Add skip-labels to evaluate-pr's output

[cotti]

This pull request enhances the PR evaluation process in the ChangelogPrEvaluationService by adding support for collecting and outputting labels that cause a PR to be skipped due to exclusion rules. The main focus is on improving traceability and diagnostics when PRs are skipped based on label configurations.

Key changes:

Skip label handling and output:

• Added a new method, CollectExcludeLabels, which gathers all unique exclude-mode labels from both global and per-product CreateRules. This method returns a comma-separated string of labels or null if none are configured.
• Modified the skip check logic in EvaluatePr to collect skip labels and pass them to the output when a PR is skipped due to all products being blocked by label rules.
• Updated the SetOutputs method to accept an optional skipLabels parameter and output it as skip-labels when present. [1] [2]
• Ensured that when a PR is evaluated without required labels, the collected skip labels are included in the outputs for better diagnostics.

[coderabbitai]

No actionable comments were generated in the recent review. 🎉

ℹ️ Recent review info

⚙️ Run configuration

Configuration used: Path: .coderabbit.yaml

Review profile: CHILL

Plan: Pro

Run ID: b6265bb8-a645-4cfb-a894-ec5e3e5defba

📥 Commits

Reviewing files that changed from the base of the PR and between cb6bf44 and 5dcf757.

📒 Files selected for processing (2)

• src/services/Elastic.Changelog/Evaluation/ChangelogPrEvaluationService.cs
• tests/Elastic.Changelog.Tests/Evaluation/ChangelogPrEvaluationServiceTests.cs

🚧 Files skipped from review as they are similar to previous changes (1)

• src/services/Elastic.Changelog/Evaluation/ChangelogPrEvaluationService.cs

---

📝 Walkthrough

Walkthrough

The PR evaluation service now aggregates exclude-mode labels from create rules (global and per-product), case-insensitively deduplicates them, and produces a comma-joined skipLabels string via a new internal CollectExcludeLabels method. SetOutputs now accepts an optional skipLabels parameter and, when provided, emits the GitHub Actions output skip-labels. EvaluatePr threads skipLabels into SetOutputs when skipping due to label rules or when the result is NoLabel.

Sequence Diagram(s)

mermaid
sequenceDiagram
participant PR as PR (labels)
participant CFG as CreateRules (global & by-product)
participant Svc as ChangelogPrEvaluationService
participant GH as GitHub Actions (outputs)

PR->>Svc: Trigger EvaluatePr
Svc->>CFG: Read create rules
CFG-->>Svc: Return rules
Svc->>Svc: CollectExcludeLabels(createRules)
Svc-->>Svc: Evaluate PR labels vs excludeLabels
alt PR matches exclude
    Svc->>Svc: SetOutputs(status: skipped, skipLabels)
    Svc->>GH: Emit outputs (status=skipped, skip-labels)
else PR has no type label
    Svc->>Svc: SetOutputs(status: no-label, skipLabels)
    Svc->>GH: Emit outputs (status=no-label, skip-labels)
else normal processing
    Svc->>Svc: SetOutputs(status: processed)
    Svc->>GH: Emit outputs (status=processed)

🚥 Pre-merge checks | ✅ 2 | ❌ 1

❌ Failed checks (1 warning)

Check name	Status	Explanation	Resolution
Docstring Coverage	⚠️ Warning	Docstring coverage is 13.33% which is insufficient. The required threshold is 80.00%.	Write docstrings for the functions missing them to satisfy the coverage threshold.

✅ Passed checks (2 passed)

Check name	Status	Explanation
Title check	✅ Passed	The title accurately and concisely describes the main change: adding skip-labels output to the evaluate-pr functionality.
Description check	✅ Passed	The description clearly explains the feature being added, the methods involved, and the purpose of the changes with relevant context about skip label handling.

_{✏️ Tip: You can configure your own custom pre-merge checks in the settings.}

✨ Finishing Touches

✨ Simplify code

• Create PR with simplified code
• Commit simplified code in branch feature/describe-skip-label

---

_{Comment @coderabbitai help to get the list of available commands and usage tips.}

[coderabbitai]

🧹 Nitpick comments (1)

src/services/Elastic.Changelog/Evaluation/ChangelogPrEvaluationService.cs (1)

220-221: Discard assignment is unnecessary.

HashSet.Add return value doesn't need explicit discard.

Suggested simplification

 		if (createRules is { Mode: FieldMode.Exclude, Labels.Count: > 0 })
 		{
 			foreach (var label in createRules.Labels)
-				_ = labels.Add(label);
+				labels.Add(label);
 		}

 		if (createRules.ByProduct is { Count: > 0 })
 		{
 			foreach (var (_, productRules) in createRules.ByProduct)
 			{
 				if (productRules is { Mode: FieldMode.Exclude, Labels.Count: > 0 })
 				{
 					foreach (var label in productRules.Labels)
-						_ = labels.Add(label);
+						labels.Add(label);
 				}
 			}
 		}

Also applies to: 230-231

🤖 Prompt for AI Agents

Verify each finding against the current code and only fix it if needed.

In `@src/services/Elastic.Changelog/Evaluation/ChangelogPrEvaluationService.cs`
around lines 220 - 221, The discard assignment is unnecessary when calling
HashSet.Add; inside the loops that iterate createRules.Labels (the block using
labels.Add) remove the "_ =" discard and call labels.Add(label) directly; apply
the same change to the similar loop at the other occurrence (the one around
lines referencing createRules.Labels again) so both uses of HashSet.Add omit the
redundant discard.

🤖 Prompt for all review comments with AI agents

Verify each finding against the current code and only fix it if needed.

Nitpick comments:
In `@src/services/Elastic.Changelog/Evaluation/ChangelogPrEvaluationService.cs`:
- Around line 220-221: The discard assignment is unnecessary when calling
HashSet.Add; inside the loops that iterate createRules.Labels (the block using
labels.Add) remove the "_ =" discard and call labels.Add(label) directly; apply
the same change to the similar loop at the other occurrence (the one around
lines referencing createRules.Labels again) so both uses of HashSet.Add omit the
redundant discard.

---

ℹ️ Review info

⚙️ Run configuration

Configuration used: Path: .coderabbit.yaml

Review profile: CHILL

Plan: Pro

Run ID: cb8c87b6-5f56-49e1-b75f-951a9e8c7c15

📥 Commits

Reviewing files that changed from the base of the PR and between e578fac and a58de4d.

📒 Files selected for processing (1)

• src/services/Elastic.Changelog/Evaluation/ChangelogPrEvaluationService.cs

[Mpdreamz]

Lgtm, maybe add a quick unit test?