We'd sometimes end up in run_external_diff() to do a dry-run diff (e.g.,
to find content-level changes for --quiet). We recognize this quiet mode
by seeing the lack of DIFF_FORMAT_PATCH in the output format.
But since introducing an explicit dry-run check via 3ed5d8bd73 (diff:
stop output garbled message in dry run mode, 2025-10-20), this logic can
never trigger. We can only get to this function by calling
diff_flush_patch(), and that comes from only two places:
1. A dry-run flush comes from diff_flush_patch_quietly(), which is
always in dry-run mode (so the other half of our "||" is true
anyway).
2. A regular flush comes from diff_flush_patch_all_file_pairs(),
which is only called when output_format has DIFF_FORMAT_PATCH in
it.
So we can simplify our "quiet" condition to just checking dry-run mode
(which used to be a specific flag, but recently became just a NULL
"file" pointer). And since it's so simple, we can just do that inline.
This makes the logic about o->file more obvious, since we handle the
NULL and non-stdout cases next to each other.
Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
As an added protection against dry-run diffs accidentally producing
output, we redirect diff_options.file to /dev/null. But as of the
previous patch, this now does nothing, since dry-run diffs are
implemented by setting "file" to NULL.
So we can drop this extra code with no change in behavior. This is
effectively a revert of 623f7af284 (diff: restore redirection to
/dev/null for diff_from_contents, 2025-10-17) and 3da4413dbc (diff: make
sure the other caller of diff_flush_patch_quietly() is silent,
2025-10-22), but:
1. We get a conflict because we already dropped the color_moved
handling in an earlier patch. But we just resolve the conflicts to
"theirs" (removing all of the code).
2. We retain the test from 623f7af284.
Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
We introduced a dry_run flag to diff_options in b55e6d36eb (diff: ensure
consistent diff behavior with ignore options, 2025-08-08), with the idea
that the lower-level diff code could skip output when it is set.
As we saw with the bugs fixed by 3ed5d8bd73 (diff: stop output garbled
message in dry run mode, 2025-10-20), it is easy to miss spots. In the
end, we located all of them by checking where diff_options.file is used.
That suggests another possible approach: we can replace the dry_run
boolean with a NULL pointer for "file", as we know that using "file" in
dry_run mode would always be an error. This turns any missed spots from
producing extra output[1] into a segfault. Which is less forgiving, but
that is the point: this is indicative of a programming error, and
complaining loudly and immediately is good.
[1] We protect ourselves against garbled output as a separate step,
courtesy of 623f7af284 (diff: restore redirection to /dev/null for
diff_from_contents, 2025-10-17). So in that sense this patch can
only introduce user-visible errors (since any "bugs" were going to
/dev/null before), but the idea is to catch them rather than quietly
send garbage to /dev/null.
Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
When running a dry-run content-level diff to check whether a "--quiet"
diff has any changes, we have always unset the color_moved variable
since the feature was added in 2e2d5ac184 (diff.c: color moved lines
differently, 2017-06-30). The reasoning is not given explicitly there,
but presumably the idea is that since color_moved requires a lot of
extra computation to match lines but does not actually affect the
found_changes flag, we want to skip it.
Later, in 3da4413dbc (diff: make sure the other caller of
diff_flush_patch_quietly() is silent, 2025-10-22) we copied the same
idea for other dry-run diffs.
But neither spot actually needs to reset this flag at all, because
diff_flush_patch() will not ever compute color_moved. Nor could it, as
it is only looking at a single file-pair, and we detect moves across
files. So color_moved is checked only when we are actually doing real
DIFF_FORMAT_PATCH output, and call diff_flush_patch_all_file_pairs().
So we can get rid of these extra lines to save and restore the
color_moved flag without changing the behavior at all. (Note that there
is no "restore" to drop for the second caller, as we know at that point
we are not generating any output and can just leave the feature
disabled).
Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Diff output usually goes to the process stdout, but it can be redirected
with the "--output" option. We store this in the "file" pointer of
diff_options, and all of the diff code should write there instead of to
stdout.
But there's one spot we missed: running an external diff cmd. We don't
redirect its output at all, so it just defaults to the stdout of the
parent process. We should instead point its stdout at our output file.
There are a few caveats to watch out for when doing so:
- The stdout field takes a descriptor, not a FILE pointer. We can pull
out the descriptor with fileno().
- The run-command API always closes the stdout descriptor we pass to
it. So we must duplicate it (otherwise we break the FILE pointer,
since it now points to a closed descriptor).
- We don't need to worry about closing our dup'd descriptor, since the
point is that run-command will do it for us (even in the case of an
error). But we do need to make sure we skip the dup() if we set
no_stdout (because then run-command will not look at it at all).
