Merge branch 'wc/find-commit-with-pattern-on-detached-head'

"git rev-parse ':/substring'" did not consider the history leading
only to HEAD when looking for a commit with the given substring,
when the HEAD is detached.  This has been fixed.

* wc/find-commit-with-pattern-on-detached-head:
  sha1-name.c: for ":/", find detached HEAD commits

Documentation/revisions.txt

@@ -184,7 +184,8 @@ existing tag object.
   A colon, followed by a slash, followed by a text, names
   a commit whose commit message matches the specified regular expression.
   This name returns the youngest matching commit which is
-  reachable from any ref. The regular expression can match any part of the
+  reachable from any ref, including HEAD.
+  The regular expression can match any part of the
   commit message. To match messages starting with a string, one can use
   e.g. ':/^foo'. The special sequence ':/!' is reserved for modifiers to what
   is matched. ':/!-foo' performs a negative match, while ':/!!foo' matches a

sha1-name.c

@@ -1650,6 +1650,7 @@ static int get_oid_with_context_1(const char *name,
 			struct commit_list *list = NULL;
 
 			for_each_ref(handle_one_ref, &list);
+			head_ref(handle_one_ref, &list);
 			commit_list_sort_by_date(&list);
 			return get_oid_oneline(name + 2, oid, list);
 		}

t/t4208-log-magic-pathspec.sh

@@ -25,6 +25,32 @@ test_expect_success '"git log :/a -- " should not be ambiguous' '
 	git log :/a --
 '
 
+test_expect_success '"git log :/detached -- " should find a commit only in HEAD' '
+	test_when_finished "git checkout master" &&
+	git checkout --detach &&
+	# Must manually call `test_tick` instead of using `test_commit`,
+	# because the latter additionally creates a tag, which would make
+	# the commit reachable not only via HEAD.
+	test_tick &&
+	git commit --allow-empty -m detached &&
+	test_tick &&
+	git commit --allow-empty -m something-else &&
+	git log :/detached --
+'
+
+test_expect_success '"git log :/detached -- " should not find an orphaned commit' '
+	test_must_fail git log :/detached --
+'
+
+test_expect_success '"git log :/detached -- " should find HEAD only of own worktree' '
+	git worktree add other-tree HEAD &&
+	git -C other-tree checkout --detach &&
+	test_tick &&
+	git -C other-tree commit --allow-empty -m other-detached &&
+	git -C other-tree log :/other-detached -- &&
+	test_must_fail git log :/other-detached --
+'
+
 test_expect_success '"git log -- :/a" should not be ambiguous' '
 	git log -- :/a
 '