run_diff_files: do not look at uninitialized stat data
If we try to diff an index entry marked CE_VALID (because it was marked with --assume-unchanged), we do not bother even running stat() on the file to see if it was removed. This started long ago with 540e694b (Prevent diff machinery from examining assume-unchanged entries on worktree, 2009-08-11). However, the subsequent code may look at our "struct stat" and expect to find actual data; currently it will find whatever cruft was left on the stack. This can cause problems in two situations: 1. We call match_stat_with_submodule with the stat data, so a submodule may be erroneously marked as changed. 2. If --find-copies-harder is in effect, we pass all entries, even unchanged ones, to diff_change, so it can list them as rename/copy sources. Since we found no change, we assume that function will realize it and not actually display any diff output. However, we end up feeding it a bogus mode, leading it to sometimes claim there was a mode change. We can fix both by splitting the CE_VALID and regular code paths, and making sure only to look at the stat information in the latter. Furthermore, we push the declaration of our "struct stat" down into the code paths that actually set it, so we cannot accidentally access it uninitialized in future code. Signed-off-by: NJeff King <peff@peff.net> Signed-off-by: NJunio C Hamano <gitster@pobox.com>
Showing
想要评论请 注册 或 登录