Allow Attachment to answer to `can_participate?` based on it's attached model by davidbeig · Pull Request #15950 · decidim/decidim

davidbeig · 2026-01-27T12:58:32Z

🎩 What? Why?

Please describe your pull request.

The model attachment is missing a can_participate? function. With this PR we are delegating that to the model at the attached_to field.

📌 Related Issues

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Fixes Notification landing fails when the notification is an attachment #15949

Testing

Describe the best way to test or validate your PR.
You can reproduce the same steps as in the related issue.

Also, you can test in the console if an attachment now answers to this function.

♥️ Thank you!

Summary by CodeRabbit

Improvements
- Attachments now inherit participation status from the content they’re attached to, so uploaded files reflect the same participation permissions and visibility as their parent items. This streamlines permission handling and improves consistency when viewing or interacting with attachments across the platform.

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coderabbitai · 2026-01-27T12:59:01Z

📝 Walkthrough

Walkthrough

Adds a delegation so Decidim::Attachment forwards can_participate? to its attached_to association, enabling can_participate? calls on attachment instances.

Changes

Cohort / File(s)	Summary
Attachment model delegation `decidim-core/app/models/decidim/attachment.rb`	Added delegation: `can_participate?` -> `attached_to` (+1 line). This prevents `NoMethodError` when callers invoke `can_participate?` on attachments.

Estimated code review effort

🎯 2 (Simple) | ⏱️ ~10 minutes

Poem

🐰 I hopped along a code-lined trail,
Found an attachment that tripped on a tale.
One tiny delegate — a hop, not a flight,
Now questions of joining return to the right light. 🥕

🚥 Pre-merge checks | ✅ 4 | ❌ 1

❌ Failed checks (1 warning)

Check name	Status	Explanation	Resolution
Docstring Coverage	⚠️ Warning	Docstring coverage is 0.00% which is insufficient. The required threshold is 80.00%.	Write docstrings for the functions missing them to satisfy the coverage threshold.

✅ Passed checks (4 passed)

Check name	Status	Explanation
Description Check	✅ Passed	Check skipped - CodeRabbit’s high-level summary is enabled.
Title check	✅ Passed	The title clearly summarizes the main change: adding a `can_participate?` delegation to the Attachment model based on its attached resource.
Linked Issues check	✅ Passed	The PR implements the primary objective from issue `#15949` by adding a `can_participate?` delegation to Attachment, enabling the notification landing to handle attachment notifications without a NoMethodError.
Out of Scope Changes check	✅ Passed	The change is minimal and focused solely on adding the `can_participate?` delegation to the Attachment model, directly addressing the linked issue without introducing unrelated modifications.

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✨ Finishing touches

📝 Generate docstrings

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coderabbitai

Actionable comments posted: 1

🤖 Fix all issues with AI agents

In `@decidim-core/app/models/decidim/attachment.rb`:
- Line 23: The current delegate line "delegate :can_participate?, to:
:attached_to" can raise NoMethodError for polymorphic targets that don't
implement can_participate?; replace this with an explicit instance method (e.g.,
def can_participate?) that mirrors the file's defensive pattern used by
organization and context: check attached_to.present? and use
attached_to.respond_to?(:can_participate?) ? attached_to.can_participate? : true
so attachments default to allowing participation when the target lacks the
method.

decidim-core/app/models/decidim/attachment.rb

microstudi · 2026-01-27T13:10:19Z

Wouldn't be best to use respond_to? wherever this method is used?

alecslupu · 2026-01-27T13:14:00Z

Wouldn't be best to use respond_to? wherever this method is used?

Or to implement what coderabbit suggests ?

davidbeig · 2026-01-27T13:20:39Z

Wouldn't be best to use respond_to? wherever this method is used?

I think that, in the notifications (where we are having this problem), the models that it can be attached to are either components or participatory spaces (both have this method as done in https://github.com/decidim/decidim/pull/15830/files)

An example in one of our instances:

irb(main):005> Decidim::Attachment.pluck(:attached_to_type).uniq
=> ["Decidim::Assembly", "Decidim::Accountability::Result", "Decidim::Meetings::Meeting", "Decidim::ParticipatoryProcess", "Decidim::Blogs::Post"]

Edit:

The models shown do this with the HasComponent concert, that includes this:

    included do
      belongs_to :component, foreign_key: "decidim_component_id", class_name: "Decidim::Component", touch: true
      delegate :organization, to: :component, allow_nil: true
      delegate :participatory_space, :can_participate_in_space?, to: :component, allow_nil: true

      alias_method :can_participate?, :can_participate_in_space?
    end

microstudi · 2026-01-27T14:32:38Z

Wouldn't be best to use respond_to? wherever this method is used?

Or to implement what coderabbit suggests ?

Sure but preventing the notifications to fail would be nice, these are no critical entries. In this case we should ignore notifications with model attached not responding to this method no?

davidbeig · 2026-01-29T09:57:45Z

Well, I've seen that the reported bug has been delivered already in the 0.30.5 and 0.31.1 :_)

alecslupu · 2026-02-04T09:43:57Z

@davidbeig is this PR ready for review?

alecslupu

👍 - Merging without associated spec

add delagate to can_participate on attached_to model in attachment

1808035

davidbeig self-assigned this Jan 27, 2026

github-actions bot added module: core type: fix PRs that implement a fix for a bug labels Jan 27, 2026

github-actions bot previously approved these changes Jan 27, 2026

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coderabbitai bot reviewed Jan 27, 2026

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decidim-core/app/models/decidim/attachment.rb Outdated Show resolved Hide resolved

apply fixes based on pr suggestions

d8e9a8b

davidbeig dismissed github-actions[bot]’s stale review via d8e9a8b January 27, 2026 13:16

github-actions bot approved these changes Jan 27, 2026

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davidbeig removed their assignment Feb 5, 2026

davidbeig requested review from alecslupu and removed request for alecslupu February 5, 2026 15:29

davidbeig assigned alecslupu Feb 5, 2026

alecslupu added release: v0.30 Issues or PRs that need to be tackled for v0.30 release: v0.31 Issues or PRs that need to be tackled for v0.31 labels Feb 5, 2026

alecslupu approved these changes Feb 5, 2026

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alecslupu merged commit 83bb852 into decidim:develop Feb 5, 2026
86 of 89 checks passed

This was referenced Feb 5, 2026

Backport 'Allow Attachment to answer to can_participate? based on it's attached model' to v0.31 #16006

Merged

Backport 'Allow Attachment to answer to can_participate? based on it's attached model' to v0.30 #16007

Merged

alecslupu mentioned this pull request Feb 5, 2026

Fix can_participate? into ParticipatoryProcessStep #16008

Merged

davidbeig mentioned this pull request Mar 16, 2026

Daily digest does not include notifications that trigger real-time emails #16143

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Allow Attachment to answer to `can_participate?` based on it's attached model#15950

Allow Attachment to answer to `can_participate?` based on it's attached model#15950
alecslupu merged 2 commits intodecidim:developfrom
openpoke:fix/attachment_can_participate

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