buildstream/_project.py

@@ -219,6 +219,19 @@ class Project():
 
         return self._cache_key
 
+    def _validate_node(self, node):
+        _yaml.node_validate(node, [
+            'format-version',
+            'element-path', 'variables',
+            'environment', 'environment-nocache',
+            'split-rules', 'elements', 'plugins',
+            'aliases', 'name',
+            'artifacts', 'options',
+            'fail-on-overlap', 'shell', 'fatal-warnings',
+            'ref-storage', 'sandbox', 'mirrors', 'remote-execution',
+            'sources', '(@)'
+        ])
+
     # create_element()
     #
     # Instantiate and return an element
@@ -402,6 +415,8 @@ class Project():
                 "Project requested format version {}, but BuildStream {}.{} only supports up until format version {}"
                 .format(format_version, major, minor, BST_FORMAT_VERSION))
 
+        self._validate_node(pre_config_node)
+
         # FIXME:
         #
         #   Performing this check manually in the absense
@@ -467,16 +482,7 @@ class Project():
 
         self._load_pass(config, self.config)
 
-        _yaml.node_validate(config, [
-            'format-version',
-            'element-path', 'variables',
-            'environment', 'environment-nocache',
-            'split-rules', 'elements', 'plugins',
-            'aliases', 'name',
-            'artifacts', 'options',
-            'fail-on-overlap', 'shell', 'fatal-warnings',
-            'ref-storage', 'sandbox', 'mirrors', 'remote-execution'
-        ])
+        self._validate_node(config)
 
         #
         # Now all YAML composition is done, from here on we just load

buildstream/source.py

@@ -973,32 +973,34 @@ class Source(Plugin):
             # the items of source_fetchers, if it happens to be a generator.
             #
             source_fetchers = iter(source_fetchers)
-            try:
 
-                while True:
+            while True:
 
-                    with context.silence():
+                with context.silence():
+                    try:
                         fetcher = next(source_fetchers)
-
-                    alias = fetcher._get_alias()
-                    for uri in project.get_alias_uris(alias, first_pass=self.__first_pass):
-                        try:
-                            fetcher.fetch(uri)
-                        # FIXME: Need to consider temporary vs. permanent failures,
-                        #        and how this works with retries.
-                        except BstError as e:
-                            last_error = e
-                            continue
-
-                        # No error, we're done with this fetcher
+                    except StopIteration:
+                        # as per PEP479, we are not allowed to let StopIteration
+                        # thrown from a context manager.
+                        # Catching it here and breaking instead.
                         break
 
-                    else:
-                        # No break occurred, raise the last detected error
-                        raise last_error
+                alias = fetcher._get_alias()
+                for uri in project.get_alias_uris(alias, first_pass=self.__first_pass):
+                    try:
+                        fetcher.fetch(uri)
+                    # FIXME: Need to consider temporary vs. permanent failures,
+                    #        and how this works with retries.
+                    except BstError as e:
+                        last_error = e
+                        continue
 
-            except StopIteration:
-                pass
+                    # No error, we're done with this fetcher
+                    break
+
+                else:
+                    # No break occurred, raise the last detected error
+                    raise last_error
 
         # Default codepath is to reinstantiate the Source
         #

tests/frontend/invalid_element_path/project.conf

+# Project config for frontend build test
+name: test
+
+elephant-path: elements

tests/frontend/show.py

@@ -36,6 +36,19 @@ def test_show(cli, datafiles, target, format, expected):
                              .format(expected, result.output))
 
 
+@pytest.mark.datafiles(os.path.join(
+    os.path.dirname(os.path.realpath(__file__)),
+    "invalid_element_path",
+))
+def test_show_invalid_element_path(cli, datafiles):
+    project = os.path.join(datafiles.dirname, datafiles.basename)
+    result = cli.run(project=project, silent=True, args=[
+        'show',
+        "foo.bst"])
+
+    result.assert_main_error(ErrorDomain.LOAD, LoadErrorReason.INVALID_DATA)
+
+
 @pytest.mark.datafiles(DATA_DIR)
 @pytest.mark.parametrize("target,except_,expected", [
     ('target.bst', 'import-bin.bst', ['import-dev.bst', 'compose-all.bst', 'target.bst']),