guest: Add a model field for the guest user and add guest user to populate_db.

[shubhamdhama]

I've added a new guest user by name Polonius.

[edit] I've no idea why tests are failing now, any help is welcomed.

[timabbott]

@shubhamdhama I think the test failures are related to your changes; probably a test that needs updating. tools/test-api; if you read zerver/lib/api_test_helpers.py, you'll see it makes an assertion about the state of the test fixtures that presumably your change made no longer true.

[timabbott]

I merged the first commit, since it still passes tests.

[timabbott]

@eeshangarg do you understand why test-api is failing with the second commit here?

[timabbott]

Oh, I think I know what's happening. Adding polonius to the test database perturbs the random seed used in generating the assignment of users to streams in this block of populate_db:

            bulk_create_streams(zulip_realm, stream_dict)                                                                                          
            recipient_streams = [Stream.objects.get(name=name, realm=zulip_realm).id                                                               
                                 for name in stream_list]  # type: List[int]                                                                       
            # Create subscriptions to streams.  The following                                                                                      
            # algorithm will give each of the users a different but                                                                                
            # deterministic subset of the streams (given a fixed list                                                                              
            # of users).                                                                                                                           
            subscriptions_to_add = []  # type: List[Subscription]                                                                                  
            event_time = timezone_now()                                                                                                            

[timabbott]

The fix is to add this hunk, which results in Polonius not being auto-subscribed to any streams:

             event_time = timezone_now()
             all_subscription_logs = []  # type: (List[RealmAuditLog])
             profiles = UserProfile.objects.select_related().filter(
-                is_bot=False).order_by("email")  # type: Sequence[UserProfile]
+                is_bot=False, is_guest=False).order_by("email")  # type: Sequence[UserProfile]
             for i, profile in enumerate(profiles):
                 # Subscribe to some streams.
                 for type_id in recipient_streams[:int(len(recipient_streams) *

I think that's what we want (guests should not have a random set of subscriptions like other users), but we should also add code to subscribe him specifically to a stream (probably Denmark, thematically).

[timabbott]

Merged that second commit as 26d2ffa

[shubhamdhama]

Ahh, I wasn't aware of this, now I got what was happening here, thanks for helping (I don't think I could figure out this easily)

[timabbott]

Yeah, this was a pretty subtle thing; the reason I took the lead on debugging this was because it seemed from the error situation like something that was very likely to be subtle and requiring some obscure knowledge :).