diff --git a/cache.h b/cache.h
index a61b2d3f0d..5c24394d84 100644
--- a/cache.h
+++ b/cache.h
@@ -477,7 +477,7 @@ extern const char *get_git_common_dir(void);
 extern char *get_object_directory(void);
 extern char *get_index_file(void);
 extern char *get_graft_file(void);
-extern int set_git_dir(const char *path);
+extern void set_git_dir(const char *path);
 extern int get_common_dir_noenv(struct strbuf *sb, const char *gitdir);
 extern int get_common_dir(struct strbuf *sb, const char *gitdir);
 extern const char *get_git_namespace(void);
diff --git a/environment.c b/environment.c
index d6dd64662c..e01acf8b11 100644
--- a/environment.c
+++ b/environment.c
@@ -296,13 +296,12 @@ char *get_graft_file(void)
 	return the_repository->graft_file;
 }
 
-int set_git_dir(const char *path)
+void set_git_dir(const char *path)
 {
 	if (setenv(GIT_DIR_ENVIRONMENT, path, 1))
-		return error("Could not set GIT_DIR to '%s'", path);
+		die("could not set GIT_DIR to '%s'", path);
 	repo_set_gitdir(the_repository, path);
 	setup_git_env();
-	return 0;
 }
 
 const char *get_log_output_encoding(void)