Fix git log --graph -u hangs
#5193
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The output_prefix() method in line-log.c may call a function pointer via
the diff_options struct. This function pointer returns a strbuf struct
and then its buffer is passed back. However, that implies that the
consumer is responsible to free the string. This is especially true
because the default behavior is to duplicate the empty string.
The existing functions used in the output_prefix pointer include:
1. idiff_prefix_cb() in diff-lib.c. This returns the data pointer, so
the value exists across multiple calls.
2. diff_output_prefix_callback() in graph.c. This uses a static strbuf
struct, so it reuses buffers across calls. These should not be
freed.
3. output_prefix_cb() in range-diff.c. This is similar to the
diff-lib.c case.
In each case, we should not be freeing this buffer. We can convert the
output_prefix() function to return a const char pointer and stop freeing
the result.
This choice is essentially the opposite of what was done in 394affd
(line-log: always allocate the output prefix, 2024-06-07).
This was discovered via 'valgrind' while investigating a public report
of a bug in 'git log --graph -L' [1].
[1] git-for-windows#5185
This issue would have been caught by the new test, when Git is compiled
with ASan to catch these double frees.
Co-authored-by: Jeff King <[email protected]>
Signed-off-by: Jeff King <[email protected]>
Signed-off-by: Derrick Stolee <[email protected]>
Now that output_prefix() returns a const char * type, it matches the behavior of diff_line_prefix() and no longer needs to exist on its own. Signed-off-by: Jeff King <[email protected]> Signed-off-by: Derrick Stolee <[email protected]>
The uses of the output_prefix function pointer in the diff_options struct is currently difficult to work with by returning a pointer to a strbuf. There is only one use that cares about the length of the string, which appears to be the only justification of the return type. We already noticed confusing memory issues around this return type, so use a const char * return type to make it clear that the caller does not own this string buffer. Signed-off-by: Jeff King <[email protected]> Signed-off-by: Derrick Stolee <[email protected]>
derrickstolee
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Oct 7, 2024
dscho
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Oct 8, 2024
This fixes git-for-windows#5185 by backporting gitgitgadget#1806 (which, sadly, seems not to have made it into Git v2.47.0).
git-for-windows-ci
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Oct 8, 2024
This fixes #5185 by backporting gitgitgadget#1806 (which, sadly, seems not to have made it into Git v2.47.0).
dscho
added a commit
that referenced
this pull request
Oct 8, 2024
This fixes #5185 by backporting gitgitgadget#1806 (which, sadly, seems not to have made it into Git v2.47.0).
git-for-windows-ci
pushed a commit
that referenced
this pull request
Oct 9, 2024
This fixes #5185 by backporting gitgitgadget#1806 (which, sadly, seems not to have made it into Git v2.47.0).
git-for-windows-ci
pushed a commit
that referenced
this pull request
Oct 9, 2024
This fixes #5185 by backporting gitgitgadget#1806 (which, sadly, seems not to have made it into Git v2.47.0).
dscho
added a commit
that referenced
this pull request
Oct 9, 2024
This fixes #5185 by backporting gitgitgadget#1806 (which, sadly, seems not to have made it into Git v2.47.0).
dscho
added a commit
that referenced
this pull request
Oct 11, 2024
This fixes #5185 by backporting gitgitgadget#1806 (which, sadly, seems not to have made it into Git v2.47.0).
dscho
added a commit
that referenced
this pull request
Nov 22, 2024
This fixes #5185 by backporting gitgitgadget#1806 (which, sadly, seems not to have made it into Git v2.47.0).
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This fixes #5185 by backporting gitgitgadget#1806 (which, sadly, seems not to have made it into Git v2.47.0).