Since git-diff has many diff modes, it dispatches to many helpers to
perform each one. But every helper simply returns "0", as it exits
directly if there are serious errors (and options like --exit-code are
handled afterwards). So let's get rid of these useless return values,
which makes the code flow more clear.
There's very little chance that we'd later want to propagate errors
instead of dying immediately. These are all static-local helpers for the
git-diff program implementing its various modes. More "lib-ified" code
would directly call the underlying functions.
Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Neither of these functions ever returns a value other than zero.
Instead, they expect unrecoverable errors to exit immediately, and
things like "--exit-code" are stored inside the diff_options struct to
be handled later via diff_result_code().
Some callers do check the return values, but many don't bother. Let's
drop the useless return values, which are misleading callers about how
the functions work. This could be seen as a step in the wrong direction,
as we might want to eventually "lib-ify" these to more cleanly return
errors up the stack, in which case we'd have to add the return values
back in. But there are some benefits to doing this now:
1. In the current code, somebody could accidentally add a "return -1"
to one of the functions, which would be erroneously ignored by many
callers. By removing the return code, the compiler can notice the
mismatch and force the developer to decide what to do.
Obviously the other option here is that we could start consistently
checking the error code in every caller. But it would be dead code,
and we wouldn't get any compile-time help in catching new cases.
2. It communicates the situation to callers, who may want to choose a
different function. These functions are really thin wrappers for
doing git-diff-files and git-diff-index within the process. But
callers who care about recovering from an error here are probably
better off using the underlying library functions, many of
which do return errors.
If somebody eventually wants to teach these functions to propagate
errors, they'll have to switch back to returning a value, effectively
reverting this patch. But at least then they will be starting with a
level playing field: they know that they will need to inspect each
caller to see how it should handle the error.
Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
When the git-diff program fails to read the index in its diff-files or
diff-index helper functions, it propagates the error up the stack. This
eventually lands in diff_result_code(), which does not handle it well
(as discussed in the previous patch).
Since the only sensible thing here is to exit with an error code (and
what we were expecting the propagated error code to cause), let's just
do that directly.
There's no test here, as I'm not even sure this case can be triggered.
The index-reading functions tend to die() themselves when encountering
any errors, and the return value is just the number of entries in the
file (and so always 0 or positive). But let's err on the conservative
side and keep checking the return value. It may be worth digging into as
a separate topic (though index-reading is low-level enough that we
probably want to eventually teach it to propagate errors anyway for
lib-ification purposes, at which point this code would already be doing
the right thing).
Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
The git-diff command has many modes (comparing worktree to index, index
to HEAD, individual blobs, etc). As a result, it dispatches to many
helper functions and cannot completely parse its options until we're in
those helper functions.
Most of them, when seeing an unknown option, exit immediately by calling
usage(). But builtin_diff_files(), which is the default if no revision
or blob arguments are given, instead prints an error() and returns -1.
One obvious shortcoming here is that the user doesn't get to see the
usual usage message. But there's a much more important bug: the -1
return is fed to diff_result_code(), which is not ready to handle it.
By default, it passes the code along as an exit code. We try to avoid
negative exit codes because they get converted to unsigned values, but
it should at least consistently show up as non-zero (i.e., a failure).
But much worse is that when --exit-code is in effect, diff_result_code()
will _ignore_ the status passed in by the caller, and instead only
report on whether the diff found changes. It didn't, of course, because
we never ran the diff, and the program unexpectedly exits with success!
We can fix this bug by just calling usage(), like the other helpers do.
Another option would of course be to teach diff_result_code() to handle
this value. But as we'll see in the next few patches, it can be cleaned
up even further. Let's just fix this bug directly to start with.
Reported-by: Romain Chossart <romainchossart@gmail.com>
Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
If loading the index fails, we print an error and then return "-1" from
the function. But since this is a builtin, we end up with exit(-1),
which produces odd results since program exit codes are unsigned.
Because of integer conversion, it usually becomes 255, which is at least
still an error, but values above 128 are usually interpreted as signal
death.
Since we know the program is exiting immediately, we can just replace
the error return with a die().
Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Many callers of run_diff_index() passed literal "1" for the option
flag word, which should better be spelled out as DIFF_INDEX_CACHED
for readablity. Everybody else passes "0" that can stay as-is.
The other bit in the option flag word is DIFF_INDEX_MERGE_BASE, but
curiously there is only one caller that can pass it, which is "git
diff-index --merge-base" itself---no internal callers uses the
feature.
