fix(impl-merge): clear stale failed labels on merge

[MarkusNeusinger]

Summary

• impl-merge.yml removed generate:<lib>, impl:<lib>:pending and impl:<lib>:failed in one comma-separated gh issue edit; gh resolves each name against the repository's label list first and rejects the whole call when one is unknown (impl:<lib>:pending is created on demand), so the fallback only added impl:<lib>:done.
• Issues [network-hierarchical] Hierarchical Network Graph with Tree Layout #3343 and [mosaic-categorical] Mosaic Plot for Categorical Association Analysis #3650 therefore carry impl:<lib>:failed next to impl:<lib>:done since the 2026-09-02 outage rescue, and every watchdog scan reports those pairs as "already retried — needs manual attention".
• The labels are now removed one at a time, each call tolerated, and the watchdog's watchdog:retried-<lib> marker is cleared with them.

Plan

N/A

Test plan

• Workflow change has no local verification loop (CLAUDE.md known gap): the run script parses as YAML and passes bash -n.
• After merge, the next impl-merge run on an issue that carries impl:<lib>:failed (e.g. a rescue of [choropleth-basic] Choropleth Map with Regional Coloring #3069's muix) leaves only impl:<lib>:done.

🤖 Generated with Claude Code

https://claude.ai/code/session_01SrKzcwZBnref1sWYtdXynu

[Copilot]

🟡 Changes recommended

The new stale-label removal loop suppresses all gh failures, which can silently leave the exact :failed/watchdog-marker labels behind on transient API errors.

Once you've addressed the issues Copilot identified, you can request another Copilot review.

Pull request overview

This PR updates the impl-merge GitHub Actions workflow to reliably clear stale “failure/retry” labels from spec issues when an implementation successfully merges, preventing watchdog scans from incorrectly flagging issues as needing manual attention. It also records the behavior change in the project changelog.

Changes:

• Update impl-merge.yml to add impl:<lib>:done and then remove stale labels (generate:<lib>, impl:<lib>:pending, impl:<lib>:failed, and watchdog:retried-<lib>) via individual tolerated calls.
• Add a [Unreleased] changelog entry describing the label-cleanup fix and the outage-rescue fallout it addresses.

File summaries

File	Description
CHANGELOG.md	Documents the fix so releases capture the operational impact and motivation.
.github/workflows/impl-merge.yml	Adjusts issue label updates to avoid gh issue edit failing the entire removal when any label name is unknown.

Review details

• Files reviewed: 2/2 changed files
• Comments generated: 1
• Review effort level: Lite

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[Copilot]

🔵 Needs a closer look

It modifies a production GitHub Actions workflow where mistakes can silently break automation and there is no local verification loop to fully validate behavior.

Review details

Suppressed comments (1)

.github/workflows/impl-merge.yml:393

• The label-removal loop suppresses all errors (2>/dev/null || true), so if gh issue edit fails for a real reason (token permissions, API outage/rate limit), the workflow will silently leave stale labels behind and you won’t have any signal in the run logs. Consider emitting at least a ::debug:: line on failure so troubleshooting doesn’t require reproducing locally.

          # (2026-09-02). A removal that fails anyway is reported, not hidden:
          # the stale label is exactly the state this step exists to clear.
          PRESENT=$(gh issue view "$ISSUE" --json labels -q '.labels[].name' 2>/dev/null || echo "")
          for stale in "generate:${LIBRARY}" "impl:${LIBRARY}:pending" \

• Files reviewed: 2/2 changed files
• Comments generated: 0 new
• Review effort level: Lite

[Copilot]

🟡 Changes recommended

The new label-cleanup step still suppresses/ignores failures when fetching current issue labels, which can silently skip the very cleanup this workflow change is meant to guarantee.

Once you've addressed the issues Copilot identified, you can request another Copilot review.

Review details

• Files reviewed: 2/2 changed files
• Comments generated: 1
• Review effort level: Lite

[Copilot]

🟡 Changes recommended

The updated workflow still suppresses gh issue view errors and can silently skip stale-label cleanup on transient failures, undermining the PR’s intent to reliably clear stale labels.

Once you've addressed the issues Copilot identified, you can request another Copilot review.

Review details

Suppressed comments (1)

.github/workflows/impl-merge.yml:392

• gh issue view errors are currently suppressed and replaced with an empty label list; if that call fails (rate limit/transient API error), this step silently skips stale-label cleanup, leaving impl:<lib>:failed / watchdog:retried-<lib> behind. Since the goal here is to clear stale state, it’s better to emit a warning when the label read fails.

          PRESENT=$(gh issue view "$ISSUE" --json labels -q '.labels[].name' 2>/dev/null || echo "")

• Files reviewed: 2/2 changed files
• Comments generated: 1
• Review effort level: Lite