Merge branch 'nd/oneline-sha1-name-from-specific-ref'

* nd/oneline-sha1-name-from-specific-ref:
  get_sha1: handle special case $commit^{/}
  get_sha1: support $commit^{/regex} syntax
  get_sha1_oneline: make callers prepare the commit list to traverse
  get_sha1_oneline: fix lifespan rule of temp_commit_buffer variable

3 files changed, 134 insertions, 28 deletions

diff --git a/Documentation/revisions.txt b/Documentation/revisions.txt
index 8b519d7448..9e92734bc1 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 8f49279642..ceb9cdd860 100644
--- a/sha1_name.c
+++ b/sha1_name.c
@@ -7,6 +7,8 @@
 #include "refs.h"
 #include "remote.h"
 
+static int get_sha1_oneline(const char *, unsigned char *, struct commit_list *);
+
 static int find_short_object_filename(int len, const char *name, unsigned char *sha1)
 {
 	struct alternate_object_database *alt;
@@ -562,6 +564,8 @@ 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 +580,37 @@ 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)
+		return -1;
+
+	hashcpy(sha1, o->sha1);
+	if (sp[0] == '/') {
+		/* "$commit^{/foo}" */
+		char *prefix;
+		int ret;
+		struct commit_list *list = NULL;
+
 		/*
-		 * At this point, the syntax look correct, so
-		 * if we do not get the needed object, we should
-		 * barf.
+		 * $commit^{/}. Some regex implementation may reject.
+		 * We don't need regex anyway. '' pattern always matches.
 		 */
-		o = peel_to_type(name, len, o, expected_type);
-		if (o) {
-			hashcpy(sha1, o->sha1);
+		if (sp[1] == '}')
 			return 0;
-		}
-		return -1;
+
+		prefix = xstrndup(sp + 1, name + len - 1 - (sp + 1));
+		commit_list_insert((struct commit *)o, &list);
+		ret = get_sha1_oneline(prefix, sha1, list);
+		free(prefix);
+		return ret;
 	}
 	return 0;
 }
@@ -686,15 +708,14 @@ static int handle_one_ref(const char *path,
 	if (object->type != OBJ_COMMIT)
 		return 0;
 	insert_by_date((struct commit *)object, list);
-	object->flags |= ONELINE_SEEN;
 	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 *list)
 {
-	struct commit_list *list = NULL, *backup = NULL, *l;
-	int retval = -1;
-	char *temp_commit_buffer = NULL;
+	struct commit_list *backup = NULL, *l;
+	int found = 0;
 	regex_t regex;
 
 	if (prefix[0] == '!') {
@@ -706,41 +727,45 @@ 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 = list; l; l = l->next)
+	for (l = list; l; l = l->next) {
+		l->item->object.flags |= ONELINE_SEEN;
 		commit_list_insert(l->item, &backup);
+	}
 	while (list) {
-		char *p;
+		char *p, *to_free = NULL;
 		struct commit *commit;
 		enum object_type type;
 		unsigned long size;
+		int matches;
 
 		commit = pop_most_recent_commit(&list, ONELINE_SEEN);
 		if (!parse_object(commit->object.sha1))
 			continue;
-		free(temp_commit_buffer);
 		if (commit->buffer)
 			p = commit->buffer;
 		else {
 			p = read_sha1_file(commit->object.sha1, &type, &size);
 			if (!p)
 				continue;
-			temp_commit_buffer = p;
+			to_free = p;
 		}
-		if (!(p = strstr(p, "\n\n")))
-			continue;
-		if (!regexec(&regex, p + 2, 0, NULL, 0)) {
+
+		p = strstr(p, "\n\n");
+		matches = p && !regexec(&regex, p + 2, 0, NULL, 0);
+		free(to_free);
+
+		if (matches) {
 			hashcpy(sha1, commit->object.sha1);
-			retval = 0;
+			found = 1;
 			break;
 		}
 	}
 	regfree(&regex);
-	free(temp_commit_buffer);
 	free_commit_list(list);
 	for (l = backup; l; l = l->next)
 		clear_commit_marks(l->item, ONELINE_SEEN);
-	return retval;
+	free_commit_list(backup);
+	return found ? 0 : -1;
 }
 
 struct grab_nth_branch_switch_cbdata {
@@ -1107,9 +1132,11 @@ int get_sha1_with_context_1(const char *name, unsigned char *sha1,
 		struct cache_entry *ce;
 		char *new_path = NULL;
 		int pos;
-		if (namelen > 2 && name[1] == '/')
-			/* don't need mode for commit */
-			return get_sha1_oneline(name + 2, sha1);
+		if (namelen > 2 && name[1] == '/') {
+			struct commit_list *list = NULL;
+			for_each_ref(handle_one_ref, &list);
+			return get_sha1_oneline(name + 2, sha1, list);
+		}
 		if (namelen < 3 ||
 		    name[2] != ':' ||
 		    name[1] < '0' || '3' < name[1])
diff --git a/t/t1511-rev-parse-caret.sh b/t/t1511-rev-parse-caret.sh
new file mode 100755
index 0000000000..e043cb7c64
--- /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