config: plumb --fixed-value into config API

The git_config_set_multivar_in_file_gently() and related methods now
take a 'flags' bitfield, so add a new bit representing the --fixed-value
option from 'git config'. This alters the purpose of the value_pattern
parameter to be an exact string match. This requires some initialization
changes in git_config_set_multivar_in_file_gently() and a new strcmp()
call in the matches() method.

The new CONFIG_FLAGS_FIXED_VALUE flag is initialized in builtin/config.c
based on the --fixed-value option, and that needs to be updated in
several callers.

This patch only affects some of the modes of 'git config', and the rest
will be completed in the next change.

Signed-off-by: Derrick Stolee <dstolee@microsoft.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

4 files changed, 73 insertions, 5 deletions

diff --git a/builtin/config.c b/builtin/config.c
index f1b73ac8b5..21892a784c 100644
--- a/builtin/config.c
+++ b/builtin/config.c
@@ -633,6 +633,7 @@ int cmd_config(int argc, const char **argv, const char *prefix)
 {
 	int nongit = !startup_info->have_repository;
 	char *value;
+	int flags = 0;
 
 	given_config_source.file = xstrdup_or_null(getenv(CONFIG_ENVIRONMENT));
 
@@ -800,6 +801,8 @@ int cmd_config(int argc, const char **argv, const char *prefix)
 			error(_("--fixed-value only applies with 'value-pattern'"));
 			usage_builtin_config();
 		}
+
+		flags |= CONFIG_FLAGS_FIXED_VALUE;
 	}
 
 	if (actions & PAGING_ACTIONS)
@@ -863,7 +866,8 @@ int cmd_config(int argc, const char **argv, const char *prefix)
 		value = normalize_value(argv[0], argv[1]);
 		UNLEAK(value);
 		return git_config_set_multivar_in_file_gently(given_config_source.file,
-							      argv[0], value, argv[2], 0);
+							      argv[0], value, argv[2],
+							      flags);
 	}
 	else if (actions == ACTION_ADD) {
 		check_write();
@@ -872,7 +876,8 @@ int cmd_config(int argc, const char **argv, const char *prefix)
 		UNLEAK(value);
 		return git_config_set_multivar_in_file_gently(given_config_source.file,
 							      argv[0], value,
-							      CONFIG_REGEX_NONE, 0);
+							      CONFIG_REGEX_NONE,
+							      flags);
 	}
 	else if (actions == ACTION_REPLACE_ALL) {
 		check_write();
@@ -881,7 +886,7 @@ int cmd_config(int argc, const char **argv, const char *prefix)
 		UNLEAK(value);
 		return git_config_set_multivar_in_file_gently(given_config_source.file,
 							      argv[0], value, argv[2],
-							      CONFIG_FLAGS_MULTI_REPLACE);
+							      flags | CONFIG_FLAGS_MULTI_REPLACE);
 	}
 	else if (actions == ACTION_GET) {
 		check_argc(argc, 1, 2);
@@ -908,7 +913,8 @@ int cmd_config(int argc, const char **argv, const char *prefix)
 		check_argc(argc, 1, 2);
 		if (argc == 2)
 			return git_config_set_multivar_in_file_gently(given_config_source.file,
-								      argv[0], NULL, argv[1], 0);
+								      argv[0], NULL, argv[1],
+								      flags);
 		else
 			return git_config_set_in_file_gently(given_config_source.file,
 							     argv[0], NULL);
@@ -918,7 +924,7 @@ int cmd_config(int argc, const char **argv, const char *prefix)
 		check_argc(argc, 1, 2);
 		return git_config_set_multivar_in_file_gently(given_config_source.file,
 							      argv[0], NULL, argv[1],
-							      CONFIG_FLAGS_MULTI_REPLACE);
+							      flags | CONFIG_FLAGS_MULTI_REPLACE);
 	}
 	else if (actions == ACTION_RENAME_SECTION) {
 		int ret;
diff --git a/config.c b/config.c
index 5b2f00f073..3b2edc0faf 100644
--- a/config.c
+++ b/config.c
@@ -2415,6 +2415,7 @@ struct config_store_data {
 	size_t baselen;
 	char *key;
 	int do_not_match;
+	const char *fixed_value;
 	regex_t *value_pattern;
 	int multi_replace;
 	struct {
@@ -2444,6 +2445,8 @@ static int matches(const char *key, const char *value,
 {
 	if (strcmp(key, store->key))
 		return 0; /* not ours */
+	if (store->fixed_value)
+		return !strcmp(store->fixed_value, value);
 	if (!store->value_pattern)
 		return 1; /* always matches */
 	if (store->value_pattern == CONFIG_REGEX_NONE)
@@ -2816,6 +2819,8 @@ int git_config_set_multivar_in_file_gently(const char *config_filename,
 			store.value_pattern = NULL;
 		else if (value_pattern == CONFIG_REGEX_NONE)
 			store.value_pattern = CONFIG_REGEX_NONE;
+		else if (flags & CONFIG_FLAGS_FIXED_VALUE)
+			store.fixed_value = value_pattern;
 		else {
 			if (value_pattern[0] == '!') {
 				store.do_not_match = 1;
diff --git a/config.h b/config.h
index 7535b1f856..c1449bb790 100644
--- a/config.h
+++ b/config.h
@@ -269,6 +269,13 @@ int git_config_key_is_valid(const char *key);
  */
 #define CONFIG_FLAGS_MULTI_REPLACE (1 << 0)
 
