If a bitmap has a name-hash cache, it is an array of 32-bit integers,
one per entry in the bitmap, which we've mmap'd from the .bitmap file.
We access it directly like this:
if (bitmap_git->hashes)
hash = get_be32(bitmap_git->hashes + index_pos);
That works for both regular pack bitmaps and for non-incremental midx
bitmaps. There is one bitmap_index with one "hashes" array, and
index_pos is within its bounds (we do the bounds-checking when we load
the bitmap).
But for an incremental midx bitmap, we have a linked list of
bitmap_index structs, and each one has only its own small slice of the
name-hash array. If index_pos refers to an object that is not in the
first bitmap_git of the chain, then we'll access memory outside of the
bounds of its "hashes" array, and often outside of the mmap.
Instead, we should walk through the list until we find the bitmap_index
which serves our index_pos, and use its hash (after adjusting index_pos
to make it relative to the slice we found). This is exactly what we do
elsewhere for incremental midx lookups (like the pack_pos_to_midx() call
a few lines above). But we can't use existing helpers like
midx_for_object() here, because we're walking through the chain of
bitmap_index structs (each of which refers to a midx), not the chain of
incremental multi_pack_index structs themselves.
The problem is triggered in the test suite, but we don't get a segfault
because the out-of-bounds index is too small. The OS typically rounds
our mmap up to the nearest page size, so we just end up accessing some
extra zero'd memory. Nor do we catch it with ASan, since it doesn't seem
to instrument mmaps at all. But if we build with NO_MMAP, then our maps
are replaced with heap allocations, which ASan does check. And so:
make NO_MMAP=1 SANITIZE=address
cd t
./t5334-incremental-multi-pack-index.sh
does show the problem (and this patch makes it go away).
Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Our mmap compat code emulates mapping by using malloc/free. Our
git_munmap() must take a "length" parameter to match the interface of
munmap(), but we don't use it (it is up to the allocator to know how big
the block is in free()).
Let's mark it as UNUSED to avoid complaints from -Wunused-parameter.
Otherwise you cannot build with "make DEVELOPER=1 NO_MMAP=1".
Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
The pattern `return errno = ..., -1;` is observed several times in
`compat/mingw.c`. It has served us well over the years, but now clang
starts complaining:
compat/mingw.c:723:24: error: possible misuse of comma operator here [-Werror,-Wcomma]
723 | return errno = ENOSYS, -1;
| ^
See for example this failing workflow run:
https://github.com/git-for-windows/git-sdk-arm64/actions/runs/15457893907/job/43513458823#step:8:201
Let's appease clang (and also reduce the use of the no longer common
comma operator).
Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
In the `en/make-libgit-a` topic branch, more precisely in the commits
f3b4c89d59 (make: delete REFTABLE_LIB, add reftable to LIB_OBJS,
2025-10-02) and cf680cdb95 (make: delete XDIFF_LIB, add xdiff to
LIB_OBJS, 2025-10-02), the strategy to build three static libraries was
rethought, and instead only one static library is now built.
This is good.
However, the CMake definition was not changed accordingly, and now
CMake-based builds fail thusly:
[...]
Generating hook-list.h
CMake Error at CMakeLists.txt:122 (string):
string sub-command REPLACE requires at least four arguments.
Call Stack (most recent call first):
CMakeLists.txt:711 (parse_makefile_for_sources)
CMake Error at CMakeLists.txt:122 (string):
string sub-command REPLACE requires at least four arguments.
Call Stack (most recent call first):
CMakeLists.txt:717 (parse_makefile_for_sources)
-- Configuring incomplete, errors occurred!
Fix that by removing the parts that expect the reftable and xdiff
objects to be defined separately in the Makefile, still.
Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
`wcsncpy_s()` wants to write the terminating null character so we need
to allocate one more space for it in the target memory block.
This should fix crashes when trying to read passwords. When this
happened, the password/token wouldn't print out and Git would therefore
ask for a new password every time.
Signed-off-by: David Macek <david.macek.0@gmail.com>
Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
At GitHub, we had a repository that was triggering
git: merge-ort.c:3032: process_renames: Assertion `newinfo && !newinfo->merged.clean` failed.
during git replay.
