Document a capability that indicates which hash algorithms are in use by
both sides of a remote connection. Use the term "object-format", since
this is the term used for the repository extension as well.
Signed-off-by: brian m. carlson <sandals@crustytoothpaste.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
It's possible a user may complain about the way that Git interacts with
their interactive shell, e.g. autocompletion or shell prompt. In that
case, it's useful for us to know which shell they're using
interactively.
Signed-off-by: Emily Shaffer <emilyshaffer@google.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Whenever GIT_CURL_VERBOSE is set, teach Git to behave as if
GIT_TRACE_CURL=1 and GIT_TRACE_CURL_NO_DATA=1 is set, instead of setting
CURLOPT_VERBOSE.
This is to prevent inadvertent revelation of sensitive data. In
particular, GIT_CURL_VERBOSE redacts neither the "Authorization" header
nor any cookies specified by GIT_REDACT_COOKIES.
Unifying the tracing mechanism also has the future benefit that any
improvements to the tracing mechanism will benefit both users of
GIT_CURL_VERBOSE and GIT_TRACE_CURL, and we do not need to remember to
implement any improvement twice.
Signed-off-by: Jonathan Tan <jonathantanmy@google.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
In Documentation/technical/commit-graph-format.txt, the definition
of the BIDX chunk specifies the length is a number of 8-byte words.
During development we discovered that using 8-byte words in the
Murmur3 hash algorithm causes issues with big-endian versus little-
endian machines. Thus, the hash algorithm was adapted to work on a
byte-by-byte basis. However, this caused a change in the definition
of a "word" in bloom.h. Now, a "word" is a single byte, which allows
filters to be as small as two bytes. These length-two filters are
demonstrated in t0095-bloom.sh, and a larger filter of length 25 is
demonstrated as well.
The original point of using 8-byte words was for alignment reasons.
It also presented opportunities for extremely sparse Bloom filters
when there were a small number of changes at a commit, creating a
very low false-positive rate. However, modifying the format at this
point is unlikely to be a valuable exercise. Also, this use of
single-byte granularity does present opportunities to save space.
It is unclear if 8-byte alignment of the filters would present any
meaningful performance benefits.
Modify the format document to reflect reality.
Signed-off-by: Derrick Stolee <dstolee@microsoft.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
When selecting a batch of pack-files to repack in the "git
multi-pack-index repack" command, Git should respect the
repack.packKeptObjects config option. When false, this option says that
the pack-files with an associated ".keep" file should not be repacked.
This config value is "false" by default.
There are two cases for selecting a batch of objects. The first is the
case where the input batch-size is zero, which specifies "repack
everything". The second is with a non-zero batch size, which selects
pack-files using a greedy selection criteria. Both of these cases are
updated and tested.
Reported-by: Son Luong Ngoc <sluongng@gmail.com>
Signed-off-by: Derrick Stolee <dstolee@microsoft.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Signed-off-by: Eric Sunshine <sunshine@sunshineco.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Occasionally a failure a user is seeing may be related to a specific
hook which is being run, perhaps without the user realizing. While the
contents of hooks can be sensitive - containing user data or process
information specific to the user's organization - simply knowing that a
hook is being run at a certain stage can help us to understand whether
something is going wrong.
Without a definitive list of hook names within the code, we compile our
own list from the documentation. This is likely prone to bitrot, but
designing a single source of truth for acceptable hooks is too much
overhead for this small change to the bugreport tool.
Signed-off-by: Emily Shaffer <emilyshaffer@google.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Document protocol changes after CVE-2020-11008, including the removal of
references to the override of attributes which is no longer recommended
after CVE-2020-5260 and that might be removed in the future.
While at it do some improvements for clarity and consistency.
Signed-off-by: Carlo Marcelo Arenas Belón <carenas@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Clarify the expected effect of all attributes and how the helpers
are expected to handle them and the context where they operate.
While at it, space the descriptions for clarity, and add a paragraph
mentioning the early termination in the list processing of helpers,
to complement the one about the special "quit" attribute.
Signed-off-by: Carlo Marcelo Arenas Belón <carenas@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Add an issue in 'Common Issues' section which addresses the confusion
between performing a 'fetch' and a 'pull'.
