From 1332bba7af022f63b1569c2804e4ee7765a43412 Mon Sep 17 00:00:00 2001
From: Alexander Medvednikov <alexander@vlang.io>
Date: Sat, 10 Oct 2020 10:34:35 +0200
Subject: [PATCH] autofree: wrap up optionals

---
 vlib/v/gen/cgen.v                            | 23 ++++++++++----------
 vlib/v/gen/fn.v                              | 15 +++++++++++++
 vlib/v/tests/valgrind/1.strings_and_arrays.v |  2 +-
 3 files changed, 27 insertions(+), 13 deletions(-)

diff --git a/vlib/v/gen/cgen.v b/vlib/v/gen/cgen.v
index 363fa69684..e65e7e4293 100644
--- a/vlib/v/gen/cgen.v
+++ b/vlib/v/gen/cgen.v
@@ -101,7 +101,7 @@ mut:
 	inside_return         bool
 	inside_or_block       bool
 	strs_to_free          []string // strings.Builder
-	strs_to_free0         []string // strings.Builder
+	// strs_to_free0         []string // strings.Builder
 	inside_call           bool
 	has_main              bool
 	inside_const          bool
@@ -827,13 +827,7 @@ fn (mut g Gen) stmt(node ast.Stmt) {
 			}
 			g.expr(node.expr)
 			if af {
-				if g.strs_to_free.len > 0 {
-					g.writeln(';\n// strs_to_free2:')
-					for s in g.strs_to_free {
-						g.writeln('string_free(&$s);')
-					}
-					g.strs_to_free = []
-				}
+				g.autofree_call_postgen()
 			}
 			if g.inside_ternary == 0 && !node.is_expr && !(node.expr is ast.IfExpr) {
 				g.writeln(';')
@@ -1381,8 +1375,10 @@ fn (mut g Gen) gen_assign_stmt(assign_stmt ast.AssignStmt) {
 	// int pos = *(int*)_t190.data;
 	mut gen_or := false
 	mut tmp_opt := ''
-	if g.pref.autofree && assign_stmt.op == .decl_assign && assign_stmt.left_types.len == 1 &&
-		assign_stmt.right[0] is ast.CallExpr {
+	is_optional := g.pref.autofree && assign_stmt.op == .decl_assign && assign_stmt.left_types.len ==
+		1 && assign_stmt.right[0] is ast.CallExpr
+	if is_optional {
+		// g.write('/* optional assignment */')
 		call_expr := assign_stmt.right[0] as ast.CallExpr
 		if call_expr.or_block.kind != .absent {
 			styp := g.typ(call_expr.return_type.set_flag(.optional))
@@ -1392,6 +1388,9 @@ fn (mut g Gen) gen_assign_stmt(assign_stmt ast.AssignStmt) {
 			gen_or = true
 			g.or_block(tmp_opt, call_expr.or_block, call_expr.return_type)
 			g.writeln('/*=============ret*/')
+			if af && is_optional {
+				g.autofree_call_postgen()
+			}
 			// return
 		}
 	}
@@ -1401,7 +1400,7 @@ fn (mut g Gen) gen_assign_stmt(assign_stmt ast.AssignStmt) {
 		if sym.kind == .multi_return {
 			// multi return
 			// TODO Handle in if_expr
-			is_optional := return_type.has_flag(.optional)
+			is_opt := return_type.has_flag(.optional)
 			mr_var_name := 'mr_$assign_stmt.pos.pos'
 			mr_styp := g.typ(return_type)
 			g.write('$mr_styp $mr_var_name = ')
@@ -1423,7 +1422,7 @@ fn (mut g Gen) gen_assign_stmt(assign_stmt ast.AssignStmt) {
 					g.write('$styp ')
 				}
 				g.expr(lx)
-				if is_optional {
+				if is_opt {
 					mr_base_styp := g.base_type(return_type)
 					g.writeln(' = (*($mr_base_styp*)${mr_var_name}.data).arg$i;')
 				} else {
diff --git a/vlib/v/gen/fn.v b/vlib/v/gen/fn.v
index f443cb453b..2317e27a7e 100644
--- a/vlib/v/gen/fn.v
+++ b/vlib/v/gen/fn.v
@@ -660,6 +660,21 @@ fn (mut g Gen) autofree_call_pregen(node ast.CallExpr) {
 	}
 }
 
+fn (mut g Gen) autofree_call_postgen() {
+	if g.strs_to_free.len == 0 {
+		return
+	}
+	g.writeln(';\n// strs_to_free2:')
+	for s in g.strs_to_free {
+		g.writeln('string_free(&$s);')
+	}
+	if !g.inside_or_block {
+		// we need to free the vars both inside the or block (in case of an error) and after it
+		// if we reset the array here, then the vars will not be freed after the block.
+		g.strs_to_free = []
+	}
+}
+
 // fn (mut g Gen) call_args(args []ast.CallArg, expected_types []table.Type, tmp_arg_vars_to_free []string) {
 // fn (mut g Gen) call_args(args []ast.CallArg, expected_types []table.Type) {
 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 af016cc047..8082812a07 100644
--- a/vlib/v/tests/valgrind/1.strings_and_arrays.v
+++ b/vlib/v/tests/valgrind/1.strings_and_arrays.v
@@ -122,7 +122,7 @@ fn main() {
 	str_inter()
 	match_expr()
 	reassign_str()
-	// optional_str()
+	optional_str()
 	// str_replace()
 	println('end')
 }