From 059b7486bff5f1b01b8c19fca06494a7936a24d9 Mon Sep 17 00:00:00 2001
From: Rico Tzschichholz <ricotz@ubuntu.com>
Date: Fri, 4 Oct 2019 14:12:46 +0200
Subject: [PATCH] vala: Fix compatible/disposable check between structs and
 their subtypes

This fixes memory leaks due to missing copy/destroy and improperly created
dup functions and allows direct assignment between structs and their
subtypes.

Fixes https://gitlab.gnome.org/GNOME/vala/issues/861
---
 codegen/valaccodestructmodule.vala   |  6 +++++-
 tests/Makefile.am                    |  1 +
 tests/structs/struct-base-types.vala | 31 ++++++++++++++++++++++++++++
 vala/valadatatype.vala               |  5 +++++
 vala/valastruct.vala                 |  4 ++++
 5 files changed, 46 insertions(+), 1 deletion(-)
 create mode 100644 tests/structs/struct-base-types.vala

diff --git a/codegen/valaccodestructmodule.vala b/codegen/valaccodestructmodule.vala
index 048cbb790..83c1a67a3 100644
--- a/codegen/valaccodestructmodule.vala
+++ b/codegen/valaccodestructmodule.vala
@@ -303,7 +303,11 @@ public abstract class Vala.CCodeStructModule : CCodeBaseModule {
 		push_function (function);
 
 		var dest_struct = new GLibValue (get_data_type_for_symbol (st), new CCodeIdentifier ("(*dest)"), true);
-		foreach (var f in st.get_fields ()) {
+		unowned Struct sym = st;
+		while (sym.base_struct != null) {
+			sym = sym.base_struct;
+		}
+		foreach (var f in sym.get_fields ()) {
 			if (f.binding == MemberBinding.INSTANCE) {
 				var value = load_field (f, load_this_parameter ((TypeSymbol) st));
 				if ((!(f.variable_type is DelegateType) || get_ccode_delegate_target (f)) && requires_copy (f.variable_type))  {
diff --git a/tests/Makefile.am b/tests/Makefile.am
index b404f7af3..011fefa1a 100644
--- a/tests/Makefile.am
+++ b/tests/Makefile.am
@@ -221,6 +221,7 @@ TESTS = \
 	enums/bug763831.vala \
 	enums/bug780050.vala \
 	structs/struct_only.vala \
+	structs/struct-base-types.vala \
 	structs/struct-empty-still.test \
 	structs/struct-no-gtype.vala \
 	structs/struct-static-field-initializer.vala \
diff --git a/tests/structs/struct-base-types.vala b/tests/structs/struct-base-types.vala
new file mode 100644
index 000000000..928f010bb
--- /dev/null
+++ b/tests/structs/struct-base-types.vala
@@ -0,0 +1,31 @@
+struct Foo {
+	public string s;
+}
+
+struct Bar : Foo {
+}
+
+void main () {
+	{
+		Bar bar = { "bar" };
+		Foo foo = bar;
+
+		assert (bar.s == "bar");
+		assert (bar.s == foo.s);
+
+		void* s1 = foo.s;
+		void* s2 = bar.s;
+		assert (s1 != s2);
+	}
+	{
+		Foo foo = { "foo" };
+		Bar bar = foo;
+
+		assert (foo.s == "foo");
+		assert (foo.s == bar.s);
+
+		void* s1 = foo.s;
+		void* s2 = bar.s;
+		assert (s1 != s2);
+	}
+}
diff --git a/vala/valadatatype.vala b/vala/valadatatype.vala
index 6dc7cd07f..e968ec989 100644
--- a/vala/valadatatype.vala
+++ b/vala/valadatatype.vala
@@ -365,6 +365,11 @@ public abstract class Vala.DataType : CodeNode {
 					return true;
 				}
 			}
+
+			// Allow compatiblity of struct subtypes in both ways
+			if (expect_struct.is_subtype_of (expr_struct)) {
+				return true;
+			}
 		}
 
 		return false;
diff --git a/vala/valastruct.vala b/vala/valastruct.vala
index f8b725fd8..7685b0819 100644
--- a/vala/valastruct.vala
+++ b/vala/valastruct.vala
@@ -447,6 +447,10 @@ public class Vala.Struct : TypeSymbol {
 			return true;
 		}
 
+		if (base_struct != null) {
+			return base_struct.is_disposable ();
+		}
+
 		foreach (Field f in fields) {
 			if (f.binding == MemberBinding.INSTANCE
 			    && f.get_attribute_bool ("CCode", "delegate_target", true)
-- 
2.47.2