Add a generic base class for Active Storage exceptions

Closes #33292.

[Andrei Makarov & George Claghorn]

activestorage/CHANGELOG.md

@@ -1,3 +1,10 @@
+*   Active Storage error classes like `ActiveStorage::IntegrityError` and
+    `ActiveStorage::UnrepresentableError` now inherit from `ActiveStorage::Error`
+    instead of `StandardError`. This permits rescuing `ActiveStorage::Error` to
+    handle all Active Storage errors.
+
+    *Andrei Makarov*, *George Claghorn*
+
 *   Uploaded files assigned to a record are persisted to storage when the record
     is saved instead of immediately.
 

activestorage/lib/active_storage/errors.rb

@@ -1,11 +1,14 @@
 # frozen_string_literal: true
 
 module ActiveStorage
-  class InvariableError < StandardError; end
-  class UnpreviewableError < StandardError; end
-  class UnrepresentableError < StandardError; end
+  # Generic base class for all Active Storage exceptions.
+  class Error < StandardError; end
+
+  class InvariableError < Error; end
+  class UnpreviewableError < Error; end
+  class UnrepresentableError < Error; end
 
   # Raised when uploaded or downloaded data does not match a precomputed checksum.
   # Indicates that a network error or a software bug caused data corruption.
-  class IntegrityError < StandardError; end
+  class IntegrityError < Error; end
 end