Revert PR #1462 and provide alternative fix

This rolls back the changes to fnmatch parsing from commit
2e40a60e except for the tests
that were added.  Instead this adds couple of new flags that can
be passed in when attempting to parse an fnmatch pattern.  Also,
this changes the pathspec match logic to special case matching a
filename with a '!' prefix against a negative pattern.

This fixes the build.

src/attr_file.c

@@ -79,13 +79,17 @@ int git_attr_file__parse_buffer(
 
 	while (!error && *scan) {
 		/* allocate rule if needed */
-		if (!rule && !(rule = git__calloc(1, sizeof(git_attr_rule)))) {
-			error = -1;
-			break;
+		if (!rule) {
+			if (!(rule = git__calloc(1, sizeof(git_attr_rule)))) {
+				error = -1;
+				break;
+			}
+			rule->match.flags = GIT_ATTR_FNMATCH_ALLOWNEG |
+				GIT_ATTR_FNMATCH_ALLOWMACRO;
 		}
 
 		/* parse the next "pattern attr attr attr" line */
-		if (!(error = git_attr_fnmatch__parse_gitattr_format(
+		if (!(error = git_attr_fnmatch__parse(
 				&rule->match, attrs->pool, context, &scan)) &&
 			!(error = git_attr_assignment__parse(
 				repo, attrs->pool, &rule->assigns, &scan)))
@@ -337,16 +341,23 @@ void git_attr_path__free(git_attr_path *info)
  * GIT_ENOTFOUND if the fnmatch does not require matching, or
  * another error code there was an actual problem.
  */
-int git_attr_fnmatch__parse_gitattr_format(
+int git_attr_fnmatch__parse(
 	git_attr_fnmatch *spec,
 	git_pool *pool,
 	const char *source,
 	const char **base)
 {
-	const char *pattern;
+	const char *pattern, *scan;
+	int slash_count, allow_space;
 
 	assert(spec && base && *base);
 
+	if (parse_optimized_patterns(spec, pool, *base))
+		return 0;
+
+	spec->flags = (spec->flags & GIT_ATTR_FNMATCH__INCOMING);
+	allow_space = ((spec->flags & GIT_ATTR_FNMATCH_ALLOWSPACE) != 0);
+
 	pattern = *base;
 
 	while (git__isspace(*pattern)) pattern++;
@@ -355,7 +366,7 @@ int git_attr_fnmatch__parse_gitattr_format(
 		return GIT_ENOTFOUND;
 	}
 
-	if (*pattern == '[') {
+	if (*pattern == '[' && (spec->flags & GIT_ATTR_FNMATCH_ALLOWMACRO) != 0) {
 		if (strncmp(pattern, "[attr]", 6) == 0) {
 			spec->flags = spec->flags | GIT_ATTR_FNMATCH_MACRO;
 			pattern += 6;
@@ -363,44 +374,11 @@ int git_attr_fnmatch__parse_gitattr_format(
 		/* else a character range like [a-e]* which is accepted */
 	}
 
-	if (*pattern == '!') {
+	if (*pattern == '!' && (spec->flags & GIT_ATTR_FNMATCH_ALLOWNEG) != 0) {
 		spec->flags = spec->flags | GIT_ATTR_FNMATCH_NEGATIVE;
 		pattern++;
 	}
 
-	if (git_attr_fnmatch__parse_shellglob_format(spec, pool, 
-		source, &pattern) < 0)
-			return -1;
-
-	*base = pattern;
-
-	return 0;
-}
-
-/*
- * Fills a spec for the purpose of pure pathspec matching, not
- * related to a gitattribute file parsing.
- *
- * This will return 0 if the spec was filled out, or
- * another error code there was an actual problem.
- */
-int git_attr_fnmatch__parse_shellglob_format(
-	git_attr_fnmatch *spec,
-	git_pool *pool,
-	const char *source,
-	const char **base)
-{
-	const char *pattern, *scan;
-	int slash_count, allow_space;
-
-	assert(spec && base && *base);
-
-	if (parse_optimized_patterns(spec, pool, *base))
-		return 0;
-
-	allow_space = (spec->flags & GIT_ATTR_FNMATCH_ALLOWSPACE) != 0;
-	pattern = *base;
-
 	slash_count = 0;
 	for (scan = pattern; *scan != '\0'; ++scan) {
 		/* scan until (non-escaped) white space */
@@ -636,7 +614,6 @@ static void git_attr_rule__clear(git_attr_rule *rule)
 	/* match.pattern is stored in a git_pool, so no need to free */
 	rule->match.pattern = NULL;
 	rule->match.length = 0;
-	rule->match.flags = 0;
 }
 
 void git_attr_rule__free(git_attr_rule *rule)

src/attr_file.h

@@ -28,6 +28,12 @@
 #define GIT_ATTR_FNMATCH_ALLOWSPACE	(1U << 6)
 #define GIT_ATTR_FNMATCH_ICASE		(1U << 7)
 #define GIT_ATTR_FNMATCH_MATCH_ALL	(1U << 8)
+#define GIT_ATTR_FNMATCH_ALLOWNEG   (1U << 9)
+#define GIT_ATTR_FNMATCH_ALLOWMACRO (1U << 10)
+
+#define GIT_ATTR_FNMATCH__INCOMING \
+	(GIT_ATTR_FNMATCH_ALLOWSPACE | \
+	 GIT_ATTR_FNMATCH_ALLOWNEG | GIT_ATTR_FNMATCH_ALLOWMACRO)
 
 extern const char *git_attr__true;
 extern const char *git_attr__false;
@@ -115,13 +121,7 @@ extern uint32_t git_attr_file__name_hash(const char *name);
  * other utilities
  */
 
