Add new error class `QueryCanceled` which will be raised when canceling statement due to user request (#31235)

This changes `StatementTimeout` to `QueryCanceled` for PostgreSQL.

In MySQL, errno 1317 (`ER_QUERY_INTERRUPTED`) is only used when the
query is manually cancelled.

But in PostgreSQL, `QUERY_CANCELED` error code (57014) which is used
`StatementTimeout` is also used when the both case. And, we can not tell
which reason happened.

So I decided to introduce new error class `QueryCanceled` closer to the
error code name.

3 files changed, 8 insertions, 1 deletions

diff --git a/activerecord/lib/active_record/connection_adapters/abstract_mysql_adapter.rb b/activerecord/lib/active_record/connection_adapters/abstract_mysql_adapter.rb
index 77ccac54bf..ede8a9c1e2 100644
--- a/activerecord/lib/active_record/connection_adapters/abstract_mysql_adapter.rb
+++ b/activerecord/lib/active_record/connection_adapters/abstract_mysql_adapter.rb
@@ -635,6 +635,7 @@ module ActiveRecord
         ER_CANNOT_ADD_FOREIGN   = 1215
         ER_CANNOT_CREATE_TABLE  = 1005
         ER_LOCK_WAIT_TIMEOUT    = 1205
+        ER_QUERY_INTERRUPTED    = 1317
         ER_QUERY_TIMEOUT        = 3024
 
         def translate_exception(exception, message)
@@ -663,6 +664,8 @@ module ActiveRecord
             LockWaitTimeout.new(message)
           when ER_QUERY_TIMEOUT
             StatementTimeout.new(message)
+          when ER_QUERY_INTERRUPTED
+            QueryCanceled.new(message)
           else
             super
           end
diff --git a/activerecord/lib/active_record/connection_adapters/postgresql_adapter.rb b/activerecord/lib/active_record/connection_adapters/postgresql_adapter.rb
index 489feadb00..7b27f6b7a0 100644
--- a/activerecord/lib/active_record/connection_adapters/postgresql_adapter.rb
+++ b/activerecord/lib/active_record/connection_adapters/postgresql_adapter.rb
@@ -420,7 +420,7 @@ module ActiveRecord
           when LOCK_NOT_AVAILABLE
             LockWaitTimeout.new(message)
           when QUERY_CANCELED
-            StatementTimeout.new(message)
+            QueryCanceled.new(message)
           else
             super
           end
diff --git a/activerecord/lib/active_record/errors.rb b/activerecord/lib/active_record/errors.rb
index 89e777ffc3..efcbd44776 100644
--- a/activerecord/lib/active_record/errors.rb
+++ b/activerecord/lib/active_record/errors.rb
@@ -343,6 +343,10 @@ module ActiveRecord
   class StatementTimeout < StatementInvalid
   end
 
+  # QueryCanceled will be raised when canceling statement due to user request.
+  class QueryCanceled < StatementInvalid
+  end
+
   # UnknownAttributeReference is raised when an unknown and potentially unsafe
   # value is passed to a query method when allow_unsafe_raw_sql is set to
   # :disabled. For example, passing a non column name value to a relation's