Don't swallow the AttributeError for an expansion like .bak.

2 files changed, 15 insertions, 2 deletions

diff --git a/src/engine/SCons/Sig/MD5.py b/src/engine/SCons/Sig/MD5.py
index c50dbb7..21cb24c 100644
--- a/src/engine/SCons/Sig/MD5.py
+++ b/src/engine/SCons/Sig/MD5.py
@@ -79,10 +79,10 @@ def signature(obj):
     """Generate a signature for an object
     """
     try:
-        contents = str(obj.get_contents())
+        gc = obj.get_contents
     except AttributeError:
         raise AttributeError, "unable to fetch contents of '%s'" % str(obj)
-    return hexdigest(md5.new(contents).digest())
+    return hexdigest(md5.new(str(gc())).digest())
 
 def to_string(signature):
     """Convert a signature to a string"""
diff --git a/src/engine/SCons/Sig/MD5Tests.py b/src/engine/SCons/Sig/MD5Tests.py
index 6285e87..67bdfc9 100644
--- a/src/engine/SCons/Sig/MD5Tests.py
+++ b/src/engine/SCons/Sig/MD5Tests.py
@@ -88,6 +88,19 @@ class MD5TestCase(unittest.TestCase):
         else:
             raise AttributeError, "unexpected get_contents() attribute"
 
+        # Make sure we don't eat AttributeErrors raised internally
+        # by the get_contents() method (or anything it calls).
+        caught = None
+        try:
+            class xxx:
+                def get_contents(self):
+                    raise AttributeError, "internal AttributeError"
+            signature(xxx())
+        except AttributeError, e:
+            assert str(e) == "internal AttributeError", e
+            caught = 1
+        assert caught, "did not catch expected AttributeError"
+
     def test_to_string(self):
         assert '698d51a19d8a121ce581499d7b701668' == to_string('698d51a19d8a121ce581499d7b701668')