Support merging got_revision mappings during transition phase.

A few rare recipes use two or more solutions side-by-side.

This allows switching one solution in isolation to use the new mapping.

Bug: 713356
Change-Id: Id51f2f777681401843004577a4de65a6c5d1e4a6
Reviewed-on: https://chromium-review.googlesource.com/484341
Commit-Queue: Andrii Shyshkalov <tandrii@chromium.org>
Reviewed-by: Andrii Shyshkalov <tandrii@chromium.org>

recipes/recipe_modules/bot_update/api.py

@@ -171,17 +171,7 @@ class BotUpdateApi(recipe_api.RecipeApi):
     self.m.gclient.set_patch_project_revision(
         self.m.properties.get('patch_project'), cfg)
 
-    # TODO(machenbach): Deprecate rev_map. We'll do a three-way dance.
+    reverse_rev_map = self.m.gclient.got_revision_reverse_mapping(cfg)
-    # When all users of got_revision_mapping use got_revision_reverse_mapping
-    # we can remove the old one. Make sure nobody uses both.
-    rev_map = cfg.got_revision_mapping.as_jsonish()
-    reverse_rev_map = cfg.got_revision_reverse_mapping.as_jsonish()
-    assert not rev_map or not reverse_rev_map
-    if rev_map:
-      reverse_rev_map = {v: k for k, v in rev_map.iteritems()}
-
-      # Make sure we never have duplicate values in the old map.
-      assert len(rev_map) == len(reverse_rev_map)
 
     flags = [
         # What do we want to check out (spec/root/rev/reverse_rev_map).
@@ -378,15 +368,13 @@ class BotUpdateApi(recipe_api.RecipeApi):
     Returns (list of str): All properties that'll hold the checked-out revision
         of the given project. An empty list if no such properties exist.
     """
-    cfg = self.m.gclient.c
-    if cfg.got_revision_mapping:
-      prop = cfg.got_revision_mapping.get(project_name)
-      return [prop] if prop else []
     # Sort for determinism. We might have several properties for the same
     # project, e.g. got_revision and got_webrtc_revision.
+    rev_reverse_map = self.m.gclient.got_revision_reverse_mapping(
+        self.m.gclient.c)
     return sorted(
         prop
-        for prop, project in cfg.got_revision_reverse_mapping.iteritems()
+        for prop, project in rev_reverse_map.iteritems()
         if project == project_name
     )
 

recipes/recipe_modules/gclient/api.py

@@ -126,6 +126,24 @@ class GclientApi(recipe_api.RecipeApi):
   def config_to_pythonish(cfg):
     return jsonish_to_python(cfg.as_jsonish(), True)
 
+  # TODO(machenbach): Remove this method when the old mapping is deprecated.
+  @staticmethod
+  def got_revision_reverse_mapping(cfg):
+    """Returns the merged got_revision_reverse_mapping.
+
+    Returns (dict): A mapping from property name -> project name. It merges the
+        values of the deprecated got_revision_mapping and the new
+        got_revision_reverse_mapping.
+    """
+    rev_map = cfg.got_revision_mapping.as_jsonish()
+    reverse_rev_map = cfg.got_revision_reverse_mapping.as_jsonish()
+    combined_length = len(rev_map) + len(reverse_rev_map)
+    reverse_rev_map.update({v: k for k, v in rev_map.iteritems()})
+
+    # Make sure we never have duplicate values in the old map.
+    assert combined_length == len(reverse_rev_map)
+    return reverse_rev_map
+
   def resolve_revision(self, revision):
     if hasattr(revision, 'resolve'):
       return revision.resolve(self.m.properties)

recipes/recipe_modules/gclient/example.py

@@ -86,6 +86,8 @@ def RunSteps(api):
         gclient_config=bl_cfg,
         with_branch_heads=True)
 
+  api.gclient.got_revision_reverse_mapping(bl_cfg)
+
   api.gclient.break_locks()
 
   del api.gclient.spec_alias