When skipping duplicates in bulk insert on MySQL, avoid assigning id when not specified

If `id` is an `AUTONUMBER` column, then my former strategy here of assigning `no_op_column` to an arbitrary column would fail in this specific scenario:

1. `model.columns.first` is an AUTONUMBER column
2. `model.columns.first` is not assigned in the insert attributes

I added three tests: the first test covers the actual error; the second test documents that this _isn't_ a problem when a value is given for the AUTONUMBER column and the third test ensures that this no-op strategy isn't secretly doing an UPSERT.

1 files changed, 2 insertions, 2 deletions

diff --git a/activerecord/lib/active_record/insert_all.rb b/activerecord/lib/active_record/insert_all.rb
index 4b02d40aa0..d7808919ee 100644
--- a/activerecord/lib/active_record/insert_all.rb
+++ b/activerecord/lib/active_record/insert_all.rb
@@ -111,7 +111,7 @@ module ActiveRecord
       class Builder
         attr_reader :model
 
-        delegate :skip_duplicates?, :update_duplicates?, to: :insert_all
+        delegate :skip_duplicates?, :update_duplicates?, :keys, to: :insert_all
 
         def initialize(insert_all)
           @insert_all, @model, @connection = insert_all, insert_all.model, insert_all.connection
@@ -122,7 +122,7 @@ module ActiveRecord
         end
 
         def values_list
-          types = extract_types_from_columns_on(model.table_name, keys: insert_all.keys)
+          types = extract_types_from_columns_on(model.table_name, keys: keys)
 
           values_list = insert_all.map_key_with_value do |key, value|
             bind = Relation::QueryAttribute.new(key, value, types[key])