Ensure that when we mix in a role, its attributes are initialized app…

…ropriately (for example, any defaults are applied).
rakudo · Sep 19, 2011 · e97afdb · e97afdb
1 parent d9b19d6
commit e97afdb
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Showing 2 changed files with 38 additions and 4 deletions.
diff --git a/src/core/Mu.pm b/src/core/Mu.pm
@@ -86,6 +86,40 @@ my class Mu {
         self
     }
 
+    method BUILD_LEAST_DERIVED(%attrinit) {
+        # Get the build plan for just this class.
+        my $build_plan := pir::find_method__PPs(self.HOW, 'BUILDPLAN')(self.HOW, self);
+        my int $count   = nqp::elems($build_plan);
+        my int $i       = 0;
+        while nqp::islt_i($i, $count) {
+            my $task := nqp::atpos($build_plan, $i);
+            $i = nqp::add_i($i, 1);
+            if nqp::iseq_i(nqp::atpos($task, 0), 0) {
+                # Custom BUILD call.
+                nqp::atpos($task, 1)(self, |%attrinit);
+            }
+            elsif nqp::iseq_i(nqp::atpos($task, 0), 1) {
+                # See if we have a value to initialize this attr
+                # with.
+                my $key_name := nqp::p6box_s(nqp::atpos($task, 2));
+                if %attrinit.exists($key_name) {
+                    nqp::getattr(self, nqp::atpos($task, 1),
+                        nqp::atpos($task, 3)) = pir::nqp_decontainerize__PP(%attrinit{$key_name});
+                }
+            }
+            elsif nqp::iseq_i(nqp::atpos($task, 0), 2) {
+                unless nqp::attrinited(self, nqp::atpos($task, 1), nqp::atpos($task, 2)) {
+                    my $attr := nqp::getattr(self, nqp::atpos($task, 1), nqp::atpos($task, 2));
+                    $attr = nqp::atpos($task, 3)(self, $attr);
+                }
+            }
+            else {
+                die "Invalid BUILDALLPLAN";
+            }
+        }
+        self
+    }
+
     proto method Numeric(|$) { * }
     multi method Numeric(Mu:U:) {
         note 'Use of uninitialized value in numeric context';

diff --git a/src/core/operators.pm b/src/core/operators.pm
@@ -10,19 +10,19 @@ sub infix:<=>(Mu \$a, Mu \$b) is rw {
 proto infix:<does>(|$) { * }
 multi infix:<does>(Mu \$obj, Mu:U \$role) is rw {
     # XXX Mutability check.
-    $obj.HOW.mixin($obj, $role);
+    $obj.HOW.mixin($obj, $role).BUILD_LEAST_DERIVED({});
 }
 multi infix:<does>(Mu \$obj, @roles) is rw {
     # XXX Mutability check.
-    $obj.HOW.mixin($obj, |@roles);
+    $obj.HOW.mixin($obj, |@roles).BUILD_LEAST_DERIVED({});
 }
 
 proto infix:<but>(|$) { * }
 multi infix:<but>(Mu \$obj, Mu:U \$role) {
-    $obj.HOW.mixin($obj.clone(), $role);
+    $obj.HOW.mixin($obj.clone(), $role).BUILD_LEAST_DERIVED({});
 }
 multi infix:<but>(Mu \$obj, @roles) {
-    $obj.HOW.mixin($obj.clone(), |@roles);
+    $obj.HOW.mixin($obj.clone(), |@roles).BUILD_LEAST_DERIVED({});
 }
 
 sub SEQUENCE($left, $right, :$exclude_end) {