git-read-tree: fix up three-way merge tests

When we collapse three entries, we need to check all of the
collapsed entries against the old pre-merge state.

diff --git a/read-tree.c b/read-tree.c
index 647f501..3746984 100644 (file)
--- a/read-tree.c
+++ b/read-tree.c
@@ -118,16 +118,12 @@ static void verify_uptodate(struct cache_entry *ce)
  * it's up-to-date or not (ie it can be a file that we
  * have updated but not committed yet).
  */
-static void verify_cleared(struct cache_entry *ce)
+static void reject_merge(struct cache_entry *ce)
 {
-       if (ce)
-               die("Entry '%s' would be overwritten by merge. Cannot merge.", ce->name);
+       die("Entry '%s' would be overwritten by merge. Cannot merge.", ce->name);
 }
 
-static int old_match(struct cache_entry *old, struct cache_entry *a)
-{
-       return old && path_matches(old, a) && same(old, a);
-}
+#define CHECK_OLD(ce) if (old && same(old, ce)) { verify_uptodate(old); old = NULL; }
 
 static void trivially_merge_cache(struct cache_entry **src, int nr)
 {
@@ -141,22 +137,28 @@ static void trivially_merge_cache(struct cache_entry **src, int nr)
 
                /* We throw away original cache entries except for the stat information */
                if (!ce_stage(ce)) {
-                       verify_cleared(old);
+                       if (old)
+                               reject_merge(old);
                        old = ce;
                        src++;
                        nr--;
                        active_nr--;
                        continue;
                }
+               if (old && !path_matches(old, ce))
+                       reject_merge(old);
                if (nr > 2 && (result = merge_entries(ce, src[1], src[2])) != NULL) {
                        /*
                         * See if we can re-use the old CE directly?
                         * That way we get the uptodate stat info.
                         */
-                       if (old_match(old, result)) {
+                       if (old && same(old, result)) {
                                *result = *old;
                                old = NULL;
                        }
+                       CHECK_OLD(ce);
+                       CHECK_OLD(src[1]);
+                       CHECK_OLD(src[2]);
                        ce = result;
                        ce->ce_flags &= ~htons(CE_STAGEMASK);
                        src += 2;
@@ -168,15 +170,13 @@ static void trivially_merge_cache(struct cache_entry **src, int nr)
                 * If we had an old entry that we now effectively
                 * overwrite, make sure it wasn't dirty.
                 */
-               if (old_match(old, ce)) {
-                       verify_uptodate(old);
-                       old = NULL;
-               }
+               CHECK_OLD(ce);
                *dst++ = ce;
                src++;
                nr--;
        }
-       verify_cleared(old);
+       if (old)
+               reject_merge(old);
 }
 
 static void merge_stat_info(struct cache_entry **src, int nr)