Make config loading failures visible

lib/ansiblelint/cli.py

@@ -10,6 +10,7 @@
 
 
 _PATH_VARS = ['exclude_paths', 'rulesdir', ]
+INVALID_CONFIG_RC = 2
 
 
 def abspath(path, base_dir):
@@ -46,17 +47,33 @@ def expand_to_normalized_paths(config, base_dir=None):
 
 
 def load_config(config_file):
-    config_path = config_file if config_file else ".ansible-lint"
-    config_path = os.path.abspath(config_path)
-
-    if not os.path.exists(config_path):
+    config_path = os.path.abspath(config_file or '.ansible-lint')
+
+    if config_file:
+        if not os.path.exists(config_path):
+            print(
+                "Config file not found '{cfg!s}'.".format(cfg=config_path),
+                file=sys.stderr,
+            )
+            sys.exit(INVALID_CONFIG_RC)
+    elif not os.path.exists(config_path):
+        # a missing default config file should not trigger an error
         return
 
     try:
         with open(config_path, "r") as stream:
             config = yaml.safe_load(stream)
-    except yaml.YAMLError:
-        return None
+    except yaml.YAMLError as e:
+        print(e, file=sys.stderr)
+        sys.exit(INVALID_CONFIG_RC)
+    # TODO(ssbarnea): implement schema validation for config file
+    if isinstance(config, list):
+        print(
+            "Invalid configuration '{cfg!s}', expected YAML mapping in the config file.".
+            format(cfg=config_path),
+            file=sys.stderr,
+        )
+        sys.exit(INVALID_CONFIG_RC)
 
     config_dir = os.path.dirname(config_path)
     expand_to_normalized_paths(config, config_dir)

test/TestCommandLineInvocationSameAsConfig.py

@@ -74,3 +74,17 @@ def test_path_from_cli_depend_on_cwd(base_arguments, monkeypatch):  # Issue 572
 
     assert 'test/test' not in options1.exclude_paths[0]
     assert 'test/test' in options2.exclude_paths[0]
+
+
+@pytest.mark.parametrize(
+    "config_file",
+    [
+        pytest.param("test/fixtures/ansible-config-invalid.yml", id="invalid"),
+        pytest.param("/dev/null/ansible-config-missing.yml", id="missing")
+    ]
+)
+def test_config_failure(base_arguments, config_file):
+    """Ensures specific config files produce error code 2."""
+    with pytest.raises(SystemExit, match="^2$"):
+        cli.get_config(base_arguments +
+                       ["-c", config_file])

test/fixtures/ansible-config-invalid.yml

@@ -0,0 +1,3 @@
+# invalid .ansible-lint config file
+- foo
+- bar