Always store errors details information with symbols

When the association is autosaved we were storing the details with
string keys. This was creating inconsistency with other details that are
added using the `Errors#add` method. It was also inconsistent with the
`Errors#messages` storage.

To fix this inconsistency we are always storing with symbols. This will
cause a small breaking change because in those cases the details could
be accessed as strings keys but now it can not.

The reason that we chose to do this breaking change is because `#details`
should be considered a low level object like `#messages` is.

Fix #26499.

[Rafael Mendonça França + Marcus Vieira]

3 files changed, 32 insertions, 15 deletions

diff --git a/activerecord/CHANGELOG.md b/activerecord/CHANGELOG.md
index 786420f51e..6cc667b754 100644
--- a/activerecord/CHANGELOG.md
+++ b/activerecord/CHANGELOG.md
@@ -1,3 +1,18 @@
+*   Always store errors details information with symbols.
+
+    When the association is autosaved we were storing the details with
+    string keys. This was creating inconsistency with other details that are
+    added using the `Errors#add` method. It was also inconsistent with the
+    `Errors#messages` storage.
+
+    To fix this inconsistency we are always storing with symbols. This will
+    cause a small breaking change because in those cases the details could
+    be accessed as strings keys but now it can not.
+
+    Fix #26499.
+
+    *Rafael Mendonça França*, *Marcus Vieira*
+
 *   Calling `touch` on a model using optimistic locking will now leave the model
     in a non-dirty state with no attribute changes.
 
diff --git a/activerecord/lib/active_record/autosave_association.rb b/activerecord/lib/active_record/autosave_association.rb
index db84876b0a..d3e0dee731 100644
--- a/activerecord/lib/active_record/autosave_association.rb
+++ b/activerecord/lib/active_record/autosave_association.rb
@@ -329,26 +329,20 @@ module ActiveRecord
         return true if record.destroyed? || (reflection.options[:autosave] && record.marked_for_destruction?)
 
         validation_context = self.validation_context unless [:create, :update].include?(self.validation_context)
+
         unless valid = record.valid?(validation_context)
           if reflection.options[:autosave]
             indexed_attribute = !index.nil? && (reflection.options[:index_errors] || ActiveRecord::Base.index_nested_attribute_errors)
 
             record.errors.each do |attribute, message|
-              if indexed_attribute
-                attribute = "#{reflection.name}[#{index}].#{attribute}"
-              else
-                attribute = "#{reflection.name}.#{attribute}"
-              end
+              attribute = normalize_reflection_attribute(indexed_attribute, reflection, index, attribute)
               errors[attribute] << message
               errors[attribute].uniq!
             end
 
             record.errors.details.each_key do |attribute|
-              if indexed_attribute
-                reflection_attribute = "#{reflection.name}[#{index}].#{attribute}"
-              else
-                reflection_attribute = "#{reflection.name}.#{attribute}"
-              end
+              reflection_attribute =
+                normalize_reflection_attribute(indexed_attribute, reflection, index, attribute).to_sym
 
               record.errors.details[attribute].each do |error|
                 errors.details[reflection_attribute] << error
@@ -362,6 +356,14 @@ module ActiveRecord
         valid
       end
 
+      def normalize_reflection_attribute(indexed_attribute, reflection, index, attribute)
+        if indexed_attribute
+          "#{reflection.name}[#{index}].#{attribute}"
+        else
+          "#{reflection.name}.#{attribute}"
+        end
+      end
+
       # Is used as a before_save callback to check while saving a collection
       # association whether or not the parent was a new record before saving.
       def before_save_collection_association
diff --git a/activerecord/test/cases/autosave_association_test.rb b/activerecord/test/cases/autosave_association_test.rb
index c6e983a106..c24d7b8835 100644
--- a/activerecord/test/cases/autosave_association_test.rb
+++ b/activerecord/test/cases/autosave_association_test.rb
@@ -443,7 +443,7 @@ class TestDefaultAutosaveAssociationOnAHasManyAssociationWithAcceptsNestedAttrib
     assert_not invalid_electron.valid?
     assert valid_electron.valid?
     assert_not molecule.valid?
-    assert_equal [{ error: :blank }], molecule.errors.details["electrons.name"]
+    assert_equal [{ error: :blank }], molecule.errors.details[:"electrons.name"]
   end
 
   def test_errors_details_should_be_indexed_when_passed_as_array
@@ -457,8 +457,8 @@ class TestDefaultAutosaveAssociationOnAHasManyAssociationWithAcceptsNestedAttrib
     assert_not tuning_peg_invalid.valid?
     assert tuning_peg_valid.valid?
     assert_not guitar.valid?
-    assert_equal [{ error: :not_a_number, value: nil }] , guitar.errors.details["tuning_pegs[1].pitch"]
-    assert_equal [], guitar.errors.details["tuning_pegs.pitch"]
+    assert_equal [{ error: :not_a_number, value: nil }], guitar.errors.details[:"tuning_pegs[1].pitch"]
+    assert_equal [], guitar.errors.details[:"tuning_pegs.pitch"]
   end
 
   def test_errors_details_should_be_indexed_when_global_flag_is_set
@@ -474,8 +474,8 @@ class TestDefaultAutosaveAssociationOnAHasManyAssociationWithAcceptsNestedAttrib
     assert_not invalid_electron.valid?
     assert valid_electron.valid?
     assert_not molecule.valid?
-    assert_equal [{ error: :blank }], molecule.errors.details["electrons[1].name"]
-    assert_equal [], molecule.errors.details["electrons.name"]
+    assert_equal [{ error: :blank }], molecule.errors.details[:"electrons[1].name"]
+    assert_equal [], molecule.errors.details[:"electrons.name"]
   ensure
     ActiveRecord::Base.index_nested_attribute_errors = old_attribute_config
   end