Improve error messages in admin panel

[entantoencuanto]

🎩 What? Why?

This PR:

• Adds a Presenter to generate a error message associated with a form with validations failed in html format including the list of validation errors
• Allows partial which displays flash messages in admin to accept a html argument and render it
• Changes error message described in Error merging proposals #5825 to use html and use a more meaningful description of the error

📌 Related Issues

• Fixes Review errors in admin panel #7619

Testing

Describe the best way to test or validate your PR.

📋 Checklist

🚨 Please review the guidelines for contributing to this repository.

• ❓ CONSIDER adding a unit test if your PR resolves an issue.
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• ✔️ DO add CHANGELOG upgrade notes if required.
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• ❌AVOID breaking the continuous integration build.
• ❌AVOID making significant changes to the overall architecture.

📷 Screenshots

Before:

After:

♥️ Thank you!

[leio10]

@decidim/product is this PR ready to be reviewed?

[andreslucena]

@decidim/product is this PR ready to be reviewed?

Yes, it's OK for us. At least this improves a bit the error message in the merging error case.

[leio10]

Nice job! 👍

@entantoencuanto I'll wait for your opinion about my comment before merging this.

[leio10]

💬 Would it be clear for the user if you do the add the errors inside the previous loop depending on the detected problems?

You can use a set to avoid adding the same error twice, like this:

errors_set = Set[]
proposals.each do |proposal|
  errors_set << :published if proposal.published? # this was not checked before, I don't know the exact logic
  errors_set << :official if proposal.official?
  errors_set << :supported if proposal.votes.any? || proposal.endorsements.any?
end

errors_set.each {|error| errors.add(:base, error)} if errors_set.any?

Of course, in the case you use this approach, you should also change the message a bit.

[entantoencuanto]

Good point, I'll make the changes you suggest, I'll ping you when ready

[entantoencuanto]

I've updated the messages and removed the published? condition, I've been looking for a reason for this condition and I haven't found anything. I've also inverted the validation message about official proposals.