Helped-by: Elijah Newren <newren@gmail.com>
Signed-off-by: Shourya Shukla <shouryashukla.oo@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
gitcredentials(7) already mentions several possible invocations that one
can use as the value for credential.helper. However, many people are
not aware that there are other options than a simple credential helper
name, so let's place some explanatory text in the documentation for
credential.helper as well.
We still refer the user to gitcredential(7) for additional explanations
and helpful examples.
Signed-off-by: brian m. carlson <sandals@crustytoothpaste.net>
Acked-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Add issue in 'Common Issues' section which addresses the problem of
Git tracking files/paths mentioned in '.gitignore'.
Signed-off-by: Shourya Shukla <shouryashukla.oo@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
In documentation pertaining to autostash behavior, we refer to the
"stash reflog". This description is too low-level as the reflog refers
to an implementation detail of how the stash works and, for end-users,
they do not need to be aware of this at all.
Change references of "stash reflog" to "stash list", which should
provide more accessible terminology for end-users.
Signed-off-by: Denton Liu <liu.denton@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
By default, files are restored from the index for --worktree, and from
HEAD for --staged. When --worktree and --staged are combined, --source
must be specified to disambiguate the restore source[1], thus making it
cumbersome to restore a file in both the worktree and the index.
However, HEAD is also a reasonable default for --worktree when combined
with --staged, so make it the default anytime --staged is used (whether
combined with --worktree or not).
[1]: Due to an oversight, the --source requirement, though documented,
is not actually enforced.
Signed-off-by: Eric Sunshine <sunshine@sunshineco.com>
Reviewed-by: Taylor Blau <me@ttaylorr.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
The advice to use "$x" rather than "x" in arithmetric expansion was
working around a dash bug fixed in 0.5.4. Even Debian oldstable has
0.5.8 these days. And in the meantime, we've added almost two dozen
instances of the "x" form which you can find with:
git grep '$(([a-z]'
and nobody seems to have complained. Let's declare this workaround
obsolete and simplify our style guide.
Helped-by: Danh Doan <congdanhqx@gmail.com>
Signed-off-by: Jeff King <peff@peff.net>
Reviewed-by: Carlo Marcelo Arenas Belón <carenas@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
It's typical to find Markdown documentation alongside source code, and
having better context for documentation changes is useful; see also
commit 69f9c87d4 (userdiff: add support for Fountain documents,
2015-07-21).
The pattern is based on the CommonMark specification 0.29, section 4.2
<https://spec.commonmark.org/> but doesn't match empty headings, as
seeing them in a hunk header is unlikely to be useful.
Only ATX headings are supported, as detecting setext headings would
require printing the line before a pattern matches, or matching a
multiline pattern. The word-diff pattern is the same as the pattern for
HTML, because many Markdown parsers accept inline HTML.
Signed-off-by: Ash Holland <ash@sorrel.sh>
Acked-by: Johannes Sixt <j6t@kdbg.org>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
There's an example of using your own bit of shell to act as a credential
helper, but it's not very realistic:
- It's stupid to hand out your secret password to _every_ host. In the
real world you'd use the config-matcher to limit it to a particular
host.
- We never provided a username. We can easily do that in another config
option (you can do it in the helper, too, but this is much more
readable).
- We were sending the secret even for store/erase operations. This
is OK because Git would just ignore it, but a real system would
probably be unlocking a password store, which you wouldn't want to do
more than necessary.
Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
We give several helper config examples, but don't make clear that these
are raw values. It's up to the user to add the appropriate quoting to
put them into a config file (either by running with "git config" and
quoting against the shell, or by adding double-quotes as appropriate
within the git-config file).
Let's flesh them out as full config blocks, which makes the syntax more
clear (and makes it possible for people to just cut-and-paste them as a
starting point). I added double-quotes to any values larger than a
single word. That isn't strictly necessary in all cases, but it
sidesteps explaining the rules about exactly when you need to quote a
value.
The existing quotes can be converted to single-quotes in one instance,
and backslash-esccaped in the other. I also swapped out backticks for
our preferred $().
Reported-by: douglas.fuller@gmail.com
Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Reading a malformed credential URL line and silently ignoring it
does not mean that we support empty lines and/or "# commented" lines
forever. We should document it to avoid confusion.