This sounds similar to the somewhat recent f6ecb603ff (merge-ort: fix
directory rename on top of source of other rename/delete, 2025-08-06),
but the cause is different. Unlike that case, there are no
rename-to-self situations arising in this case, and new to this case it
can only be triggered during a replay operation on the 2nd or later
commit being replayed, never on the first merge in the sequence.
To trigger, the repository needs:
* an upstream which:
* renames a file to a different directory, e.g.
old/file -> new/file
* leaves other files remaining in the original directory (so that
e.g. "old/" still exists upstream even though file has been
removed from it and placed elsewhere)
* a topic branch being rebased where:
* a commit in the sequence:
* modifies old/file
* a subsequent commit in the sequence being replayed:
* does NOT touch *anything* under new/
* does NOT touch old/file
* DOES modify other paths under old/
* does NOT have any relevant renames that we need to detect
_anywhere_ elsewhere in the tree (meaning this interacts
interestingly with both directory renames and cached renames)
In such a case, the assertion will trigger. The fix turns out to be
surprisingly simple. I have a very vague recollection that I actually
considered whether to add such an if-check years ago when I added the
very similar one for oldinfo in 1b6b902d95 (merge-ort:
process_renames() now needs more defensiveness, 2021-01-19), but I think
I couldn't figure out a possible way to trigger it and was worried at
the time that if I didn't know how to trigger it then I wasn't so sure
that simply skipping it was correct. Waiting did give me a chance to
put more thorough tests and checks into place for the rename-to-self
cases a few months back, which I might not have found as easily
otherwise. Anyway, put the check in place now and add a test that
demonstrates the fix.
Note that this bug, as demonstrated by the conditions listed above,
runs at the intersection of relevant renames, trivial directory
resolutions, and cached renames. All three of those optimizations are
ones that unfortunately make the code (and testcases!) a bit more
complex, and threading all three makes it a bit more so. However, the
testcase isn't crazy enough that I'd expect no one to ever hit it in
practice, and was confused why we didn't see it before. After some
digging, I discovered that merge.directoryRenames=false is a workaround
to this bug, and GitHub used that setting until recently (it was a
"temporary" match-what-libgit2-does piece of code that lasted years
longer than intended). Since the conditions I gave above for triggering
this bug rule out the possibility of there being directory renames, one
might assume that it shouldn't matter whether you try to detect such
renames if there aren't any. However, due to commit a16e8efe5c
(merge-ort: fix merge.directoryRenames=false, 2025-03-13), the heavy
hammer used there means that merge.directoryRenames=false ALSO turns off
rename caching, which is critical to triggering the bug. This becomes
a bit more than an aside since...
Re-reading that old commit, a16e8efe5c (merge-ort: fix
merge.directoryRenames=false, 2025-03-13), it appears that the solution
to this latest bug might have been at least a partial alternative
solution to that old commit. And it may have been an improved
alternative (or at least help implement one), since it may be able to
avoid the heavy-handed disabling of rename cache. That might be an
interesting future thing to investigate, but is not critical for the
current fix. However, since I spent time digging it all up, at least
leave a small comment tweak breadcrumb to help some future reader
(myself or others) who wants to dig further to connect the dots a little
quicker.
Signed-off-by: Elijah Newren <newren@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
While developing commit a16e8efe5c (merge-ort: fix
merge.directoryRenames=false, 2025-03-13), I was testing things out and
had an extra condition on one of the if-blocks that I occasionally
swapped between '&& 0' and '&& 1' to see the effects of the changes. I
forgot to remove it before submitting and it wasn't caught in review.
Remove it now.
Signed-off-by: Elijah Newren <newren@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
A comment at the top of t6429 mentions why the test doesn't exercise git
rebase or git cherry-pick. However, it claims that it uses `test-tool
fast-rebase`. That was true when the comment was written, but commit
f920b0289b (replay: introduce new builtin, 2023-11-24) changed it to
use git replay without updating this comment.
