Merge branch 'jc/maint-1.6.0-diff-borrow-carefully' into maint-1.6.1

[thirdparty/git.git] / diff.c

diff --git a/diff.c b/diff.c
index 416c5aa722afc8d10e4bc910e7b297b3eb0a2760..635fbc9d98995359b045de8a7a8594af2fe0e335 100644 (file)
--- a/diff.c
+++ b/diff.c
@@ -1649,7 +1649,8 @@ static int reuse_worktree_file(const char *name, const unsigned char *sha1, int
        struct stat st;
        int pos, len;
 
-       /* We do not read the cache ourselves here, because the
+       /*
+        * We do not read the cache ourselves here, because the
         * benchmark with my previous version that always reads cache
         * shows that it makes things worse for diff-tree comparing
         * two linux-2.6 kernel trees in an already checked out work
@@ -1689,6 +1690,13 @@ static int reuse_worktree_file(const char *name, const unsigned char *sha1, int
        if (hashcmp(sha1, ce->sha1) || !S_ISREG(ce->ce_mode))
                return 0;
 
+       /*
+        * If ce is marked as "assume unchanged", there is no
+        * guarantee that work tree matches what we are looking for.
+        */
+       if (ce->ce_flags & CE_VALID)
+               return 0;
+
        /*
         * If ce matches the file in the work tree, we can reuse it.
         */