diff: fix OOM on AIX when finding similar deltas in empty diff#4761
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The function `git_diff_find_similar` keeps a function of cache similarity metrics signatures, whose size depends on the number of deltas passed in via the `diff` parameter. In case where the diff is empty and thus doesn't have any deltas at all, we may end up allocating this cache via a call to `git__calloc(0, sizeof(void *))`. At least on AIX, allocating 0 bytes will result in a `NULL` pointer being returned, which causes us to erroneously return an OOM error. Fix this situation by simply returning early in case where we are being passed an empty diff, as we cannot find any similarities in that case anyway.
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The function
git_diff_find_similarkeeps a function of cachesimilarity metrics signatures, whose size depends on the number of
deltas passed in via the
diffparameter. In case where the diff isempty and thus doesn't have any deltas at all, we may end up allocating
this cache via a call to
git__calloc(0, sizeof(void *)). At least onAIX, allocating 0 bytes will result in a
NULLpointer being returned,which causes us to erroneously return an OOM error.
Fix this situation by simply returning early in case where we are being
passed an empty diff, as we cannot find any similarities in that case
anyway.
This should fix #4748