diff-cache shows differences for unmerged paths without --cache.

While manually resolving a merge conflict, being able to run
diff-cache without --cache option between files in the work tree
and either of the ancestor trees is helpful to verify the hand
merged result.  However, diff-cache refuses to handle unmerged
paths, even when run without --cache option.

This changes the behaviour so that the above use case will
report the differences between the compared tree and the magic
0{40} SHA1 (i.e. "look at the work tree").  When there is no
corresponding file in the work tree, or when the command is run
with "--cache" option, it continues to report "unmerged".

Signed-off-by: Junio C Hamano <junkio@cox.net>

diff --git a/diff-cache.c b/diff-cache.c
index ef522cd..7e87d28 100644 (file)
--- a/diff-cache.c
+++ b/diff-cache.c
@@ -57,14 +57,17 @@ static void show_new_file(struct cache_entry *new)
        show_file("+", new, sha1, mode);
 }
 
-static int show_modified(struct cache_entry *old, struct cache_entry *new)
+static int show_modified(struct cache_entry *old,
+                        struct cache_entry *new,
+                        int report_missing)
 {
        unsigned int mode, oldmode;
        unsigned char *sha1;
        unsigned char old_sha1_hex[60];
 
        if (get_stat_data(new, &sha1, &mode) < 0) {
-               show_file("-", old, old->sha1, old->ce_mode);
+               if (report_missing)
+                       show_file("-", old, old->sha1, old->ce_mode);
                return -1;
        }
 
@@ -101,7 +104,7 @@ static int diff_cache(struct cache_entry **ac, int entries)
                                break;
                        }
                        /* Show difference between old and new */
-                       show_modified(ac[1], ce);
+                       show_modified(ac[1], ce, 1);
                        break;
                case 1:
                        /* No stage 3 (merge) entry? That means it's been deleted */
@@ -109,7 +112,19 @@ static int diff_cache(struct cache_entry **ac, int entries)
                                show_file("-", ce, ce->sha1, ce->ce_mode);
                                break;
                        }
-                       /* Otherwise we fall through to the "unmerged" case */
+                       /* We come here with ce pointing at stage 1
+                        * (original tree) and ac[1] pointing at stage
+                        * 3 (unmerged).  show-modified with
+                        * report-mising set to false does not say the
+                        * file is deleted but reports true if work
+                        * tree does not have it, in which case we
+                        * fall through to report the unmerged state.
+                        * Otherwise, we show the differences between
+                        * the original tree and the work tree.
+                        */
+                       if (!cached_only && !show_modified(ce, ac[1], 0))
+                               break;
+                       /* fallthru */
                case 3:
                        if (generate_patch)
                                diff_unmerge(ce->name);