builtin/config: convert key to a local variable

The `key` variable is used by the `get_value()` function for two
purposes:

  - It is used to store the result of `git_config_parse_key()`, which is
    then passed on to `collect_config()`.

  - It is used as a store to convert the provided key to an
    all-lowercase key when `use_key_regexp` is set.

Neither of these cases warrant a global variable at all. In the former
case we can pass the key via `struct collect_config_data`. And in the
latter case we really only want to have it as a temporary local variable
such that we can free associated memory.

Refactor the code accordingly to reduce our reliance on global state.

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

Author: pks-t

builtin/config.c

@@ -123,7 +123,6 @@ struct config_display_options {
 	.key_delim = ' ', \
 }
 
-static char *key;
 static int use_key_regexp;
 static int do_all;
 static int fixed_value;
@@ -325,6 +324,7 @@ struct collect_config_data {
 	const struct config_display_options *display_opts;
 	struct strbuf_list *values;
 	const char *value_pattern;
+	const char *key;
 	regex_t *regexp;
 	regex_t *key_regexp;
 	int do_not_match;
@@ -337,7 +337,7 @@ static int collect_config(const char *key_, const char *value_,
 	struct strbuf_list *values = data->values;
 	const struct key_value_info *kvi = ctx->kvi;
 
-	if (!use_key_regexp && strcmp(key_, key))
+	if (!use_key_regexp && strcmp(key_, data->key))
 		return 0;
 	if (use_key_regexp && regexec(data->key_regexp, key_, 0, NULL, 0))
 		return 0;
@@ -364,6 +364,7 @@ static int get_value(const struct config_location_options *opts,
 		.display_opts = display_opts,
 		.values = &values,
 	};
+	char *key = NULL;
 	int i;
 
 	if (use_key_regexp) {
@@ -395,6 +396,8 @@ static int get_value(const struct config_location_options *opts,
 			ret = CONFIG_INVALID_KEY;
 			goto free_strings;
 		}
+
+		data.key = key;
 	}
 
 	if (regex_ && (flags & CONFIG_FLAGS_FIXED_VALUE))