diff --git a/builtin/for-each-repo.c b/builtin/for-each-repo.c
index 6aeac37148..ce8f7a9908 100644
--- a/builtin/for-each-repo.c
+++ b/builtin/for-each-repo.c
@@ -32,6 +32,7 @@ int cmd_for_each_repo(int argc, const char **argv, const char *prefix)
 	static const char *config_key = NULL;
 	int i, result = 0;
 	const struct string_list *values;
+	int err;
 
 	const struct option options[] = {
 		OPT_STRING(0, "config", &config_key, N_("config"),
@@ -45,14 +46,11 @@ int cmd_for_each_repo(int argc, const char **argv, const char *prefix)
 	if (!config_key)
 		die(_("missing --config=<config>"));
 
-	values = repo_config_get_value_multi(the_repository,
-					     config_key);
-
-	/*
-	 * Do nothing on an empty list, which is equivalent to the case
-	 * where the config variable does not exist at all.
-	 */
-	if (!values)
+	err = repo_config_get_string_multi(the_repository, config_key, &values);
+	if (err < 0)
+		usage_msg_optf(_("got bad config --config=%s"),
+			       for_each_repo_usage, options, config_key);
+	else if (err)
 		return 0;
 
 	for (i = 0; !result && i < values->nr; i++)
diff --git a/builtin/gc.c b/builtin/gc.c
index c58fe8c936..efc1b9a0fd 100644
--- a/builtin/gc.c
+++ b/builtin/gc.c
@@ -1494,7 +1494,6 @@ static int maintenance_register(int argc, const char **argv, const char *prefix)
 	};
 	int found = 0;
 	const char *key = "maintenance.repo";
-	char *config_value;
 	char *maintpath = get_maintpath();
 	struct string_list_item *item;
 	const struct string_list *list;
@@ -1509,13 +1508,10 @@ static int maintenance_register(int argc, const char **argv, const char *prefix)
 	git_config_set("maintenance.auto", "false");
 
 	/* Set maintenance strategy, if unset */
-	if (!git_config_get_string("maintenance.strategy", &config_value))
-		free(config_value);
-	else
+	if (git_config_get("maintenance.strategy"))
 		git_config_set("maintenance.strategy", "incremental");
 
-	list = git_config_get_value_multi(key);
-	if (list) {
+	if (!git_config_get_string_multi(key, &list)) {
 		for_each_string_list_item(item, list) {
 			if (!strcmp(maintpath, item->string)) {
 				found = 1;
@@ -1581,11 +1577,10 @@ static int maintenance_unregister(int argc, const char **argv, const char *prefi
 	if (config_file) {
 		git_configset_init(&cs);
 		git_configset_add_file(&cs, config_file);
-		list = git_configset_get_value_multi(&cs, key);
-	} else {
-		list = git_config_get_value_multi(key);
 	}
-	if (list) {
+	if (!(config_file
+	      ? git_configset_get_string_multi(&cs, key, &list)
+	      : git_config_get_string_multi(key, &list))) {
 		for_each_string_list_item(item, list) {
 			if (!strcmp(maintpath, item->string)) {
 				found = 1;
diff --git a/builtin/log.c b/builtin/log.c
index 4693385e8e..0c6556b2d7 100644
--- a/builtin/log.c
+++ b/builtin/log.c
@@ -185,10 +185,10 @@ static void set_default_decoration_filter(struct decoration_filter *decoration_f
 	int i;
 	char *value = NULL;
 	struct string_list *include = decoration_filter->include_ref_pattern;
-	const struct string_list *config_exclude =
-			git_config_get_value_multi("log.excludeDecoration");
+	const struct string_list *config_exclude;
 
-	if (config_exclude) {
+	if (!git_config_get_string_multi("log.excludeDecoration",
+					 &config_exclude)) {
 		struct string_list_item *item;
 		for_each_string_list_item(item, config_exclude)
 			string_list_append(decoration_filter->exclude_ref_config_pattern,
diff --git a/builtin/submodule--helper.c b/builtin/submodule--helper.c
index 65a053261a..6cd807471e 100644
--- a/builtin/submodule--helper.c
+++ b/builtin/submodule--helper.c
@@ -559,7 +559,7 @@ static int module_init(int argc, const char **argv, const char *prefix)
 	 * If there are no path args and submodule.active is set then,
 	 * by default, only initialize 'active' modules.
 	 */
-	if (!argc && git_config_get_value_multi("submodule.active"))
+	if (!argc && !git_config_get("submodule.active"))
 		module_list_active(&list);
 
 	info.prefix = prefix;
@@ -2745,7 +2745,7 @@ static int module_update(int argc, const char **argv, const char *prefix)
 		 * If there are no path args and submodule.active is set then,
 		 * by default, only initialize 'active' modules.
 		 */
-		if (!argc && git_config_get_value_multi("submodule.active"))
+		if (!argc && !git_config_get("submodule.active"))
 			module_list_active(&list);
 
 		info.prefix = opt.prefix;
@@ -3142,7 +3142,6 @@ static int config_submodule_in_gitmodules(const char *name, const char *var, con
 static void configure_added_submodule(struct add_data *add_data)
 {
 	char *key;
-	const char *val;
 	struct child_process add_submod = CHILD_PROCESS_INIT;
 	struct child_process add_gitmodules = CHILD_PROCESS_INIT;
 
