[vala/wip/bug567269: 1/7] Improve constructor chain-up checks

[Rico Tzschichholz <ricotz src gnome org>]

commit 1a61c014656992ef9f1af98f926ff0011a91b614
Author: Simon Werbeck <simon werbeck gmail com>
Date:   Wed Nov 26 11:53:31 2014 +0100

    Improve constructor chain-up checks
    
    The only valid expressions for chaining up are:
     * this[.named] ()
     * base[.named] ()
     * Object () - for GObject style chain-ups
    
    This patch should prevent invalid chain-ups such as:
    * Foo.named (), where Foo is not a valid base class
    * (new Foo ()) (), i.e. invoking expressions that return an object
    
    In preparation to fixing bug 567269, is_chainup() was turned into a
    property.

 vala/valamethodcall.vala |   98 ++++++++++++++++++---------------------------
 1 files changed, 39 insertions(+), 59 deletions(-)
---
diff --git a/vala/valamethodcall.vala b/vala/valamethodcall.vala
index 4e9d474..f620316 100644
--- a/vala/valamethodcall.vala
+++ b/vala/valamethodcall.vala
@@ -46,6 +46,8 @@ public class Vala.MethodCall : Expression {
         */
        public bool is_constructv_chainup { get; private set; }
 
+       public bool is_chainup { get; private set; }
+
        private Expression _call;
        
        private List<Expression> argument_list = new ArrayList<Expression> ();
@@ -140,28 +142,6 @@ public class Vala.MethodCall : Expression {
                return call.is_accessible (sym);
        }
 
-       bool is_chainup () {
-               if (!(call.symbol_reference is CreationMethod)) {
-                       return false;
-               }
-
-               var expr = call;
-
-               var ma = (MemberAccess) call;
-               if (ma.inner != null) {
-                       expr = ma.inner;
-               }
-
-               ma = expr as MemberAccess;
-               if (ma != null && ma.member_name == "this") {
-                       return true;
-               } else if (expr is BaseAccess) {
-                       return true;
-               } else {
-                       return false;
-               }
-       }
-
        public override bool check (CodeContext context) {
                if (checked) {
                        return !error;
@@ -231,11 +211,28 @@ public class Vala.MethodCall : Expression {
                }
 
                var mtype = call.value_type;
+               var gobject_chainup = call.symbol_reference == context.analyzer.object_type;
+               is_chainup = gobject_chainup;
+
+               if (!gobject_chainup) {
+                       var expr = call;
+                       var ma = expr as MemberAccess;
+                       if (ma != null && ma.symbol_reference is CreationMethod) {
+                               expr = ma.inner;
+                               ma = expr as MemberAccess;
+                       }
+                       if (ma != null && ma.member_name == "this") {
+                               // this[.with_foo] ()
+                               is_chainup = true;
+                       } else if (expr is BaseAccess) {
+                               // base[.with_foo] ()
+                               is_chainup = true;
+                       }
+               }
 
                CreationMethod base_cm = null;
 
-               if (mtype is ObjectType || call.symbol_reference == context.analyzer.object_type) {
-                       // constructor chain-up
+               if (is_chainup) {
                        var cm = context.analyzer.find_current_method () as CreationMethod;
                        if (cm == null) {
                                error = true;
@@ -261,8 +258,14 @@ public class Vala.MethodCall : Expression {
                                        Report.error (source_reference, "chain up to `%s' not 
supported".printf (base_cm.get_full_name ()));
                                        return false;
                                }
-                       } else {
-                               // GObject chain up
+                       } else if (call.symbol_reference is CreationMethod && 
call.symbol_reference.parent_symbol is Class) {
+                               base_cm = (CreationMethod) call.symbol_reference;
+                               if (!base_cm.has_construct_function) {
+                                       error = true;
+                                       Report.error (source_reference, "chain up to `%s' not 
supported".printf (base_cm.get_full_name ()));
+                                       return false;
+                               }
+                       } else if (gobject_chainup) {
                                var cl = cm.parent_symbol as Class;
                                if (cl == null || !cl.is_subtype_of (context.analyzer.object_type)) {
                                        error = true;
@@ -286,17 +289,6 @@ public class Vala.MethodCall : Expression {
                                return false;
                        }
 
-                       if (is_chainup ()) {
-                               var cm = context.analyzer.find_current_method () as CreationMethod;
-                               if (cm != null) {
-                                       if (cm.chain_up) {
-                                               error = true;
-                                               Report.error (source_reference, "Multiple constructor calls 
in the same constructor are not permitted");
-                                               return false;
-                                       }
-                                       cm.chain_up = true;
-                               }
-                       }
                        var struct_creation_expression = new ObjectCreationExpression ((MemberAccess) call, 
source_reference);
                        struct_creation_expression.struct_creation = true;
                        foreach (Expression arg in get_argument_list ()) {
@@ -307,30 +299,18 @@ public class Vala.MethodCall : Expression {
                        parent_node.replace_expression (this, struct_creation_expression);
                        struct_creation_expression.check (context);
                        return true;
-               } else if (call is MemberAccess
-                          && call.symbol_reference is CreationMethod) {
-                       // constructor chain-up
-                       var cm = context.analyzer.find_current_method () as CreationMethod;
-                       if (cm == null) {
-                               error = true;
-                               Report.error (source_reference, "use `new' operator to create new objects");
-                               return false;
-                       } else if (cm.chain_up) {
-                               error = true;
-                               Report.error (source_reference, "Multiple constructor calls in the same 
constructor are not permitted");
-                               return false;
-                       }
-                       cm.chain_up = true;
-
-                       base_cm = (CreationMethod) call.symbol_reference;
-                       if (!base_cm.has_construct_function) {
-                               error = true;
-                               Report.error (source_reference, "chain up to `%s' not supported".printf 
(base_cm.get_full_name ()));
-                               return false;
-                       }
+               } else if (!is_chainup && call is MemberAccess && call.symbol_reference is CreationMethod) {
+                       error = true;
+                       Report.error (source_reference, "use `new' operator to create new objects");
+                       return false;
                }
 
-               if (mtype != null && mtype.is_invokable ()) {
+               if (!is_chainup && mtype is ObjectType) {
+                       // prevent funny stuff like (new Object ()) ()
+                       error = true;
+                       Report.error (source_reference, "invocation not supported in this context");
+                       return false;
+               } else if (mtype != null && mtype.is_invokable ()) {
                        // call ok, expression is invokable
                } else if (call.symbol_reference is Class) {
                        error = true;