dry-schema: Undefined method `visit_constructor' for custom Hash constructor

Describe the bug:

It may be a regression, or an undocumented syntax change. I’m trying to coerce a JSON string param into a hash through a custom constructor. It worked in 1.4.3 but now fails in 1.5.0.

The corresponding versions of dry-types pulled in by dry-schema were 1.2.2 and 1.4.0 respectively.

To Reproduce:

require 'dry-schema'
require 'dry-types'
require 'json'

module Types
  include Dry.Types()
  JSONHash = Types::Hash.constructor do |h|
    h.is_a?(::Hash) ? h : ::JSON.parse(h)
  end
end

Schema = Dry::Schema.Params do
  required(:foo).filled(Types::JSONHash)
end

h = Schema.call(foo: %q({ "hello": "hi" })).to_h
puts "#{h[:foo].class.name} -- #{h[:foo].inspect}"

With dry-schema 1.4.3, here’s the output

Hash -- {"hello"=>"hi"}

With dry-schema 1.5.0, I get this:

...
undefined method `visit_constructor' for #<Dry::Schema::Compiler:0x00007fc2ba917858> (NoMethodError)
Did you mean?  visit_attr

Expected behavior

Behavior described above for 1.4.3 seems correct.

Your environment

Affects my production application: YES
Ruby version: ruby 2.7.1p83
macOS Catalina

About this issue

Original URL
State: closed
Created 4 years ago
Reactions: 7
Comments: 15 (10 by maintainers)

Commits related to this issue

Fix handling of constructor types Fixes #280 — committed to dry-rb/dry-schema by solnic 3 years ago
Merge pull request #365 from dry-rb/280-fix-handling-of-constructor-types [changelog] fixed: "Using constructor types should work fine now ie `required(:foo).filled(Types::Params::Integer.construc... — committed to dry-rb/dry-schema by solnic 3 years ago

Most upvoted comments

So, like I mentioned a little…over…a year…ago…this was caused by the fact that a custom type would not be set in various cases. I gave it a shot to see if at least the scenarios mentioned in this issue can be addressed and I succeeded. I’m not too confident that this issue will go away 100% so I’ll revisit this when working on 2.0.0.

For now, this specific issue (as in, the scenarios mentioned here) will be addressed in the upcoming 1.7.0 release.

solnic on Jun 29, 2021

oh noez! 😕 thanks for the report, I’ll fix it in 1.5.1

solnic on Apr 6, 2020

@solnic Great news! Thank you for the fix.

rykov on Jun 29, 2021

If I can follow the code, I would help with the issue; but I can’t read the dry-rb code at all. Probably the issue is on me, or dry-rb might used too many Ruby features.

@midnight-wonderer don’t worry about this, you jumped into literally one of the most complicated codebases in dry-rb land 🙂 The schema DSL has a lot of additional complexity because it still works with or without type specifications and this will be greatly simplified in 2.0.0 (if I had a penny every time I mention this…lol). Furthermore, debugging issues with types also requires knowledge about dry-types and that’s a journey on its own. Then if you want to understand how predicates are handled, you’d need to understand dry-logic first.

If you take a look at the PR where I addressed the issue, you’ll see that it was a one-file change. The trick is to know where to look 🙂

solnic on Jun 29, 2021

@solnic sure, it’s on the surface. Fixing this particular error shouldn’t be a problem, but I didn’t try. My concern is I saw a more substantial problem with constructors and schemas, but I don’t remember what that was 😕

flash-gordon on Sep 9, 2020