Change an unmatched closing bracket from an IndexError to a ScannerError.

Since it's a problem with the user's document, it should be some kind of YAMLError at least.

2 files changed, 17 insertions, 1 deletions

diff --git a/_test/test_issues.py b/_test/test_issues.py
index 62c1d92..171eb2b 100644
--- a/_test/test_issues.py
+++ b/_test/test_issues.py
@@ -380,3 +380,15 @@ class TestIssues:
 
         yaml = ruamel.yaml.YAML(typ='safe')
         yaml.load('phone: 0123456789')
+
+    def test_issue_232(self):
+        import ruamel.yaml
+        from ruamel import yaml
+        with pytest.raises(ruamel.yaml.scanner.ScannerError, match='unmatched'):
+          yaml.safe_load(']')
+        with pytest.raises(ruamel.yaml.scanner.ScannerError, match='unmatched'):
+          yaml.load(']')
+        with pytest.raises(ruamel.yaml.scanner.ScannerError, match='expected'):
+          yaml.safe_load('{]')
+        with pytest.raises(ruamel.yaml.scanner.ScannerError, match='expected'):
+          yaml.load('{]')
diff --git a/scanner.py b/scanner.py
index 741cda6..b8e9ece 100644
--- a/scanner.py
+++ b/scanner.py
@@ -532,8 +532,12 @@ class Scanner(object):
         # Reset possible simple key on the current level.
         self.remove_possible_simple_key()
         # Decrease the flow level.
+        if not self.flow_context:
+          raise ScannerError(None, None, 'unmatched ending bracket', self.reader.get_mark())
         popped = self.flow_context.pop()
-        assert popped == to_pop
+        if popped != to_pop:
+          raise ScannerError(None, None, 'expected %s found %s' % (to_pop, popped),
+                             self.reader.get_mark())
         # No simple keys after ']' or '}'.
         self.allow_simple_key = False
         # Add FLOW-SEQUENCE-END or FLOW-MAPPING-END.