Merge branch 'es/worktree-repair-both-moved'

"git worktree repair" learned to deal with the case where both the
repository and the worktree moved.

* es/worktree-repair-both-moved:
  worktree: teach `repair` to fix multi-directional breakage

Author: gitster

Documentation/git-worktree.txt

@@ -143,6 +143,11 @@ locate it. Running `repair` within the recently-moved working tree will
 reestablish the connection. If multiple linked working trees are moved,
 running `repair` from any working tree with each tree's new `<path>` as
 an argument, will reestablish the connection to all the specified paths.
++
+If both the main working tree and linked working trees have been moved
+manually, then running `repair` in the main working tree and specifying the
+new `<path>` of each linked working tree will reestablish all connections
+in both directions.
 
 unlock::
 

builtin/worktree.c

@@ -1052,10 +1052,10 @@ static int repair(int ac, const char **av, const char *prefix)
 	int rc = 0;
 
 	ac = parse_options(ac, av, prefix, options, worktree_usage, 0);
-	repair_worktrees(report_repair, &rc);
 	p = ac > 0 ? av : self;
 	for (; *p; p++)
 		repair_worktree_at_path(*p, report_repair, &rc);
+	repair_worktrees(report_repair, &rc);
 	return rc;
 }
 

t/t2406-worktree-repair.sh

@@ -104,6 +104,16 @@ test_expect_success 'repo not found; .git not file' '
 	test_i18ngrep ".git is not a file" err
 '
 
+test_expect_success 'repo not found; .git not referencing repo' '
+	test_when_finished "rm -rf side not-a-repo && git worktree prune" &&
+	git worktree add --detach side &&
+	sed s,\.git/worktrees/side$,not-a-repo, side/.git >side/.newgit &&
+	mv side/.newgit side/.git &&
+	mkdir not-a-repo &&
+	test_must_fail git worktree repair side 2>err &&
+	test_i18ngrep ".git file does not reference a repository" err
+'
+
 test_expect_success 'repo not found; .git file broken' '
 	test_when_finished "rm -rf orig moved && git worktree prune" &&
 	git worktree add --detach orig &&
@@ -176,4 +186,20 @@ test_expect_success 'repair multiple gitdir files' '
 	test_must_be_empty err
 '
 
+test_expect_success 'repair moved main and linked worktrees' '
+	test_when_finished "rm -rf main side mainmoved sidemoved" &&
+	test_create_repo main &&
+	test_commit -C main init &&
+	git -C main worktree add --detach ../side &&
+	sed "s,side/\.git$,sidemoved/.git," \
+		main/.git/worktrees/side/gitdir >expect-gitdir &&
+	sed "s,main/.git/worktrees/side$,mainmoved/.git/worktrees/side," \
+		side/.git >expect-gitfile &&
+	mv main mainmoved &&
+	mv side sidemoved &&
+	git -C mainmoved worktree repair ../sidemoved &&
+	test_cmp expect-gitdir mainmoved/.git/worktrees/side/gitdir &&
+	test_cmp expect-gitfile sidemoved/.git
+'
+
 test_done

worktree.c

@@ -644,6 +644,42 @@ static int is_main_worktree_path(const char *path)
 	return !cmp;
 }
 
+/*
+ * If both the main worktree and linked worktree have been moved, then the
+ * gitfile /path/to/worktree/.git won't point into the repository, thus we
+ * won't know which <repo>/worktrees/<id>/gitdir to repair. However, we may
+ * be able to infer the gitdir by manually reading /path/to/worktree/.git,
+ * extracting the <id>, and checking if <repo>/worktrees/<id> exists.
+ */
+static char *infer_backlink(const char *gitfile)
+{
+	struct strbuf actual = STRBUF_INIT;
+	struct strbuf inferred = STRBUF_INIT;
+	const char *id;
+
+	if (strbuf_read_file(&actual, gitfile, 0) < 0)
+		goto error;
+	if (!starts_with(actual.buf, "gitdir:"))
+		goto error;
+	if (!(id = find_last_dir_sep(actual.buf)))
+		goto error;
+	strbuf_trim(&actual);
+	id++; /* advance past '/' to point at <id> */
+	if (!*id)
+		goto error;
+	strbuf_git_common_path(&inferred, the_repository, "worktrees/%s", id);
+	if (!is_directory(inferred.buf))
+		goto error;
+
+	strbuf_release(&actual);
+	return strbuf_detach(&inferred, NULL);
+
+error:
+	strbuf_release(&actual);
+	strbuf_release(&inferred);
+	return NULL;
+}
+
 /*
  * Repair <repo>/worktrees/<id>/gitdir if missing, corrupt, or not pointing at
  * the worktree's path.
@@ -675,6 +711,11 @@ void repair_worktree_at_path(const char *path,
 	if (err == READ_GITFILE_ERR_NOT_A_FILE) {
 		fn(1, realdotgit.buf, _("unable to locate repository; .git is not a file"), cb_data);
 		goto done;
+	} else if (err == READ_GITFILE_ERR_NOT_A_REPO) {
+		if (!(backlink = infer_backlink(realdotgit.buf))) {
+			fn(1, realdotgit.buf, _("unable to locate repository; .git file does not reference a repository"), cb_data);
+			goto done;
+		}
 	} else if (err) {
 		fn(1, realdotgit.buf, _("unable to locate repository; .git file broken"), cb_data);
 		goto done;