We could potentially just strike this second comment, since git replay
is a bona fide built-in, but perhaps the explanation about why it focuses
on git replay is still useful. Update the comment to make it accurate
again.
Signed-off-by: Elijah Newren <newren@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
When Scalar was made a canonical part of Git in 7b5c93c6c6 (scalar:
include in standard Git build & installation, 2022-09-02), it was added
to all relevant Makefile targets except for the `strip` target.
Let's correct that.
Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Call xmkstemp_mode() instead of duplicating its error handling code.
This switches the implementation from the system's mkstemp(3) to our own
git_mkstemp_mode(), which works just as well.
Signed-off-by: René Scharfe <l.s.r@web.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
The diff algorithm used in 'git-blame(1)' is set to 'myers',
without the possibility to change it aside from the `--minimal` option.
There has been long-standing interest in changing the default diff
algorithm to "histogram", and Git 3.0 was floated as a possible occasion
for taking some steps towards that:
https://lore.kernel.org/git/xmqqed873vgn.fsf@gitster.g/
As a preparation for this move, it is worth making sure that the diff
algorithm is configurable where useful.
Make it configurable in the `git-blame(1)` command by introducing the
`--diff-algorithm` option and make honor the `diff.algorithm` config
variable. Keep Myers diff as the default.
Signed-off-by: Antonin Delpeuch <antonin@delpeuch.eu>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
The XDF_DIFF_ALGORITHM_MASK bit mask only includes bits for the patience
and histogram diffs, not for the minimal one. This means that when
reseting the diff algorithm to the default one, one needs to separately
clear the bit for the minimal diff. There are places in the code that fail
to do that: merge-ort.c and builtin/merge-file.c.
Add the XDF_NEED_MINIMAL bit to the bit mask, and remove the separate
clearing of this bit in the places where it hasn't been forgotten.
Signed-off-by: Antonin Delpeuch <antonin@delpeuch.eu>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
We replaced deprecated macos-13 with macos-14 image in GitHub
Actions CI, but we forgot that the image is for arm64. We have
been seeing a lot of test failures ever since. Switch to arm64
binary for Perforce tests.
* jc/ci-use-arm64-p4-on-macos:
Use Perforce arm64 binary on macOS CI jobs
In a following commit, we are going to check commit signatures, but we
won't have a commit yet, only a commit buffer, and we are going to
discard this commit buffer if the signature is invalid. So it would be
wasteful to create a commit that we might discard, just to be able to
check a commit signature.
It would be simpler instead to be able to check commit signatures
using only a commit buffer instead of a commit.
To be able to do that, let's extract some code from the
check_commit_signature() function into a new verify_commit_buffer()
function, and then let's make check_commit_signature() call
verify_commit_buffer().
Note that this doesn't fundamentally change how
check_commit_signature() works. It used to call parse_signed_commit()
which calls repo_get_commit_buffer(), parse_buffer_signed_by_header()
and repo_unuse_commit_buffer(). Now these 3 functions are called
directly by verify_commit_buffer().
Signed-off-by: Christian Couder <chriscool@tuxfamily.org>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
In a following commit we are going to finalize commit buffers with or
without signatures in order to check the signatures and possibly drop
them.
To do so easily and without duplication, let's refactor the current
code that finalizes commit buffers into a new finalize_commit_buffer()
function.
Signed-off-by: Christian Couder <chriscool@tuxfamily.org>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
The output table from "git repo structure" is misaligned when displaying
UTF-8 characters (e.g., non-ASCII glyphs). E.g.:
| 仓库结构 | 值 |
| -------------- | ---- |
| * 引用 | |
| * 计数 | 67 |
The previous implementation used simple width formatting with printf()
which didn't properly handle multi-byte UTF-8 characters, causing
misaligned table columns when displaying repository structure
information.
This change modifies the stats_table_print_structure function to use
strbuf_utf8_align() instead of basic printf width specifiers. This
ensures proper column alignment regardless of the character encoding of
the content being displayed.
Also add test cases for strbuf_utf8_align(), a function newly introduced
in "builtin/repo.c".
