patch, 2 partsget_sha1_oneline: allow to input commit_list

diff --git a/sha1_name.c b/sha1_name.c
index 2c3a5fb..c298285 100644
--- a/sha1_name.c
+++ b/sha1_name.c
@@ -690,7 +690,9 @@ static int handle_one_ref(const char *path,
 	return 0;
 }
 
-static int get_sha1_oneline(const char *prefix, unsigned char *sha1)
+static int get_sha1_oneline(const char *prefix,
+			    unsigned char *sha1,
+			    struct commit_list *original_list)
 {
 	struct commit_list *list = NULL, *backup = NULL, *l;
 	int retval = -1;
@@ -706,7 +708,12 @@ static int get_sha1_oneline(const char *prefix, unsigned char *sha1)
 	if (regcomp(&regex, prefix, REG_EXTENDED))
 		die("Invalid search pattern: %s", prefix);
 
-	for_each_ref(handle_one_ref, &list);
+	for (l = original_list; l; l = l->next) {
+		commit_list_insert(l->item, &list);
+		l->item->object.flags |= ONELINE_SEEN;
+	}
+	if (!list)
+		for_each_ref(handle_one_ref, &list);
 	for (l = list; l; l = l->next)
 		commit_list_insert(l->item, &backup);
 	while (list) {
@@ -1090,7 +1097,7 @@ int get_sha1_with_context_1(const char *name, unsigned char *sha1,
 		int pos;
 		if (namelen > 2 && name[1] == '/')
 			/* don't need mode for commit */
-			return get_sha1_oneline(name + 2, sha1);
+			return get_sha1_oneline(name + 2, sha1, NULL);
 		if (namelen < 3 ||
 		    name[2] != ':' ||
 		    name[1] < '0' || '3' < name[1])

Documentation/revisions.txt, sha1_name.c, t/t1511-rev-parse-caret.sh

diff --git a/Documentation/revisions.txt b/Documentation/revisions.txt
index 3d4b79c..174fa8e 100644
--- a/Documentation/revisions.txt
+++ b/Documentation/revisions.txt
@@ -106,6 +106,12 @@ the `$GIT_DIR/refs` directory or from the `$GIT_DIR/packed-refs` file.
   and dereference the tag recursively until a non-tag object is
   found.
 
+* A suffix '{caret}' to a revision parameter followed by a brace
+  pair that contains a text led by a slash (e.g. `HEAD^{/fix nasty bug}`):
+  this is the same as `:/fix nasty bug` syntax below except that
+  it returns the youngest matching commit which is reachable from
+  the ref before '{caret}'.
+
 * A colon, followed by a slash, followed by a text (e.g. `:/fix nasty bug`): this names
   a commit whose commit message matches the specified regular expression.
   This name returns the youngest matching commit which is
diff --git a/sha1_name.c b/sha1_name.c
index c298285..f1a86d9 100644
--- a/sha1_name.c
+++ b/sha1_name.c
@@ -527,6 +527,7 @@ struct object *peel_to_type(const char *name, int namelen,
 	}
 }
 
+static int get_sha1_oneline(const char *, unsigned char *, struct commit_list *);
 static int peel_onion(const char *name, int len, unsigned char *sha1)
 {
 	unsigned char outer[20];
@@ -562,6 +563,8 @@ static int peel_onion(const char *name, int len, unsigned char *sha1)
 		expected_type = OBJ_BLOB;
 	else if (sp[0] == '}')
 		expected_type = OBJ_NONE;
+	else if (sp[0] == '/')
+		expected_type = OBJ_COMMIT;
 	else
 		return -1;
 
@@ -576,19 +579,29 @@ static int peel_onion(const char *name, int len, unsigned char *sha1)
 		if (!o || (!o->parsed && !parse_object(o->sha1)))
 			return -1;
 		hashcpy(sha1, o->sha1);
+		return 0;
 	}
-	else {
-		/*
-		 * At this point, the syntax look correct, so
-		 * if we do not get the needed object, we should
-		 * barf.
-		 */
-		o = peel_to_type(name, len, o, expected_type);
-		if (o) {
-			hashcpy(sha1, o->sha1);
-			return 0;
-		}
+
+	/*
+	 * At this point, the syntax look correct, so if we do not get
+	 * the needed object, we should barf.
+	 */
+	o = peel_to_type(name, len, o, expected_type);
+	if (!o)
 		return -1;
+
+	hashcpy(sha1, o->sha1);
+	if (sp[0] == '/') { /* ^{/foo} */
+		struct commit_list *list = NULL;
+		char *prefix;
+		int ret;
+
+		commit_list_insert((struct commit *)o, &list);
+		prefix = xstrndup(sp + 1, name + len - 1 - (sp + 1));
+		ret = get_sha1_oneline(prefix, sha1, list);
+		free(prefix);
+		free_commit_list(list);
+		return ret;
 	}
 	return 0;
 }
diff --git a/t/t1511-rev-parse-caret.sh b/t/t1511-rev-parse-caret.sh
new file mode 100755
index 0000000..5c8439c
--- /dev/null
+++ b/t/t1511-rev-parse-caret.sh
@@ -0,0 +1,73 @@
+#!/bin/sh
+
+test_description='tests for ref^{stuff}'
+
+. ./test-lib.sh
+
+test_expect_success 'setup' '
+	echo blob >a-blob &&
+	git tag -a -m blob blob-tag `git hash-object -w a-blob`
+	mkdir a-tree &&
+	echo moreblobs >a-tree/another-blob &&
+	git add . &&
+	TREE_SHA1=`git write-tree` &&
+	git tag -a -m tree tree-tag "$TREE_SHA1" &&
+	git commit -m Initial &&
+	git tag -a -m commit commit-tag &&
+	git branch ref &&
+	git checkout master &&
+	echo modified >>a-blob &&
+	git add -u &&
+	git commit -m Modified
+'
+
+test_expect_success 'ref^{non-existent}' '
+	test_must_fail git rev-parse ref^{non-existent}
+'
+
+test_expect_success 'ref^{}' '
+	git rev-parse ref >expected &&
+	git rev-parse ref^{} >actual &&
+	test_cmp expected actual &&
+	git rev-parse commit-tag^{} >actual &&
+	test_cmp expected actual
+'
+
+test_expect_success 'ref^{commit}' '
+	git rev-parse ref >expected &&
+	git rev-parse ref^{commit} >actual &&
+	test_cmp expected actual &&
+	git rev-parse commit-tag^{commit} >actual &&
+	test_cmp expected actual &&
+	test_must_fail git rev-parse tree-tag^{commit} &&
+	test_must_fail git rev-parse blob-tag^{commit}
+'
+
+test_expect_success 'ref^{tree}' '
+	echo $TREE_SHA1 >expected &&
+	git rev-parse ref^{tree} >actual &&
+	test_cmp expected actual &&
+	git rev-parse commit-tag^{tree} >actual &&
+	test_cmp expected actual &&
+	git rev-parse tree-tag^{tree} >actual &&
+	test_cmp expected actual &&
+	test_must_fail git rev-parse blob-tag^{tree}
+'
+
+test_expect_success 'ref^{/}' '
+	git rev-parse master >expected &&
+	git rev-parse master^{/} >actual &&
+	test_cmp expected actual
+'
+
+test_expect_success 'ref^{/non-existent}' '
+	test_must_fail git rev-parse master^{/non-existent}
+'
+
+test_expect_success 'ref^{/Initial}' '
+	git rev-parse ref >expected &&
+	git rev-parse master^{/Initial} >actual &&
+	test_cmp expected actual
+'
+
+test_done