Switch to static URIs, new URI format in both protocols for new statuses (#4815)

* Decouple Status#local? from uri being nil

* Replace on-the-fly URI generation with stored URIs

- Generate URI in after_save hook for local statuses
- Use static value in TagManager when available, fallback to tag format
- Make TagManager use ActivityPub::TagManager to understand new format
- Adjust tests

* Use other heuristic for locality of old statuses, do not perform long query

* Exclude tombstone stream entries from Atom feed

* Prevent nil statuses from landing in Pubsubhubbub::DistributionWorker

* Fix URI not being saved (#4818)

* Add more specs for Status

* Save generated uri immediately

and also fix method order to minimize diff.

* Fix alternate HTML URL in Atom

* Fix tests

* Remove not-null constraint from statuses migration to speed it up

spec/models/status_spec.rb

@@ -13,9 +13,15 @@ RSpec.describe Status, type: :model do
     end
 
     it 'returns false if a remote URI is set' do
-      subject.uri = 'a'
+      alice.update(domain: 'example.com')
+      subject.save
       expect(subject.local?).to be false
     end
+
+    it 'returns true if a URI is set and `local` is true' do
+      subject.update(uri: 'example.com', local: true)
+      expect(subject.local?).to be true
+    end
   end
 
   describe '#reblog?' do
@@ -495,7 +501,7 @@ RSpec.describe Status, type: :model do
     end
   end
 
-  describe 'before_create' do
+  describe 'before_validation' do
     it 'sets account being replied to correctly over intermediary nodes' do
       first_status = Fabricate(:status, account: bob)
       intermediary = Fabricate(:status, thread: first_status, account: alice)
@@ -512,5 +518,22 @@ RSpec.describe Status, type: :model do
       parent = Fabricate(:status, text: 'First')
       expect(Status.create(account: alice, thread: parent, text: 'Response').conversation_id).to eq parent.conversation_id
     end
+
+    it 'sets `local` to true for status by local account' do
+      expect(Status.create(account: alice, text: 'foo').local).to be true
+    end
+
+    it 'sets `local` to false for status by remote account' do
+      alice.update(domain: 'example.com')
+      expect(Status.create(account: alice, text: 'foo').local).to be false
+    end
+  end
+
+  describe 'after_create' do
+    it 'saves ActivityPub uri as uri for local status' do
+      status = Status.create(account: alice, text: 'foo')
+      status.reload
+      expect(status.uri).to start_with('https://')
+    end
   end
 end