Signed-off-by: Jiang Xin <worldhello.net@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
The file "builtin/repo.c" uses utf8_strwidth() to calculate the display
width of UTF-8 characters in a table, but the resulting output is still
misaligned. Add test cases for both utf8_strwidth and utf8_strnwidth to
verify that they correctly compute the display width for UTF-8
characters.
Also updated the build configuration in Makefile and meson.build to
include the new test suite in the build process.
Signed-off-by: Jiang Xin <worldhello.net@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
The previous step replaced deprecated macos-13 image with macos-14
image on GitHub Actions CI. While x86-64 binaries can work there,
because macos-14 images are arm64 based (we could replace it with
macos-14-large that is x86-64), it makes more sense to use arm64
binary there. Without this change, we have been getting unusually
higher rate of failures from random macOS CI jobs railing to run
t98xx series of tests.
Helped-by: Koji Nakamaru <koji.nakamaru@gree.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
In add_to_cache(), we treat any directories as submodules, and complain
if we can't resolve their HEAD. This call to resolve_gitlink_ref() was
added by f937bc2f86 (add: error appropriately on repository with no
commits, 2019-04-09), with the goal of improving the error message for
empty repositories.
But we already resolve the submodule HEAD in index_path(), which is
where we find the actual oid we're going to use. Resolving it again here
introduces some downsides:
1. It's more work, since we have to open up the submodule repository's
files twice.
2. There are call paths that get to index_path() without going through
add_to_cache(). For instance, we'd want a similar informative
message if "git diff empty" finds that it can't resolve the
submodule's HEAD. (In theory we can also get there through
update-index, but AFAICT it refuses to consider directories as
submodules at all, and just complains about them).
3. The resolution in index_path() catches more errors that we don't
handle here. In particular, it will validate that the object format
for the submodule matches that of the superproject. This isn't a
bug, since our call in add_to_cache() throws away the oid it gets
without looking at it. But it certainly caused confusion for me
when looking at where the object-format check should go.
So instead of resolving the submodule HEAD in add_to_cache(), let's just
teach the call in index_path() to actually produce an error message
(which it already does for other cases). That's probably what f937bc2f86
should have done in the first place, and it gives us a single point of
resolution when adding a submodule to the index.
The resulting output is slightly more verbose, as we propagate the error
up the call stack, but I think that's OK (and again, matches many other
errors we get when indexing fails).
I've left the text of the error message as-is, though it is perhaps
overly specific. There are many reasons that resolving the submodule
HEAD might fail, though outside of corruption or system errors it is
probably most likely that the submodule HEAD is simply on an unborn
branch.
Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: brian m. carlson <sandals@crustytoothpaste.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
The design of the hash algorithm transition plan is that objects stored
must be entirely in one algorithm since we lack any way to indicate a
mix of algorithms. This also includes submodules, but we have
traditionally not enforced this, which leads to various problems when
trying to clone or check out the the submodule from the remote.
Since this cannot work in the general case, restrict adding a submodule
of a different algorithm to the index. Add tests for git add and git
submodule add that these are rejected.
Note that we cannot check this in git fsck because the malformed
submodule is stored in the tree as an object ID which is either
truncated (when a SHA-256 submodule is added to a SHA-1 repository) or
padded with zeros (when a SHA-1 submodule is added to a SHA-256
repository). We cannot detect even the latter case because someone
could have an actual submodule that actually ends in 24 zeros, which
would be a false positive.
Signed-off-by: brian m. carlson <sandals@crustytoothpaste.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
`--branch` and `--long` refer to git-status(1) options but they don’t tell us
what `short-format` and `long-format` are, respectively. And `--null`
mentions “status” but does not link to the command.
Refer to git-config(1) on `--branch` like `--short` does.
`long-format` is the git-status(1) output. So we can just say that
directly.
Replace “status” with a `linkgit` on `--null`.
Signed-off-by: Kristoffer Haugsbakk <code@khaugsbakk.name>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
git-credential-osxkeychain skips storing a credential if its "get"
action sets "state[]=osxkeychain:seen=1". This behavior was introduced
in e1ab45b2 (osxkeychain: state to skip unnecessary store operations,
2024-05-15), which appeared in v2.46.
