Fix issue #2811 spurious rebuilds due to incorrect waiting_parents on nodes when builder has more than one target and source file generated

1 files changed, 19 insertions, 0 deletions

diff --git a/src/engine/SCons/Node/__init__.py b/src/engine/SCons/Node/__init__.py
index 131953b..e4c8e6c 100644
--- a/src/engine/SCons/Node/__init__.py
+++ b/src/engine/SCons/Node/__init__.py
@@ -784,6 +784,25 @@ class Node(object, with_metaclass(NoSlotsPyPy)):
         for parent in self.waiting_parents:
             parent.implicit = None
 
+            # Handle issue where builder emits more than one target and
+            # the source file for the builder is generated.
+            # in that case only the first target was getting it's .implicit
+            # cleared when the source file is built (second scan). 
+            # leaving only partial implicits from scan before source file is generated
+            # typically the compiler only. Then scanned files are appended
+            # This is persisted to sconsign and rebuild causes false rebuilds
+            # because the ordering of the implicit list then changes to what it
+            # should have been.
+            # This is at least the following bugs
+            # https://github.com/SCons/scons/issues/2811
+            # https://jira.mongodb.org/browse/SERVER-33111
+            try:
+                for peer in parent.attributes.target_peers:
+                    peer.implicit = None
+            except AttributeError as e:
+                pass
+
+
         self.clear()
 
         if self.pseudo: