fix: add concurrency group to child-repo-sync workflow

[mateodelnorte]

Summary

• Adds concurrency: { group: child-repo-sync, cancel-in-progress: false } to on-child-update.yml
• When multiple child repos merge simultaneously, their sync runs now queue instead of racing

Problem

Merging 5 repos at once triggered 5+ concurrent on-child-update runs. Multiple runs tried to push the same branch name simultaneously, causing push failures and orphaned duplicate PRs (e.g., #54, #55).

The existing idempotency logic handles some race conditions but fails when the winning run's PR isn't visible yet to the losers' find_existing_pr check.

Fix

cancel-in-progress: false ensures runs queue and execute sequentially — each gets a clean shot at creating its sync branch and PR without contention.

🤖 Generated with Claude Code

Summary by CodeRabbit

• Chores
  • Improved workflow concurrency management to ensure sequential execution of critical synchronization operations and prevent interruption of in-progress runs.

[greptile-apps]

Greptile Summary

This PR adds a concurrency group to the on-child-update.yml workflow to serialize concurrent sync runs triggered by multiple child repos merging at the same time. The intent is correct and the approach (cancel-in-progress: false) is the right one for this use case — however, the concurrency: block was placed in the wrong position in the file.

Key changes:

• Adds concurrency: { group: child-repo-sync, cancel-in-progress: false } to prevent race conditions when multiple child repos dispatch events simultaneously.

Issue found:

• P0 — YAML structural error: The concurrency: block was inserted between workflow_dispatch: and its inputs: sub-key (lines 6–17). This orphans the inputs: block outside the on: section with 4-space indentation, which is invalid at the top level. GitHub's parser will either reject the workflow or silently drop the workflow_dispatch inputs. The concurrency: block must be moved to after the closing of the full on: block (i.e., after line 33 where the actor input ends).

Confidence Score: 2/5

• Not safe to merge — the YAML structural error will break the workflow, requiring a targeted one-line fix to move the concurrency block to after the on: section.
• The fix strategy (concurrency group with cancel-in-progress: false) is exactly right, but the implementation introduces a critical YAML syntax error by splitting the workflow_dispatch block. One concrete positional fix is all that's needed to make this mergeable.
• .github/workflows/on-child-update.yml — the concurrency: block must be repositioned to after line 33 (end of on: inputs).

Important Files Changed

Filename	Overview
.github/workflows/on-child-update.yml	The concurrency block was inserted between workflow_dispatch: and its inputs: child key, splitting the on: section and producing invalid YAML that will break workflow dispatch inputs and likely fail to parse entirely.

Sequence Diagram

sequenceDiagram
    participant CR1 as Child Repo 1
    participant CR2 as Child Repo 2
    participant GHA as GitHub Actions
    participant CQ as Concurrency Queue
    participant Meta as Meta Repo

    CR1->>GHA: repository_dispatch child-repo-updated
    CR2->>GHA: repository_dispatch child-repo-updated

    GHA->>CQ: Enqueue run for CR1 (group: child-repo-sync)
    GHA->>CQ: Enqueue run for CR2 (group: child-repo-sync, cancel-in-progress: false → queued)

    CQ->>Meta: Run 1 (CR1): checkout → push sync/CR1/sha → create PR → auto-merge
    CQ->>Meta: Run 2 (CR2): checkout → push sync/CR2/sha → create PR → auto-merge

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Comments Outside Diff (1)

1. .github/workflows/on-child-update.yml, line 6-17 (link)

   concurrency block breaks workflow_dispatch inputs

   The concurrency: block was inserted between workflow_dispatch: and its inputs: child key. This splits the on: block in two — inputs: is now orphaned outside the on: context with 4-space indentation, which is invalid at the top-level scope of a GitHub Actions workflow YAML. GitHub's parser will either reject the workflow entirely or silently drop the workflow_dispatch inputs, breaking manual dispatch.

   The concurrency: block must be a top-level sibling of on:, permissions:, and jobs: — it should come after the entire on: block.

