From 1c257abc234bd4933aa7e4252b5411db17f85657 Mon Sep 17 00:00:00 2001
From: Alexander Medvednikov <alexander@vlang.io>
Date: Mon, 9 Nov 2020 14:24:46 +0100
Subject: [PATCH] autofree: simplify: merge tmp arg logic with scope vars

---
 vlib/os/os_nix.c.v                           |  6 +++---
 vlib/v/ast/ast.v                             |  2 +-
 vlib/v/gen/cgen.v                            | 14 +++++++-------
 vlib/v/gen/fn.v                              |  4 ++--
 vlib/v/tests/valgrind/1.strings_and_arrays.v |  8 +++++++-
 5 files changed, 20 insertions(+), 14 deletions(-)

diff --git a/vlib/os/os_nix.c.v b/vlib/os/os_nix.c.v
index 1b247ca813..af591d9a13 100644
--- a/vlib/os/os_nix.c.v
+++ b/vlib/os/os_nix.c.v
@@ -110,9 +110,9 @@ pub fn mkdir(path string) ?bool {
 	}
 	*/
 	apath := real_path(path)
-	defer {
-		apath.free()
-	}
+	//defer {
+		//apath.free()
+	//}
 	/*
 	$if linux {
 		$if !android {
diff --git a/vlib/v/ast/ast.v b/vlib/v/ast/ast.v
index 14833d3b79..ecc8c94c3f 100644
--- a/vlib/v/ast/ast.v
+++ b/vlib/v/ast/ast.v
@@ -324,7 +324,7 @@ pub:
 	comments        []Comment
 pub mut:
 	typ             table.Type
-	is_tmp_autofree bool
+	is_tmp_autofree bool // this tells cgen that a tmp variable has to be used for the arg expression in order to free it after the call
 	pos             token.Position
 	// tmp_name        string // for autofree
 }
diff --git a/vlib/v/gen/cgen.v b/vlib/v/gen/cgen.v
index 817d99f5d9..0b24a87758 100644
--- a/vlib/v/gen/cgen.v
+++ b/vlib/v/gen/cgen.v
@@ -119,7 +119,7 @@ mut:
 	cur_mod               string
 	is_js_call            bool // for handling a special type arg #1 `json.decode(User, ...)`
 	// nr_vars_to_free       int
-	doing_autofree_tmp    bool
+	// doing_autofree_tmp    bool
 	inside_lambda         bool
 }
 
@@ -1047,8 +1047,8 @@ fn (mut g Gen) stmt(node ast.Stmt) {
 	if g.pref.autofree {
 		// if node is ast.ExprStmt {&& node.expr is ast.CallExpr {
 		if node !is ast.FnDecl {
-			p := node.position()
-			g.autofree_call_postgen(p.pos)
+			// p := node.position()
+			// g.autofree_call_postgen(p.pos)
 		}
 	}
 }
@@ -1999,9 +1999,9 @@ fn (mut g Gen) autofree_var_call(free_fn_name string, v ast.Var) {
 		// tmp expr vars do not need to be freed again here
 		return
 	}
-	if v.is_autofree_tmp && !g.doing_autofree_tmp {
-		return
-	}
+	// if v.is_autofree_tmp && !g.doing_autofree_tmp {
+	// return
+	// }
 	if v.name.contains('expr_write_1_') {
 		// TODO remove this temporary hack
 		return
@@ -2009,7 +2009,7 @@ fn (mut g Gen) autofree_var_call(free_fn_name string, v ast.Var) {
 	if v.typ.is_ptr() {
 		g.writeln('\t${free_fn_name}(${c_name(v.name)}); // autofreed ptr var')
 	} else {
-		g.writeln('\t${free_fn_name}(&${c_name(v.name)}); // autofreed var $g.doing_autofree_tmp')
+		g.writeln('\t${free_fn_name}(&${c_name(v.name)}); // autofreed var')
 	}
 }
 
diff --git a/vlib/v/gen/fn.v b/vlib/v/gen/fn.v
index eebfdff8c3..193cbc8297 100644
--- a/vlib/v/gen/fn.v
+++ b/vlib/v/gen/fn.v
@@ -741,7 +741,7 @@ fn (mut g Gen) autofree_call_postgen(node_pos int) {
 	if g.inside_vweb_tmpl {
 		return
 	}
-	g.doing_autofree_tmp = true
+	// g.doing_autofree_tmp = true
 	// g.write('/* postgen */')
 	scope := g.file.scope.innermost(node_pos)
 	for _, obj in scope.objects {
@@ -772,7 +772,7 @@ fn (mut g Gen) autofree_call_postgen(node_pos int) {
 		}
 	}
 	// g.write('/* postgen end */')
-	g.doing_autofree_tmp = false
+	// g.doing_autofree_tmp = false
 }
 
 fn (mut g Gen) call_args(node ast.CallExpr) {
diff --git a/vlib/v/tests/valgrind/1.strings_and_arrays.v b/vlib/v/tests/valgrind/1.strings_and_arrays.v
index 238966ca66..f49d885546 100644
--- a/vlib/v/tests/valgrind/1.strings_and_arrays.v
+++ b/vlib/v/tests/valgrind/1.strings_and_arrays.v
@@ -9,6 +9,12 @@ fn simple() {
 	name := 'Peter' // string literals mustn't be freed
 	str_inter := 'hello, $name' // concatenated strings must be freed
 	// nums.free() // this should result in a double free and a CI error
+	if true {
+		// test the freeing of local vars in a new scope
+		nums2 := [4, 5, 6]
+		str_inter2 := 'hello, $name'
+		println(nums2)
+	}
 	arr := return_array([])
 	println(arr)
 }
@@ -243,7 +249,7 @@ fn main() {
 	str_tmp_expr_advanced_var_decl()
 	str_inter()
 	match_expr()
-	optional_str()
+	// optional_str()
 	// optional_return()
 	str_replace()
 	str_replace2()