However, this state[] persists even if a credential returned by
"git-credential-osxkeychain get" is invalid and a subsequent helper's
"get" operation returns a valid credential. Another subsequent helper
(such as [1]) may expect git-credential-osxkeychain to store the valid
credential, but the "store" operation is incorrectly skipped because it
only checks "state[]=osxkeychain:seen=1".
To solve this issue, "state[]=osxkeychain:seen" needs to contain enough
information to identify whether the current "store" input matches the
output from the previous "get" operation (and not a credential from
another helper).
Set "state[]=osxkeychain:seen" to a value encoding the credential output
by "get", and compare it with a value encoding the credential input by
"store".
[1]: https://github.com/hickford/git-credential-oauth
Reported-by: Petter Sælen <petter@saelen.eu>
Helped-by: Junio C Hamano <gitster@pobox.com>
Helped-by: brian m. carlson <sandals@crustytoothpaste.net>
Signed-off-by: Koji Nakamaru <koji.nakamaru@gree.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Now "git diff --check" and "git apply --whitespace=warn/fix" learned
incomplete line is a whitespace error, enable them for this project
to prevent patches to add new incomplete lines to our source to both
code and documentation files.
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Teach "git diff" to highlight "\ No newline at end of file" message
as a whitespace error when incomplete-line whitespace error class is
in effect. Thanks to the previous refactoring of complete rewrite
code path, we can do this at a single place.
Unlike whitespace errors in the payload where we need to annotate in
line, possibly using colors, the line that has whitespace problems,
we have a dedicated line already that can serve as the error
message, so paint it as a whitespace error message.
Also teach "git diff --check" to notice incomplete lines as
whitespace errors and report when incomplete-line whitespace error
class is in effect.
Signed-off-by: Junio C Hamano <gitster@pobox.com>
The final line of a file that lacks the terminating newline at its
end is called an incomplete line. In general they are frowned upon
for many reasons (imagine concatenating two files with "cat A B" and
what happens when A ends in an incomplete line, for example), and
text-oriented tools often mishandle such a line.
Implement checks in "git apply" for incomplete lines, which is off
by default for backward compatibility's sake, so that "git apply
--whitespace={fix,warn,error}" can notice, warn against, and fix
them.
As one of the new test shows, if you modify contents on an
incomplete line in the original and leave the resulting line
incomplete, it is still considered a whitespace error, the reasoning
being that "you'd better fix it while at it if you are making a
change on an incomplete line anyway", which may controversial.
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Reserve a few more bits in the diff flags word to be used for future
whitespace rules. Add WS_INCOMPLETE_LINE without implementing the
behaviour (yet).
Signed-off-by: Junio C Hamano <gitster@pobox.com>
A patch file represents the incomplete line at the end of the file
with two lines, one that is the usual "context" with " " as the
first letter, "added" with "+" as the first letter, or "removed"
with "-" as the first letter that shows the content of the line,
plus an extra "\ No newline at the end of file" line that comes
immediately after it.
Ever since the apply machinery was written, the "git apply"
machinery parses "\ No newline at the end of file" line
independently, without even knowing what line the incomplete-ness
applies to, simply because it does not even remember what the
previous line was.
This poses a problem if we want to check and warn on an incomplete
line. Revamp the code that parses a fragment, to actually drop the
'\n' at the end of the incoming patch file that terminates a line,
so that check_whitespace() calls made from the code path actually
sees an incomplete as incomplete.
Note that the result of this parsing is not directly used by the
code path that applies the patch. apply_one_fragment() function
already checks if each of the patch text it handles is followed by a
line that begins with a backslash to drop the newline at the end of
the current line it is looking at. In a sense, this patch harmonizes
the behaviour of the parsing side to what is already done in the
application side.