   Prompt To Fix With AI

   This is a comment left during a code review.
   Path: .github/workflows/on-child-update.yml
   Line: 6-17
   
   Comment:
   **`concurrency` block breaks `workflow_dispatch` inputs**
   
   The `concurrency:` block was inserted between `workflow_dispatch:` and its `inputs:` child key. This splits the `on:` block in two — `inputs:` is now orphaned outside the `on:` context with 4-space indentation, which is invalid at the top-level scope of a GitHub Actions workflow YAML. GitHub's parser will either reject the workflow entirely or silently drop the `workflow_dispatch` inputs, breaking manual dispatch.
   
   The `concurrency:` block must be a top-level sibling of `on:`, `permissions:`, and `jobs:` — it should come **after** the entire `on:` block.
   
   
   
   How can I resolve this? If you propose a fix, please make it concise.

Prompt To Fix All With AI

This is a comment left during a code review.
Path: .github/workflows/on-child-update.yml
Line: 6-17

Comment:
**`concurrency` block breaks `workflow_dispatch` inputs**

The `concurrency:` block was inserted between `workflow_dispatch:` and its `inputs:` child key. This splits the `on:` block in two — `inputs:` is now orphaned outside the `on:` context with 4-space indentation, which is invalid at the top-level scope of a GitHub Actions workflow YAML. GitHub's parser will either reject the workflow entirely or silently drop the `workflow_dispatch` inputs, breaking manual dispatch.

The `concurrency:` block must be a top-level sibling of `on:`, `permissions:`, and `jobs:` — it should come **after** the entire `on:` block.

```suggestion
  workflow_dispatch:
    inputs:
      repo_name:
        description: 'Child repo name'
        required: true
        default: 'test-repo'
      short_sha:
        description: 'Short SHA'
        required: true
        default: 'abc1234'
      message:
        description: 'Commit message'
        required: true
        default: 'feat: test commit'
      type:
        description: 'Commit type'
        required: true
        default: 'feat'
      actor:
        description: 'Actor'
        required: true
        default: 'test-user'

concurrency:
  group: child-repo-sync
  cancel-in-progress: false

```

How can I resolve this? If you propose a fix, please make it concise.

_{Reviews (1): Last reviewed commit: "fix: add concurrency group to child-repo..." | Re-trigger Greptile}

[mateodelnorte]

Fixed — moved concurrency: block to after the on: section so workflow_dispatch.inputs isn't orphaned.

[coderabbitai]

No actionable comments were generated in the recent review. 🎉

ℹ️ Recent review info

⚙️ Run configuration

Configuration used: Organization UI

Review profile: ASSERTIVE

Plan: Pro

Run ID: cc0419a7-2e4e-47cf-b932-7e962af9b9af

📥 Commits

Reviewing files that changed from the base of the PR and between edf502a and be66815.

📒 Files selected for processing (1)

• .github/workflows/on-child-update.yml

---

Walkthrough

A workflow-level concurrency configuration is added to the GitHub Actions workflow file, establishing a shared concurrency group named child-repo-sync with in-progress run cancellation disabled, ensuring sequential workflow execution.

Changes

Cohort / File(s)	Summary
GitHub Actions Workflow Configuration .github/workflows/on-child-update.yml	Added concurrency configuration with group child-repo-sync and cancel-in-progress: false to serialize workflow runs.

Estimated code review effort

🎯 1 (Trivial) | ⏱️ ~2 minutes

Poem

🐰 Hop, hop, the rabbit scripts align,
With concurrency locks, all runs now in line,
No races, no clashes, just order and grace,
One sync at a time in the child-repo space!
✨

🚥 Pre-merge checks | ✅ 3

✅ Passed checks (3 passed)

Check name	Status	Explanation
Description Check	✅ Passed	Check skipped - CodeRabbit’s high-level summary is enabled.
Title check	✅ Passed	The title 'fix: add concurrency group to child-repo-sync workflow' directly and accurately summarizes the main change—adding a concurrency configuration to the GitHub Actions workflow to prevent concurrent runs and race conditions.
Docstring Coverage	✅ Passed	No functions found in the changed files to evaluate docstring coverage. Skipping docstring coverage check.

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✨ Finishing Touches

🧪 Generate unit tests (beta)

• Create PR with unit tests
• Commit unit tests in branch fix/sync-concurrency-group

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