Crash when we try to pass a query string to a POFile that doesn't exist yet.

[Diogo Matsubara]

Steps to reproduce:
1. http://localhost:8086/distros/ubuntu/hoary/+source/evolution/+pots/evolution-2.2/
2. Notice that French isn't listed, which means we don't have a POFile for it yet.
3. Manually change the URL to:
http://localhost:8086/distros/ubuntu/hoary/+source/evolution/+pots/evolution-2.2/fr/+translate?alt=nb&show=untranslated
3. Crash like this: OOPS-133D157

[Diogo Matsubara (matsubara)]

<kiko-fud> I bet the problem is that dummypofile doesn't implement pofile.getPOTMsgSetTranslated pofile.getPOTMsgSetFuzzy or pofile.getPOTMsgSetUntranslated

<kiko-fud> the actual bug is DummyPOFile doesn't implement IPOFile even though it says it does.
<kiko-fud>so that would need to be fixed

[Christian Reis (kiko)]

When I say fixed I mean either:

a) Implementing the full IPOFile interface
b) Reducing the IPOFile interface, potentially by making some of the methods private
c) Changing from using IPOFile to something else.

The fact that this can be fixed with a band-aid shouldn't let us overlook the root of this problem.

[Diogo Matsubara (matsubara)]

Another way to reproduce a similar problem with the DummyPOFile.

Steps to reproduce (using sample data):
1.
http://localhost:8086/distros/ubuntu/hoary/+source/pmount/+pots/pmount/pt_BR/+translate
2. Selecte on 'Show:' select box 'untranslated' and click on Filter
3. Crash with a traceback like:
    * Module canonical.launchpad.browser.pofile, line 324, in initialize
      self.batchnav = BatchNavigator(
    * Module canonical.launchpad.browser.pofile, line 506, in getSelectedPOTMsgSet
      return pofile.getPOTMsgSetUntranslated()

AttributeError: 'DummyPOFile' object has no attribute 'getPOTMsgSetUntranslated'

[Diogo Matsubara (matsubara)]

OOPS-186D228 and OOPS-186B476 recent oopses

[Данило Шеган (danilo)]

After discussion with SteveA, I was advised not to check if DummyPOFile implements full IPOFile interface.

So instead, I've added a test to check that none of the selections in a combo box is breaking (this test is going to be useful irregardless if the solution is actually considered fine).

For the fix, I just implemented three missing methods in DummyPOFile.

[Carlos Perelló Marín (carlos)]

Actually, what we should do is to split our interfaces to have a read only one and a write one.

DummyPOFile should implement the read only one and POFile both.

Of course, I'm not talking about doing that to solve this bug, just noting what we should plan to do in the future.