toml: fix memory corruption when returning new date/time types (#12507)

vlib/toml/any.v

@@ -26,10 +26,10 @@ pub fn (a Any) string() string {
 		// ... certain call-patterns to this function will cause a memory corruption.
 		// See `tests/toml_memory_corruption_test.v` for a matching regression test.
 		string { return (a as string).clone() }
-		DateTime { return a.str() }
-		Date { return a.str() }
-		Time { return a.str() }
-		else { return a.str() }
+		DateTime { return a.str().clone() }
+		Date { return a.str().clone() }
+		Time { return a.str().clone() }
+		else { return a.str().clone() }
 	}
 }
 
@@ -126,7 +126,8 @@ pub fn (a Any) bool() bool {
 pub fn (a Any) date() Date {
 	match a {
 		// string {  } // TODO
-		Date { return a }
+		// NOTE `.clone()` is to avoid memory corruption see `pub fn (a Any) string() string`
+		Date { return Date{a.str().clone()} }
 		else { return Date{''} }
 	}
 }
@@ -135,7 +136,8 @@ pub fn (a Any) date() Date {
 pub fn (a Any) time() Time {
 	match a {
 		// string {  } // TODO
-		Time { return a }
+		// NOTE `.clone()` is to avoid memory corruption see `pub fn (a Any) string() string`
+		Time { return Time{a.str().clone()} }
 		else { return Time{''} }
 	}
 }
@@ -144,7 +146,8 @@ pub fn (a Any) time() Time {
 pub fn (a Any) datetime() DateTime {
 	match a {
 		// string {  } // TODO
-		DateTime { return a }
+		// NOTE `.clone()` is to avoid memory corruption see `pub fn (a Any) string() string`
+		DateTime { return DateTime{a.str().clone()} }
 		else { return DateTime{''} }
 	}
 }

vlib/toml/tests/datetime_test.v

@@ -56,17 +56,17 @@ fn test_dates() {
 	od_time := toml.Date{'1979-05-27'}
 	ld1 := toml_doc.value('ld1')
 	assert ld1.date() == od_time
-	// assert ld1.string() == '1979-05-27' // TODO memory corruption
+	assert ld1.string() == '1979-05-27'
 
 	// lt1 test section
 	mut ot_time := toml.Time{'07:32:00'}
 	lt1 := toml_doc.value('lt1')
 	assert lt1.time() == ot_time
-	// assert lt1.string() == '07:32:00' // TODO memory corruption
+	assert lt1.string() == '07:32:00'
 
 	// lt2 test section
 	ot_time = toml.Time{'00:32:00.999999'}
 	lt2 := toml_doc.value('lt2')
 	assert lt2.time() == ot_time
-	// assert lt2.string() == '00:32:00.999999'  // TODO memory corruption
+	assert lt2.string() == '00:32:00.999999'
 }

vlib/toml/tests/toml_memory_corruption_test.v

@@ -22,3 +22,42 @@ fn test_toml_known_memory_corruption() {
 	assert any_name.string() == 'Tom Preston-Werner'
 	assert toml_doc.value('owner.name') as string == 'Tom Preston-Werner'
 }
+
+fn test_toml_known_memory_corruption_2() {
+	toml_txt := '
+	# Local Date-Time
+	ldt1 = 1979-05-27T07:32:00
+	ldt2 = 1979-05-27T00:32:00.999999
+	# Local Date
+	ld1 = 1979-05-27
+	# Local Time
+	lt1 = 07:32:00
+	lt2 = 00:32:00.999999
+'
+	toml_doc := toml.parse(toml_txt) or { panic(err) }
+
+	// ldt1 test section
+	odt_time := toml.DateTime{'1979-05-27T07:32:00'}
+	ldt1 := toml_doc.value('ldt1')
+	assert ldt1.string() == '1979-05-27T07:32:00' // Running this before yielded a double free segfault
+	assert ldt1.datetime() == odt_time
+	assert ldt1.string() == '1979-05-27T07:32:00' // Used to yield a memory corruption
+
+	// ld1 test section
+	od_time := toml.Date{'1979-05-27'}
+	ld1 := toml_doc.value('ld1')
+	assert ld1.date() == od_time
+	assert ld1.string() == '1979-05-27' // Used to yield a memory corruption
+
+	// lt1 test section
+	mut ot_time := toml.Time{'07:32:00'}
+	lt1 := toml_doc.value('lt1')
+	assert lt1.time() == ot_time
+	assert lt1.string() == '07:32:00' // Used to yield a memory corruption
+
+	// lt2 test section
+	ot_time = toml.Time{'00:32:00.999999'}
+	lt2 := toml_doc.value('lt2')
+	assert lt2.time() == ot_time
+	assert lt2.string() == '00:32:00.999999' // Used to yield a memory corruption
+}