@@ -3187,7 +3186,7 @@ static void configure_added_submodule(struct add_data *add_data)
 	 * is_submodule_active(), since that function needs to find
 	 * out the value of "submodule.active" again anyway.
 	 */
-	if (!git_config_get_string_tmp("submodule.active", &val)) {
+	if (!git_config_get("submodule.active")) {
 		/*
 		 * If the submodule being added isn't already covered by the
 		 * current configured pathspec, set the submodule's active flag
diff --git a/builtin/worktree.c b/builtin/worktree.c
index 80d05e246d..476325ef98 100644
--- a/builtin/worktree.c
+++ b/builtin/worktree.c
@@ -320,7 +320,6 @@ static void copy_filtered_worktree_config(const char *worktree_git_dir)
 
 	if (file_exists(from_file)) {
 		struct config_set cs = { { 0 } };
-		const char *core_worktree;
 		int bare;
 
 		if (safe_create_leading_directories(to_file) ||
@@ -339,7 +338,7 @@ static void copy_filtered_worktree_config(const char *worktree_git_dir)
 				to_file, "core.bare", NULL, "true", 0))
 			error(_("failed to unset '%s' in '%s'"),
 				"core.bare", to_file);
-		if (!git_configset_get_value(&cs, "core.worktree", &core_worktree) &&
+		if (!git_configset_get(&cs, "core.worktree") &&
 			git_config_set_in_file_gently(to_file,
 							"core.worktree", NULL))
 			error(_("failed to unset '%s' in '%s'"),
diff --git a/config.c b/config.c
index 0b2679994e..a30490fd58 100644
--- a/config.c
+++ b/config.c
@@ -2292,23 +2292,29 @@ void read_very_early_config(config_fn_t cb, void *data)
 	config_with_options(cb, data, NULL, &opts);
 }
 
-static struct config_set_element *configset_find_element(struct config_set *cs, const char *key)
+RESULT_MUST_BE_USED
+static int configset_find_element(struct config_set *cs, const char *key,
+				  struct config_set_element **dest)
 {
 	struct config_set_element k;
 	struct config_set_element *found_entry;
 	char *normalized_key;
+	int ret;
+
 	/*
 	 * `key` may come from the user, so normalize it before using it
 	 * for querying entries from the hashmap.
 	 */
-	if (git_config_parse_key(key, &normalized_key, NULL))
-		return NULL;
+	ret = git_config_parse_key(key, &normalized_key, NULL);
+	if (ret)
+		return ret;
 
 	hashmap_entry_init(&k.ent, strhash(normalized_key));
 	k.key = normalized_key;
 	found_entry = hashmap_get_entry(&cs->config_hash, &k, ent, NULL);
 	free(normalized_key);
-	return found_entry;
+	*dest = found_entry;
+	return 0;
 }
 
 static int configset_add_value(struct config_set *cs, const char *key, const char *value)
@@ -2317,8 +2323,11 @@ static int configset_add_value(struct config_set *cs, const char *key, const cha
 	struct string_list_item *si;
 	struct configset_list_item *l_item;
 	struct key_value_info *kv_info = xmalloc(sizeof(*kv_info));
+	int ret;
 
-	e = configset_find_element(cs, key);
+	ret = configset_find_element(cs, key, &e);
+	if (ret)
+		return ret;
 	/*
 	 * Since the keys are being fed by git_config*() callback mechanism, they
 	 * are already normalized. So simply add them without any further munging.
@@ -2412,24 +2421,65 @@ int git_configset_add_file(struct config_set *cs, const char *filename)
 int git_configset_get_value(struct config_set *cs, const char *key, const char **value)
 {
 	const struct string_list *values = NULL;
+	int ret;
+
 	/*
 	 * Follows "last one wins" semantic, i.e., if there are multiple matches for the
 	 * queried key in the files of the configset, the value returned will be the last
 	 * value in the value list for that key.
 	 */
-	values = git_configset_get_value_multi(cs, key);
+	if ((ret = git_configset_get_value_multi(cs, key, &values)))
+		return ret;
 
-	if (!values)
-		return 1;
 	assert(values->nr > 0);
 	*value = values->items[values->nr - 1].string;
 	return 0;
 }
 
