pass empty map, when embed is empty

[antonovga]

No description provided.

[coveralls]

Pull Request Test Coverage Report for Build a8bdbf495c9a87ebc4f8f3a126ff734ad203db6c-PR-18

Warning: This coverage report may be inaccurate.

This pull request's base commit is no longer the HEAD commit of its target branch. This means it includes changes from outside the original pull request, including, potentially, unrelated coverage changes.

• For more information on this, see Tracking coverage changes with pull request builds.
• To avoid this issue with future PRs, see these Recommended CI Configurations.
• For a quick fix, rebase this PR at GitHub. Your next report should be accurate.

Details

• 2 of 2 (100.0%) changed or added relevant lines in 1 file are covered.
• No unchanged relevant lines lost coverage.
• Overall coverage increased (+0.1%) to 90.643%

---

Totals
Change from base Build c33f7ef2c6749bf70c3719da76ba8caafb43c70f:	0.1%
Covered Lines:	155
Relevant Lines:	171

---

💛 - Coveralls

[bluzky]

Hi @antonovga,
Thank you for your PR but I think this change will break current code, current behaviour, return nil by default but in this PR return empty map.
To handle your use case, you can use this

schema = %{
  user: [type: %{
     email: [type: :string, required: true]
  }, default: %{}]
}

[bluzky]

I'm gonna close this PR.

[antonovga]

This PR addresses two problems with nested params:

1. When you pass bad formed params, it fails to parse it and throws 500 error

2. When you have schema with required nested field and don't pass nested fields at all, it validates params and returns valid: true

If this is intended behavior, you should definitely write this in documentation.