng Long ad506e6780 midx: fix a formatting issue in "multi-pack-index.txt"
There is a formatting issue  in "multi-pack-index.html", corresponding
to the nesting bulleted list of a wrong usage in "multi-pack-index.txt"
and this commit fix the problem.

In ASCIIDOC, it doesn't treat an indented character as the
beginning of a sub-list. If we want to write a nested bulleted list, we
could just use ASTERISK without any DASH like:

      "
      * Level 1 list item
      ** Level 2 list item
      *** Level 3 list item
      ** Level 2 list item
      * Level 1 list item
      ** Level 2 list item
      * Level 1 list item
      "

The DASH can be used for bulleted list too, But the DASH is suggested
only to be used as the marker for the first level because the DASH
doesn’t work well or a best practice for nested lists,
like (dash is as level 2 below):

      "
      * Level 1 list item
      - Level 2 list item
      * Level 1 list item
      "

ASTERISK is recommanded to use because it works intuitively and clearly
("marker length = nesting level") in nested lists, but the DASH can't.
However, when you want to write a non-nested bulleted lists, DASH works
too, like:

      "
      - Level 1 list item
      - Level 1 list item
      - Level 1 list item
      "

Reviewed-by: Taylor Blau <me@ttaylorr.com>
Reviewed-by: Derrick Stolee <stolee@gmail.com>
Signed-off-by: Teng Long <dyroneteng@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2021-11-18 11:31:07 -08:00
Junio C Hamano 5a73c6bdc7 Merge branch 'js/trace2-raise-format-version'
When we added a new event type to trace2 event stream, we forgot to
raise the format version number, which has been corrected.

* js/trace2-raise-format-version:
  trace2: increment event format version
2021-11-12 15:29:25 -08:00
Josh Steadmon 04480e67fe trace2: increment event format version
In 64bc752 (trace2: add trace2_child_ready() to report on background
children, 2021-09-20), we added a new "child_ready" event. In
Documentation/technical/api-trace2.txt, we promise that adding a new
event type will result in incrementing the trace2 event format version
number, but this was not done. Correct this in code & docs.

Signed-off-by: Josh Steadmon <steadmon@google.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2021-11-11 15:01:04 -08:00
Calvin Wan 74db416c9c protocol-v2.txt: align delim-pkt spec with usage
The current protocol EBNF allows command-request to end with the
capability list, if no command specific arguments follow, but the
protocol requires that after the capability list, there must be a
delim-pkt regardless of the number of command specific arguments.  Fixed
the EBNF to match. Both JGit and libgit2's implementation has the
delim-pkt as mandatory. JGit's code is not publicly linkable, but
libgit2 is linked below[1]. As for currently implemented commands on v2
(ls-ref and fetch), the delim packet is already being passed through

[1]: https://github.com/libgit2/libgit2/blob/main/src/transports/git.c

Reported-by: Ivan Frade <ifrade@google.com>
Signed-off-by: Calvin Wan <calvinwan@google.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2021-11-11 14:53:18 -08:00
Junio C Hamano 97ab03b12a Merge branch 'jc/doc-commit-header-continuation-line'
Doc update.

* jc/doc-commit-header-continuation-line:
  signature-format.txt: explain and illustrate multi-line headers
2021-10-25 16:07:00 -07:00
Junio C Hamano af303ee392 Merge branch 'jh/builtin-fsmonitor-part1'
Built-in fsmonitor (part 1).

* jh/builtin-fsmonitor-part1:
  t/helper/simple-ipc: convert test-simple-ipc to use start_bg_command
  run-command: create start_bg_command
  simple-ipc/ipc-win32: add Windows ACL to named pipe
  simple-ipc/ipc-win32: add trace2 debugging
  simple-ipc: move definition of ipc_active_state outside of ifdef
  simple-ipc: preparations for supporting binary messages.
  trace2: add trace2_child_ready() to report on background children
2021-10-13 15:15:58 -07:00
Junio C Hamano f6c013dfa1 signature-format.txt: explain and illustrate multi-line headers
A signature attached to a signed commit, and the contents of the
commit that merged a signed tag, are both recorded as a value of an
object header field as a multi-line value, and are subject to the
formatting convention for multi-line values in the headers, with a
leading SP signaling that the rest of the line is a continuation of
the previous line.  Most notably, an empty line in such a multi-line
value would result in a line with a sole SP on it.

