Issue 18010: pydoc search chokes on import errors

After installing Django, I get the following error in test_pydoc:

======================================================================
FAIL: test_url_requests (test.test_pydoc.PydocUrlHandlerTest)
----------------------------------------------------------------------
Traceback (most recent call last):
  File "/home/antoine/cpython/finalize/Lib/test/test_pydoc.py", line 581, in test_url_requests
    self.assertEqual(result, title, text)
AssertionError: 'Pydoc: Error - search?key=pydoc' != 'Pydoc: Search Results'
- Pydoc: Error - search?key=pydoc
+ Pydoc: Search Results

The reason is attempting to import a django.something module raises the following error:

django.core.exceptions.ImproperlyConfigured: Requested setting DATABASES, but settings are not configured. You must either define the environment variable DJANGO_SETTINGS_MODULE or call settings.configure() before accessing settings

... which isn't silenced by pydoc.

Now I agree this is fundamentally obnoxious on Django's part, but unfortunately it isn't the only package (IIRC) to behave in this way, meaning it would be nice from pydoc to silence all such errors when an import is attempted.

Isn't issue10060 related?

Not exactly. issue10060 is about a crash when loading an extension module, not an exception being raised and propagated through pydoc.

Patch attached.

The patch looks good.

Would be nice to have a test.

Here is a test case. I had to insert a temporary directory into sys.path, based off my patch in Issue 25184. Let me know if it doesn’t look too evil :)

Oh, I were not expected that the test will be so complex, and now I'm not sure that want it. :-(  But looks it can't be written simpler. The patch LGTM in any case.

New changeset 9098731de840 by Martin Panter in branch '3.4':
Issue #18010: Fix pydoc web server search to handle package exceptions
https://hg.python.org/cpython/rev/9098731de840

New changeset 8702efa1feb4 by Martin Panter in branch '3.5':
Issue #18010: Merge pydoc web search fix from 3.4 into 3.5
https://hg.python.org/cpython/rev/8702efa1feb4

New changeset d86ff708f545 by Martin Panter in branch 'default':
Issue #18010: Merge pydoc web search fix from 3.5
https://hg.python.org/cpython/rev/d86ff708f545

In Python 2, it looks like instead of the web server search function there is a GUI search function. Here is a patch to fix the equivalent problem there. However I am not volunteering to make a test case; there does not seem to be any GUI tests to start with.

gui-search.patch LGTM.

New changeset 1ab20d3c9dc6 by Martin Panter in branch '2.7':
Issue #18010: Fix pydoc GUI search to handle package exceptions
https://hg.python.org/cpython/rev/1ab20d3c9dc6

messages: + msg254162
stage: commit review -> patch review

nosy: + martin.panter
messages: + msg253892

stage: test needed -> patch review