Teach --dirstat not to completely ignore rearranged lines within a file

diff --git a/diff.c b/diff.c
index 4f5270b8dbc05c820c24075b499fe26afacf52a8..1f44cb4237317fd2e36bc9b00047b67f7e844e17 100644 (file)
--- a/diff.c
+++ b/diff.c
@@ -1548,6 +1548,16 @@ static void show_dirstat(struct diff_options *options)
                else
                        content_changed = 1;
 
+               if (!content_changed) {
+                       /*
+                        * The SHA1 has not changed, so pre-/post-content is
+                        * identical. We can therefore skip looking at the
+                        * file contents altogether.
+                        */
+                       damage = 0;
+                       goto found_damage;
+               }
+
                if (DIFF_OPT_TST(options, DIRSTAT_BY_FILE)) {
                        /*
                         * In --dirstat-by-file mode, we don't really need to
@@ -1556,7 +1566,7 @@ static void show_dirstat(struct diff_options *options)
                         * add this file to the list of results
                         * (with each file contributing equal damage).
                         */
-                       damage = content_changed ? 1 : 0;
+                       damage = 1;
                        goto found_damage;
                }
 
@@ -1583,8 +1593,15 @@ static void show_dirstat(struct diff_options *options)
                 * Original minus copied is the removed material,
                 * added is the new material.  They are both damages
                 * made to the preimage.
+                * If the resulting damage is zero, we know that
+                * diffcore_count_changes() considers the two entries to
+                * be identical, but since content_changed is true, we
+                * know that there must have been _some_ kind of change,
+                * so we force all entries to have damage > 0.
                 */
                damage = (p->one->size - copied) + added;
+               if (!damage)
+                       damage = 1;
 
 found_damage:
                ALLOC_GROW(dir.files, dir.nr + 1, dir.alloc);