- When the output is going to stdout, it would not be wrong to dup()
the descriptor, but we don't need to. We can skip that extra work
with a simple pointer comparison.
- It seems like you'd need to fflush() the descriptor before handing
off a copy to the child process to prevent out-of-order writes. But
that was true even before this patch! It works because run-command
always calls fflush(NULL) before running the child.
The new test shows the breakage (and fix). The need for duplicating the
descriptor doesn't need a new test; that is covered by the later test
"GIT_EXTERNAL_DIFF with more than one changed files".
Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
The code to squelch output from "git diff -w --name-status"
etc. for paths that "git diff -w -p" would have stayed silent
leaked output from dry-run patch generation, which has been
corrected.
* jc/diff-from-contents-fix:
diff: make sure the other caller of diff_flush_patch_quietly() is silent
Recently we attempted to improve "git diff -w" and friends to
handle cases where patch output would be suppressed, but it
introduced a bug that emits unnecessary output, which has been
corrected.
* jk/diff-from-contents-fix:
diff: restore redirection to /dev/null for diff_from_contents
Earlier, b55e6d36 (diff: ensure consistent diff behavior with
ignore options, 2025-08-08) introduced "dry-run" mode to the
diff machinery so that content-based diff filtering (like
ignoring space changes or those that match -I<regex>) can first
try to produce a patch without emitting any output to see if
under the given diff filtering condition we would get any output
lines, and a new helper function diff_flush_patch_quietly() was
introduced to use the mode to see an individual filepair needs
to be shown.
However, the solution was not complete. When files are deleted,
file modes change, or there are unmerged entries in the index,
dry-run mode still produces output because we overlooked these
conditions, and as a result, dry-run mode was not quiet.
To fix this, return early in emit_diff_symbol_from_struct() if
we are in dry-run mode. This function will be called by all the
emit functions to output the results. Returning early can avoid
diff output when files are deleted or file modes are changed.
Stop print message in dry-run mode if we have unmerged entries
in index. Discard output of external diff tool in dry-run mode.
Signed-off-by: Lidong Yan <yldhome2d2@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Earlier, we added is a protection for the loop that computes "git
diff --quiet -w" to ensure calls to the diff_flush_patch_quietly()
helper stays quiet. Do the same for another loop that deals with
options like "--name-status" to make calls to the same helper.
Helped-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Documentation updates.
* je/doc-pull:
doc: git-pull: clarify how to exit a conflicted merge
doc: git-pull: delete the example
doc: git-pull: clarify options for integrating remote branch
doc: git-pull: move <repository> and <refspec> params
The beginning of SHA1-SHA256 interoperability work.
* bc/sha1-256-interop-01:
t1010: use BROKEN_OBJECTS prerequisite
t: allow specifying compatibility hash
fsck: consider gpgsig headers expected in tags
rev-parse: allow printing compatibility hash
docs: add documentation for loose objects
docs: improve ambiguous areas of pack format documentation
docs: reflect actual double signature for tags
docs: update offset order for pack index v3
docs: update pack index v3 format
CI update.
* js/ci-github-actions-update:
build(deps): bump actions/github-script from 7 to 8
build(deps): bump actions/setup-python from 5 to 6
build(deps): bump actions/checkout from 4 to 5
build(deps): bump actions/download-artifact from 4 to 5
An earlier addition to "git diff --no-index A B" to limit the
output with pathspec after the two directories misbehaved when
these directories were given with a trailing slash, which has been
corrected.
* jk/diff-no-index-with-pathspec-fix:
diff --no-index: fix logic for paths ending in '/'
A few more things that patch authors can do to help maintainer to
keep track of their topics better.
* tb/doc-submitting-patches:
SubmittingPatches: guidance for multi-series efforts
SubmittingPatches: extend release-notes experiment to topic names
The code in "git add -p" and friends to iterate over hunks was
riddled with bugs, which has been corrected.
* rs/add-patch-options-fix:
add-patch: reset "permitted" at loop start
add-patch: let options a and d roll over like y and n
add-patch: let options k and K roll over like j and J
add-patch: let options y, n, j, and e roll over to next undecided
add-patch: document that option J rolls over
add-patch: improve help for options j, J, k, and K
Instead of three library archives (one for git, one for reftable,
and one for xdiff), roll everything into a single libgit.a archive.
This would help later effort to FFI into Rust.
