Fix numpy docstring args being misparsed as section headers (fixes #439)

fire/docstrings.py

@@ -597,6 +597,14 @@ def _google_section_permitted(line_info, state):
   """
   if state.section.indentation is None:  # We're not in a section yet.
     return True
+  if state.section.format == Formats.NUMPY:
+    colon_index = line_info.remaining.find(':')
+    if colon_index > 0 and line_info.remaining[colon_index - 1].isspace():
+      # Numpy-style parameter lines have a space before the colon (e.g.
+      # "argument : int"), unlike Google section headers (e.g. "Args:"). Such
+      # a line is a parameter, not a new section, even if the parameter's name
+      # matches a section title (e.g. an argument named "argument").
+      return False
   return (line_info.indentation <= state.section.indentation
           or line_info.indentation < state.section.line1_indentation)
 

fire/docstrings_test.py

@@ -258,6 +258,28 @@ def test_numpy_format_multiline_arg_description(self):
     )
     self.assertEqual(expected_docstring_info, docstring_info)
 
+  def test_numpy_format_arg_name_matches_section_title(self):
+    docstring = """Run.
+
+    Parameters
+    ----------
+    executable :
+            Executable to run
+    argument :
+            Positional argument to the executable
+    """
+    docstring_info = docstrings.parse(docstring)
+    expected_docstring_info = DocstringInfo(
+        summary='Run.',
+        args=[
+            ArgInfo(name='executable', type='',
+                    description='Executable to run'),
+            ArgInfo(name='argument', type='',
+                    description='Positional argument to the executable'),
+        ],
+    )
+    self.assertEqual(expected_docstring_info, docstring_info)
+
   def test_multisection_docstring(self):
     docstring = """Docstring summary.