Examples in the signature-format technical documentation include a
few of these cases but we did not show these otherwise invisible SPs
in the example.  These trailing spaces cannot be seen on display or
on paper, and forces the readers to look for them in their editors
or pagers, even if we added them to the document.

Extend the overview section to explain the multi-line value
formatting and highlight these otherwise invisible SPs by inventing
the "a dollar-sign at the end of line that appears after SP merely
signals that there is a SP there, and the dollar-sign itself does
not appear in the real file" notation, inspired by "cat -e" output,
to help readers to learn exactly where such "a single SP that is
originally an empty line" appears in the examples.

Reported-by: Rob Browning <rlb@defaultvalue.org>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2021-10-12 19:06:24 -07:00
Junio C Hamano b39b0e1a82 Merge branch 'ew/midx-doc-update'
Doc tweak.

* ew/midx-doc-update:
  doc/technical: update note about core.multiPackIndex
2021-10-06 13:40:12 -07:00
Junio C Hamano bb1677fc29 Merge branch 'jk/reduce-malloc-in-v2-servers'
Code cleanup to limit memory consumption and tighten protocol
message parsing.

* jk/reduce-malloc-in-v2-servers:
  ls-refs: reject unknown arguments
  serve: reject commands used as capabilities
  serve: reject bogus v2 "command=ls-refs=foo"
  docs/protocol-v2: clarify some ls-refs ref-prefix details
  ls-refs: ignore very long ref-prefix counts
  serve: drop "keys" strvec
  serve: provide "receive" function for session-id capability
  serve: provide "receive" function for object-format capability
  serve: add "receive" method for v2 capabilities table
  serve: return capability "value" from get_capability()
  serve: rename is_command() to parse_command()
2021-09-28 13:06:53 -07:00
Eric Wong 0d0d8d8a11 doc/technical: update note about core.multiPackIndex
MIDX files are used by default since commit 18e449f86b
(midx: enable core.multiPackIndex by default, 2020-09-25)

Helped-by: Taylor Blau <me@ttaylorr.com>
Signed-off-by: Eric Wong <e@80x24.org>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2021-09-24 08:39:53 -07:00
Junio C Hamano 0e35107e7d Merge branch 'ab/retire-option-argument'
An oddball OPTION_ARGUMENT feature has been removed from the
parse-options API.

* ab/retire-option-argument:
  parse-options API: remove OPTION_ARGUMENT feature
  difftool: use run_command() API in run_file_diff()
  difftool: prepare "diff" cmdline in cmd_difftool()
  difftool: prepare "struct child_process" in cmd_difftool()
2021-09-23 13:44:48 -07:00
Junio C Hamano cabb41d0f6 Merge branch 'jk/http-server-protocol-versions'
Taking advantage of the CGI interface, http-backend has been
updated to enable protocol v2 automatically when the other side
asks for it.

* jk/http-server-protocol-versions:
  docs/protocol-v2: point readers transport config discussion
  docs/git: discuss server-side config for GIT_PROTOCOL
  docs/http-backend: mention v2 protocol
  http-backend: handle HTTP_GIT_PROTOCOL CGI variable
  t5551: test v2-to-v0 http protocol fallback
2021-09-23 13:44:47 -07:00
Junio C Hamano 5331af2352 Merge branch 'ab/serve-cleanup'
Code clean-up around "git serve".

* ab/serve-cleanup:
  upload-pack: document and rename --advertise-refs
  serve.[ch]: remove "serve_options", split up --advertise-refs code
  {upload,receive}-pack tests: add --advertise-refs tests
  serve.c: move version line to advertise_capabilities()
  serve: move transfer.advertiseSID check into session_id_advertise()
  serve.[ch]: don't pass "struct strvec *keys" to commands
  serve: use designated initializers
  transport: use designated initializers
  transport: rename "fetch" in transport_vtable to "fetch_refs"
  serve: mark has_capability() as static
2021-09-20 15:20:43 -07:00
Junio C Hamano 0649303820 Merge branch 'tb/multi-pack-bitmaps'
The reachability bitmap file used to be generated only for a single
pack, but now we've learned to generate bitmaps for history that
span across multiple packfiles.

