includehandler: improve reporting of yaml format errors

When passing a yaml file that is incorrectly formatted, the parser
raises an error. This error needs to be caught, as otherwise a huge
splat is given back to the user which hides the error.

We now handle this case and report the line at which the error most
likely occurred.

Reported-by: Jan Kiszka <[email protected]>
Signed-off-by: Felix Moessbauer <[email protected]>
Signed-off-by: Jan Kiszka <[email protected]>

Author: fmoessbauer

kas/includehandler.py

@@ -69,8 +69,15 @@ def load_config(filename):
         with open(filename, 'rb') as fds:
             config = json.load(fds)
     elif ext in ['.yml', '.yaml']:
-        with open(filename, 'rb') as fds:
-            config = yaml.safe_load(fds)
+        try:
+            with open(filename, 'rb') as fds:
+                config = yaml.safe_load(fds)
+        except yaml.YAMLError as e:
+            msg = f'Error in line {e.problem_mark.line + 1}' \
+                  if hasattr(e, 'problem_mark') else ''
+            raise LoadConfigException(
+                f'Configuration file is not valid YAML: {msg}',
+                filename)
     else:
         raise LoadConfigException('Config file extension not recognized',
                                   filename)

tests/test_includehandler.py

@@ -120,6 +120,14 @@ def test_err_version_invalid_format(self):
 
         self.util_exception_content(testvector)
 
+    def test_err_parse_yaml(self):
+        exception = includehandler.LoadConfigException
+        testvector = [
+            # misaligned column
+            ('header:\n  version: 17\n repo:', exception),
+        ]
+        self.util_exception_content(testvector)
+
     def test_header_valid(self):
         testvector = [
             'header: {version: 4}',