-extern int git_attr_fnmatch__parse_gitattr_format(
-	git_attr_fnmatch *spec,
-	git_pool *pool,
-	const char *source,
-	const char **base);
-
-extern int git_attr_fnmatch__parse_shellglob_format(
+extern int git_attr_fnmatch__parse(
 	git_attr_fnmatch *spec,
 	git_pool *pool,
 	const char *source,

src/ignore.c

@@ -37,9 +37,9 @@ static int parse_ignore_file(
 			GITERR_CHECK_ALLOC(match);
 		}
 
-		match->flags = GIT_ATTR_FNMATCH_ALLOWSPACE;
+		match->flags = GIT_ATTR_FNMATCH_ALLOWSPACE | GIT_ATTR_FNMATCH_ALLOWNEG;
 
-		if (!(error = git_attr_fnmatch__parse_gitattr_format(
+		if (!(error = git_attr_fnmatch__parse(
 			match, ignores->pool, context, &scan)))
 		{
 			match->flags |= GIT_ATTR_FNMATCH_IGNORE;

src/pathspec.c

@@ -83,9 +83,9 @@ int git_pathspec__vinit(
 		if (!match)
 			return -1;
 
-		match->flags = GIT_ATTR_FNMATCH_ALLOWSPACE;
+		match->flags = GIT_ATTR_FNMATCH_ALLOWSPACE | GIT_ATTR_FNMATCH_ALLOWNEG;
 
-		ret = git_attr_fnmatch__parse_shellglob_format(match, strpool, NULL, &pattern);
+		ret = git_attr_fnmatch__parse(match, strpool, NULL, &pattern);
 		if (ret == GIT_ENOTFOUND) {
 			git__free(match);
 			continue;
@@ -160,6 +160,15 @@ static int pathspec_match_one(
 		path[match->length] == '/')
 		result = 0;
 
+	/* if we didn't match and this is a negative match, check for exact
+	 * match of filename with leading '!'
+	 */
+	if (result == FNM_NOMATCH &&
+		(match->flags & GIT_ATTR_FNMATCH_NEGATIVE) != 0 &&
+		*path == '!' &&
+		ctxt->strncomp(path + 1, match->pattern, match->length) == 0)
+		return 1;
+
 	if (result == 0)
 		return (match->flags & GIT_ATTR_FNMATCH_NEGATIVE) ? 0 : 1;
 	return -1;

tests-clar/attr/file.c

@@ -49,7 +49,6 @@ void test_attr_file__match_variants(void)
 	cl_assert(rule);
 	cl_assert_equal_s("pat0", rule->match.pattern);
 	cl_assert(rule->match.length == strlen("pat0"));
-	cl_assert(rule->match.flags == 0);
 	cl_assert(rule->assigns.length == 1);
 	assign = get_assign(rule,0);
 	cl_assert_equal_s("attr0", assign->name);
@@ -59,16 +58,16 @@ void test_attr_file__match_variants(void)
 	rule = get_rule(1);
 	cl_assert_equal_s("pat1", rule->match.pattern);
 	cl_assert(rule->match.length == strlen("pat1"));
-	cl_assert(rule->match.flags == GIT_ATTR_FNMATCH_NEGATIVE);
+	cl_assert((rule->match.flags & GIT_ATTR_FNMATCH_NEGATIVE) != 0);
 
 	rule = get_rule(2);
 	cl_assert_equal_s("pat2", rule->match.pattern);
 	cl_assert(rule->match.length == strlen("pat2"));
-	cl_assert(rule->match.flags == GIT_ATTR_FNMATCH_DIRECTORY);
+	cl_assert((rule->match.flags & GIT_ATTR_FNMATCH_DIRECTORY) != 0);
 
 	rule = get_rule(3);
 	cl_assert_equal_s("pat3dir/pat3file", rule->match.pattern);
-	cl_assert(rule->match.flags == GIT_ATTR_FNMATCH_FULLPATH);
+	cl_assert((rule->match.flags & GIT_ATTR_FNMATCH_FULLPATH) != 0);
 
 	rule = get_rule(4);
 	cl_assert_equal_s("pat4.*", rule->match.pattern);
@@ -89,7 +88,6 @@ void test_attr_file__match_variants(void)
 	rule = get_rule(8);
 	cl_assert_equal_s("pat8 with spaces", rule->match.pattern);
 	cl_assert(rule->match.length == strlen("pat8 with spaces"));
-	cl_assert(rule->match.flags == 0);
 
 	rule = get_rule(9);
 	cl_assert_equal_s("pat9", rule->match.pattern);