* tb/multi-pack-bitmaps: (29 commits)
  pack-bitmap: drop bitmap_index argument from try_partial_reuse()
  pack-bitmap: drop repository argument from prepare_midx_bitmap_git()
  p5326: perf tests for MIDX bitmaps
  p5310: extract full and partial bitmap tests
  midx: respect 'GIT_TEST_MULTI_PACK_INDEX_WRITE_BITMAP'
  t7700: update to work with MIDX bitmap test knob
  t5319: don't write MIDX bitmaps in t5319
  t5310: disable GIT_TEST_MULTI_PACK_INDEX_WRITE_BITMAP
  t0410: disable GIT_TEST_MULTI_PACK_INDEX_WRITE_BITMAP
  t5326: test multi-pack bitmap behavior
  t/helper/test-read-midx.c: add --checksum mode
  t5310: move some tests to lib-bitmap.sh
  pack-bitmap: write multi-pack bitmaps
  pack-bitmap: read multi-pack bitmaps
  pack-bitmap.c: avoid redundant calls to try_partial_reuse
  pack-bitmap.c: introduce 'bitmap_is_preferred_refname()'
  pack-bitmap.c: introduce 'nth_bitmap_object_oid()'
  pack-bitmap.c: introduce 'bitmap_num_objects()'
  midx: avoid opening multiple MIDXs when writing
  midx: close linked MIDXs, avoid leaking memory
  ...
2021-09-20 15:20:39 -07:00
Jeff Hostetler 64bc75244b trace2: add trace2_child_ready() to report on background children
Create "child_ready" event to capture the state of a child process
created in the background.

When a child command is started a "child_start" event is generated in
the Trace2 log.  For normal synchronous children, a "child_exit" event
is later generated when the child exits or is terminated.  The two events
include information, such as the "child_id" and "pid", to allow post
analysis to match-up the command line and exit status.

When a child is started in the background (and may outlive the parent
process), it is not possible for the parent to emit a "child_exit"
event.  Create a new "child_ready" event to indicate whether the
child was successfully started.  Also include the "child_id" and "pid"
to allow similar post processing.

This will be used in a later commit with the new "start_bg_command()".

Signed-off-by: Jeff Hostetler <jeffhost@microsoft.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2021-09-20 08:57:58 -07:00
Jeff King 9db5fb4fb3 docs/protocol-v2: clarify some ls-refs ref-prefix details
We've never documented the fact that a client can provide multiple
ref-prefix capabilities. Let's describe the behavior.

We also never discussed the "best effort" nature of the prefixes. The
client side of git.git has always treated them this way, filtering the
result with local patterns. And indeed any client must do this, because
the prefix patterns are not sufficient to express the usual refspecs
(and so for "foo" we ask for "refs/heads/foo", "refs/tags/foo", and so
on).

So this may be considered a change in the spec with respect to client
expectations / requirements, but it's mostly codifying existing
behavior.

Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2021-09-15 12:25:19 -07:00
Junio C Hamano 0057847208 Merge branch 'ab/serve-cleanup' into jk/reduce-malloc-in-v2-servers
* ab/serve-cleanup:
  upload-pack: document and rename --advertise-refs
  serve.[ch]: remove "serve_options", split up --advertise-refs code
  {upload,receive}-pack tests: add --advertise-refs tests
  serve.c: move version line to advertise_capabilities()
  serve: move transfer.advertiseSID check into session_id_advertise()
  serve.[ch]: don't pass "struct strvec *keys" to commands
  serve: use designated initializers
  transport: use designated initializers
  transport: rename "fetch" in transport_vtable to "fetch_refs"
  serve: mark has_capability() as static
2021-09-14 10:56:05 -07:00
Ævar Arnfjörð Bjarmason 4c25356e0e parse-options API: remove OPTION_ARGUMENT feature
As was noted in 1a85b49b87 (parse-options: make OPT_ARGUMENT() more
useful, 2019-03-14) there's only ever been one user of the
OPT_ARGUMENT(), that user was added in 20de316e33 (difftool: allow
running outside Git worktrees with --no-index, 2019-03-14).