Signed-off-by: Junio C Hamano <gitster@pobox.com>
In a03b55530a (merge: teach --autostash option, 2020-04-07), the
--autostash option was introduced for `git merge`. Notably, when
`git merge --quit` is run with an autostash entry present, it is saved
into the stash reflog. This is contrasted with the current behaviour of
`git rebase --quit` where the autostash entry is simply just dropped out
of existence.
Adopt the behaviour of `git merge --quit` in `git rebase --quit` and
save the autostash entry into the stash reflog instead of just deleting
it.
Signed-off-by: Denton Liu <liu.denton@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
--root implies we want to rebase all commits since the beginning of
history. --fork-point means we want to use the reflog of the specified
upstream to find the best common ancestor between <upstream> and
<branch> and only rebase commits since that common ancestor. These
options are clearly contradictory, so throw an error (instead of
segfaulting on a NULL pointer) if both are specified.
Reported-by: Alexander Berg <alexander.berg@atos.net>
Documentation-by: Alban Gruin <alban.gruin@gmail.com>
Signed-off-by: Elijah Newren <newren@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
356aea6 ("doc: move extensions.worktreeConfig to the right place",
2018-11-14) moved the explanation of extension.worktreeConfig from
config.txt to technical/repository-version.txt. However, the former
still contains a reference to the removed paragraph. We could fix it
referencing the gitrepository-layout man page, which contains the moved
explanation. But the git-worktree man page has additional information
and recommendations for the worktree config file, so let's reference it
instead.
Signed-off-by: Matheus Tavares <matheus.bernardino@usp.br>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
git-commit(1) says ISO-8601 is one of our supported date format.
ISO-8601 allows timestamps to have a fractional number of seconds.
We represent time only in terms of whole seconds, so we never bothered
parsing fractional seconds. However, it's better for us to parse and
throw away the fractional part than to refuse to parse the timestamp
at all.
And refusing parsing fractional second part may confuse the parse to
think fractional and timezone as day and month in this example:
2008-02-14 20:30:45.019-04:00
While doing this, make sure that we only interpret the number after the
second and the dot as fractional when and only when the date is known,
since only ISO-8601 allows the fractional part, and we've taught our
users to interpret "12:34:56.7.days.ago" as a way to specify a time
relative to current time.
Reported-by: Brian M. Carlson <sandals@crustytoothpaste.net>
Helped-by: Junio C Hamano <gitster@pobox.com>
Signed-off-by: Đoàn Trần Công Danh <congdanhqx@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
This reverts commit 684ceae32d.
Users fetching from linux-next and other kernel remotes are reporting
that the limited ref advertisement causes negotiation to reach
MAX_IN_VAIN, resulting in too-large fetches.
Reported-by: Lubomir Rintel <lkundrak@v3.sk>
Reported-by: "Dixit, Ashutosh" <ashutosh.dixit@intel.com>
Reported-by: Jiri Slaby <jslaby@suse.cz>
Reported-by: Konstantin Ryabitsev <konstantin@linuxfoundation.org>
Signed-off-by: Jonathan Nieder <jrnieder@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
In the example by Jon Loeliger the selector 'A^2' was duplicated. This
might confuse readers.
Signed-off-by: Michael F. Schönitzer <michael@schoenitzer.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
grep does not follow the conventions used by other Git commands when
printing paths that contain unusual characters (as double-quotes or
newlines). Commands such as ls-files, commit, status and diff will:
- Quote and escape unusual pathnames, by default.
- Print names verbatim and unquoted when "-z" is used.
But grep *never* quotes/escapes absolute paths with unusual chars and
*always* quotes/escapes relative ones, even with "-z". Besides being
inconsistent in its own output, the deviation from other Git commands
can be confusing. So let's make it follow the two rules above and add
some tests for this new behavior. Note that, making grep quote/escape
all unusual paths by default, also make it fully compliant with the
core.quotePath configuration, which is currently ignored for absolute
paths.
