Print --debug={tree,dtree,includes} even if the build has an error.

4 files changed, 52 insertions, 19 deletions

diff --git a/src/CHANGES.txt b/src/CHANGES.txt
index ebfc13c..021d1d4 100644
--- a/src/CHANGES.txt
+++ b/src/CHANGES.txt
@@ -147,6 +147,9 @@ RELEASE 0.97 - XXX
   - Add specific exceptions to try:-except: blocks without any listed,
     so that they won't catch and mask keyboard interrupts.
 
+  - Make --debug={tree,dtree,stree} print something even when there's
+    a build failure.
+
   From Wayne Lee:
 
   - Avoid "maximum recursion limit" errors when removing $(-$) pairs
diff --git a/src/engine/SCons/Script/__init__.py b/src/engine/SCons/Script/__init__.py
index 7d139a1..71c2f03 100644
--- a/src/engine/SCons/Script/__init__.py
+++ b/src/engine/SCons/Script/__init__.py
@@ -121,25 +121,6 @@ class BuildTask(SCons.Taskmaster.Task):
         else:
             SCons.Taskmaster.Task.executed(self)
 
-        # print the tree here instead of in execute() because
-        # this method is serialized, but execute isn't:
-        if print_tree and self.top:
-            print
-            SCons.Util.print_tree(self.targets[0], get_all_children)
-        if print_stree and self.top:
-            print
-            SCons.Util.print_tree(self.targets[0], get_all_children,
-                                  showtags=2)
-        if print_dtree and self.top:
-            print
-            SCons.Util.print_tree(self.targets[0], get_derived_children)
-        if print_includes and self.top:
-            t = self.targets[0]
-            tree = t.render_include_tree()
-            if tree:
-                print
-                print tree
-
     def failed(self):
         # Handle the failure of a build task.  The primary purpose here
         # is to display the various types of Errors and Exceptions
@@ -182,6 +163,25 @@ class BuildTask(SCons.Taskmaster.Task):
 
         self.exc_clear()
 
+    def postprocess(self):
+        if self.top:
+            t = self.targets[0]
+            if print_tree:
+                print
+                SCons.Util.print_tree(t, get_all_children)
+            if print_stree:
+                print
+                SCons.Util.print_tree(t, get_all_children, showtags=2)
+            if print_dtree:
+                print
+                SCons.Util.print_tree(t, get_derived_children)
+            if print_includes:
+                tree = t.render_include_tree()
+                if tree:
+                    print
+                    print tree
+        SCons.Taskmaster.Task.postprocess(self)
+
     def make_ready(self):
         """Make a task ready for execution"""
         SCons.Taskmaster.Task.make_ready(self)
diff --git a/src/engine/SCons/Taskmaster.py b/src/engine/SCons/Taskmaster.py
index 6bd5e21..b528f44 100644
--- a/src/engine/SCons/Taskmaster.py
+++ b/src/engine/SCons/Taskmaster.py
@@ -152,8 +152,16 @@ class Task:
         for t in self.targets:
             t.set_state(SCons.Node.failed)
         self.tm.failed(self.node)
+        next_top = self.tm.next_top_level_candidate()
         self.tm.stop()
 
+        if next_top:
+            # We're stopping because of a build failure, but give the
+            # calling Task class a chance to postprocess() the top-level
+            # target under which the build failure occurred.
+            self.targets = [next_top]
+            self.top = 1
+
     def fail_continue(self):
         """Explicit continue-the-build failure.
 
@@ -426,6 +434,14 @@ class Taskmaster:
 
         return not self.ready and (self.pending or self.executing)
 
+    def next_top_level_candidate(self):
+        candidates = self.candidates[:]
+        candidates.reverse()
+        for c in candidates:
+            if c in self.targets:
+                return c
+        return None
+
     def stop(self):
         """Stop the current build completely."""
         self.candidates = []
diff --git a/src/engine/SCons/TaskmasterTests.py b/src/engine/SCons/TaskmasterTests.py
index cc4ba0c..a3e4219 100644
--- a/src/engine/SCons/TaskmasterTests.py
+++ b/src/engine/SCons/TaskmasterTests.py
@@ -625,6 +625,20 @@ class TaskmasterTestCase(unittest.TestCase):
         tm = MyTM()
         assert tm.is_blocked()
 
+    def test_next_top_level_candidate(self):
+        """Test the next_top_level_candidate() method
+        """
+        n1 = Node("n1")
+        n2 = Node("n2", [n1])
+        n3 = Node("n3", [n2])
+
+        tm = SCons.Taskmaster.Taskmaster([n3])
+        t = tm.next_task()
+        assert tm.executing == [n1], tm.executing
+        t.fail_stop()
+        assert t.targets == [n3], t.targets
+        assert t.top == 1, t.top
+
     def test_stop(self):
         """Test the stop() method