Fix multi-solution use case with conflicting custom_deps overrides.

gclient.py

Index: gclient.py
diff --git a/gclient.py b/gclient.py
index c23b0023cfc56b21c65f152a529671c65c2e4ccb..0fcd099157dcc93c76f564648773444ddde7b959 100644
--- a/gclient.py
+++ b/gclient.py
@@ -325,10 +325,21 @@ class Dependency(gclient_utils.WorkItem, DependencySettings):
     # This require a full tree traversal with locks.
     siblings = [d for d in self.root.subtree(False) if d.name == self.name]
     for sibling in siblings:
-      if self.url != sibling.url:
-        raise gclient_utils.Error(
-            'Dependency %s specified more than once:\n  %s\nvs\n  %s' %
-            (self.name, sibling.hierarchy(), self.hierarchy()))
+      self_url = self.LateOverride(self.url)
+      sibling_url = sibling.LateOverride(sibling.url)
+      if self_url != sibling_url:

[szager1, 2012/10/09 18:30:11]

if self_url and sibling_url and self_url != sibling_url

That would change the behavior for empty string; not sure how you want to handle
that.

[M-A Ruel, 2012/10/09 18:38:22]

Agreed, I changed it.

+        # Allow to have only one to be None.
+        if bool(self_url is None) == bool(sibling_url is None):
+          raise gclient_utils.Error(
+              ('Dependency %s specified more than once:\n'
+              '  %s [%s]\n'
+              'vs\n'
+              '  %s [%s]') % (
+                self.name,
+                sibling.hierarchy(),
+                sibling_url,
+                self.hierarchy(),
+                self_url))
       # In theory we could keep it as a shadow of the other one. In
       # practice, simply ignore it.
       logging.warn('Won\'t process duplicate dependency %s' % sibling)