From 9475ba38e7d6eda1014fc18a60e6b3680d6bf99e Mon Sep 17 00:00:00 2001
From: Elijah Cohen <cohen@eli173.com>
Date: Fri, 19 Sep 2025 01:59:54 +0000
Subject: [PATCH] fixed a memory error in strcat

---
 src/builtins/strings.c |  2 +-
 src/test.c             | 10 ++++++++++
 2 files changed, 11 insertions(+), 1 deletion(-)

diff --git a/src/builtins/strings.c b/src/builtins/strings.c
index b067d6b..e94d67b 100644
--- a/src/builtins/strings.c
+++ b/src/builtins/strings.c
@@ -48,7 +48,7 @@ Sexpr* s_strcat(Sexpr* b, Sexpr* rest, Sexpr* env) {
 #endif // typecheck
 	char* fs = unquote(fst)->value.str;
 	char* ss = unquote(snd)->value.str;
-	char* out = malloc(sizeof(char)*(strlen(fs)+strlen(ss)));
+	char* out = malloc(sizeof(char)*(strlen(fs)+strlen(ss)+1));
 	strcpy(out, fs);
 	strcat(out, ss);
 	sexpr_free(snd);
diff --git a/src/test.c b/src/test.c
index a273ec2..8f91df0 100644
--- a/src/test.c
+++ b/src/test.c
@@ -382,6 +382,13 @@ void eval_tests() {
 	
 }
 
+void diagnose_strcat() {
+	Sexpr* env = init_dict();
+	env = load_env(env);
+	assert_eq(env, "strcat \"hell\" \"o\"", "\"hello\"");
+	sexpr_free(env);
+}
+
 void many_asserts() {
 	Sexpr* env = init_dict();
 	env = load_env(env);
@@ -440,6 +447,8 @@ void many_asserts() {
 	assert_eq(env, "strexpand \"test\"", "list \"t\" \"e\" \"s\" \"t\"");
 	assert_eq(env, "substr \"oo\" \"looopy", "list 2 3");
 	assert_eq(env, "strtok \" /\" \"this is/a test\"", "list \"this\" \"is\" \"a\" \"test\"");
+	assert_eq(env, "strlen \"hey\"", "3");
+	assert_eq(env, "strcat \"hey \" \"there\"", "\"hey there\"");
 
 	printf("meta\n");
 	assert_eq(env, "utob 512", "+");
@@ -536,6 +545,7 @@ void run_tests(){
 	//test_string_parsing();
 	//eval_tests();
 	many_asserts();
+	//diagnose_strcat();
 	//memtest_eval();
 	//mem_testing();
 	//mem_parser();
-- 
2.39.5