-const struct string_list *git_configset_get_value_multi(struct config_set *cs, const char *key)
+int git_configset_get_value_multi(struct config_set *cs, const char *key,
+				  const struct string_list **dest)
 {
-	struct config_set_element *e = configset_find_element(cs, key);
-	return e ? &e->value_list : NULL;
+	struct config_set_element *e;
+	int ret;
+
+	if ((ret = configset_find_element(cs, key, &e)))
+		return ret;
+	else if (!e)
+		return 1;
+	*dest = &e->value_list;
+
+	return 0;
+}
+
+static int check_multi_string(struct string_list_item *item, void *util)
+{
+	return item->string ? 0 : config_error_nonbool(util);
+}
+
+int git_configset_get_string_multi(struct config_set *cs, const char *key,
+				   const struct string_list **dest)
+{
+	int ret;
+
+	if ((ret = git_configset_get_value_multi(cs, key, dest)))
+		return ret;
+	if ((ret = for_each_string_list((struct string_list *)*dest,
+					check_multi_string, (void *)key)))
+		return ret;
+
+	return 0;
+}
+
+int git_configset_get(struct config_set *cs, const char *key)
+{
+	struct config_set_element *e;
+	int ret;
+
+	if ((ret = configset_find_element(cs, key, &e)))
+		return ret;
+	else if (!e)
+		return 1;
+	return 0;
 }
 
 int git_configset_get_string(struct config_set *cs, const char *key, char **dest)
@@ -2568,6 +2618,12 @@ void repo_config(struct repository *repo, config_fn_t fn, void *data)
 	configset_iter(repo->config, fn, data);
 }
 
+int repo_config_get(struct repository *repo, const char *key)
+{
+	git_config_check_init(repo);
+	return git_configset_get(repo->config, key);
+}
+
 int repo_config_get_value(struct repository *repo,
 			  const char *key, const char **value)
 {
@@ -2575,11 +2631,18 @@ int repo_config_get_value(struct repository *repo,
 	return git_configset_get_value(repo->config, key, value);
 }
 
-const struct string_list *repo_config_get_value_multi(struct repository *repo,
-						      const char *key)
+int repo_config_get_value_multi(struct repository *repo, const char *key,
+				const struct string_list **dest)
 {
 	git_config_check_init(repo);
-	return git_configset_get_value_multi(repo->config, key);
+	return git_configset_get_value_multi(repo->config, key, dest);
+}
+
+int repo_config_get_string_multi(struct repository *repo, const char *key,
+				 const struct string_list **dest)
+{
+	git_config_check_init(repo);
+	return git_configset_get_string_multi(repo->config, key, dest);
 }
 
 int repo_config_get_string(struct repository *repo,
@@ -2682,14 +2745,25 @@ void git_config_clear(void)
 	repo_config_clear(the_repository);
 }
 
+int git_config_get(const char *key)
+{
+	return repo_config_get(the_repository, key);
+}
+
 int git_config_get_value(const char *key, const char **value)
 {
 	return repo_config_get_value(the_repository, key, value);
 }
 
-const struct string_list *git_config_get_value_multi(const char *key)
+int git_config_get_value_multi(const char *key, const struct string_list **dest)
 {
-	return repo_config_get_value_multi(the_repository, key);
+	return repo_config_get_value_multi(the_repository, key, dest);
+}
+
+int git_config_get_string_multi(const char *key,
+				const struct string_list **dest)
+{
+	return repo_config_get_string_multi(the_repository, key, dest);
 }
 
 int git_config_get_string(const char *key, char **dest)
@@ -2836,7 +2910,8 @@ void git_die_config(const char *key, const char *err, ...)
 		error_fn(err, params);
 		va_end(params);
 	}
-	values = git_config_get_value_multi(key);
+	if (git_config_get_value_multi(key, &values))
+		BUG("for key '%s' we must have a value to report on", key);
 	kv_info = values->items[values->nr - 1].util;
 	git_die_config_linenr(key, kv_info->filename, kv_info->linenr);
 }
diff --git a/config.h b/config.h
index 7606246531..4a6e3f19e5 100644
--- a/config.h
+++ b/config.h
@@ -450,10 +450,31 @@ int git_configset_add_file(struct config_set *cs, const char *filename);
 /**
  * Finds and returns the value list, sorted in order of increasing priority
  * for the configuration variable `key` and config set `cs`. When the
- * configuration variable `key` is not found, returns NULL. The caller
- * should not free or modify the returned pointer, as it is owned by the cache.
+ * configuration variable `key` is not found, returns 1 without touching
+ * `value`.
+ *
+ * The key will be parsed for validity with git_config_parse_key(), on
+ * error a negative value will be returned.
+ *
+ * The caller should not free or modify the returned pointer, as it is
+ * owned by the cache.
  */
-const struct string_list *git_configset_get_value_multi(struct config_set *cs, const char *key);
+RESULT_MUST_BE_USED
+int git_configset_get_value_multi(struct config_set *cs, const char *key,
+				  const struct string_list **dest);
+
+/**
+ * A validation wrapper for git_configset_get_value_multi() which does
+ * for it what git_configset_get_string() does for
+ * git_configset_get_value().
+ *
+ * The configuration syntax allows for "[section] key", which will
+ * give us a NULL entry in the "struct string_list", as opposed to
+ * "[section] key =" which is the empty string. Most users of the API
+ * are not prepared to handle NULL in a "struct string_list".
+ */
+int git_configset_get_string_multi(struct config_set *cs, const char *key,
+				   const struct string_list **dest);
 
