Allow base path overrides when running a recipe.

recipe_modules/path/config.py

Index: recipe_modules/path/config.py
diff --git a/recipe_modules/path/config.py b/recipe_modules/path/config.py
index d86c4e4bcdefe43c800a22f9359d5cef4cd6aac6..2f99779b7ee5efcaaedeecab640839f1de884f22 100644
--- a/recipe_modules/path/config.py
+++ b/recipe_modules/path/config.py
@@ -4,8 +4,9 @@
 
 from recipe_engine.config import config_item_context, ConfigGroup, Dict, Static
 from recipe_engine.config_types import Path
+from recipe_engine.types import FrozenDict
 
-def BaseConfig(CURRENT_WORKING_DIR, TEMP_DIR, **_kwargs):
+def BaseConfig(CURRENT_WORKING_DIR, TEMP_DIR, BASE_PATH_OVERRIDES, **_kwargs):
   assert CURRENT_WORKING_DIR[0].endswith(('\\', '/'))
   assert TEMP_DIR[0].endswith(('\\', '/'))
   return ConfigGroup(
@@ -17,6 +18,7 @@ def BaseConfig(CURRENT_WORKING_DIR, TEMP_DIR, **_kwargs):
 
     CURRENT_WORKING_DIR = Static(tuple(CURRENT_WORKING_DIR)),
     TEMP_DIR = Static(tuple(TEMP_DIR)),
+    BASE_PATH_OVERRIDES = Static(FrozenDict(BASE_PATH_OVERRIDES)),
   )
 
 def test_name(args):  # pragma: no cover
@@ -31,22 +33,24 @@ config_ctx = config_item_context(BaseConfig)
 def BASE(c):
   c.base_paths['cwd'] = c.CURRENT_WORKING_DIR
   c.base_paths['tmp_base'] = c.TEMP_DIR
+  for k, v in c.BASE_PATH_OVERRIDES.iteritems():
+    c.base_paths[k] = v  # pragma: no cover
 
 @config_ctx()
 def buildbot(c):
-  c.base_paths['root'] = c.CURRENT_WORKING_DIR[:-4]
-  c.base_paths['slave_build'] = c.CURRENT_WORKING_DIR
+  c.base_paths.setdefault('root', c.CURRENT_WORKING_DIR[:-4])
+  c.base_paths.setdefault('slave_build', c.CURRENT_WORKING_DIR)
   for token in ('build_internal', 'build', 'depot_tools'):
-    c.base_paths[token] = c.base_paths['root'] + (token,)
+    c.base_paths.setdefault(token, c.base_paths['root'] + (token,))
   c.dynamic_paths['checkout'] = None
 
 @config_ctx()
 def example(c):
-  c.base_paths['slave_build'] = c.CURRENT_WORKING_DIR
+  c.base_paths.setdefault('slave_build', c.CURRENT_WORKING_DIR)
   c.dynamic_paths['borts'] = None
 
 @config_ctx(includes=['buildbot'])
 def swarming(c):
-  c.base_paths['slave_build'] = (
+  c.base_paths.setdefault('slave_build', (

[martiniss, 2016/01/19 23:29:37]

This won't work as is.... base_paths already has a value for slave_build, so
this won't change it. Should just assign here.

       c.CURRENT_WORKING_DIR[:1] +
-      ('b', 'fake_build', 'slave', 'fake_slave', 'build'))
+      ('b', 'fake_build', 'slave', 'fake_slave', 'build')))