loadelement.py & loader: Added file suffix check

_loader/loader.py: Added Suffix check and warning for named elements
_loader/loadelement.py: Added Suffix check and warning for dependencies

buildstream/_loader/loader.py

@@ -97,6 +97,7 @@ class Loader():
     # Returns: The toplevel LoadElement
     def load(self, targets, rewritable=False, ticker=None, fetch_subprojects=False):
 
+        invalid_elements = []
         for filename in targets:
             if os.path.isabs(filename):
                 # XXX Should this just be an assertion ?
@@ -106,6 +107,18 @@ class Loader():
                                 "path to the base project directory: {}"
                                 .format(filename, self._basedir))
 
+            if not filename.endswith(".bst") and not filename.endswith("/") and not filename.endswith(".conf"):
+                invalid_elements.append(filename)
+
+        if invalid_elements:
+            # TODO CoreWarnings should probably move somewhere else
+            from ..plugin import CoreWarnings
+
+            self._context.warn(self.project, None,
+                               "Target elements '{}' do not have expected file extension `.bst` "
+                               "Improperly named elements will not be discoverable by commands"
+                               .format(invalid_elements),
+                               warning_token=CoreWarnings.BAD_ELEMENT_SUFFIX)
         # First pass, recursively load files and populate our table of LoadElements
         #
         deps = []
@@ -269,7 +282,12 @@ class Loader():
         self._elements[filename] = element
 
         # Load all dependency files for the new LoadElement
+        invalid_elements = []
         for dep in element.deps:
+            if not dep.name.endswith(".bst") and not dep.name.endswith("/") and not dep.name.endswith(".conf"):
+                invalid_elements.append(dep.name)
+                continue
+
             if dep.junction:
                 self._load_file(dep.junction, rewritable, ticker, fetch_subprojects, yaml_cache)
                 loader = self._get_loader(dep.junction, rewritable=rewritable, ticker=ticker,
@@ -278,12 +296,19 @@ class Loader():
                 loader = self
 
             dep_element = loader._load_file(dep.name, rewritable, ticker, fetch_subprojects, yaml_cache)
-
             if _yaml.node_get(dep_element.node, str, Symbol.KIND) == 'junction':
                 raise LoadError(LoadErrorReason.INVALID_DATA,
                                 "{}: Cannot depend on junction"
                                 .format(dep.provenance))
-
+        if invalid_elements:
+            # TODO CoreWarnings should probably move somewhere else
+            from ..plugin import CoreWarnings
+
+            self._context.warn(self.project, None,
+                               "Target elements '{}' do not have expected file extension `.bst` "
+                               "Improperly named elements will not be discoverable by commands"
+                               .format(invalid_elements),
+                               warning_token=CoreWarnings.BAD_ELEMENT_SUFFIX)
         return element
 
     # _check_circular_deps():