 /**
  * Clears `config_set` structure, removes all saved variable-value pairs.
@@ -465,6 +486,13 @@ void git_configset_clear(struct config_set *cs);
  * value in the 'dest' pointer.
  */
 
+/**
+ * git_configset_get() returns negative values on error, see
+ * repo_config_get() below.
+ */
+RESULT_MUST_BE_USED
+int git_configset_get(struct config_set *cs, const char *key);
+
 /*
  * Finds the highest-priority value for the configuration variable `key`
  * and config set `cs`, stores the pointer to it in `value` and returns 0.
@@ -485,10 +513,22 @@ int git_configset_get_pathname(struct config_set *cs, const char *key, const cha
 /* Functions for reading a repository's config */
 struct repository;
 void repo_config(struct repository *repo, config_fn_t fn, void *data);
+
+/**
+ * Run only the discover part of the repo_config_get_*() functions
+ * below, in addition to 1 if not found, returns negative values on
+ * error (e.g. if the key itself is invalid).
+ */
+RESULT_MUST_BE_USED
+int repo_config_get(struct repository *repo, const char *key);
 int repo_config_get_value(struct repository *repo,
 			  const char *key, const char **value);
-const struct string_list *repo_config_get_value_multi(struct repository *repo,
-						      const char *key);
+RESULT_MUST_BE_USED
+int repo_config_get_value_multi(struct repository *repo, const char *key,
+				const struct string_list **dest);
+RESULT_MUST_BE_USED
+int repo_config_get_string_multi(struct repository *repo, const char *key,
+				 const struct string_list **dest);
 int repo_config_get_string(struct repository *repo,
 			   const char *key, char **dest);
 int repo_config_get_string_tmp(struct repository *repo,
@@ -521,8 +561,15 @@ void git_protected_config(config_fn_t fn, void *data);
  * manner, the config API provides two functions `git_config_get_value`
  * and `git_config_get_value_multi`. They both read values from an internal
  * cache generated previously from reading the config files.
+ *
+ * For those git_config_get*() functions that aren't documented,
+ * consult the corresponding repo_config_get*() function's
+ * documentation.
  */
 
+RESULT_MUST_BE_USED
+int git_config_get(const char *key);
+
 /**
  * Finds the highest-priority value for the configuration variable `key`,
  * stores the pointer to it in `value` and returns 0. When the
@@ -535,10 +582,17 @@ int git_config_get_value(const char *key, const char **value);
 /**
  * Finds and returns the value list, sorted in order of increasing priority
  * for the configuration variable `key`. When the configuration variable
- * `key` is not found, returns NULL. The caller should not free or modify
- * the returned pointer, as it is owned by the cache.
+ * `key` is not found, returns 1 without touching `value`.
+ *
+ * The caller should not free or modify the returned pointer, as it is
+ * owned by the cache.
  */
-const struct string_list *git_config_get_value_multi(const char *key);
+RESULT_MUST_BE_USED
+int git_config_get_value_multi(const char *key,
+			       const struct string_list **dest);
+RESULT_MUST_BE_USED
+int git_config_get_string_multi(const char *key,
+				const struct string_list **dest);
 
 /**
  * Resets and invalidates the config cache.
diff --git a/pack-bitmap.c b/pack-bitmap.c
index ca7c81b5c9..f8ab6be411 100644
--- a/pack-bitmap.c
+++ b/pack-bitmap.c
@@ -2318,7 +2318,11 @@ int bitmap_is_midx(struct bitmap_index *bitmap_git)
 
 const struct string_list *bitmap_preferred_tips(struct repository *r)
 {
-	return repo_config_get_value_multi(r, "pack.preferbitmaptips");
+	const struct string_list *dest;
+
+	if (!repo_config_get_string_multi(r, "pack.preferbitmaptips", &dest))
+		return dest;
+	return NULL;
 }
 
 int bitmap_is_preferred_refname(struct repository *r, const char *refname)
diff --git a/submodule.c b/submodule.c
index 2a057c35b7..c9579f9a3f 100644
--- a/submodule.c
+++ b/submodule.c
@@ -275,8 +275,7 @@ int is_tree_submodule_active(struct repository *repo,
 	free(key);
 