Reported-by: Greg Hurrell <greg@hurrell.net>
Helped-by: Johannes Schindelin <johannes.schindelin@gmx.de>
Signed-off-by: Matheus Tavares <matheus.bernardino@usp.br>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
To help pinpoint the source of a regression, it is useful to know some
info about the compiler which the user's Git client was built with. By
adding a generic get_compiler_info() in 'compat/' we can choose which
relevant information to share per compiler; to get started, let's
demonstrate the version of glibc if the user built with 'gcc'.
Signed-off-by: Emily Shaffer <emilyshaffer@google.com>
Helped-by: Đoàn Trần Công Danh <congdanhqx@gmail.com>
Helped-by: Johannes Schindelin <Johannes.Schindelin@gmx.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
The contents of uname() can give us some insight into what sort of
system the user is running on, and help us replicate their setup if need
be. The domainname field is not guaranteed to be available, so don't
collect it.
Signed-off-by: Emily Shaffer <emilyshaffer@google.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Knowing which version of Git a user has and how it was built allows us
to more precisely pin down the circumstances when a certain issue
occurs, so teach bugreport how to tell us the same output as 'git
version --build-options'.
It's not ideal to directly call 'git version --build-options' because
that output goes to stdout. Instead, wrap the version string in a helper
within help.[ch] library, and call that helper from within the bugreport
library.
Signed-off-by: Emily Shaffer <emilyshaffer@google.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Teach Git how to prompt the user for a good bug report: reproduction
steps, expected behavior, and actual behavior. Later, Git can learn how
to collect some diagnostic information from the repository.
If users can send us a well-written bug report which contains diagnostic
information we would otherwise need to ask the user for, we can reduce
the number of question-and-answer round trips between the reporter and
the Git contributor.
Users may also wish to send a report like this to their local "Git
expert" if they have put their repository into a state they are confused
by.
Signed-off-by: Emily Shaffer <emilyshaffer@google.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
In 'git log', the --decorate-refs-exclude option appends a pattern
to a string_list. This list is used to prevent showing some refs
in the decoration output, or even by --simplify-by-decoration.
Users may want to use their refs space to store utility refs that
should not appear in the decoration output. For example, Scalar [1]
runs a background fetch but places the "new" refs inside the
refs/scalar/hidden/<remote>/* refspace instead of refs/<remote>/*
to avoid updating remote refs when the user is not looking. However,
these "hidden" refs appear during regular 'git log' queries.
A similar idea to use "hidden" refs is under consideration for core
Git [2].
Add the 'log.excludeDecoration' config option so users can exclude
some refs from decorations by default instead of needing to use
--decorate-refs-exclude manually. The config value is multi-valued
much like the command-line option. The documentation is careful to
point out that the config value can be overridden by the
--decorate-refs option, even though --decorate-refs-exclude would
always "win" over --decorate-refs.
Since the 'log.excludeDecoration' takes lower precedence to
--decorate-refs, and --decorate-refs-exclude takes higher
precedence, the struct decoration_filter needed another field.
This led also to new logic in load_ref_decorations() and
ref_filter_match().
There are several tests in t4202-log.sh that test the
--decorate-refs-(include|exclude) options, so these are extended.
Since the expected output is already stored as a file, most tests
could simply replace a "--decorate-refs-exclude" option with an
in-line config setting. Other tests involve the precedence of
the config option compared to command-line options and needed more
modification.
[1] https://github.com/microsoft/scalar
[2] https://lore.kernel.org/git/77b1da5d3063a2404cd750adfe3bb8be9b6c497d.1585946894.git.gitgitgadget@gmail.com/
Helped-by: Junio C Hamano <gister@pobox.com>
Signed-off-by: Derrick Stolee <dstolee@microsoft.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
The "mboxrd" pretty format was introduced in 9f23e04061 (pretty: support
"mboxrd" output format, 2016-06-05) but wasn't mentioned in the
documentation.
Signed-off-by: Emma Brooks <me@pluvano.com>
Acked-by: Eric Wong <e@80x24.org>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
When operating on a stream of commit OIDs on stdin, 'git commit-graph
write' checks that each OID refers to an object that is indeed a commit.
This is convenient to make sure that the given input is well-formed, but
can sometimes be undesirable.