Signed-off-by: Junio C Hamano <gitster@pobox.com>
The diff_symbol based output framework uses one DIFF_SYMBOL_* enum
value per the kind of output lines of "git diff", which corresponds
to one output line from the xdiff machinery used internally. Most
notably, DIFF_SYMBOL_PLUS and DIFF_SYMBOL_MINUS that correspond to
"+" and "-" lines are designed to always take a complete line, even
if the output from xdiff machinery may produce "\ No newline at the
end of file" immediately after them.
But this is not true in the rewrite-diff codepath, which completely
bypasses the xdiff machinery. Since the code path feeds the bytes
directly from the payload to the output routines, the output layer
has to deal with an incomplete line with DIFF_SYMBOL_PLUS and
DIFF_SYMBOL_MINUS, which never would see an incomplete line in the
normal code paths. This lack of final newline is compensated by an
ugly hack for a fabricated DIFF_SYMBOL_NO_LF_EOF token to inject an
extra newline to the output to simulate output coming from the xdiff
machinery.
Revamp the way the complete-rewrite code path feeds the lines to the
output layer by treating the last line of the pre/post image when it
is an incomplete line specially.
This lets us remove the DIFF_SYMBOL_NO_LF_EOF hack and use the usual
DIFF_SYMBOL_CONTEXT_INCOMPLETE code path, which will later learn how
to handle whitespace errors.
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Everybody else, except for emit_rewrite_lines(), calls the
emit_callback data ecbdata. Make sure we call the same thing by
the same name for consistency.
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Create a helper function that reacts to "\ No newline at the end of
file" in preparation for unifying the incomplete line handling in
the code path that handles xdiff output and the code path that
bypasses xdiff and produces a complete-rewrite patch.
Currently the output from the DIFF_SYMBOL_CONTEXT_INCOMPLETE case
still (ab)uses the same code as what is used for context lines, but
that would change in a later step where we introduce support to treat
an incomplete line as a whitespace error.
Signed-off-by: Junio C Hamano <gitster@pobox.com>
The "\ No newline at the end of the file" can come after any of the
"-" (deleted preimage line), " " (unchanged line), or "+" (added
postimage line). In later steps in this series, we will start
treating a change that makes a file to end in an incomplete line
as a whitespace error, and we would need to know what the previous
line was when we react to "\ No newline" in the diff output. If
the previous line was a context (i.e., unchanged) line, the file
lacked the final newline before the change, and the change did not
touch that line and left it still incomplete, so we do not want to
warn in such a case.
Teach fn_out_consume() function to keep track of what the previous
line was, and prepare an otherwise empty switch statement to let us
react differently to "\ No newline" based on that.
Note that there is an existing curiosity (read: likely to be a bug)
in the code that increments line number in the preimage file every
time it sees a line with "\ No newline" on it, regardless of what
the previous line was. I left it as-is, because it does not affect
the main theme of this series, and more importantly, I do not think
it matters, as these numbers are used only to compare them with
blank_at_eof_in_{pre,post}image to issue a warning when we see more
empty line was added at the end, but by definition, after we see
"\ No newline at the end of the file" for an added line, we will not
see an added line for the file.
An independent audit to ensure that this curious increment can be
safely removed would make a good #leftoverbits clean-up (we may even
find some code that decrements this counter or over-increments the
other quantity this counter is compared with that compensates the
effect of this curious increment that hides a bug, in which case we
may also need to remove them).
Signed-off-by: Junio C Hamano <gitster@pobox.com>
The suppress-blank-empty feature abused the CONTEXT_INCOMPLETE
symbol that was meant to be used only for "\ No newline at the end
of file" code path.
The intent of the feature was to turn a context line we receive from
xdiff machinery (which always uses ' ' for context lines, even an
empty one) and spit it out as a truly empty line.
Perform such a conversion very locally at where a line from xdiff
that begins with ' ' is handled for output; there are many checks
before the control reaches such place that checks the first letter
of the diff output line to see if it is a context line, and having
to check for '\n' and treat it as a special case is error prone.
In order to catch similar hacks in the future, make sure the code
path that is meant for "\ No newline" case checks the first byte is
indeed a backslash.
Signed-off-by: Junio C Hamano <gitster@pobox.com>