 	/* submodule.active is set */
-	sl = repo_config_get_value_multi(repo, "submodule.active");
-	if (sl) {
+	if (!repo_config_get_string_multi(repo, "submodule.active", &sl)) {
 		struct pathspec ps;
 		struct strvec args = STRVEC_INIT;
 		const struct string_list_item *item;
diff --git a/t/helper/test-config.c b/t/helper/test-config.c
index 4ba9eb6560..6dc4c37444 100644
--- a/t/helper/test-config.c
+++ b/t/helper/test-config.c
@@ -14,6 +14,8 @@
  * get_value_multi -> prints all values for the entered key in increasing order
  *		     of priority
  *
+ * get -> print return value for the entered key
+ *
  * get_int -> print integer value for the entered key or die
  *
  * get_bool -> print bool value for the entered key or die
@@ -95,8 +97,7 @@ int cmd__config(int argc, const char **argv)
 			goto exit1;
 		}
 	} else if (argc == 3 && !strcmp(argv[1], "get_value_multi")) {
-		strptr = git_config_get_value_multi(argv[2]);
-		if (strptr) {
+		if (!git_config_get_value_multi(argv[2], &strptr)) {
 			for (i = 0; i < strptr->nr; i++) {
 				v = strptr->items[i].string;
 				if (!v)
@@ -109,6 +110,26 @@ int cmd__config(int argc, const char **argv)
 			printf("Value not found for \"%s\"\n", argv[2]);
 			goto exit1;
 		}
+	} else if (argc == 3 && !strcmp(argv[1], "get")) {
+		int ret;
+
+		if (!(ret = git_config_get(argv[2])))
+			goto exit0;
+		else if (ret == 1)
+			printf("Value not found for \"%s\"\n", argv[2]);
+		else if (ret == -CONFIG_INVALID_KEY)
+			printf("Key \"%s\" is invalid\n", argv[2]);
+		else if (ret == -CONFIG_NO_SECTION_OR_NAME)
+			printf("Key \"%s\" has no section\n", argv[2]);
+		else
+			/*
+			 * A normal caller should just check "ret <
+			 * 0", but for our own tests let's BUG() if
+			 * our whitelist of git_config_parse_key()
+			 * return values isn't exhaustive.
+			 */
+			BUG("Key \"%s\" has unknown return %d", argv[2], ret);
+		goto exit1;
 	} else if (argc == 3 && !strcmp(argv[1], "get_int")) {
 		if (!git_config_get_int(argv[2], &val)) {
 			printf("%d\n", val);
@@ -159,8 +180,7 @@ int cmd__config(int argc, const char **argv)
 				goto exit2;
 			}
 		}
-		strptr = git_configset_get_value_multi(&cs, argv[2]);
-		if (strptr) {
+		if (!git_configset_get_value_multi(&cs, argv[2], &strptr)) {
 			for (i = 0; i < strptr->nr; i++) {
 				v = strptr->items[i].string;
 				if (!v)
diff --git a/t/t0068-for-each-repo.sh b/t/t0068-for-each-repo.sh
index 3648d439a8..4b90b74d5d 100755
--- a/t/t0068-for-each-repo.sh
+++ b/t/t0068-for-each-repo.sh
@@ -40,4 +40,23 @@ test_expect_success 'do nothing on empty config' '
 	git for-each-repo --config=bogus.config -- help --no-such-option
 '
 
+test_expect_success 'error on bad config keys' '
+	test_expect_code 129 git for-each-repo --config=a &&
+	test_expect_code 129 git for-each-repo --config=a.b. &&
+	test_expect_code 129 git for-each-repo --config="'\''.b"
+'
+
+test_expect_success 'error on NULL value for config keys' '
+	cat >>.git/config <<-\EOF &&
+	[empty]
+		key
+	EOF
+	cat >expect <<-\EOF &&
+	error: missing value for '\''empty.key'\''
+	EOF
+	test_expect_code 129 git for-each-repo --config=empty.key 2>actual.raw &&
+	grep ^error actual.raw >actual &&
+	test_cmp expect actual
+'
+
 test_done
diff --git a/t/t1308-config-set.sh b/t/t1308-config-set.sh
index b38e158d3b..7def7053e1 100755
--- a/t/t1308-config-set.sh
+++ b/t/t1308-config-set.sh
@@ -58,6 +58,8 @@ test_expect_success 'setup default config' '
 		skin = false
 		nose = 1
 		horns
+	[value]
+		less
 	EOF
 '
 
@@ -116,6 +118,45 @@ test_expect_success 'find value with the highest priority' '
 	check_config get_value case.baz "hask"
 '
 
