Raise specific errors after upstream retries exhausted in snippet/LOC commands (#8617)

Instead of re-raising the raw RestClient exception after max retries,
raise named errors (SnippetGeneratorTemporarilyUnavailable and
LocCounterTemporarilyUnavailable) so they can be identified and
managed in Sentry independently.

Closes #8588

Co-authored-by: Claude Opus 4.6 <noreply@anthropic.com>

Author: iHiD

app/commands/iteration/count_lines_of_code.rb

@@ -6,6 +6,7 @@ class Iteration::CountLinesOfCode
   initialize_with :iteration, retries_count: 0
 
   MAX_RETRIES = 3
+  LocCounterTemporarilyUnavailable = Class.new(StandardError)
 
   def call
     # Sometimes the iteration might be deleted
@@ -37,7 +38,8 @@ def call
     iteration.update_column(:num_loc, num_loc)
     Solution::UpdateNumLoc.(iteration.solution)
   rescue RestClient::BadGateway, RestClient::ServiceUnavailable, RestClient::GatewayTimeout
-    raise if retries_count >= MAX_RETRIES
+    # This error is manually ignored on Sentry unless it escalates
+    raise LocCounterTemporarilyUnavailable if retries_count >= MAX_RETRIES
 
     self.class.defer(iteration, retries_count: retries_count + 1, wait: rand(30..90))
   ensure

app/commands/iteration/generate_snippet.rb

@@ -6,6 +6,7 @@ class Iteration::GenerateSnippet
   initialize_with :iteration, retries_count: 0
 
   MAX_RETRIES = 3
+  SnippetGeneratorTemporarilyUnavailable = Class.new(StandardError)
 
   def call
     # Sometimes the iteration might be deleted
@@ -38,7 +39,8 @@ def call
 
     raise
   rescue RestClient::BadGateway, RestClient::ServiceUnavailable, RestClient::GatewayTimeout
-    raise if retries_count >= MAX_RETRIES
+    # This error is manually ignored on Sentry unless it escalates
+    raise SnippetGeneratorTemporarilyUnavailable if retries_count >= MAX_RETRIES
 
     self.class.defer(iteration, retries_count: retries_count + 1, wait: rand(30..90))
   end

test/commands/iteration/count_lines_of_code_test.rb

@@ -118,7 +118,7 @@ class Iteration::CountLinesOfCodeTest < ActiveJob::TestCase
 
     RestClient.stubs(:post).raises(RestClient::BadGateway)
 
-    assert_raises RestClient::BadGateway do
+    assert_raises Iteration::CountLinesOfCode::LocCounterTemporarilyUnavailable do
       Iteration::CountLinesOfCode.(iteration, retries_count: 3)
     end
   end

test/commands/iteration/generate_snippet_test.rb

@@ -115,7 +115,7 @@ class Iteration::GenerateSnippetTest < ActiveJob::TestCase
 
     RestClient.stubs(:post).raises(RestClient::BadGateway)
 
-    assert_raises RestClient::BadGateway do
+    assert_raises Iteration::GenerateSnippet::SnippetGeneratorTemporarilyUnavailable do
       Iteration::GenerateSnippet.(iteration, retries_count: 3)
     end
   end