diff: Fix rename pretty-print when suffix and prefix overlap

diff --git a/diff.c b/diff.c
index 9038f190ece061696a3290acf8f1e9951e9d0a6c..e1d82c9672599072fb946d157d54bd72aa0fa7db 100644 (file)
--- a/diff.c
+++ b/diff.c
@@ -1177,7 +1177,16 @@ static char *pprint_rename(const char *a, const char *b)
        old = a + len_a;
        new = b + len_b;
        sfx_length = 0;
-       while (a <= old && b <= new && *old == *new) {
+       /*
+        * Note:
+        * if pfx_length is 0, old/new will never reach a - 1 because it
+        * would mean the whole string is common suffix. But then, the
+        * whole string would also be a common prefix, and we would not
+        * have pfx_length equals 0.
+        */
+       while (a + pfx_length - 1 <= old &&
+              b + pfx_length - 1 <= new &&
+              *old == *new) {
                if (*old == '/')
                        sfx_length = len_a - (old - a);
                old--;