Dedup Action

Find and report duplicate tickets created by spec sync. Designed for scheduled runs — opens (or updates) a rolling tracking issue listing proposed cleanups when duplicates are detected. Wraps the existing canon dedup CLI which auto-detects the configured ticket system.

uses: canonhq/canon/actions/dedup@v1

Inputs

Name	Required	Default	Description
apply	no	false	Apply the cleanup automatically (vs. dry-run + report)
spec	no	""	Filter to a single spec file
mode	no	issue	issue or summary
rolling-issue-title	no	Canon dedup report	Title of the rolling issue
rolling-issue-labels	no	canon,dedup	Labels for the rolling issue
python-version	no	3.12
canon-version	no	>=1.0.0,<2.0.0

Outputs

Name	Description
log-path	Absolute path to the captured dedup log on the runner
applied	Whether the action ran in apply mode (true / false)

Example: weekly dry-run report

name: Canon Dedup Report
on:
  schedule:
    - cron: "0 9 * * 1"
  workflow_dispatch:

jobs:
  dedup:
    runs-on: ubuntu-latest
    permissions:
      contents: read
      issues: write
    steps:
      - uses: actions/checkout@v4
      - uses: canonhq/canon/actions/dedup@v1

Example: nightly auto-apply

name: Canon Dedup Apply
on:
  schedule:
    - cron: "0 5 * * *"

jobs:
  dedup:
    runs-on: ubuntu-latest
    permissions:
      contents: read
      issues: write
    steps:
      - uses: actions/checkout@v4
      - uses: canonhq/canon/actions/dedup@v1
        with:
          apply: "true"

What it does

1. Installs the Canon CLI
2. Runs canon dedup --dry-run (or canon dedup when apply: true)
3. Captures the full CLI output to a log file at log-path
4. Always writes a step summary with the captured log inside a collapsed <details> block
5. In mode: issue, opens or updates a rolling tracking issue identified by the <!-- canon:action:dedup:rolling --> magic marker — but only if the log mentions the words "duplicate" or "dedup" so quiet runs don't churn the issue

Permissions

Mode	Required permissions
mode: issue	contents: read, issues: write
mode: summary	contents: read

When apply: true, the action also needs whatever permissions the underlying ticket system requires (typically issues: write and pull-requests: write for GitHub Issues, or environment-supplied credentials for Jira/Linear via the sync action's pattern).

Pitfalls

• apply: true mutates real tickets. Start with the default dry-run mode, review the rolling issue, and only enable apply once you trust the dedup logic on your data.
• The "duplicates detected" check is heuristic. The action greps the log for duplicate|dedup to decide whether to update the rolling issue. If you have a customized log format, the filter may false-fire. File an issue and we'll widen the regex.
• canon dedup requires a ticket adapter. If your repo's CANON.yaml doesn't configure a ticket system, the CLI exits with an error and the action surfaces it via the step summary.