when and concat break preceding oneOf

[Philipp91]

// Regular oneOf validation, nothing interesting.
await Yup.string().oneOf(['a'])..isValid('a'); // true
await Yup.string().oneOf(['a'])..isValid('b'); // false

// Followed by a when() that does not trigger, everything stays correct and the same.
await Yup.string().oneOf(['a']).when('x', {is: () => false, then: Yup.string()}).isValid('a'); // true
await Yup.string().oneOf(['a']).when('x', {is: () => false, then: Yup.string()}).isValid('b'); // false

// Followed by a when() that triggers, incorrectly marks as invalid.
await Yup.string().oneOf(['a']).when('x', {is: () => true, then: Yup.string()}).isValid('a'); // false

The last one with validate() throws "ValidationError: this must be one of the following values: ". There are no values listed. Seems like this.schema._whitelist is empty.

[Philipp91]

Debugged it a bit further, this should be equivalent to:

await Yup.string().max(3).concat(Yup.string().oneOf(['a'])).isValid('a'); // true
await Yup.string().oneOf(['a']).concat(Yup.string().max(3)).isValid('a'); // false

[Philipp91]

Perhaps this is already fixed by #444.

[Philipp91]

It's not fixed at head. Here's a failing test case to reproduce:

  it('concat should preserve oneOf', async function() {
    let inst = string().oneOf(['a']).concat(string().default('hi'));

    await inst.isValid('a').should.become(true);
  });

Probably the concat function (or the prependDeep() that it uses) need to be made aware of RefSet (currently it just overwrites one with the other) and merge two RefSets such that either one is forced to be empty (and the other one is returned), or the inner one (IIUC that's the target in prependDeep) takes precendence in case of conflicts, i.e. whitelistOut = (whitelistSource UNION whitelistTarget) SETMINUS blacklistTarget and blacklistOut = (blacklistSource UNION blacklistTarget) SETMINUS whitelistTarget. This may require RefSet to move to its own file, or to expose a RefSet.merge() or RefSet.prependDeep() function that can be called from outside.

Let me know if you want me to send a PR.

[gregie156]

@Philipp91 Your fix looks solid. Are you going to push it into the main Yup repo?

edit: Oh, I see you opened a PR and they are dragging their feet approving it.