For example, server operators may wish to feed the refnames that were
updated during a push to 'git commit-graph write --input=stdin-commits',
and silently discard refs that don't point at commits. This can be done
by combing the output of 'git for-each-ref' with '--format
%(*objecttype)', but this requires opening up a potentially large number
of objects. Instead, it is more convenient to feed the updated refs to
the commit-graph machinery, and let it throw out refs that don't point
to commits.
Introduce '--[no-]check-oids' to make such a behavior possible. With
'--check-oids' (the default behavior to retain backwards compatibility),
'git commit-graph write' will barf on a non-commit line in its input.
With 'no-check-oids', such lines will be silently ignored, making the
above possible by specifying this option.
No matter which is supplied, 'git commit-graph write' retains the
behavior from the previous commit of rejecting non-OID inputs like
"HEAD" and "refs/heads/foo" as before.
Signed-off-by: Taylor Blau <me@ttaylorr.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
When using split commit-graphs, it is sometimes useful to completely
replace the commit-graph chain with a new base.
For example, consider a scenario in which a repository builds a new
commit-graph incremental for each push. Occasionally (say, after some
fixed number of pushes), they may wish to rebuild the commit-graph chain
with all reachable commits.
They can do so with
$ git commit-graph write --reachable
but this removes the chain entirely and replaces it with a single
commit-graph in 'objects/info/commit-graph'. Unfortunately, this means
that the next push will have to move this commit-graph into the first
layer of a new chain, and then write its new commits on top.
Avoid such copying entirely by allowing the caller to specify that they
wish to replace the entirety of their commit-graph chain, while also
specifying that the new commit-graph should become the basis of a fresh,
length-one chain.
This addresses the above situation by making it possible for the caller
to instead write:
$ git commit-graph write --reachable --split=replace
which writes a new length-one chain to 'objects/info/commit-graphs',
making the commit-graph incremental generated by the subsequent push
relatively cheap by avoiding the aforementioned copy.
In order to do this, remove an assumption in 'write_commit_graph_file'
that chains are always at least two incrementals long.
Signed-off-by: Taylor Blau <me@ttaylorr.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
In the previous commit, we laid the groundwork for supporting different
splitting strategies. In this commit, we introduce the first splitting
strategy: 'no-merge'.
Passing '--split=no-merge' is useful for callers which wish to write a
new incremental commit-graph, but do not want to spend effort condensing
the incremental chain [1]. Previously, this was possible by passing
'--size-multiple=0', but this no longer the case following 63020f175f
(commit-graph: prefer default size_mult when given zero, 2020-01-02).
When '--split=no-merge' is given, the commit-graph machinery will never
condense an existing chain, and it will always write a new incremental.
[1]: This might occur when, for example, a server administrator running
some program after each push may want to ensure that each job runs
proportional in time to the size of the push, and does not "jump" when
the commit-graph machinery decides to trigger a merge.
Signed-off-by: Taylor Blau <me@ttaylorr.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
With '--split', the commit-graph machinery writes new commits in another
incremental commit-graph which is part of the existing chain, and
optionally decides to condense the chain into a single commit-graph.
This is done to ensure that the asymptotic behavior of looking up a
commit in an incremental chain is not dominated by the number of
incrementals in that chain. It can be controlled by the '--max-commits'
and '--size-multiple' options.
In the next two commits, we will introduce additional splitting
strategies that can exert additional control over:
- when a split commit-graph is and isn't written, and
- when the existing commit-graph chain is discarded completely and
replaced with another graph
To prepare for this, make '--split' take an optional strategy (as in
'--split[=<strategy>]'), and add a new enum to describe which strategy
is being used. For now, no strategies are given, and the only enumerated
value is 'COMMIT_GRAPH_SPLIT_UNSPECIFIED', indicating the absence of a
strategy.
Signed-off-by: Taylor Blau <me@ttaylorr.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
When rebasing against an upstream that has had many commits since the
original branch was created:
O -- O -- ... -- O -- O (upstream)
\
-- O (my-dev-branch)
it must read the contents of every novel upstream commit, in addition to
the tip of the upstream and the merge base, because "git rebase"
attempts to exclude commits that are duplicates of upstream ones. This
can be a significant performance hit, especially in a partial clone,
wherein a read of an object may end up being a fetch.
