Add _yaml.validate_node

3 files changed, 43 insertions, 0 deletions

diff --git a/buildstream/_yaml.py b/buildstream/_yaml.py
index 5ba540fc9..aead2ed84 100644
--- a/buildstream/_yaml.py
+++ b/buildstream/_yaml.py
@@ -575,6 +575,19 @@ def node_sanitize(node):
     return node
 
 
+def validate_node(node, valid_keys):
+
+    # Probably the fastest way to do this: https://stackoverflow.com/a/23062482
+    valid_keys = set(valid_keys)
+    valid_keys.add(PROVENANCE_KEY)
+    invalid = next((key for key in node if key not in valid_keys), None)
+
+    if invalid:
+        provenance = node_get_provenance(node, key=invalid)
+        raise LoadError(LoadErrorReason.INVALID_DATA,
+                        "[{}]: Unexpected key: {}".format(provenance, invalid))
+
+
 def node_chain_copy(source):
     copy = collections.ChainMap({}, source)
     for key, value in source.items():
diff --git a/tests/yaml/data/invalid.yaml b/tests/yaml/data/invalid.yaml
new file mode 100644
index 000000000..bc7f1ae22
--- /dev/null
+++ b/tests/yaml/data/invalid.yaml
@@ -0,0 +1,8 @@
+kind: pony
+description: The vehicle of choice for rainbow travel
+mods:
+  - happy
+  - sad
+children:
+  - naam: dopey
+    mood: silly
diff --git a/tests/yaml/yaml.py b/tests/yaml/yaml.py
index ec632674f..e972f89f4 100644
--- a/tests/yaml/yaml.py
+++ b/tests/yaml/yaml.py
@@ -163,6 +163,28 @@ def test_composited_array_append_provenance(datafiles):
 
 
 @pytest.mark.datafiles(os.path.join(DATA_DIR))
+def test_validate_node(datafiles):
+
+    valid = os.path.join(datafiles.dirname,
+                         datafiles.basename,
+                         'basics.yaml')
+    invalid = os.path.join(datafiles.dirname,
+                           datafiles.basename,
+                           'invalid.yaml')
+
+    base = _yaml.load(valid)
+
+    _yaml.validate_node(base, ['kind', 'description', 'moods', 'children', 'extra'])
+
+    base = _yaml.load(invalid)
+
+    with pytest.raises(LoadError) as exc:
+        _yaml.validate_node(base, ['kind', 'description', 'moods', 'children', 'extra'])
+
+    assert (exc.value.reason == LoadErrorReason.INVALID_DATA)
+
+
+@pytest.mark.datafiles(os.path.join(DATA_DIR))
 def test_node_get(datafiles):
 
     filename = os.path.join(datafiles.dirname,