The OPT_ARGUMENT() feature itself was added way back in
580d5bffde (parse-options: new option type to treat an option-like
parameter as an argument., 2008-03-02), but as discussed in
1a85b49b87 wasn't used until 20de316e33 in 2019.

Now that the preceding commit has migrated this code over to using
"struct strvec" to manage the "args" member of a "struct
child_process", we can just use that directly instead of relying on
OPT_ARGUMENT.

This has a minor change in behavior in that if we'll pass --no-index
we'll now always pass it as the first argument, before we'd pass it in
whatever position the caller did. Preserving this was the real value
of OPT_ARGUMENT(), but as it turns out we didn't need that either. We
can always inject it as the first argument, the other end will parse
it just the same.

Note that we cannot remove the "out" and "cpidx" members of "struct
parse_opt_ctx_t" added in 580d5bffde, while they were introduced with
OPT_ARGUMENT() we since used them for other things.

Signed-off-by: Ævar Arnfjörð Bjarmason <avarab@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2021-09-12 23:27:38 -07:00
Jeff King 1b421e7a5a docs/protocol-v2: point readers transport config discussion
We recently added tips for server admins to configure various transports
to support v2's GIT_PROTOCOL variable. While the protocol-v2 document is
pretty technical and not of interest to most admins, it may be a
starting point for them to figure out how to turn on v2. Let's put some
pointers from there to the other documentation.

Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2021-09-10 15:35:00 -07:00
Junio C Hamano aca13c2355 Merge branch 'en/merge-strategy-docs'
Documentation updates.

* en/merge-strategy-docs:
  Update error message and code comment
  merge-strategies.txt: add coverage of the `ort` merge strategy
  git-rebase.txt: correct out-of-date and misleading text about renames
  merge-strategies.txt: fix simple capitalization error
  merge-strategies.txt: avoid giving special preference to patience algorithm
  merge-strategies.txt: do not imply using copy detection is desired
  merge-strategies.txt: update wording for the resolve strategy
  Documentation: edit awkward references to `git merge-recursive`
  directory-rename-detection.txt: small updates due to merge-ort optimizations
  git-rebase.txt: correct antiquated claims about --rebase-merges
2021-08-30 16:06:01 -07:00
Junio C Hamano 6f64eeab60 Merge branch 'es/trace2-log-parent-process-name'
trace2 logs learned to show parent process name to see in what
context Git was invoked.

* es/trace2-log-parent-process-name:
  tr2: log parent process name
  tr2: make process info collection platform-generic
2021-08-24 15:32:40 -07:00
Taylor Blau 917a54c017 Documentation: describe MIDX-based bitmaps
Update the technical documentation to describe the multi-pack bitmap
format. This patch merely introduces the new format, and describes its
high-level ideas. Git does not yet know how to read nor write these
multi-pack variants, and so the subsequent patches will:

  - Introduce code to interpret multi-pack bitmaps, according to this
    document.

  - Then, introduce code to write multi-pack bitmaps from the 'git
    multi-pack-index write' sub-command.

Finally, the implementation will gain tests in subsequent patches (as
opposed to inline with the patch teaching Git how to write multi-pack
bitmaps) to avoid a cyclic dependency.

Signed-off-by: Taylor Blau <me@ttaylorr.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2021-08-24 13:21:13 -07:00
Ævar Arnfjörð Bjarmason 98e2d9d6f7 upload-pack: document and rename --advertise-refs
The --advertise-refs documentation in git-upload-pack added in
9812f2136b (upload-pack.c: use parse-options API, 2016-05-31) hasn't
been entirely true ever since v2 support was implemented in
e52449b672 (connect: request remote refs using v2, 2018-03-15). Under
v2 we don't advertise the refs at all, but rather dump the
capabilities header.

This option has always been an obscure internal implementation detail,
it wasn't even documented for git-receive-pack. Since it has exactly
one user let's rename it to --http-backend-info-refs, which is more
accurate and points the reader in the right direction. Let's also
cross-link this from the protocol v1 and v2 documentation.

I'm retaining a hidden --advertise-refs alias in case there's any
external users of this, and making both options hidden to the bash
completion (as with most other internal-only options).

Signed-off-by: Ævar Arnfjörð Bjarmason <avarab@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2021-08-05 08:59:37 -07:00