builtin/show-ref: convert pattern to a local variable

The `pattern` variable is a global variable that tracks either the
reference names (not patterns!) for the `--verify` mode or the patterns
for the non-verify mode. This is a bit confusing due to the slightly
different meanings.

Convert the variable to be local. While this does not yet fix the double
meaning of the variable, this change allows us to address it in a
subsequent patch more easily by explicitly splitting up the different
subcommands of git-show-ref(1).

Note that we introduce a `struct show_ref_data` to pass the patterns to
`show_ref()`. While this is overengineered now, we will extend this
structure in a subsequent patch.

Signed-off-by: Patrick Steinhardt <[email protected]>
Signed-off-by: Junio C Hamano <[email protected]>

Author: pks-t

builtin/show-ref.c

@@ -20,7 +20,6 @@ static const char * const show_ref_usage[] = {
 
 static int deref_tags, show_head, tags_only, heads_only, found_match, verify,
 	   quiet, hash_only, abbrev, exclude_arg;
-static const char **pattern;
 static const char *exclude_existing_arg;
 
 static void show_one(const char *refname, const struct object_id *oid)
@@ -50,15 +49,21 @@ static void show_one(const char *refname, const struct object_id *oid)
 	}
 }
 
+struct show_ref_data {
+	const char **patterns;
+};
+
 static int show_ref(const char *refname, const struct object_id *oid,
-		    int flag UNUSED, void *cbdata UNUSED)
+		    int flag UNUSED, void *cbdata)
 {
+	struct show_ref_data *data = cbdata;
+
 	if (show_head && !strcmp(refname, "HEAD"))
 		goto match;
 
-	if (pattern) {
+	if (data->patterns) {
 		int reflen = strlen(refname);
-		const char **p = pattern, *m;
+		const char **p = data->patterns, *m;
 		while ((m = *p++) != NULL) {
 			int len = strlen(m);
 			if (len > reflen)
@@ -180,6 +185,9 @@ static const struct option show_ref_options[] = {
 
 int cmd_show_ref(int argc, const char **argv, const char *prefix)
 {
+	struct show_ref_data show_ref_data = {0};
+	const char **patterns;
+
 	git_config(git_default_config, NULL);
 
 	argc = parse_options(argc, argv, prefix, show_ref_options,
@@ -188,38 +196,40 @@ int cmd_show_ref(int argc, const char **argv, const char *prefix)
 	if (exclude_arg)
 		return exclude_existing(exclude_existing_arg);
 
-	pattern = argv;
-	if (!*pattern)
-		pattern = NULL;
+	patterns = argv;
+	if (!*patterns)
+		patterns = NULL;
 
 	if (verify) {
-		if (!pattern)
+		if (!patterns)
 			die("--verify requires a reference");
-		while (*pattern) {
+		while (*patterns) {
 			struct object_id oid;
 
-			if ((starts_with(*pattern, "refs/") || !strcmp(*pattern, "HEAD")) &&
-			    !read_ref(*pattern, &oid)) {
-				show_one(*pattern, &oid);
+			if ((starts_with(*patterns, "refs/") || !strcmp(*patterns, "HEAD")) &&
+			    !read_ref(*patterns, &oid)) {
+				show_one(*patterns, &oid);
 			}
 			else if (!quiet)
-				die("'%s' - not a valid ref", *pattern);
+				die("'%s' - not a valid ref", *patterns);
 			else
 				return 1;
-			pattern++;
+			patterns++;
 		}
 		return 0;
 	}
 
+	show_ref_data.patterns = patterns;
+
 	if (show_head)
-		head_ref(show_ref, NULL);
+		head_ref(show_ref, &show_ref_data);
 	if (heads_only || tags_only) {
 		if (heads_only)
-			for_each_fullref_in("refs/heads/", show_ref, NULL);
+			for_each_fullref_in("refs/heads/", show_ref, &show_ref_data);
 		if (tags_only)
-			for_each_fullref_in("refs/tags/", show_ref, NULL);
+			for_each_fullref_in("refs/tags/", show_ref, &show_ref_data);
 	} else {
-		for_each_ref(show_ref, NULL);
+		for_each_ref(show_ref, &show_ref_data);
 	}
 	if (!found_match) {
 		if (verify && !quiet)