diff --git a/builtin/log.c b/builtin/log.c
index c211d66d1d..634dc782cc 100644
--- a/builtin/log.c
+++ b/builtin/log.c
@@ -231,7 +231,8 @@ static void cmd_log_init_finish(int argc, const char **argv, const char *prefix,
 	}
 
 	if (mailmap) {
-		rev->mailmap = xcalloc(1, sizeof(struct string_list));
+		rev->mailmap = xmalloc(sizeof(struct string_list));
+		string_list_init_nodup(rev->mailmap);
 		read_mailmap(rev->mailmap);
 	}
 
@@ -2173,8 +2174,10 @@ int cmd_format_patch(int argc, const char **argv, const char *prefix)
 		prepare_bases(&bases, base, list, nr);
 	}
 
-	if (in_reply_to || thread || cover_letter)
-		rev.ref_message_ids = xcalloc(1, sizeof(struct string_list));
+	if (in_reply_to || thread || cover_letter) {
+		rev.ref_message_ids = xmalloc(sizeof(*rev.ref_message_ids));
+		string_list_init_nodup(rev.ref_message_ids);
+	}
 	if (in_reply_to) {
 		const char *msgid = clean_message_id(in_reply_to);
 		string_list_append(rev.ref_message_ids, msgid);
diff --git a/builtin/shortlog.c b/builtin/shortlog.c
index 26c5c0cf93..fcde07c936 100644
--- a/builtin/shortlog.c
+++ b/builtin/shortlog.c
@@ -81,8 +81,10 @@ static void insert_one_record(struct shortlog *log,
 		format_subject(&subject, oneline, " ");
 		buffer = strbuf_detach(&subject, NULL);
 
-		if (item->util == NULL)
-			item->util = xcalloc(1, sizeof(struct string_list));
+		if (!item->util) {
+			item->util = xmalloc(sizeof(struct string_list));
+			string_list_init_nodup(item->util);
+		}
 		string_list_append(item->util, buffer);
 	}
 }
diff --git a/merge-recursive.c b/merge-recursive.c
index 1ee6364e8b..32bbba5fbb 100644
--- a/merge-recursive.c
+++ b/merge-recursive.c
@@ -522,10 +522,10 @@ static struct stage_data *insert_stage_data(struct repository *r,
  */
 static struct string_list *get_unmerged(struct index_state *istate)
 {
-	struct string_list *unmerged = xcalloc(1, sizeof(struct string_list));
+	struct string_list *unmerged = xmalloc(sizeof(struct string_list));
 	int i;
 
-	unmerged->strdup_strings = 1;
+	string_list_init_dup(unmerged);
 
 	/* TODO: audit for interaction with sparse-index. */
 	ensure_full_index(istate);