Merge branch 'jc/unresolve-removal'

"checkout --merge -- path" and "update-index --unresolve path" did
not resurrect conflicted state that was resolved to remove path,
but now they do.

* jc/unresolve-removal:
  checkout: allow "checkout -m path" to unmerge removed paths
  checkout/restore: add basic tests for --merge
  checkout/restore: refuse unmerging paths unless checking out of the index
  update-index: remove stale fallback code for "--unresolve"
  update-index: use unmerge_index_entry() to support removal
  resolve-undo: allow resurrecting conflicted state that resolved to deletion
  update-index: do not read HEAD and MERGE_HEAD unconditionally

1 files changed, 12 insertions, 86 deletions

diff --git a/builtin/update-index.c b/builtin/update-index.c
index 97617c587e..7bcaa1476c 100644
--- a/builtin/update-index.c
+++ b/builtin/update-index.c
@@ -609,9 +609,6 @@ static const char * const update_index_usage[] = {
 	NULL
 };
 
-static struct object_id head_oid;
-static struct object_id merge_head_oid;
-
 static struct cache_entry *read_one_ent(const char *which,
 					struct object_id *ent, const char *path,
 					int namelen, int stage)
@@ -642,84 +639,17 @@ static struct cache_entry *read_one_ent(const char *which,
 
 static int unresolve_one(const char *path)
 {
-	int namelen = strlen(path);
-	int pos;
-	int ret = 0;
-	struct cache_entry *ce_2 = NULL, *ce_3 = NULL;
-
-	/* See if there is such entry in the index. */
-	pos = index_name_pos(&the_index, path, namelen);
-	if (0 <= pos) {
-		/* already merged */
-		pos = unmerge_index_entry_at(&the_index, pos);
-		if (pos < the_index.cache_nr) {
-			const struct cache_entry *ce = the_index.cache[pos];
-			if (ce_stage(ce) &&
-			    ce_namelen(ce) == namelen &&
-			    !memcmp(ce->name, path, namelen))
-				return 0;
-		}
-		/* no resolve-undo information; fall back */
-	} else {
-		/* If there isn't, either it is unmerged, or
-		 * resolved as "removed" by mistake.  We do not
-		 * want to do anything in the former case.
-		 */
-		pos = -pos-1;
-		if (pos < the_index.cache_nr) {
-			const struct cache_entry *ce = the_index.cache[pos];
-			if (ce_namelen(ce) == namelen &&
-			    !memcmp(ce->name, path, namelen)) {
-				fprintf(stderr,
-					"%s: skipping still unmerged path.\n",
-					path);
-				goto free_return;
-			}
-		}
-	}
-
-	/* Grab blobs from given path from HEAD and MERGE_HEAD,
-	 * stuff HEAD version in stage #2,
-	 * stuff MERGE_HEAD version in stage #3.
-	 */
-	ce_2 = read_one_ent("our", &head_oid, path, namelen, 2);
-	ce_3 = read_one_ent("their", &merge_head_oid, path, namelen, 3);
-
-	if (!ce_2 || !ce_3) {
-		ret = -1;
-		goto free_return;
-	}
-	if (oideq(&ce_2->oid, &ce_3->oid) &&
-	    ce_2->ce_mode == ce_3->ce_mode) {
-		fprintf(stderr, "%s: identical in both, skipping.\n",
-			path);
-		goto free_return;
-	}
-
-	remove_file_from_index(&the_index, path);
-	if (add_index_entry(&the_index, ce_2, ADD_CACHE_OK_TO_ADD)) {
-		error("%s: cannot add our version to the index.", path);
-		ret = -1;
-		goto free_return;
-	}
-	if (!add_index_entry(&the_index, ce_3, ADD_CACHE_OK_TO_ADD))
-		return 0;
-	error("%s: cannot add their version to the index.", path);
-	ret = -1;
- free_return:
-	discard_cache_entry(ce_2);
-	discard_cache_entry(ce_3);
-	return ret;
-}
-
-static void read_head_pointers(void)
-{
-	if (read_ref("HEAD", &head_oid))
-		die("No HEAD -- no initial commit yet?");
-	if (read_ref("MERGE_HEAD", &merge_head_oid)) {
-		fprintf(stderr, "Not in the middle of a merge.\n");
-		exit(0);
-	}
+	struct string_list_item *item;
+	int res = 0;
+
+	if (!the_index.resolve_undo)
+		return res;
+	item = string_list_lookup(the_index.resolve_undo, path);
+	if (!item)
+		return res; /* no resolve-undo record for the path */
+	res = unmerge_index_entry(&the_index, path, item->util, 0);
+	FREE_AND_NULL(item->util);
+	return res;
 }
 
 static int do_unresolve(int ac, const char **av,
@@ -728,11 +658,6 @@ static int do_unresolve(int ac, const char **av,
 	int i;
 	int err = 0;
 
-	/* Read HEAD and MERGE_HEAD; if MERGE_HEAD does not exist, we
-	 * are not doing a merge, so exit with success status.
-	 */
-	read_head_pointers();
-
 	for (i = 1; i < ac; i++) {
 		const char *arg = av[i];
 		char *p = prefix_path(prefix, prefix_length, arg);
@@ -751,6 +676,7 @@ static int do_reupdate(const char **paths,
 	int pos;
 	int has_head = 1;
 	struct pathspec pathspec;
+	struct object_id head_oid;
 
 	parse_pathspec(&pathspec, 0,
 		       PATHSPEC_PREFER_CWD,