fix: handle duplicate InvitationLogEntry on retry (v2)

[mroderick]

Summary

Second attempt at fixing the "Member has already been taken" validation error when re-sending workshop invitations.

Problem

The previous fix (PR #2556) used find_or_initialize_by with status included in the query:

@log.entries.find_or_initialize_by(member: member, invitation: invitation, status: :success)

However, the InvitationLogEntry uniqueness constraint is:

validates :member_id, uniqueness: { scope: %i[invitation_type invitation_id] }

This validates (member_id, invitation_type, invitation_id), NOT status. The bug:

1. First invitation attempt → logs success → entry saved with status = success
2. Second invitation attempt → find_or_initialize_by(member, invitation, :failed) → finds the success entry but with wrong status → tries to save → VALIDATION ERROR

The previous fix worked for most cases but failed when:

• A member had both a success and failure entry for the same invitation
• The status query returned an entry with a different status than expected

Solution

Split the check - query by (member, invitation) only, ignoring status:

def find_or_build_entry(member, invitation, status)
  # First check: any existing entry for this member+invitation?
  existing_entry = @log.entries.find_by(member: member, invitation: invitation)
  return existing_entry if existing_entry

  # No entry exists - create new one
  @log.entries.new(
    member: member,
    invitation: invitation,
    status: status
  )
end

This ensures:

• If any entry exists (success OR failure), return it
• Only create new entry if none exists
• The uniqueness constraint is never violated

Additional Fix

Also add autosave: false to the has_many :entries association in InvitationLog:

has_many :entries, class_name: 'InvitationLogEntry', dependent: :destroy, autosave: false

Why: In Rails 5+, has_many defaults to autosave: true. When fail_batch calls @log.update!, Rails attempts to autosave all associated entries. If any unpersisted entries exist in memory with validation issues, this causes Validation failed: Entries is invalid errors.

This happened when I tried to re-invite people for the Berlin chapter this morning:

https://app.rollbar.com/a/codebar-production/fix/item/codebar-production/674#detail

Changes

• app/services/invitation_logger.rb - Separate find/build logic to query without status
• app/models/invitation_log.rb - Add autosave: false to entries association

Testing

41 examples pass, including retry behavior tests.

[olleolleolle]

Perhaps the find_or... with a block (the block is used to set attributes on the non-found record)

https://api.rubyonrails.org/classes/ActiveRecord/Relation.html#method-i-find_or_create_by

# Find the first user named "Scarlett" or create a new one with a
# particular last name.
User.find_or_create_by(first_name: 'Scarlett') do |user|
  user.last_name = 'Johansson'
end

[mroderick]

Thanks for the suggestion! Your insight led to a cleaner solution.

The issue with find_or_create_by + block is that it persists immediately, so the existing persisted? check wouldn't work. But we can instead check processed_at - once an entry is processed, it shouldn't be counted again:

def find_or_build_entry(member, invitation, status)
  @log.entries.find_or_create_by(member: member, invitation: invitation) do |entry|
    entry.status = status
  end
end

def log_success(member, invitation = nil)
  entry = find_or_build_entry(member, invitation, :success)
  return entry if entry.processed_at  # Already processed → skip

  entry.assign_attributes(processed_at: Time.current)
  save_entry(entry, :success_count)
end

This is more idiomatic Rails - the block only runs on create, not on find. And using processed_at as the "already handled" flag works regardless of status, handling both same-status and cross-status retries correctly.

Appreciate the nudge to find the cleaner approach!

[olleolleolle]

🌟