Allow extending profiles and merging their contents. (#592)

catkin_tools/context.py

@@ -69,6 +69,7 @@ class Context(object):
         'authors',
         'maintainers',
         'licenses',
+        'extends',
     ]
 
     EXTRA_KEYS = [
@@ -193,7 +194,28 @@ def load(
 
         # Get the metadata stored in the workspace if it was found
         if workspace:
-            config_metadata = metadata.get_metadata(workspace, profile, 'config')
+            key_origins = {}
+            visited_profiles = []
+
+            def get_metadata_recursive(profile):
+                config_metadata = metadata.get_metadata(workspace, profile, 'config')
+                visited_profiles.append(profile)
+                if "extends" in config_metadata.keys() and config_metadata["extends"] is not None:
+                    base_profile = config_metadata["extends"]
+                    if base_profile in visited_profiles:
+                        raise IOError("Profile dependency circle detected at dependency from '%s' to '%s'!"
+                                      % (profile, base_profile))
+                    base = get_metadata_recursive(base_profile)
+                    base.update(config_metadata)
+                    for key in config_metadata.keys():
+                        key_origins[key] = profile
+                    return base
+                for key in config_metadata.keys():
+                    key_origins[key] = profile
+                return config_metadata
+
+            config_metadata = get_metadata_recursive(profile)
+
             context_args.update(config_metadata)
 
         # User-supplied args are used to update stored args
@@ -208,8 +230,14 @@ def load(
                         context_args[k] = [w for w in context_args[k] if w not in v]
                     else:
                         context_args[k] = v
+                    if workspace:
+                        key_origins[k] = profile
                 else:
                     context_args[k] = v
+                    if workspace:
+                        key_origins[k] = profile
+
+        context_args["key_origins"] = key_origins
 
         # Create the build context
         ctx = Context(**context_args)
@@ -223,11 +251,28 @@ def load(
     @classmethod
     def save(cls, context):
         """Save a context in the associated workspace and profile."""
-        metadata.update_metadata(
-            context.workspace,
-            context.profile,
-            'config',
-            context.get_stored_dict())
+
+        data = context.get_stored_dict()
+        files = {}
+
+        def save_in_file(file, key, value):
+            if file in files.keys():
+                files[file][key] = value
+            else:
+                files[file] = {key: value}
+
+        for key, val in data.items():
+            if key in context.key_origins:
+                save_in_file(context.key_origins[key], key, val)
+            else:
+                save_in_file(context.profile, key, val)
+
+        for profile, content in files.items():
+            metadata.update_metadata(
+                context.workspace,
+                profile,
+                'config',
+                content)
 
     def get_stored_dict(self):
         """Get the context parameters which should be stored persistently."""
@@ -253,6 +298,8 @@ def __init__(
         authors=None,
         maintainers=None,
         licenses=None,
+        extends=None,
+        key_origins={},
         **kwargs
     ):
         """Creates a new Context object, optionally initializing with parameters
@@ -304,13 +351,16 @@ def __init__(
         :param maintainers: a list of default maintainers
         :type licenses: list
         :param licenses: a list of default licenses
+        :type extends: string
+        :param extends: the name of a profile to use as a base and inherit settings from
         """
         self.__locked = False
 
         # Validation is done on assignment
         self.workspace = workspace
 
         self.extend_path = extend_path if extend_path else None
+        self.key_origins = key_origins
 
         self.profile = profile
 
@@ -363,6 +413,8 @@ def __init__(
         self.env_cmake_prefix_path = None
         self.cmake_prefix_path = None
 
+        self.extends = extends
+
     def load_env(self):
 
         # Check for CMAKE_PREFIX_PATH in manual cmake args
@@ -772,6 +824,14 @@ def licenses(self):
     def licenses(self, value):
         self.__licenses = value
 
+    @property
+    def extends(self):
+        return self.__extends
+
+    @extends.setter
+    def extends(self, value):
+        self.__extends = value
+
     @property
     def private_devel_path(self):
         """The path to the hidden directory in the develspace that

catkin_tools/metadata.py

@@ -428,8 +428,11 @@ def update_metadata(workspace_path, profile, verb, new_data={}, no_init=False, m
 
     # Update the metadata for this verb
     data.update(new_data)
-    with open(metadata_file_path, 'w') as metadata_file:
-        yaml.dump(data, metadata_file, default_flow_style=False)
+    try:
+        with open(metadata_file_path, 'w') as metadata_file:
+            yaml.dump(data, metadata_file, default_flow_style=False)
+    except PermissionError:
+        print("Could not write to metadata file '%s'!" % (metadata_file_path))
 
     return data