git/xdiff, branch v2.23.2

Merge branch 'cb/xdiff-no-system-includes-in-dot-c'

2019-07-31T21:38:56Z

Compilation fix. * cb/xdiff-no-system-includes-in-dot-c: xdiff: remove duplicate headers from xpatience.c xdiff: remove duplicate headers from xhistogram.c xdiff: drop system includes in xutils.c

Merge branch 'jk/xdiff-clamp-funcname-context-index'

2019-07-29T19:39:13Z

The internal diff machinery can be made to read out of bounds while looking for --funcion-context line in a corner case, which has been corrected. * jk/xdiff-clamp-funcname-context-index: xdiff: clamp function context indices in post-image

xdiff: remove duplicate headers from xpatience.c

2019-07-29T04:51:22Z

92b7de93fb (Implement the patience diff algorithm, 2009-01-07) added them but were already part of xinclude.h Signed-off-by: Carlo Marcelo Arenas Belón Signed-off-by: Junio C Hamano

xdiff: remove duplicate headers from xhistogram.c

2019-07-29T04:51:21Z

8c912eea94 ("teach --histogram to diff", 2011-07-12) included them, but were already part of xinclude.h Signed-off-by: Carlo Marcelo Arenas Belón Signed-off-by: Junio C Hamano

xdiff: drop system includes in xutils.c

2019-07-29T04:51:19Z

After b46054b374 ("xdiff: use git-compat-util", 2019-04-11), two system headers added with 6942efcfa9 ("xdiff: load full words in the inner loop of xdl_hash_record", 2012-04-06) to xutils.c are no longer needed and could conflict as shown below from an OpenIndiana build: In file included from xdiff/xinclude.h:26:0, from xdiff/xutils.c:25: ./git-compat-util.h:4:0: warning: "_FILE_OFFSET_BITS" redefined #define _FILE_OFFSET_BITS 64 In file included from /usr/include/limits.h:37:0, from xdiff/xutils.c:23: /usr/include/sys/feature_tests.h:231:0: note: this is the location of the previous definition #define _FILE_OFFSET_BITS 32 Make sure git-compat-util.h is the first header (through xinclude.h) Signed-off-by: Carlo Marcelo Arenas Belón Signed-off-by: Junio C Hamano

xdiff: clamp function context indices in post-image

2019-07-23T21:26:13Z

After finding a function line for --function-context in the pre-image, xdl_emit_diff() calculates the equivalent line in the post-image. It assumes that the lines between changes are the same on both sides. If the option --ignore-blank-lines was also given then this is not necessarily true. Clamp the calculation results for start and end of the function context to prevent out-of-bounds array accesses. Note that this _just_ fixes the case where our mismatch sends us off the beginning of the file. There are likely other cases where our assumption causes us to go to the wrong line within the file. Nobody has developed a test case yet, and the ultimate fix is likely more complicated than this patch. But this at least prevents a segfault in the meantime. Credit for finding the bug goes to "Liu Wei of Tencent Security Xuanwu Lab". Reported-by: 刘炜 Helped-by: René Scharfe Signed-off-by: Jeff King Signed-off-by: Junio C Hamano

xdiff: use xmalloc/xrealloc

2019-04-12T04:34:17Z

Most of xdiff uses a bare malloc() to allocate memory, and returns an error when we get NULL. However, there are a few spots which don't check the return value and may segfault, including at least xdl_merge() and xpatience.c's find_longest_common_sequence(). Let's use xmalloc() everywhere instead, so that we get a graceful die() for these cases, without having to do further auditing. This does mean the existing cases which check errors will now die() instead of returning an error up the stack. But: - that's how the rest of Git behaves already for malloc errors - all of the callers of xdi_diff(), etc, die upon seeing an error So while we might one day want to fully lib-ify the diff code and make it possible to use as part of a long-running process, we're not close to that now. And because we're just tweaking the xdl_malloc() macro here, we're not really moving ourselves any further away from that. We could, for example, simplify some of the functions which handle malloc() errors which can no longer occur. But that would probably be taking us in the wrong direction. This also makes our malloc handling more consistent with the rest of Git, including enforcing GIT_ALLOC_LIMIT and trying to reclaim pack memory when needed. Reported-by: 王健强 Signed-off-by: Jeff King Signed-off-by: Junio C Hamano

xdiff: use git-compat-util

2019-04-12T04:34:17Z

Since the xdiff library was not originally part of Git, it does its own system includes. Let's instead use git-compat-util, which has two benefits: 1. It adjusts for any system-specific quirks in how or what we should include (though xdiff's needs are light enough that this hasn't been a problem in the past). 2. It lets us use wrapper functions like xmalloc(). Signed-off-by: Jeff King Signed-off-by: Junio C Hamano

xdiff: provide a separate emit callback for hunks

2018-11-02T11:43:02Z

The xdiff library always emits hunk header lines to our callbacks as formatted strings like "@@ -a,b +c,d @@\n". This is convenient if we're going to output a diff, but less so if we actually need to compute using those numbers, which requires re-parsing the line. In preparation for moving away from this, let's teach xdiff a new callback function which gets the broken-out hunk information. To help callers that don't want to use this new callback, if it's NULL we'll continue to format the hunk header into a string. Note that this function renames the "outf" callback to "out_line", as well. This isn't strictly necessary, but helps in two ways: 1. Now that there are two callbacks, it's nice to use more descriptive names. 2. Many callers did not zero the emit_callback_data struct, and needed to be modified to set ecb.out_hunk to NULL. By changing the name of the existing struct member, that guarantees that any new callers from in-flight topics will break the build and be examined manually. Signed-off-by: Jeff King Signed-off-by: Junio C Hamano

Merge branch 'sb/indent-heuristic-optim'

2018-08-17T20:09:57Z

"git diff --indent-heuristic" had a bad corner case performance. * sb/indent-heuristic-optim: xdiff: reduce indent heuristic overhead