Misleading "Successfully merged" status when PR modifies incomplete file

[avvstancamarcello]

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Description

When merging Pull Requests that modify an incomplete file (e.g., a truncated index.html), GitHub displays "Successfully merged" even though the resulting file remains incomplete.
This creates a false positive that misleads users into thinking the full intended content has been applied.

Steps to Reproduce

1. Create a file index.html that is truncated at line 1000 (missing closing tags, JavaScript code, etc.)
2. Create a PR that modifies lines 1-500 of this incomplete file
3. Approve and merge the PR
4. GitHub shows: ✅ "Pull request successfully merged and closed"
5. Check the resulting file: Still truncated at line 1000

Expected Behavior

GitHub should warn users when:

• A PR modifies a file that appears incomplete (missing closing tags)
• The base file has structural issues
• The merge succeeds technically but produces an incomplete result

Actual Behavior

• GitHub reports "Successfully merged" ✅
• No warnings about file completeness
• Users assume the full content was applied
• The file remains incomplete

Real-World Impact

In my repository avvstancamarcello/LHISA-lecce-Italy-salento:

• PRs Allow disabling "Mark as answer" for specific categories #22, Discussion: Issue title in Push Notification #23, How do I enable Discussions on a repo? #24, Switching languages is not supported on GitHub mobile #25, Reference PR comment in new discussion #26 all showed "Successfully merged"
• Each PR correctly modified the existing content
• But the base file (index.html) was truncated at line 1000
• Result: All merges "succeeded" but the file is still incomplete
• 85+ hours wasted debugging "why merged code isn't working"

Proposed Solutions

Option 1: File Integrity Checks

Add warnings when merging to files with:

• Unclosed HTML tags (<script> without </script>)
• Unclosed braces in JS/CSS
• Suspicious truncation patterns

Option 2: Merge Status Clarification

Change status message to:

Guidelines

• I have read the above statement and can confirm my post is relevant to the GitHub feature areas Issues and/or Projects.

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[avvstancamarcello]

propongo di avvisare l'utente del rischio che il Merge non ha funzionato , e che il file può essere ancora privo delle modifiche dichiarate da Github: ✅ Richiesta pull unita correttamente (contenuto esistente modificato) ⚠️ Nota: il file di base potrebbe essere incompleto: verificare la struttura completa del file.

[avvstancamarcello]

Option 3: Pre-merge Validation

Run basic linting/validation before merge:

• HTML validation
• JS syntax check
• Warn if file ends mid-function

Evidence

Repository: https://github.com/avvstancamarcello/LHISA-lecce-Italy-salento

Problematic commit: 732d33ff9a0f753f21d35aee8accb8f7e191631f
File: index.html
Issue: File stops at line 1000, missing entire JavaScript section

Recent PRs (all showing "Successfully merged"):

• Allow disabling "Mark as answer" for specific categories #22 (merged 14 Dec 15:25) ✅
• Discussion: Issue title in Push Notification #23 (merged 14 Dec 16:32) ✅
• How do I enable Discussions on a repo? #24 (merged 14 Dec 17:43) ✅
• Switching languages is not supported on GitHub mobile #25 (merged 14 Dec 18:28) ✅
• Reference PR comment in new discussion #26 (merged 14 Dec 19:03) ✅

All technically correct merges, but base file incomplete.

Technical Details

• Platform: GitHub. com
• Browser: All (verified on Chrome, Firefox, Edge)
• Account Type: Standard user
• Repository Type: Public
• Merge Method: Merge commit (tested), Squash and merge (same issue)

Related GitHub Features

• GitHub Actions could help with validation
• Branch protection rules don't catch this
• Required status checks don't validate file completeness

Community Impact

This affects:

• ✅ Beginners who trust "Successfully merged" implicitly
• ✅ CI/CD pipelines that rely on merge success status
• ✅ Automated deployments that assume merged = complete

Suggested Label

bug, user-experience, merge, false-positive

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Additional Context

This is not a Git issue (Git correctly merges the diff), but a GitHub UX issue where the platform's messaging doesn't reflect the practical outcome for users.

The phrase "Successfully merged" should ideally mean "Your changes are now complete and functional," not just "The git operation succeeded technically."