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.

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)