Provide a traceback if a Python-function builder throws an exception (Crain).

3 files changed, 28 insertions, 1 deletions

diff --git a/src/engine/SCons/Node/NodeTests.py b/src/engine/SCons/Node/NodeTests.py
index 37b9f37..1050767 100644
--- a/src/engine/SCons/Node/NodeTests.py
+++ b/src/engine/SCons/Node/NodeTests.py
@@ -60,6 +60,10 @@ class ExceptBuilder:
     def execute(self, **kw):
         raise SCons.Errors.BuildError
 
+class ExceptBuilder2:
+    def execute(self, **kw):
+        raise "foo"
+
 class Environment:
     def Dictionary(self, *args):
 	pass
@@ -91,6 +95,22 @@ class NodeTestCase(unittest.TestCase):
         else:
             raise TestFailed, "did not catch expected BuildError"
 
+        node = SCons.Node.Node()
+        node.builder_set(ExceptBuilder2())
+        node.env_set(Environment())
+        try:
+            node.build()
+        except SCons.Errors.BuildError, e:
+            # On a generic (non-BuildError) exception from a Builder,
+            # the Node should throw a BuildError exception with
+            # the args set to the exception value, type, and traceback.
+            assert len(e.args) == 3, `e.args`
+            assert e.args[0] == 'foo', e.args[0]
+            assert e.args[1] is None
+            assert type(e.args[2]) is type(sys.exc_traceback), e.args[2]
+        else:
+            raise TestFailed, "did not catch expected BuildError"
+
     def test_build(self):
 	"""Test building a node
 	"""
diff --git a/src/engine/SCons/Node/__init__.py b/src/engine/SCons/Node/__init__.py
index f2d379f..c641895 100644
--- a/src/engine/SCons/Node/__init__.py
+++ b/src/engine/SCons/Node/__init__.py
@@ -35,6 +35,7 @@ from SCons.Errors import BuildError
 import string
 import types
 import copy
+import sys
 
 # Node states
 #
@@ -77,7 +78,10 @@ class Node:
             stat = self.builder.execute(env = self.env.Dictionary(),
                                         target = self, source = self.sources)
         except:
-            raise BuildError(node = self, errstr = "Exception")
+            raise BuildError(self, "Exception",
+                             sys.exc_type,
+                             sys.exc_value,
+                             sys.exc_traceback)
         if stat:
             raise BuildError(node = self, errstr = "Error %d" % stat)
 
diff --git a/src/engine/SCons/Script/__init__.py b/src/engine/SCons/Script/__init__.py
index 1788fab..acbd6c0 100644
--- a/src/engine/SCons/Script/__init__.py
+++ b/src/engine/SCons/Script/__init__.py
@@ -76,6 +76,9 @@ class BuildTask(SCons.Taskmaster.Task):
                 self.target.build()
             except BuildError, e:
                 sys.stderr.write("scons: *** [%s] %s\n" % (e.node, e.errstr))
+                if e.errstr == 'Exception':
+                    traceback.print_exception(e.args[0], e.args[1],
+                                              e.args[2])
                 raise
 
     def executed(self):