Add a flag to "git rebase" to allow suppression of this feature. This
flag only works when using the "merge" backend.
This flag changes the behavior of sequencer_make_script(), called from
do_interactive_rebase() <- run_rebase_interactive() <-
run_specific_rebase() <- cmd_rebase(). With this flag, limit_list()
(indirectly called from sequencer_make_script() through
prepare_revision_walk()) will no longer call cherry_pick_list(), and
thus PATCHSAME is no longer set. Refraining from setting PATCHSAME both
means that the intermediate commits in upstream are no longer read (as
shown by the test) and means that no PATCHSAME-caused skipping of
commits is done by sequencer_make_script(), either directly or through
make_script_with_merges().
Signed-off-by: Jonathan Tan <jonathantanmy@google.com>
Signed-off-by: Elijah Newren <newren@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Commit d48e5e21da ("rebase (interactive-backend): make --keep-empty the
default", 2020-02-15) turned --keep-empty (for keeping commits which
start empty) into the default. The logic underpinning that commit was:
1) 'git commit' errors out on the creation of empty commits without an
override flag
2) Once someone determines that the override is worthwhile, it's
annoying and/or harmful to required them to take extra steps in
order to keep such commits around (and to repeat such steps with
every rebase).
While the logic on which the decision was made is sound, the result was
a bit of an overcorrection. Instead of jumping to having --keep-empty
being the default, it jumped to making --keep-empty the only available
behavior. There was a simple workaround, though, which was thought to
be good enough at the time. People could still drop commits which
started empty the same way the could drop any commits: by firing up an
interactive rebase and picking out the commits they didn't want from the
list. However, there are cases where external tools might create enough
empty commits that picking all of them out is painful. As such, having
a flag to automatically remove start-empty commits may be beneficial.
Provide users a way to drop commits which start empty using a flag that
existed for years: --no-keep-empty. Interpret --keep-empty as
countermanding any previous --no-keep-empty, but otherwise leaving
--keep-empty as the default.
This might lead to some slight weirdness since commands like
git rebase --empty=drop --keep-empty
git rebase --empty=keep --no-keep-empty
look really weird despite making perfect sense (the first will drop
commits which become empty, but keep commits that started empty; the
second will keep commits which become empty, but drop commits which
started empty). However, --no-keep-empty was named years ago and we are
predominantly keeping it for backward compatibility; also we suspect it
will only be used rarely since folks already have a simple way to drop
commits they don't want with an interactive rebase.
Reported-by: Bryan Turner <bturner@atlassian.com>
Reported-by: Sami Boukortt <sami@boukortt.com>
Signed-off-by: Elijah Newren <newren@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
While many users who intentionally create empty commits do not want them
thrown away by a rebase, there are third-party tools that generate empty
commits that a user might not want. In the past, users have used rebase
to get rid of such commits (a side-effect of the fact that the --apply
backend is not currently capable of keeping them). While such users
could fire up an interactive rebase and just remove the lines
corresponding to empty commits, that might be difficult if the
third-party tool generates many of them. Simplify this task for users
by marking such lines with a suffix of " # empty" in the todo list.
Suggested-by: Sami Boukortt <sami@boukortt.com>
Signed-off-by: Elijah Newren <newren@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
The default file history simplification of "git log -- <path>" or
"git rev-list -- <path>" focuses on providing the smallest set of
commits that first contributed a change. The revision walk greatly
restricts the set of walked commits by visiting only the first
TREESAME parent of a merge commit, when one exists. This means
that portions of the commit-graph are not walked, which can be a
performance benefit, but can also "hide" commits that added changes
but were ignored by a merge resolution.
The --full-history option modifies this by walking all commits and
reporting a merge commit as "interesting" if it has _any_ parent
that is not TREESAME. This tends to be an over-representation of
important commits, especially in an environment where most merge
commits are created by pull request completion.
Suppose we have a commit A and we create a commit B on top that
changes our file. When we merge the pull request, we create a merge
commit M. If no one else changed the file in the first-parent
history between M and A, then M will not be TREESAME to its first
parent, but will be TREESAME to B. Thus, the simplified history
will be "B". However, M will appear in the --full-history mode.
