diff --git a/Documentation/technical/api-config.txt b/Documentation/technical/api-config.txt
index 01f64d187f..b0aeb2e481 100644
--- a/Documentation/technical/api-config.txt
+++ b/Documentation/technical/api-config.txt
@@ -47,6 +47,18 @@ will first feed the user-wide one to the callback, and then the
 repo-specific one; by overwriting, the higher-priority repo-specific
 value is left at the end).
 
+The `git_config_with_options` function lets the caller examine config
+while adjusting some of the default behavior of `git_config`. It should
+almost never be used by "regular" git code that is looking up
+configuration variables. It is intended for advanced callers like
+`git-config`, which are intentionally tweaking the normal config-lookup
+process. It takes one extra parameter:
+
+`filename`::
+If this parameter is non-NULL, it specifies the name of a file to
+parse for configuration, rather than looking in the usual files. Regular
+`git_config` defaults to `NULL`.
+
 There is a special version of `git_config` called `git_config_early`.
 This version takes an additional parameter to specify the repository
 config, instead of having it looked up via `git_path`. This is useful
diff --git a/cache.h b/cache.h
index 0d0c51a394..604236a28f 100644
--- a/cache.h
+++ b/cache.h
@@ -1113,6 +1113,7 @@ extern int git_config_from_file(config_fn_t fn, const char *, void *);
 extern void git_config_push_parameter(const char *text);
 extern int git_config_from_parameters(config_fn_t fn, void *data);
 extern int git_config(config_fn_t fn, void *);
+extern int git_config_with_options(config_fn_t fn, void *, const char *filename);
 extern int git_config_early(config_fn_t fn, void *, const char *repo_config);
 extern int git_parse_ulong(const char *, unsigned long *);
 extern int git_config_int(const char *, const char *);
diff --git a/config.c b/config.c
index bc2e23379f..531d4d43e7 100644
--- a/config.c
+++ b/config.c
@@ -879,9 +879,6 @@ int git_config_early(config_fn_t fn, void *data, const char *repo_config)
 	int ret = 0, found = 0;
 	const char *home = NULL;
 
-	/* Setting $GIT_CONFIG makes git read _only_ the given config file. */
-	if (config_exclusive_filename)
-		return git_config_from_file(fn, config_exclusive_filename, data);
 	if (git_config_system() && !access(git_etc_gitconfig(), R_OK)) {
 		ret += git_config_from_file(fn, git_etc_gitconfig(),
 					    data);
@@ -917,11 +914,19 @@ int git_config_early(config_fn_t fn, void *data, const char *repo_config)
 	return ret == 0 ? found : ret;
 }
 
-int git_config(config_fn_t fn, void *data)
+int git_config_with_options(config_fn_t fn, void *data,
+			    const char *filename)
 {
 	char *repo_config = NULL;
 	int ret;
 
+	/*
+	 * If we have a specific filename, use it. Otherwise, follow the
+	 * regular lookup sequence.
+	 */
+	if (filename)
+		return git_config_from_file(fn, filename, data);
+
 	repo_config = git_pathdup("config");
 	ret = git_config_early(fn, data, repo_config);
 	if (repo_config)
@@ -929,6 +934,11 @@ int git_config(config_fn_t fn, void *data)
 	return ret;
 }
 
+int git_config(config_fn_t fn, void *data)
+{
+	return git_config_with_options(fn, data, config_exclusive_filename);
+}
+
 /*
  * Find all the stuff for git_config_set() below.
  */