* en/make-libgit-a:
make: delete REFTABLE_LIB, add reftable to LIB_OBJS
make: delete XDIFF_LIB, add xdiff to LIB_OBJS
In --quiet mode, since we produce only an exit code for "something was
changed" and no actual output, we can often get by with just a
tree-level diff. However, certain options require us to actually look at
the file contents (e.g., if we are ignoring whitespace changes). We have
a flag "diff_from_contents" for that, and if it is set we call
diff_flush() on each path.
To avoid producing any output (since we were asked to be --quiet), we
traditionally just redirected the output to /dev/null. That changed in
b55e6d36eb (diff: ensure consistent diff behavior with ignore options,
2025-08-08), which replaced that with a "dry_run" flag. In theory, with
dry_run set, we should produce no output. But it carries a risk of
regression: if we forget to respect dry_run in any of the output paths,
we'll accidentally produce output.
And indeed, there is at least one such regression in that commit, as it
covered only the case where we actually call into xdiff, and not
creation or deletion diffs, where we manually generate the headers. We
even test this case in t4035, but only with diff-tree, which does not
show the bug by default because it does not require diff_from_contents.
But git-diff does, because it allows external diff programs by default
(so we must dig into each diff filepair to decide if it requires running
an external diff that may declare two distinct blobs to actually be the
same).
We should fix all of those code paths to respect dry_run correctly, but
in the meantime we can protect ourselves more fully by restoring the
redirection to /dev/null. This gives us an extra layer of protection
against regressions dues to other code paths we've missed.
Though the original issue was reported with "git diff" (and due to its
default of --ext-diff), I've used "diff-tree -w" in the new test. It
triggers the same issue, but I think the fact that "-w" implies
diff_from_contents is a bit more obvious, and fits in with the rest of
t4035.
Reported-by: Jake Zimmerman <jake@zimmerman.io>
Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Carry over the fixups from 8c3d7c5f (RelNotes: minor fixups before
2.51.1, 2025-10-15).
Signed-off-by: Kristoffer Haugsbakk <code@khaugsbakk.name>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Update old-style shell path checks to use the modern test
helpers 'test_path_is_file' and 'test_path_is_dir' for improved
runtime diagnosis.
Signed-off-by: Solly <solobarine@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
From user feedback:
- One user is confused about why `git reset --merge`
(why not just `git reset`?). Handle this by mentioning
`git merge --abort` and `git reset --abort` instead, which have a
more obvious meaning.
- 2 users want to know what "In older versions of Git" means exactly
(in versions older than 1.7.0). Handle this by removing the warning
since it was added 15 years ago (in 3f8fc184c0)
Signed-off-by: Julia Evans <julia@jvns.ca>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
From user feedback: this example is confusing because it implies that
`git pull` will run `git merge` by default, but the default is
`--ff-only`.
We could instead show an example of a fast-forward merge, but that may
not add a lot since fast-forward merges are relatively simple. This lets
us keep the description short.
Signed-off-by: Julia Evans <julia@jvns.ca>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
From user feedback:
- One user is confused about the current default ("I was convinced that
the git default was still to merge on pull")
- One user is confused about why "git fetch" isn't mentioned earlier
- One user says they always forget what the arguments to `git pull` are
and that it's not immediately obvious that `--no-rebase` means "merge"
- One user wants `--ff-only` to be mentioned
Resolve this by listing the options for integrating the the remote
branch. This should help users figure out at a glance which one they
want to do, and make it clearer that --ff-only is the default.
Signed-off-by: Julia Evans <julia@jvns.ca>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
From user feedback:
- it's confusing that we use both <branch> and <refspec> to refer to the
second argument
- one user is not clear about what `refs/heads/*:refs/remotes/origin/*`
is meant to be an example of ("is it like a path?")
The DESCRIPTION section is also doing a lot right now: it's trying to
describe both how the <repository> and <refspec> arguments work (which
is pretty complex, as seen in the DEFAULT BEHAVIOUR section)
as well as how `git pull` calls `git fetch` and merge/rebase/etc
depending on the arguments.
Handle this by moving the description of the <repository> and <refspec>
arguments to the OPTIONS section, so that we can focus on the
merge/rebase/etc behaviour in the DESCRIPTION section, and refer folks
to the later sections for details.
Use the term "upstream" instead of 'the "remote" and "merge"
configuration for the current branch' since users are more likely to
know what an "upstream" is.
Signed-off-by: Julia Evans <julia@jvns.ca>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Documentation mark-up fix.
* ja/doc-markup-attached-paragraph-fix:
doc: fix indentation of refStorage item in git-config(1)
doc: change the markup of paragraphs following a nested list item
Clarify the "--merge-base" command line option in "git merge-tree".
* en/doc-merge-tree-describe-merge-base:
Documentation/git-merge-tree.adoc: clarify the --merge-base option
Jeff King