+/*
+ * When CONFIG_FLAGS_FIXED_VALUE is specified, match key/value pairs
+ * by string comparison (not regex match) to the provided value_pattern
+ * parameter.
+ */
+#define CONFIG_FLAGS_FIXED_VALUE (1 << 1)
+
 int git_config_set_multivar_gently(const char *, const char *, const char *, unsigned);
 void git_config_set_multivar(const char *, const char *, const char *, unsigned);
 int git_config_set_multivar_in_file_gently(const char *, const char *, const char *, const char *, unsigned);
diff --git a/t/t1300-config.sh b/t/t1300-config.sh
index 841ed204d6..4293ba22af 100755
--- a/t/t1300-config.sh
+++ b/t/t1300-config.sh
@@ -1994,4 +1994,54 @@ test_expect_success 'refuse --fixed-value for incompatible actions' '
 	test_must_fail git config --file=config --fixed-value --unset-all dev.null
 '
 
+test_expect_success '--fixed-value uses exact string matching' '
+	test_when_finished rm -f config initial &&
+	META="a+b*c?d[e]f.g" &&
+	git config --file=initial fixed.test "$META" &&
+
+	cp initial config &&
+	git config --file=config fixed.test bogus "$META" &&
+	git config --file=config --list >actual &&
+	cat >expect <<-EOF &&
+	fixed.test=$META
+	fixed.test=bogus
+	EOF
+	test_cmp expect actual &&
+
+	cp initial config &&
+	git config --file=config --fixed-value fixed.test bogus "$META" &&
+	git config --file=config --list >actual &&
+	cat >expect <<-\EOF &&
+	fixed.test=bogus
+	EOF
+	test_cmp expect actual &&
+
+	cp initial config &&
+	test_must_fail git config --file=config --unset fixed.test "$META" &&
+	git config --file=config --fixed-value --unset fixed.test "$META" &&
+	test_must_fail git config --file=config fixed.test &&
+
+	cp initial config &&
+	test_must_fail git config --file=config --unset-all fixed.test "$META" &&
+	git config --file=config --fixed-value --unset-all fixed.test "$META" &&
+	test_must_fail git config --file=config fixed.test &&
+
+	cp initial config &&
+	git config --file=config --replace-all fixed.test bogus "$META" &&
+	git config --file=config --list >actual &&
+	cat >expect <<-EOF &&
+	fixed.test=$META
+	fixed.test=bogus
+	EOF
+	test_cmp expect actual &&
+
+	git config --file=config --fixed-value --replace-all fixed.test bogus "$META" &&
+	git config --file=config --list >actual &&
+	cat >expect <<-EOF &&
+	fixed.test=bogus
+	fixed.test=bogus
+	EOF
+	test_cmp expect actual
+'
+
 test_done