refs: loosen restriction on wildcard "*" refspecs

Loosen restrictions on refspecs by allowing patterns that have a "*"
within a component instead of only as the whole component.

Remove the logic to accept a single "*" as a whole component from
check_refname_format(), and implement an extended form of that logic
in check_refname_component().  Pass the pointer to the flags argument
to the latter, as it has to clear REFNAME_REFSPEC_PATTERN bit when
it sees "*".

Teach check_refname_component() function to allow an asterisk "*"
only when REFNAME_REFSPEC_PATTERN is set in the flags, and drop the
bit after seeing a "*", to ensure that one side of a refspec
contains at most one asterisk.

This will allow us to accept refspecs such as `for/bar*:foo/baz*`.
Any refspec which functioned before shall continue functioning with
the new logic.

Signed-off-by: Jacob Keller <jacob.keller@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

1 files changed, 20 insertions, 16 deletions

diff --git a/refs.c b/refs.c
index 0900f54..3127518 100644
--- a/refs.c
+++ b/refs.c
@@ -21,12 +21,13 @@ struct ref_lock {
  * 2: ., look for a preceding . to reject .. in refs
  * 3: {, look for a preceding @ to reject @{ in refs
  * 4: A bad character: ASCII control characters, and
- *    "*", ":", "?", "[", "\", "^", "~", SP, or TAB
+ *    ":", "?", "[", "\", "^", "~", SP, or TAB
+ * 5: *, reject unless REFNAME_REFSPEC_PATTERN is set
  */
 static unsigned char refname_disposition[256] = {
 	1, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4,
 	4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4,
-	4, 0, 0, 0, 0, 0, 0, 0, 0, 0, 4, 0, 0, 0, 2, 1,
+	4, 0, 0, 0, 0, 0, 0, 0, 0, 0, 5, 0, 0, 0, 2, 1,
 	0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 4, 0, 0, 0, 0, 4,
 	0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
 	0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 4, 4, 0, 4, 0,
@@ -73,12 +74,13 @@ static unsigned char refname_disposition[256] = {
  * - any path component of it begins with ".", or
  * - it has double dots "..", or
  * - it has ASCII control characters, or
- * - it has "*", ":", "?", "[", "\", "^", "~", SP, or TAB anywhere, or
+ * - it has ":", "?", "[", "\", "^", "~", SP, or TAB anywhere, or
+ * - it has "*" anywhere unless REFNAME_REFSPEC_PATTERN is set, or
  * - it ends with a "/", or
  * - it ends with ".lock", or
  * - it contains a "@{" portion
  */
-static int check_refname_component(const char *refname, int flags)
+static int check_refname_component(const char *refname, int *flags)
 {
 	const char *cp;
 	char last = '\0';
@@ -99,6 +101,16 @@ static int check_refname_component(const char *refname, int flags)
 			break;
 		case 4:
 			return -1;
+		case 5:
+			if (!(*flags & REFNAME_REFSPEC_PATTERN))
+				return -1; /* refspec can't be a pattern */
+
+			/*
+			 * Unset the pattern flag so that we only accept
+			 * a single asterisk for one side of refspec.
+			 */
+			*flags &= ~ REFNAME_REFSPEC_PATTERN;
+			break;
 		}
 		last = ch;
 	}
@@ -123,18 +135,10 @@ int check_refname_format(const char *refname, int flags)
 
 	while (1) {
 		/* We are at the start of a path component. */
-		component_len = check_refname_component(refname, flags);
-		if (component_len <= 0) {
-			if ((flags & REFNAME_REFSPEC_PATTERN) &&
-					refname[0] == '*' &&
-					(refname[1] == '\0' || refname[1] == '/')) {
-				/* Accept one wildcard as a full refname component. */
-				flags &= ~REFNAME_REFSPEC_PATTERN;
-				component_len = 1;
-			} else {
-				return -1;
-			}
-		}
+		component_len = check_refname_component(refname, &flags);
+		if (component_len <= 0)
+			return -1;
+
 		component_count++;
 		if (refname[component_len] == '\0')
 			break;