Fix sqlite migrations with custom primary keys

Previously, if a record was created with a custom primary key, that
table could not be migrated using sqlite. While attempting to copy the
table, the type of the primary key was ignored.

Once that was corrected, copying the indexes would fail because custom
primary keys are autoindexed by sqlite by default.

To correct that, this skips copying the index if the index name begins
with "sqlite_". This is a reserved word that indicates that the
index is an internal schema object. SQLite prohibits applications from
creating objects whose names begin with "sqlite_", so this string should
be safe to use as a check.
ref https://www.sqlite.org/fileformat2.html#intschema

2 files changed, 23 insertions, 1 deletions

diff --git a/activerecord/lib/active_record/connection_adapters/sqlite3_adapter.rb b/activerecord/lib/active_record/connection_adapters/sqlite3_adapter.rb
index daece2bffd..3197b522b3 100644
--- a/activerecord/lib/active_record/connection_adapters/sqlite3_adapter.rb
+++ b/activerecord/lib/active_record/connection_adapters/sqlite3_adapter.rb
@@ -395,10 +395,11 @@ module ActiveRecord
 
         def copy_table(from, to, options = {})
           from_primary_key = primary_key(from)
+          from_primary_key_column = columns(from).select { |column| column.name == from_primary_key }.first
           options[:id] = false
           create_table(to, options) do |definition|
             @definition = definition
-            @definition.primary_key(from_primary_key) if from_primary_key.present?
+            @definition.primary_key(from_primary_key, from_primary_key_column.type) if from_primary_key.present?
             columns(from).each do |column|
               column_name = options[:rename] ?
                 (options[:rename][column.name] ||
@@ -422,6 +423,9 @@ module ActiveRecord
         def copy_table_indexes(from, to, rename = {})
           indexes(from).each do |index|
             name = index.name
+            # indexes sqlite creates for internal use start with `sqlite_` and
+            # don't need to be copied
+            next if name.starts_with?("sqlite_")
             if to == "a#{from}"
               name = "t#{name}"
             elsif from == "a#{to}"
diff --git a/activerecord/test/cases/adapters/sqlite3/sqlite3_adapter_test.rb b/activerecord/test/cases/adapters/sqlite3/sqlite3_adapter_test.rb
index 1f057fe5c6..14f4997d5b 100644
--- a/activerecord/test/cases/adapters/sqlite3/sqlite3_adapter_test.rb
+++ b/activerecord/test/cases/adapters/sqlite3/sqlite3_adapter_test.rb
@@ -360,6 +360,24 @@ module ActiveRecord
         end
       end
 
+      class Barcode < ActiveRecord::Base
+      end
+
+      def test_existing_records_have_custom_primary_key
+        connection = Barcode.connection
+        connection.create_table(:barcodes, primary_key: "code", id: :string, limit: 42, force: true) do |t|
+          t.text :other_attr
+        end
+        code = "214fe0c2-dd47-46df-b53b-66090b3c1d40"
+        Barcode.create! code: code, other_attr: "xxx"
+
+        connection.change_table "barcodes" do |t|
+          connection.remove_column("barcodes", "other_attr")
+        end
+
+        assert_equal code, Barcode.first.id
+      end
+
       def test_supports_extensions
         assert_not @conn.supports_extensions?, "does not support extensions"
       end