Bug: Incorrect type inference for varchar column as UUID in where query with JRuby JDBC adapter

[ubinexy-tw]

Overview

I've encountered an error when using the JRuby JDBC adapter for PostgreSQL. It seems ActiveRecord incorrectly infers the data type of string values as uuid if its format resembles a UUID,. This happens even if the corresponding database column is explicitly defined as character varying (varchar).

Steps to Reproduce

The following standalone script reliably reproduces the issue.

# frozen_string_literal: true

require 'bundler/inline'

gemfile do
  source 'https://rubygems.org'
  gem 'activerecord', '~> 7.1.5.2'
  gem 'activerecord-jdbcpostgresql-adapter', '~> 71.0'
  gem 'jruby-openssl'
end

require 'active_record'
require 'logger'

# 1. Database Configuration
db_config = {
  adapter:  'jdbcpostgresql',
  host:     'localhost',
  database: ENV['db_database'],
  username: ENV['db_username'],
  password: ENV['db_password']
}

ActiveRecord::Base.establish_connection(db_config)
ActiveRecord::Base.logger = Logger.new(STDOUT)

# 2. Schema and Model
ActiveRecord::Schema.define do
  drop_table :items, if_exists: true
  create_table :items do |t|
    t.string :external_id, limit: 36 # Explicitly character varying
    t.string :name
  end
end

class Item < ActiveRecord::Base
end

# 3. Seed Data
Item.create!(external_id: 'a068351235251000f07fa89bcaf80000', name: 'Existing Item 1')
Item.create!(external_id: 'e2d08afc53614c37b32b31270bb8bee3', name: 'Existing Item 2')

# 4. Reproduce the Bug
ids_to_include = [
  {
    id: 'a068351235251000f07fa89bcaf80000'
  },
  {
    id: 'a068351235251000f07fa89bcaf80002'
  }
].map { |item| item[:id] }

puts "\n--- DEMONSTRATING THE BUG ---"
begin
  # This query fails due to incorrect type inference
  failing_query = Item.where(external_id: ids_to_include)
  failing_query.to_a
  puts "✅ SUCCESS (NO BUG): The query worked unexpectedly."
rescue ActiveRecord::StatementInvalid => e
  puts "❌ FAILURE (BUG REPRODUCED): The query failed as expected."
  puts "   Error Class: #{e.class}"
  puts "   Error Message: #{e.message}"
end

puts "\n--> Script finished."

Expected Behavior

The query Item.where(workday_style_id: ids_to_include) should execute successfully. It should generate a SQL query where the bind parameters for the IN clause are treated as strings (varchar), matching the column type.

Actual Behavior

However, the query fails with an ActiveRecord::StatementInvalid exception. The underlying PostgreSQL error is PG::UndefinedFunction: ERROR: operator does not exist: character varying <> uuid.

This indicates that the adapter sent the string parameters to the database typed as uuid instead of varchar.