diff --git a/builtin/gc.c b/builtin/gc.c
index 72bac2554f..e7406bf667 100644
--- a/builtin/gc.c
+++ b/builtin/gc.c
@@ -167,9 +167,9 @@ static void gc_config(void)
 	git_config_get_bool("gc.autodetach", &detach_auto);
 	git_config_get_bool("gc.cruftpacks", &cruft_packs);
 	git_config_get_ulong("gc.maxcruftsize", &max_cruft_size);
-	git_config_get_expiry("gc.pruneexpire", &prune_expire);
-	git_config_get_expiry("gc.worktreepruneexpire", &prune_worktrees_expire);
-	git_config_get_expiry("gc.logexpiry", &gc_log_expire);
+	git_config_get_expiry("gc.pruneexpire", (char **) &prune_expire);
+	git_config_get_expiry("gc.worktreepruneexpire", (char **) &prune_worktrees_expire);
+	git_config_get_expiry("gc.logexpiry", (char **) &gc_log_expire);
 
 	git_config_get_ulong("gc.bigpackthreshold", &big_pack_threshold);
 	git_config_get_ulong("pack.deltacachesize", &max_delta_cache_size);
diff --git a/config.c b/config.c
index 6421894614..dfa4df1417 100644
--- a/config.c
+++ b/config.c
@@ -2766,9 +2766,9 @@ int git_config_get_pathname(const char *key, char **dest)
 	return repo_config_get_pathname(the_repository, key, dest);
 }
 
-int git_config_get_expiry(const char *key, const char **output)
+int git_config_get_expiry(const char *key, char **output)
 {
-	int ret = git_config_get_string(key, (char **)output);
+	int ret = git_config_get_string(key, output);
 	if (ret)
 		return ret;
 	if (strcmp(*output, "now")) {
diff --git a/config.h b/config.h
index 54b47dec9e..4801391c32 100644
--- a/config.h
+++ b/config.h
@@ -701,7 +701,7 @@ int git_config_get_split_index(void);
 int git_config_get_max_percent_split_change(void);
 
 /* This dies if the configured or default date is in the future */
-int git_config_get_expiry(const char *key, const char **output);
+int git_config_get_expiry(const char *key, char **output);
 
 /* parse either "this many days" integer, or "5.days.ago" approxidate */
 int git_config_get_expiry_in_days(const char *key, timestamp_t *, timestamp_t now);
diff --git a/read-cache.c b/read-cache.c
index 48bf24f87c..7f393ee687 100644
--- a/read-cache.c
+++ b/read-cache.c
@@ -3176,18 +3176,24 @@ static int write_split_index(struct index_state *istate,
 	return ret;
 }
 
-static const char *shared_index_expire = "2.weeks.ago";
-
 static unsigned long get_shared_index_expire_date(void)
 {
 	static unsigned long shared_index_expire_date;
 	static int shared_index_expire_date_prepared;
 
 	if (!shared_index_expire_date_prepared) {
+		const char *shared_index_expire = "2.weeks.ago";
+		char *value = NULL;
+
 		git_config_get_expiry("splitindex.sharedindexexpire",
-				      &shared_index_expire);
+				      &value);
+		if (value)
+			shared_index_expire = value;
+
 		shared_index_expire_date = approxidate(shared_index_expire);
 		shared_index_expire_date_prepared = 1;
+
+		free(value);
 	}
 
 	return shared_index_expire_date;