Fix issue 5230 by having pydoc's safeimport check to see if the import

error was thrown from itself in order to decide if the module can't be
found.  Thanks to Lucas Prado Melo for collaborating on the fix and tests.

4 files changed, 51 insertions, 3 deletions

diff --git a/Lib/pydoc.py b/Lib/pydoc.py
index 76a2b64..57071a1 100755
--- a/Lib/pydoc.py
+++ b/Lib/pydoc.py
@@ -55,6 +55,7 @@ Richard Chamberlain, for the first implementation of textdoc.
 import sys, imp, os, re, types, inspect, __builtin__, pkgutil
 from repr import Repr
 from string import expandtabs, find, join, lower, split, strip, rfind, rstrip
+from traceback import extract_tb
 try:
     from collections import deque
 except ImportError:
@@ -299,9 +300,9 @@ def safeimport(path, forceload=0, cache={}):
         elif exc is SyntaxError:
             # A SyntaxError occurred before we could execute the module.
             raise ErrorDuringImport(value.filename, info)
-        elif exc is ImportError and \
-             split(lower(str(value)))[:2] == ['no', 'module']:
-            # The module was not found.
+        elif exc is ImportError and extract_tb(tb)[-1][2]=='safeimport':
+            # The import error occurred directly in this function,
+            # which means there is no such module in the path.
             return None
         else:
             # Some other error occurred during the importing process.
diff --git a/Lib/test/test_pydoc.py b/Lib/test/test_pydoc.py
index 7990d3a..c1c19f6 100644
--- a/Lib/test/test_pydoc.py
+++ b/Lib/test/test_pydoc.py
@@ -1,5 +1,6 @@
 import sys
 import os
+import os.path
 import difflib
 import subprocess
 import re
@@ -7,6 +8,8 @@ import pydoc
 import inspect
 import unittest
 import test.test_support
+from contextlib import contextmanager
+from test.test_support import TESTFN, forget, rmtree, EnvironmentVarGuard
 
 from test import pydoc_mod
 
@@ -166,6 +169,9 @@ war</tt></dd></dl>
 # output pattern for missing module
 missing_pattern = "no Python documentation found for '%s'"
 
+# output pattern for module with bad imports
+badimport_pattern = "problem in %s - <type 'exceptions.ImportError'>: No module named %s"
+
 def run_pydoc(module_name, *args):
     """
     Runs pydoc on the specified module. Returns the stripped
@@ -237,6 +243,42 @@ class PyDocDocTest(unittest.TestCase):
         self.assertEqual(expected, result,
             "documentation for missing module found")
 
+    def test_badimport(self):
+        # This tests the fix for issue 5230, where if pydoc found the module
+        # but the module had an internal import error pydoc would report no doc
+        # found.
+        modname = 'testmod_xyzzy'
+        testpairs = (
+            ('i_am_not_here', 'i_am_not_here'),
+            ('test.i_am_not_here_either', 'i_am_not_here_either'),
+            ('test.i_am_not_here.neither_am_i', 'i_am_not_here.neither_am_i'),
+            ('i_am_not_here.{}'.format(modname), 'i_am_not_here.{}'.format(modname)),
+            ('test.{}'.format(modname), modname),
+            )
+
+        @contextmanager
+        def newdirinpath(dir):
+            os.mkdir(dir)
+            sys.path.insert(0, dir)
+            yield
+            sys.path.pop(0)
+            rmtree(dir)
+
+        with newdirinpath(TESTFN), EnvironmentVarGuard() as env:
+            env['PYTHONPATH'] = TESTFN
+            fullmodname = os.path.join(TESTFN, modname)
+            sourcefn = fullmodname + os.extsep + "py"
+            for importstring, expectedinmsg in testpairs:
+                f = open(sourcefn, 'w')
+                f.write("import {}\n".format(importstring))
+                f.close()
+                try:
+                    result = run_pydoc(modname)
+                finally:
+                    forget(modname)
+                expected = badimport_pattern % (modname, expectedinmsg)
+                self.assertEqual(expected, result)
+
     def test_input_strip(self):
         missing_module = " test.i_am_not_here "
         result = run_pydoc(missing_module)
diff --git a/Misc/ACKS b/Misc/ACKS
index 82cd4a3..5cc07e5 100644
--- a/Misc/ACKS
+++ b/Misc/ACKS
@@ -479,6 +479,7 @@ Andrew McNamara
 Craig McPheeters
 Lambert Meertens
 Bill van Melle
+Lucas Prado Melo
 Luke Mewburn
 Mike Meyer
 Steven Miale
diff --git a/Misc/NEWS b/Misc/NEWS
index 2985c3a..a4e92f4 100644
--- a/Misc/NEWS
+++ b/Misc/NEWS
@@ -327,6 +327,10 @@ Core and Builtins
 Library
 -------
 
+- Issue #5230: pydoc would report no documentation found if a module generated
+  a 'not found' import error when loaded; it now reports the import errors.
+  Thanks to Lucas Prado Melo for initial fix and collaboration on the tests.
+
 - Issue #6314: logging.basicConfig() performs extra checks on the "level"
   argument.