+test_expect_success 'return value for an existing key' '
+	test-tool config get lamb.chop >out 2>err &&
+	test_must_be_empty out &&
+	test_must_be_empty err
+'
+
+test_expect_success 'return value for value-less key' '
+	test-tool config get value.less >out 2>err &&
+	test_must_be_empty out &&
+	test_must_be_empty err
+'
+
+test_expect_success 'return value for a missing key' '
+	cat >expect <<-\EOF &&
+	Value not found for "missing.key"
+	EOF
+	test_expect_code 1 test-tool config get missing.key >actual 2>err &&
+	test_cmp actual expect &&
+	test_must_be_empty err
+'
+
+test_expect_success 'return value for a bad key: CONFIG_INVALID_KEY' '
+	cat >expect <<-\EOF &&
+	Key "fails.iskeychar.-" is invalid
+	EOF
+	test_expect_code 1 test-tool config get fails.iskeychar.- >actual 2>err &&
+	test_cmp actual expect &&
+	test_must_be_empty out
+'
+
+test_expect_success 'return value for a bad key: CONFIG_NO_SECTION_OR_NAME' '
+	cat >expect <<-\EOF &&
+	Key "keynosection" has no section
+	EOF
+	test_expect_code 1 test-tool config get keynosection >actual 2>err &&
+	test_cmp actual expect &&
+	test_must_be_empty out
+'
+
 test_expect_success 'find integer value for a key' '
 	check_config get_int lamb.chop 65
 '
@@ -146,6 +187,71 @@ test_expect_success 'find multiple values' '
 	check_config get_value_multi case.baz sam bat hask
 '
 
+test_NULL_in_multi () {
+	local op="$1" &&
+	local file="$2" &&
+
+	test_expect_success "$op: NULL value in config${file:+ in $file}" '
+		config="$file" &&
+		if test -z "$config"
+		then
+			config=.git/config &&
+			test_when_finished "mv $config.old $config" &&
+			mv "$config" "$config".old
+		fi &&
+
+		# Value-less in the middle of a list
+		cat >"$config" <<-\EOF &&
+		[a]key=x
+		[a]key
+		[a]key=y
+		EOF
+		case "$op" in
+		*_multi)
+			cat >expect <<-\EOF
+			x
+			(NULL)
+			y
+			EOF
+			;;
+		*)
+			cat >expect <<-\EOF
+			y
+			EOF
+			;;
+		esac &&
+		test-tool config "$op" a.key $file >actual &&
+		test_cmp expect actual &&
+
+		# Value-less at the end of a least
+		cat >"$config" <<-\EOF &&
+		[a]key=x
+		[a]key=y
+		[a]key
+		EOF
+		case "$op" in
+		*_multi)
+			cat >expect <<-\EOF
+			x
+			y
+			(NULL)
+			EOF
+			;;
+		*)
+			cat >expect <<-\EOF
+			(NULL)
+			EOF
+			;;
+		esac &&
+		test-tool config "$op" a.key $file >actual &&
+		test_cmp expect actual
+	'
+}
+
+test_NULL_in_multi "get_value_multi"
+test_NULL_in_multi "configset_get_value" "my.config"
+test_NULL_in_multi "configset_get_value_multi" "my.config"
+
 test_expect_success 'find value from a configset' '
 	cat >config2 <<-\EOF &&
 	[case]
@@ -207,7 +313,7 @@ test_expect_success 'proper error on error in default config files' '
 	cp .git/config .git/config.old &&
 	test_when_finished "mv .git/config.old .git/config" &&
 	echo "[" >>.git/config &&
-	echo "fatal: bad config line 34 in file .git/config" >expect &&
+	echo "fatal: bad config line 36 in file .git/config" >expect &&
 	test_expect_code 128 test-tool config get_value foo.bar 2>actual &&
 	test_cmp expect actual
 '
diff --git a/t/t3309-notes-merge-auto-resolve.sh b/t/t3309-notes-merge-auto-resolve.sh
index 141d3e4ca4..9bd5dbf341 100755
--- a/t/t3309-notes-merge-auto-resolve.sh
+++ b/t/t3309-notes-merge-auto-resolve.sh
@@ -360,7 +360,12 @@ test_expect_success 'merge z into y with invalid strategy => Fail/No changes' '
 
 test_expect_success 'merge z into y with invalid configuration option => Fail/No changes' '
 	git config core.notesRef refs/notes/y &&
-	test_must_fail git -c notes.mergeStrategy="foo" notes merge z &&
+	cat >expect <<-\EOF &&
+	error: unknown notes merge strategy foo
+	fatal: unable to parse '\''notes.mergeStrategy'\'' from command-line config
+	EOF
+	test_must_fail git -c notes.mergeStrategy="foo" notes merge z 2>actual &&
+	test_cmp expect actual &&
 	# Verify no changes (y)
 	verify_notes y y
 '
diff --git a/t/t4202-log.sh b/t/t4202-log.sh
index 2ce2b41174..ae73aef922 100755
--- a/t/t4202-log.sh
+++ b/t/t4202-log.sh
@@ -835,6 +835,21 @@ test_expect_success 'log.decorate configuration' '
 