A bit tricky call to the function is in builtin/submodule--helper.c
where the .cached member in a private struct is set/reset as a plain
Boolean flag, which happens to be "1" and happens to match the value
of DIFF_INDEX_CACHED.
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Fix a minor regression that some compiler might notice.
* 'jk/function-pointer-mismatches-fix' (early part):
fsck: use enum object_type for fsck_walk callback
We prefer for callback functions to match the signature with which
they'll be called, rather than casting them to the correct type when
assigning function pointers. Even though casting often works in the real
world, it is a violation of the standard.
We did a mass conversion in 939af16eac (hashmap_cmp_fn takes
hashmap_entry params, 2019-10-06), but have grown a few new cases since
then. Because of the cast, the compiler does not complain. However, as
of clang-18, UBSan will catch these at run-time, and the case in
range-diff.c triggers when running t3206.
After seeing that one, I scanned the results of:
git grep '_fn)[^(]' '*.c' | grep -v typedef
and found a similar case in compat/terminal.c (which presumably isn't
called in the test suite, since it doesn't trigger UBSan). There might
be other cases lurking if the cast is done using a typedef that doesn't
end in "_fn", but loosening it finds too many false positives. I also
looked for:
git grep ' = ([a-z_]*) *[a-z]' '*.c'
to find assignments that cast, but nothing looked like a function.
The resulting code is unfortunately a little longer, but the bonus of
using container_of() is that we are no longer restricted to the
hashmap_entry being at the start of the struct.
Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
We switched the function interface for fsck callbacks in a1aad71601
(fsck.h: use "enum object_type" instead of "int", 2021-03-28). However,
we accidentally flipped the type back to "int" as part of 0b4e9013f1
(fsck: mark unused parameters in various fsck callbacks, 2023-07-03).
The mistake happened because that commit was written before a1aad71601
and rebased forward, and I screwed up while resolving the conflict.
Curiously, the compiler does not warn about this mismatch, at least not
when using gcc and clang on Linux (nor in any of our CI environments).
Based on 28abf260a5 (builtin/fsck.c: don't conflate "int" and "enum" in
callback, 2021-06-01), I'd guess that this would cause the AIX xlc
compiler to complain. I noticed because clang-18's UBSan now identifies
mis-matched function calls at runtime, and does complain of this case
when running the test suite.
I'm not entirely clear on whether this mismatch is a problem in
practice. Compilers are certainly free to make enums smaller than "int"
if they don't need the bits, but I suspect that they have to promote
back to int for function calls (though I didn't dig in the standard, and
I won't be surprised if I'm simply wrong and the real-world impact would
depend on the ABI).
Regardless, switching it back to enum is obviously the right thing to do
here; the switch to "int" was simply a mistake.
Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
"diff-tree -b --exit-code" without "--patch" exits with 0 status,
not because it finds that the two input files are equivalent while
ignoring whitespaces, but because the implied "--raw" mode always
exits with 0 when whitespace tweaking options like "-b" and "-w"
are given, which is a long-standing bug.
We are about to fix it so that "--raw" and friends report the
differences with the exit status (even though they ignore the
whitespace tweaking options when producing their output), which
will make this test, which succeeded for a wrong reason, start
failing. Remove it.
Signed-off-by: Junio C Hamano <gitster@pobox.com>
When options like "-w" is used while "--exit-code" option is in
effect, instead of the usual "do we have any filepair whose preimage
and postimage have different <mode,object>?" check, we need to compare
the contents of the blobs, taking into account that certain changes
are considered no-op.
With the previous step, we taught "--patch" codepath to set the
.found_changes bit correctly, even for a change that only affects
the mode and not object. The "--stat" codepath, however, did not
set the .found_changes bit at all. This lead to
$ git diff --stat -w --exit-code
for a change that does have an output to exit with status 0.
Set the bit by inspecting the list of paths the diffstat output is
given for (a mode-only change will still appear as a "0-line added
0-line deleted" change) to fix it.
Signed-off-by: Junio C Hamano <gitster@pobox.com>
The codepath to notice the content-level changes, taking certain
no-op changes like "ignore whitespace" into account, forgot that
a mode-only change is still a change. This resulted in
$ git diff --patch --exit-code -w
to exit with status 0 even when there is such a mode-only change,
breaking both "--patch" and "--quiet" output formats.
Teach the builtin_diff() codepath that creation and deletion as well
as mode changes are all interesting changes.
Note that the test specifically checks removal of an empty file,
because if there is anything in the preimage (i.e. the removed file
is not empty), the removal would still trigger textual patch output
and the codepath for that does update .found_changes bit to report
that it found an interesting change. We need to make sure that the
.found_changes bit is set even without triggering textual patch
output.
