Handle concatenated string, parentheses, newlines, and add more tests.

Author: serhiy-storchaka

Lib/pydoc.py

@@ -387,18 +387,27 @@ def ispackage(path):
 def source_synopsis(file):
     """Return the one-line summary of a file object, if present"""
 
+    string = ''
     try:
         tokens = tokenize.generate_tokens(file.readline)
         for tok_type, tok_string, _, _, _ in tokens:
             if tok_type == tokenize.STRING:
-                docstring = ast.literal_eval(tok_string)
-                if isinstance(docstring, str):
-                    return docstring.strip().split('\n')[0].strip()
-                return None
+                string += tok_string
+            elif tok_type == tokenize.NEWLINE:
+                with warnings.catch_warnings():
+                    # Ignore the "invalid escape sequence" warning.
+                    warnings.simplefilter("ignore", SyntaxWarning)
+                    docstring = ast.literal_eval(string)
+                if not isinstance(docstring, str):
+                    return None
+                return docstring.strip().split('\n')[0].strip()
+            elif tok_type == tokenize.OP and tok_string in ('(', ')'):
+                string += tok_string
             elif tok_type not in (tokenize.COMMENT, tokenize.NL, tokenize.ENCODING):
                 return None
-    except (tokenize.TokenError, UnicodeDecodeError, SyntaxError, ValueError) as e:
+    except (tokenize.TokenError, UnicodeDecodeError, SyntaxError):
         return None
+    return None
 
 def synopsis(filename, cache={}):
     """Get the one-line summary out of a module file."""

Lib/test/test_pydoc/test_pydoc.py

@@ -4,6 +4,7 @@
 import contextlib
 import importlib.util
 import inspect
+import io
 import pydoc
 import py_compile
 import keyword
@@ -921,6 +922,12 @@ def test_source_synopsis(self):
             ('""""""',
              ''),
 
+            ('"""Embedded\0null byte"""',
+             None),
+
+            ('"""Embedded null byte"""\0',
+             None),
+
             ('"""Café and résumé."""',
              'Café and résumé.'),
 
@@ -933,8 +940,32 @@ def test_source_synopsis(self):
             ("'Single single quotes'",
              'Single single quotes'),
 
+            ('"""split\\\nline"""',
+             'splitline'),
+
+            ('"""Unrecognized escape \\sequence"""',
+             'Unrecognized escape \\sequence'),
+
+            ('"""Invalid escape seq\\uence"""',
+             None),
+
+            ('r"""Raw \\string"""',
+             'Raw \\string'),
+
+            ('b"""Bytes literal"""',
+             None),
+
+            ('f"""f-string"""',
+             None),
+
             ('"""Concatenated""" \\\n"string" \'literals\'',
              'Concatenatedstringliterals'),
+
+            ('("""In """\n"""parentheses""")',
+             'In parentheses'),
+
+            ('()', # tuple
+             None),
         ]
 
         for source, expected in test_cases:
@@ -943,6 +974,12 @@ def test_source_synopsis(self):
                 result = pydoc.source_synopsis(source_file)
                 self.assertEqual(result, expected)
 
+        # Encoding error.
+        source = b'"""\xff"""'
+        with io.TextIOWrapper(io.BytesIO(source), encoding='utf-8') as source_file:
+            result = pydoc.source_synopsis(source_file)
+            self.assertIsNone(result)
+
         with tempfile.NamedTemporaryFile(mode='w+', encoding='utf-8') as temp_file:
             temp_file.write('"""Real file test."""\n')
             temp_file.flush()