 '
 
+test_expect_success 'parse log.excludeDecoration with no value' '
+	cp .git/config .git/config.orig &&
+	test_when_finished mv .git/config.orig .git/config &&
+
+	cat >>.git/config <<-\EOF &&
+	[log]
+		excludeDecoration
+	EOF
+	cat >expect <<-\EOF &&
+	error: missing value for '\''log.excludeDecoration'\''
+	EOF
+	git log --decorate=short 2>actual &&
+	test_cmp expect actual
+'
+
 test_expect_success 'decorate-refs with glob' '
 	cat >expect.decorate <<-\EOF &&
 	Merge-tag-reach
diff --git a/t/t5304-prune.sh b/t/t5304-prune.sh
index d65a5f94b4..5500dd0842 100755
--- a/t/t5304-prune.sh
+++ b/t/t5304-prune.sh
@@ -72,8 +72,16 @@ test_expect_success 'gc: implicit prune --expire' '
 '
 
 test_expect_success 'gc: refuse to start with invalid gc.pruneExpire' '
-	git config gc.pruneExpire invalid &&
-	test_must_fail git gc
+	test_when_finished "rm -rf repo" &&
+	git init repo &&
+	>repo/.git/config &&
+	git -C repo config gc.pruneExpire invalid &&
+	cat >expect <<-\EOF &&
+	error: Invalid gc.pruneexpire: '\''invalid'\''
+	fatal: bad config variable '\''gc.pruneexpire'\'' in file '\''.git/config'\'' at line 2
+	EOF
+	test_must_fail git -C repo gc 2>actual &&
+	test_cmp expect actual
 '
 
 test_expect_success 'gc: start with ok gc.pruneExpire' '
diff --git a/t/t5310-pack-bitmaps.sh b/t/t5310-pack-bitmaps.sh
index 7d8dee41b0..526a5a506e 100755
--- a/t/t5310-pack-bitmaps.sh
+++ b/t/t5310-pack-bitmaps.sh
@@ -404,6 +404,26 @@ test_bitmap_cases () {
 		)
 	'
 
+	test_expect_success 'pack.preferBitmapTips' '
+		git init repo &&
+		test_when_finished "rm -rf repo" &&
+		(
+			cd repo &&
+			git config pack.writeBitmapLookupTable '"$writeLookupTable"' &&
+			test_commit_bulk --message="%s" 103 &&
+
+			cat >>.git/config <<-\EOF &&
+			[pack]
+				preferBitmapTips
+			EOF
+			cat >expect <<-\EOF &&
+			error: missing value for '\''pack.preferbitmaptips'\''
+			EOF
+			git repack -adb 2>actual &&
+			test_cmp expect actual
+		)
+	'
+
 	test_expect_success 'complains about multiple pack bitmaps' '
 		rm -fr repo &&
 		git init repo &&
diff --git a/t/t5552-skipping-fetch-negotiator.sh b/t/t5552-skipping-fetch-negotiator.sh
index 165427d57e..b55a9f65e6 100755
--- a/t/t5552-skipping-fetch-negotiator.sh
+++ b/t/t5552-skipping-fetch-negotiator.sh
@@ -3,6 +3,22 @@
 test_description='test skipping fetch negotiator'
 . ./test-lib.sh
 
+test_expect_success 'fetch.negotiationalgorithm config' '
+	test_when_finished "rm -rf repo" &&
+	git init repo &&
+	cat >repo/.git/config <<-\EOF &&
+	[fetch]
+	negotiationAlgorithm
+	EOF
+	cat >expect <<-\EOF &&
+	error: missing value for '\''fetch.negotiationalgorithm'\''
+	fatal: bad config variable '\''fetch.negotiationalgorithm'\'' in file '\''.git/config'\'' at line 2
+	EOF
+	test_expect_code 128 git -C repo fetch >out 2>actual &&
+	test_must_be_empty out &&
+	test_cmp expect actual
+'
+
 have_sent () {
 	while test "$#" -ne 0
 	do
diff --git a/t/t7004-tag.sh b/t/t7004-tag.sh
index 04a4b44183..32b312fa80 100755
--- a/t/t7004-tag.sh
+++ b/t/t7004-tag.sh
@@ -1871,6 +1871,23 @@ test_expect_success 'invalid sort parameter in configuratoin' '
 	test_must_fail git tag -l "foo*"
 '
 