However, suppose that a number of topics T1, T2, ..., Tn were
created based on commits C1, C2, ..., Cn between A and M as
follows:
A----C1----C2--- ... ---Cn----M------P1---P2--- ... ---Pn
\ \ \ \ / / / /
\ \__.. \ \/ ..__T1 / Tn
\ \__.. /\ ..__T2 /
\_____________________B \____________________/
If the commits T1, T2, ... Tn did not change the file, then all of
P1 through Pn will be TREESAME to their first parent, but not
TREESAME to their second. This means that all of those merge commits
appear in the --full-history view, with edges that immediately
collapse into the lower history without introducing interesting
single-parent commits.
The --simplify-merges option was introduced to remove these extra
merge commits. By noticing that the rewritten parents are reachable
from their first parents, those edges can be simplified away. Finally,
the commits now look like single-parent commits that are TREESAME to
their "only" parent. Thus, they are removed and this issue does not
cause issues anymore. However, this also ends up removing the commit
M from the history view! Even worse, the --simplify-merges option
requires walking the entire history before returning a single result.
Many Git users are using Git alongside a Git service that provides
code storage alongside a code review tool commonly called "Pull
Requests" or "Merge Requests" against a target branch. When these
requests are accepted and merged, they typically create a merge
commit whose first parent is the previous branch tip and the second
parent is the tip of the topic branch used for the request. This
presents a valuable order to the parents, but also makes that merge
commit slightly special. Users may want to see not only which
commits changed a file, but which pull requests merged those commits
into their branch. In the previous example, this would mean the
users want to see the merge commit "M" in addition to the single-
parent commit "C".
Users are even more likely to want these merge commits when they
use pull requests to merge into a feature branch before merging that
feature branch into their trunk.
In some sense, users are asking for the "first" merge commit to
bring in the change to their branch. As long as the parent order is
consistent, this can be handled with the following rule:
Include a merge commit if it is not TREESAME to its first
parent, but is TREESAME to a later parent.
These merges look like the merge commits that would result from
running "git pull <topic>" on a main branch. Thus, the option to
show these commits is called "--show-pulls". This has the added
benefit of showing the commits created by closing a pull request or
merge request on any of the Git hosting and code review platforms.
To test these options, extend the standard test example to include
a merge commit that is not TREESAME to its first parent. It is
surprising that that option was not already in the example, as it
is instructive.
In particular, this extension demonstrates a common issue with file
history simplification. When a user resolves a merge conflict using
"-Xours" or otherwise ignoring one side of the conflict, they create
a TREESAME edge that probably should not be TREESAME. This leads
users to become frustrated and complain that "my change disappeared!"
In my experience, showing them history with --full-history and
--simplify-merges quickly reveals the problematic merge. As mentioned,
this option is expensive to compute. The --show-pulls option
_might_ show the merge commit (usually titled "resolving conflicts")
more quickly. Of course, this depends on the user having the correct
parent order, which is backwards when using "git pull master" from a
topic branch.
There are some special considerations when combining the --show-pulls
option with --simplify-merges. This requires adding a new PULL_MERGE
object flag to store the information from the initial TREESAME
comparisons. This helps avoid dropping those commits in later filters.
This is covered by a test, including how the parents can be simplified.
Since "struct object" has already ruined its 32-bit alignment by using
33 bits across parsed, type, and flags member, let's not make it worse.
PULL_MERGE is used in revision.c with the same value (1u<<15) as
REACHABLE in commit-graph.c. The REACHABLE flag is only used when
writing a commit-graph file, and a revision walk using --show-pulls
does not happen in the same process. Care must be taken in the future
to ensure this remains the case.
Update Documentation/rev-list-options.txt with significant details
around this option. This requires updating the example in the
History Simplification section to demonstrate some of the problems
with TREESAME second parents.
Signed-off-by: Derrick Stolee <dstolee@microsoft.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Before, `--autostash` only worked with `git pull --rebase`. However, in
the last patch, merge learned `--autostash` as well so there's no reason
why we should have this restriction anymore. Teach pull to pass
`--autostash` to merge, just like it did for rebase.
Signed-off-by: Denton Liu <liu.denton@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
brian m. carlson