Signed-off-by: Junio C Hamano <gitster@pobox.com>
When "--exit-code" is asked and the code cannot just answer by
comparing the object names on both sides but needs to inspect and
compare the contents, there are two ways that the result is found
out.
Some output modes, like "--stat" and "--patch", inherently have to
inspect the contents in order to show the differences in the way
they do. The codepaths for these modes set the .found_changes bit
as they compute what to show.
However, other output modes do not need to inspect the contents to
show the differences in the way they do. The most notable example
is "--quiet", which does not need to compute any output to show.
When they are asked to report "--exit-code", they run the codepaths
for the "--patch" output with their output redirected to "/dev/null",
only to set the .found_changes bit.
Currently, this fallback invocation of "--patch" output is done
after the "--stat" output format and its friends and before the
"--patch" and internal callback logic. Move it to the end of
the sequence to clarify the fallback status of this code block.
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Typo/grammofix to documentation added during this cycle.
* tl/notes-separator:
notes doc: tidy up `--no-stripspace` paragraph
notes doc: split up run-on sentences
With `--stdin`, we read *from* standard input, not *for*.
Signed-off-by: Martin Ågren <martin.agren@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
When commit 00bf685975 (show-ref doc: update for internal consistency,
2023-05-19) switched from double quotes to backticks around our {caret}
macro, we started rendering "{caret}" literally. Fix this by replacing
by a "^" character.
Signed-off-by: Martin Ågren <martin.agren@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Where we document the `--no-stripspace` option, remove a superfluous
"For" to fix the grammar. Mark option names and command names using
`backticks` to set them in monospace.
Signed-off-by: Martin Ågren <martin.agren@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
When commit c4e2aa7d45 (notes.c: introduce "--[no-]stripspace" option,
2023-05-27) mentioned the new `--no-stripspace` in the documentation for
`-m` and `-F`, it created run-on sentences. It also used slightly
different language in the two sections for no apparent reason. Split the
sentences in two to improve readability, and while touching the two
sites, make them more similar.
Signed-off-by: Martin Ågren <martin.agren@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
In 7ba7c52d76 (upload-pack: fix race condition in error messages,
2023-08-10), we have fixed a race in t5516-fetch-push.sh where sometimes
error messages got intermingled. This was done by splitting up the call
to `die()` such that we print the error message before writing to the
remote side, followed by a call to `exit(1)` afterwards.
This causes a subtle regression though as `die()` causes us to exit with
exit code 128, whereas we now call `exit(1)`. It's not really clear
whether we want to guarantee any specific error code in this case, and
neither do we document anything like that. But on the other hand, it
seems rather clear that this is an unintended side effect of the change
given that this change in behaviour was not mentioned at all.
Restore the status-quo by exiting with 128. The test in t5703 to
ensure that "git fetch" fails by using test_must_fail, which does
not care between exiting 1 and 128, so this changes will not affect
any test.
Signed-off-by: Patrick Steinhardt <ps@pks.im>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
* 'master' of github.com:git/git: (34 commits)
Git 2.42-rc2
t4053: avoid writing to unopened pipe
t4053: avoid race when killing background processes
Git 2.42-rc1
git maintenance: avoid console window in scheduled tasks on Windows
win32: add a helper to run `git.exe` without a foreground window
t9001: remove excessive GIT_SEND_EMAIL_NOTTY=1
mv: handle lstat() failure correctly
parse-options: disallow negating OPTION_SET_INT 0
repack: free geometry struct
send-email: avoid creating more than one Term::ReadLine object
send-email: drop FakeTerm hack
t0040: declare non-tab indentation to be okay in this script
advice: handle "rebase" in error_resolve_conflict()
A few more topics before -rc1
mailmap: change primary address for Glen Choo
gitignore: ignore clangd .cache directory
docs: update when `git bisect visualize` uses `gitk`
compat/mingw: implement a native locate_in_PATH()
run-command: conditionally define locate_in_PATH()
...
Windows updates.
* ds/maintenance-on-windows-fix:
git maintenance: avoid console window in scheduled tasks on Windows
win32: add a helper to run `git.exe` without a foreground window
Adjust to newer Term::ReadLine to prevent it from breaking
the interactive prompt code in send-email.
* jk/send-email-with-new-readline:
send-email: avoid creating more than one Term::ReadLine object
send-email: drop FakeTerm hack
Developer support to detect meaningless combination of options.
* rs/parse-opt-forbid-set-int-0-without-noneg:
parse-options: disallow negating OPTION_SET_INT 0