+test_expect_success 'version sort handles empty value for versionsort.{prereleaseSuffix,suffix}' '
+	cp .git/config .git/config.orig &&
+	test_when_finished mv .git/config.orig .git/config &&
+
+	cat >>.git/config <<-\EOF &&
+	[versionsort]
+		prereleaseSuffix
+		suffix
+	EOF
+	cat >expect <<-\EOF &&
+	error: missing value for '\''versionsort.suffix'\''
+	error: missing value for '\''versionsort.prereleasesuffix'\''
+	EOF
+	git tag -l --sort=version:refname 2>actual &&
+	test_cmp expect actual
+'
+
 test_expect_success 'version sort with prerelease reordering' '
 	test_config versionsort.prereleaseSuffix -rc &&
 	git tag foo1.6-rc1 &&
diff --git a/t/t7413-submodule-is-active.sh b/t/t7413-submodule-is-active.sh
index 7cdc263764..887d181b72 100755
--- a/t/t7413-submodule-is-active.sh
+++ b/t/t7413-submodule-is-active.sh
@@ -51,6 +51,22 @@ test_expect_success 'is-active works with submodule.<name>.active config' '
 	test-tool -C super submodule is-active sub1
 '
 
+test_expect_success 'is-active handles submodule.active config missing a value' '
+	cp super/.git/config super/.git/config.orig &&
+	test_when_finished mv super/.git/config.orig super/.git/config &&
+
+	cat >>super/.git/config <<-\EOF &&
+	[submodule]
+		active
+	EOF
+
+	cat >expect <<-\EOF &&
+	error: missing value for '\''submodule.active'\''
+	EOF
+	test-tool -C super submodule is-active sub1 2>actual &&
+	test_cmp expect actual
+'
+
 test_expect_success 'is-active works with basic submodule.active config' '
 	test_when_finished "git -C super config submodule.sub1.URL ../sub" &&
 	test_when_finished "git -C super config --unset-all submodule.active" &&
diff --git a/t/t7900-maintenance.sh b/t/t7900-maintenance.sh
index 823331e44a..487e326b3f 100755
--- a/t/t7900-maintenance.sh
+++ b/t/t7900-maintenance.sh
@@ -524,6 +524,44 @@ test_expect_success 'register and unregister' '
 	git maintenance unregister --config-file ./other --force
 '
 
+test_expect_success 'register with no value for maintenance.repo' '
+	cp .git/config .git/config.orig &&
+	test_when_finished mv .git/config.orig .git/config &&
+
+	cat >>.git/config <<-\EOF &&
+	[maintenance]
+		repo
+	EOF
+	cat >expect <<-\EOF &&
+	error: missing value for '\''maintenance.repo'\''
+	EOF
+	git maintenance register 2>actual &&
+	test_cmp expect actual &&
+	git config maintenance.repo
+'
+
+test_expect_success 'unregister with no value for maintenance.repo' '
+	cp .git/config .git/config.orig &&
+	test_when_finished mv .git/config.orig .git/config &&
+
+	cat >>.git/config <<-\EOF &&
+	[maintenance]
+		repo
+	EOF
+	cat >expect <<-\EOF &&
+	error: missing value for '\''maintenance.repo'\''
+	EOF
+	test_expect_code 128 git maintenance unregister 2>actual.raw &&
+	grep ^error actual.raw >actual &&
+	test_cmp expect actual &&
+	git config maintenance.repo &&
+
+	git maintenance unregister --force 2>actual.raw &&
+	grep ^error actual.raw >actual &&
+	test_cmp expect actual &&
+	git config maintenance.repo
+'
+
 test_expect_success !MINGW 'register and unregister with regex metacharacters' '
 	META="a+b*c" &&
 	git init "$META" &&
diff --git a/versioncmp.c b/versioncmp.c
index 069ee94a4d..7498da96e0 100644
--- a/versioncmp.c
+++ b/versioncmp.c
@@ -160,15 +160,21 @@ int versioncmp(const char *s1, const char *s2)
 	}
 
 	if (!initialized) {
-		const struct string_list *deprecated_prereleases;
+		const char *const newk = "versionsort.suffix";
+		const char *const oldk = "versionsort.prereleasesuffix";
+		const struct string_list *newl;
+		const struct string_list *oldl;
+		int new = git_config_get_string_multi(newk, &newl);
+		int old = git_config_get_string_multi(oldk, &oldl);
+
+		if (!new && !old)
+			warning("ignoring %s because %s is set", oldk, newk);
+		if (!new)
+			prereleases = newl;
+		else if (!old)
+			prereleases = oldl;
+
 		initialized = 1;
-		prereleases = git_config_get_value_multi("versionsort.suffix");
-		deprecated_prereleases = git_config_get_value_multi("versionsort.prereleasesuffix");
-		if (prereleases) {
-			if (deprecated_prereleases)
-				warning("ignoring versionsort.prereleasesuffix because versionsort.suffix is set");
-		} else
-			prereleases = deprecated_prereleases;
 	}
 	if (prereleases && swap_prereleases(s1, s2, (const char *) p1 - s1 - 1,
 					    &diff))