Fix setting breakpoint in non-finalized class

runtime/vm/debugger.cc

Index: runtime/vm/debugger.cc
===================================================================
--- runtime/vm/debugger.cc	(revision 31442)
+++ runtime/vm/debugger.cc	(working copy)
@@ -1392,6 +1392,13 @@
   for (intptr_t i = 1; i < num_classes; i++) {
     if (class_table.HasValidClassAt(i)) {
       cls = class_table.At(i);
+      // If the class is not finalized, e.g. if it hasn't been parsed
+      // yet entirely, we can ignore it. If it contains a function with
+      // a latent breakpoint, we will detect it if and when the function
+      // gets compiled.
+      if (!cls.is_finalized()) {
+        continue;
+      }
       // Note: we need to check the functions of this class even if
       // the class is defined in a differenct 'script'. There could
       // be mixin functions from the given script in this class.
@@ -1475,9 +1482,17 @@
   for (intptr_t i = 1; i < num_classes; i++) {
     if (class_table.HasValidClassAt(i)) {
       cls = class_table.At(i);
-      // Note: we need to check the functions of this class even if
-      // the class is defined in a differenct 'script'. There could
+      // Note: if this class has been parsed and finalized already,
+      // we need to check the functions of this class even if
+      // it is defined in a differenct 'script'. There could
       // be mixin functions from the given script in this class.
+      // However, if this class is not parsed yet (not finalized),
+      // we can ignore it and avoid the side effect of parsing it.
+      if ((cls.script() != script.raw()) && !cls.is_finalized()) {
+        continue;
+      }
+      // Parse class definition if not done yet.
+      cls.EnsureIsFinalized(isolate_);

[Ivan Posva, 2014/01/03 20:21:13]

What happens if there is a compilation failure during the compilation? We should
probably drop the compilation failure on the floor and wait for some other code
to run into it again.

[hausner, 2014/01/03 20:52:52]

The compilation error gets dropped and the class remains unfinalized. It appears
to have no class members. When the program later references the class, it will
produce an appropriate compilation error.

       functions = cls.functions();
       if (!functions.IsNull()) {
         const intptr_t num_functions = functions.Length();