From 25db5e96a3d88b8ba7d26315d5bb07d37d72eafb Mon Sep 17 00:00:00 2001
From: Alexander Medvednikov <alexander@medvednikov.com>
Date: Wed, 6 May 2020 11:11:57 +0000
Subject: [PATCH] strings.builder: fix a memory leak

---
 vlib/strings/builder.c.v | 2 +-
 vlib/v/gen/cgen.v        | 7 +++++--
 2 files changed, 6 insertions(+), 3 deletions(-)

diff --git a/vlib/strings/builder.c.v b/vlib/strings/builder.c.v
index c59718ca84..00739206a4 100644
--- a/vlib/strings/builder.c.v
+++ b/vlib/strings/builder.c.v
@@ -106,7 +106,7 @@ pub fn (b mut Builder) free() {
 	}
 	// QTODO checker bug
 	s := b.initial_size
-	b.buf = []byte{cap: s}
+	//b.buf = []byte{cap: s}
 	b.len = 0
 	b.str_calls = 0
 }
diff --git a/vlib/v/gen/cgen.v b/vlib/v/gen/cgen.v
index 1af035a062..919cd83174 100644
--- a/vlib/v/gen/cgen.v
+++ b/vlib/v/gen/cgen.v
@@ -3310,7 +3310,7 @@ fn (mut g Gen) gen_str_for_array(info table.Array, styp, str_fn_name string) {
 		g.auto_str_funcs.writeln('\t\tstring x = ${field_styp}_str(it);')
 	}
 	g.auto_str_funcs.writeln('\t\tstrings__Builder_write(&sb, x);')
-	if info.elem_type != table.bool_type {
+	if g.pref.autofree && info.elem_type != table.bool_type {
 		// no need to free "true"/"false" literals
 		g.auto_str_funcs.writeln('\t\tstring_free(x);')
 	}
@@ -3319,7 +3319,10 @@ fn (mut g Gen) gen_str_for_array(info table.Array, styp, str_fn_name string) {
 	g.auto_str_funcs.writeln('\t\t}')
 	g.auto_str_funcs.writeln('\t}')
 	g.auto_str_funcs.writeln('\tstrings__Builder_write(&sb, tos3("]"));')
-	g.auto_str_funcs.writeln('\treturn strings__Builder_str(&sb);')
+	g.auto_str_funcs.writeln('\tstring res = strings__Builder_str(&sb);')
+	g.auto_str_funcs.writeln('\tstrings__Builder_free(&sb);')
+	// g.auto_str_funcs.writeln('\treturn strings__Builder_str(&sb);')
+	g.auto_str_funcs.writeln('\treturn res;')
 	g.auto_str_funcs.writeln('}')
 }