Merge pull request #40212 from Shopify/active-record-exceptions-wrapping

Translate Mysql2 errors in Mysql2Adapter#quote_string (take 2)

activerecord/CHANGELOG.md

+*   All connection adapters `execute` now raises `ActiveRecord::ConnectionNotEstablished` rather than
+    `ActiveRecord::InvalidStatement` when they encounter a connection error.
+
+    *Jean Boussier*
+
+*   `Mysql2Adapter#quote_string` now raises `ActiveRecord::ConnectionNotEstablished` rather than
+    `ActiveRecord::InvalidStatement` when it can't connect to the MySQL server.
+
+    *Jean Boussier*
+
 *   Add support for check constraints that are `NOT VALID` via `validate: false` (PostgreSQL-only).
 
     *Alex Robbin*

activerecord/lib/active_record/connection_adapters/abstract_mysql_adapter.rb

@@ -650,6 +650,12 @@ def extract_precision(sql_type)
 
         def translate_exception(exception, message:, sql:, binds:)
           case error_number(exception)
+          when nil
+            if exception.message.match?(/MySQL client is not connected/i)
+              ConnectionNotEstablished.new(exception)
+            else
+              super
+            end
           when ER_DB_CREATE_EXISTS
             DatabaseAlreadyExists.new(message, sql: sql, binds: binds)
           when ER_DUP_ENTRY

activerecord/lib/active_record/connection_adapters/postgresql_adapter.rb

@@ -478,6 +478,12 @@ def translate_exception(exception, message:, sql:, binds:)
           return exception unless exception.respond_to?(:result)
 
           case exception.result.try(:error_field, PG::PG_DIAG_SQLSTATE)
+          when nil
+            if exception.message.match?(/connection is closed/i)
+              ConnectionNotEstablished.new(exception)
+            else
+              super
+            end
           when UNIQUE_VIOLATION
             RecordNotUnique.new(message, sql: sql, binds: binds)
           when FOREIGN_KEY_VIOLATION

activerecord/lib/active_record/connection_adapters/sqlite3_adapter.rb

@@ -475,17 +475,18 @@ def copy_table_contents(from, to, columns, rename = {})
         end
 
         def translate_exception(exception, message:, sql:, binds:)
-          case exception.message
           # SQLite 3.8.2 returns a newly formatted error message:
           #   UNIQUE constraint failed: *table_name*.*column_name*
           # Older versions of SQLite return:
           #   column *column_name* is not unique
-          when /column(s)? .* (is|are) not unique/, /UNIQUE constraint failed: .*/
+          if exception.message.match?(/(column(s)? .* (is|are) not unique|UNIQUE constraint failed: .*)/i)
             RecordNotUnique.new(message, sql: sql, binds: binds)
-          when /.* may not be NULL/, /NOT NULL constraint failed: .*/
+          elsif exception.message.match?(/(.* may not be NULL|NOT NULL constraint failed: .*)/i)
             NotNullViolation.new(message, sql: sql, binds: binds)
-          when /FOREIGN KEY constraint failed/i
+          elsif exception.message.match?(/FOREIGN KEY constraint failed/i)
             InvalidForeignKey.new(message, sql: sql, binds: binds)
+          elsif exception.message.match?(/called on a closed database/i)
+            ConnectionNotEstablished.new(exception)
           else
             super
           end

activerecord/test/cases/adapters/mysql2/connection_test.rb

@@ -58,7 +58,7 @@ def test_successful_reconnection_after_timeout_with_verify
   def test_execute_after_disconnect
     @connection.disconnect!
 
-    error = assert_raise(ActiveRecord::StatementInvalid) do
+    error = assert_raise(ActiveRecord::ConnectionNotEstablished) do
       @connection.execute("SELECT 1")
     end
     assert_kind_of Mysql2::Error, error.cause
@@ -67,7 +67,7 @@ def test_execute_after_disconnect
   def test_quote_after_disconnect
     @connection.disconnect!
 
-    assert_raise(ActiveRecord::StatementInvalid) do
+    assert_raise(ActiveRecord::ConnectionNotEstablished) do
       @connection.quote("string")
     end
   end

activerecord/test/cases/disconnected_test.rb

@@ -22,8 +22,10 @@ def setup
     test "can't execute statements while disconnected" do
       @connection.execute "SELECT count(*) from products"
       @connection.disconnect!
-      assert_raises(ActiveRecord::StatementInvalid) do
-        @connection.execute "SELECT count(*) from products"
+      assert_raises(ActiveRecord::ConnectionNotEstablished) do
+        silence_warnings do
+          @connection.execute "SELECT count(*) from products"
+        end
       end
     end
   end