#940286: pydoc.Helper.help() ignores input/output init parameters.

Lib/pydoc.py

@@ -1310,6 +1310,11 @@ doubt, consult the module reference at the location listed above.
             line += '\n' + self.indent(str(doc))
         return line
 
+class _PlainTextDoc(TextDoc):
+    """Subclass of TextDoc which overrides string styling"""
+    def bold(self, text):
+        return text
+
 # --------------------------------------------------------- user interfaces
 
 def pager(text):
@@ -1464,6 +1469,7 @@ def locate(path, forceload=0):
 # --------------------------------------- interactive interpreter interface
 
 text = TextDoc()
+plaintext = _PlainTextDoc()
 html = HTMLDoc()
 
 def resolve(thing, forceload=0):
@@ -1476,8 +1482,11 @@ def resolve(thing, forceload=0):
     else:
         return thing, getattr(thing, '__name__', None)
 
-def render_doc(thing, title='Python Library Documentation: %s', forceload=0):
+def render_doc(thing, title='Python Library Documentation: %s', forceload=0,
+        renderer=None):
     """Render text documentation, given an object or a path to an object."""
+    if renderer is None:
+        renderer = text
     object, name = resolve(thing, forceload)
     desc = describe(object)
     module = inspect.getmodule(object)
@@ -1496,12 +1505,16 @@ def render_doc(thing, title='Python Library Documentation: %s', forceload=0):
         # document its available methods instead of its value.
         object = type(object)
         desc += ' object'
-    return title % desc + '\n\n' + text.document(object, name)
+    return title % desc + '\n\n' + renderer.document(object, name)
 
-def doc(thing, title='Python Library Documentation: %s', forceload=0):
+def doc(thing, title='Python Library Documentation: %s', forceload=0,
+        output=None):
     """Display text documentation, given an object or a path to an object."""
     try:
-        pager(render_doc(thing, title, forceload))
+        if output is None:
+            pager(render_doc(thing, title, forceload))
+        else:
+            output.write(render_doc(thing, title, forceload, plaintext))
     except (ImportError, ErrorDuringImport) as value:
         print(value)
 
@@ -1755,9 +1768,9 @@ has the same effect as typing a particular string at the help> prompt.
             elif request in self.symbols: self.showsymbol(request)
             elif request in self.keywords: self.showtopic(request)
             elif request in self.topics: self.showtopic(request)
-            elif request: doc(request, 'Help on %s:')
+            elif request: doc(request, 'Help on %s:', output=self._output)
         elif isinstance(request, Helper): self()
-        else: doc(request, 'Help on %s:')
+        else: doc(request, 'Help on %s:', output=self._output)
         self.output.write('\n')
 
     def intro(self):

Lib/test/test_pydoc.py

@@ -9,9 +9,11 @@ import inspect
 import unittest
 import test.support
 import xml.etree
+import textwrap
+from io import StringIO
 from contextlib import contextmanager
-from test.support import (
-    TESTFN, forget, rmtree, EnvironmentVarGuard, reap_children)
+from test.support import TESTFN, forget, rmtree, EnvironmentVarGuard, \
+     reap_children, captured_output
 
 from test import pydoc_mod
 
@@ -327,6 +329,41 @@ class PyDocDocTest(unittest.TestCase):
         self.assertEqual(stripid("<type 'exceptions.Exception'>"),
                          "<type 'exceptions.Exception'>")
 
+    @unittest.skipIf(sys.flags.optimize >= 2,
+                     'Docstrings are omitted with -O2 and above')
+    def test_help_output_redirect(self):
+        # issue 940286, if output is set in Helper, then all output from
+        # Helper.help should be redirected
+        old_pattern = expected_text_pattern
+        getpager_old = pydoc.getpager
+        getpager_new = lambda: (lambda x: x)
+        self.maxDiff = None
+
+        buf = StringIO()
+        helper = pydoc.Helper(output=buf)
+        unused, doc_loc = get_pydoc_text(pydoc_mod)
+        module = "test.pydoc_mod"
+        help_header = """
+        Help on module test.pydoc_mod in test:
+
+        """.lstrip()
+        help_header = textwrap.dedent(help_header)
+        expected_help_pattern = help_header + expected_text_pattern
+
+        pydoc.getpager = getpager_new
+        try:
+            with captured_output('stdout') as output, \
+                 captured_output('stderr') as err:
+                helper.help(module)
+                result = buf.getvalue().strip()
+                expected_text = expected_help_pattern % \
+                                (doc_loc, inspect.getabsfile(pydoc_mod))
+                self.assertEqual('', output.getvalue())
+                self.assertEqual('', err.getvalue())
+                self.assertEqual(expected_text, result)
+        finally:
+            pydoc.getpager = getpager_old
+
 
 class TestDescriptions(unittest.TestCase):
 

Misc/NEWS

@@ -33,6 +33,8 @@ Core and Builtins
 Library
 -------
 
+- Issue #940286: pydoc.Helper.help() ignores input/output init parameters.
+
 - Issue #1745035: Add a command size and data size limit to smtpd.py, to
   prevent DoS attacks.  Patch by Savio Sena.