Fix verification_retry_count not incrementing

...properly when `calculate_checksum` returns without error, but
`verification_state` fails to transition to `verification_succeeded`.

ee/lib/gitlab/geo/verification_state.rb

@@ -220,6 +220,10 @@ module Gitlab
 
         track_checksum_result!(checksum, calculation_started_at)
       rescue => e
+        # Reset any potential changes from track_checksum_result, i.e.
+        # verification_retry_count may have been cleared.
+        reset
+
         verification_failed_with_message!('Error during verification', e)
       end
 

ee/spec/lib/gitlab/geo/verification_state_spec.rb

@@ -195,7 +195,7 @@ RSpec.describe Gitlab::Geo::VerificationState do
     end
   end
 
-  describe '#track_checksum_attempt!' do
+  describe '#track_checksum_attempt!', :aggregate_failures do
     context 'when verification was not yet started' do
       it 'starts verification' do
         expect do
@@ -234,12 +234,39 @@ RSpec.describe Gitlab::Geo::VerificationState do
     end
 
     context 'when an error occurs while yielding' do
-      it 'sets verification_failed' do
-        subject.track_checksum_attempt! do
-          raise 'an error'
+      context 'when the record was failed' do
+        it 'sets verification_failed and increments verification_retry_count' do
+          subject.verification_failed_with_message!('foo')
+
+          subject.track_checksum_attempt! do
+            raise 'an error'
+          end
+
+          expect(subject.reload.verification_failed?).to be_truthy
+          expect(subject.verification_retry_count).to eq(2)
         end
+      end
+    end
 
-        expect(subject.reload.verification_failed?).to be_truthy
+    context 'when the yielded block returns nil' do
+      context 'when the record was pending' do
+        it 'sets verification_failed and sets verification_retry_count to 1' do
+          subject.track_checksum_attempt! { nil }
+
+          expect(subject.reload.verification_failed?).to be_truthy
+          expect(subject.verification_retry_count).to eq(1)
+        end
+      end
+
+      context 'when the record was failed' do
+        it 'sets verification_failed and increments verification_retry_count' do
+          subject.verification_failed_with_message!('foo')
+
+          subject.track_checksum_attempt! { nil }
+
+          expect(subject.reload.verification_failed?).to be_truthy
+          expect(subject.verification_retry_count).to eq(2)
+        end
       end
     end
   end