fix: prevent comment UI from disappearing when editing empty text

[SylvainChevalier]

Fixes issue where the comment edit UI would disappear when all text was deleted during editing. The comment persisted in the database but was removed from the UI immediately.

The fix adds a check to exclude editing mode from the cleanup logic that removes empty comments from the UI.

Fixes #4077

Generated with Claude Code

Summary by CodeRabbit

• Bug Fixes
  • Improved comment editing stability: comments are now only removed when their text is empty, they contain no key factors, and they are not currently being edited. Editing state changes are correctly respected so comments won't be prematurely removed during an active edit.

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[coderabbitai]

📝 Walkthrough

Walkthrough

Added an isEditing guard to the effect that removes empty comments so it only runs when the comment is not being edited; the effect's dependency array was updated to include isEditing.

Changes

Cohort / File(s)	Summary
Comment removal effect front_end/src/components/comment_feed/comment.tsx	Added isEditing guard to prevent removal of comments while actively editing; updated effect dependency array to include isEditing.

Estimated code review effort

🎯 2 (Simple) | ⏱️ ~10 minutes

Poem

🐇 I nibble on code in the light,
A vanished comment gave me a fright.
With a gentle guard placed,
The typing won't be erased,
Now edits stay safe through the night.

🚥 Pre-merge checks | ✅ 4

✅ 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 accurately describes the main change: preventing comment UI from disappearing when editing empty text, which directly addresses the bug being fixed.
Linked Issues check	✅ Passed	The code changes directly address issue #4077 by adding an isEditing guard to prevent comment removal during edit mode, fixing the issue where deleting all text caused UI disappearance.
Out of Scope Changes check	✅ Passed	All changes are scoped to fixing the specific bug in issue #4077; the modifications only affect comment cleanup logic with an editing state guard.

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✨ Finishing touches

• 📝 Generate docstrings

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📜 Recent review details

Configuration used: Organization UI

Review profile: CHILL

Plan: Pro

📥 Commits

Reviewing files that changed from the base of the PR and between 1133825 and 122cafa.

📒 Files selected for processing (1)

• front_end/src/components/comment_feed/comment.tsx

⏰ Context from checks skipped due to timeout of 90000ms. You can increase the timeout in your CodeRabbit configuration to a maximum of 15 minutes (900000ms). (3)

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🔇 Additional comments (1)

front_end/src/components/comment_feed/comment.tsx (1)

401-405: LGTM! Clean fix for the disappearing comment issue.

The !isEditing guard correctly prevents the cleanup effect from running while the user is actively editing. The dependency array properly includes isEditing to ensure the effect re-evaluates when editing state changes.

The fix handles the lifecycle correctly:

• During editing: empty text won't trigger removal
• After save: if text is empty and no key factors, comment is appropriately removed
• After cancel: original text is restored before isEditing flips, preserving the comment

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[github-actions]

🚀 Preview Environment

Your preview environment is ready!

Resource	Details
🌐 Preview URL	https://metaculus-pr-4105-claude-issue-4077-20260119-143.fly.dev
📦 Docker Image	ghcr.io/metaculus/metaculus:claude-issue-4077-20260119-143-0dca79d
🗄️ PostgreSQL	NeonDB branch preview/pr-4105-claude-issue-4077-20260119-143
⚡ Redis	Fly Redis mtc-redis-pr-4105-claude-issue-4077-20260119-143

Details

• Commit: 0dca79dd2b77dca35588af900cb124f883fb06f4
• Branch: claude/issue-4077-20260119-1435
• Fly App: metaculus-pr-4105-claude-issue-4077-20260119-143

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[SylvainChevalier]

Tested in Preview Environment, works.