Exclude .github/CODEOWNERS (and .github/**) from CI triggers across all AzDO pipelines

[Copilot]

Context

PR #13214 added documentation/** and .github/** path exclusions to .vsts-dotnet-ci.yml, but two other push-triggered pipelines still had simple trigger lists with no path filtering, causing full CI runs on CODEOWNERS-only changes.

Changes Made

• .vsts-dotnet.yml — Converted simple trigger list to structured format; added paths.exclude for documentation/** and .github/**
• azure-pipelines/.vsts-dotnet-exp-perf.yml — Same treatment for exp/* / perf/* triggers
• azure-pipelines/check-documentation-only-change.yml — Added comment clarifying that .github/CODEOWNERS is already matched by the existing ^\.github/ pattern (no logic change)

Push triggers now skip CI for .github/CODEOWNERS (and all .github/** / documentation/**) changes across all three active push-triggered pipelines. PR triggers are intentionally left unchanged so required checks continue to satisfy branch protection; the check-documentation-only-change.yml template already gates expensive test jobs via onlyDocChanged.

Testing

No executable code changed — YAML-only.

Notes

Pipelines with trigger: none (vs-insertion.yml, vmr-sb-validation.yml) are unaffected.

Original prompt

Update Azure DevOps pipeline YAML configuration in dotnet/msbuild so that changes to CODEOWNERS do not trigger CI pipelines.

Context:

• Prior merged PR Exclude documentation and .github from CI triggers #13214 added trigger.paths.exclude for documentation/** and .github/** in .vsts-dotnet-ci.yml (push CI only) and expanded azure-pipelines/check-documentation-only-change.yml to treat .github/ changes as non-build files while keeping onlyDocChanged variable.
• We now specifically want CODEOWNERS changes to not trigger AzDO pipelines, and we want this applied across all pipelines in the repo (not just .vsts-dotnet-ci.yml).
• Also check PR Exclude documentation and .github from CI triggers #13214 for repo-specific checks that may need updating (e.g., templates/gates that decide to skip expensive jobs when non-build-only changes are detected).

Requirements:

1. Find all Azure DevOps pipeline YAML definitions in the repo (commonly: .vsts-*.yml, azure-pipelines*.yml, files under azure-pipelines/, and any other YAMLs that contain top-level trigger: and/or pr: blocks).
2. For each pipeline that triggers on GitHub changes, ensure changes limited to .github/CODEOWNERS do not start CI runs.
   • Prefer trigger.paths.exclude for .github/CODEOWNERS.
   • If a pipeline already excludes .github/**, ensure .github/CODEOWNERS is covered; otherwise add a specific exclusion.
   • Consider both trigger: (push) and pr: filters. Align with repo policy from PR Exclude documentation and .github from CI triggers #13214: push triggers may exclude non-build-only changes, while PR builds may still need to run to satisfy required checks. If CODEOWNERS-only PRs still must pass required checks, implement repo’s existing “non-build-only change” gate to early-exit expensive jobs instead of excluding PR triggers entirely.
3. Update/extend any repo-specific “only documentation/non-build change” detection templates (like azure-pipelines/check-documentation-only-change.yml) so that CODEOWNERS-only changes are considered non-build-only, and downstream jobs can skip expensive test runs.
   • Ensure the existing variable contract (onlyDocChanged) remains unchanged.
   • Make matching robust for .github/CODEOWNERS.
4. Keep changes minimal and consistent across pipelines; don’t break DevDiv-specific behavior.
5. Add/adjust comments in pipeline YAML where needed to explain the intent.

Deliverable:

• Open a PR against main with all required YAML/template updates.
• Ensure the PR description summarizes which pipelines were updated and how CODEOWNERS-only changes are handled for push vs PR triggers.

The following is the prior conversation context from the user's chat exploration (may be truncated):

User: CodeOwners changes in the MSBuild repo shouldn't trigger CI pipelines in azdo

Assistant: To prevent CODEOWNERS-only changes from triggering Azure DevOps (AzDO) pipelines for dotnet/msbuild, you need to add a path-based exclusion for .github/CODEOWNERS in your AzDO pipeline triggers.

If the pipeline is defined in YAML

In the relevant azure-pipelines.yml (or any YAML that defines CI triggers), add a paths.exclude entry:

trigger:
  branches:
    include:
    - "*"
  paths:
    exclude:
    - .github/CODEOWNERS

If you also have PR validation triggers, exclude it there too:

pr:
  branches:
    include:
    - "*"
  paths:
    exclude:
    - .github/CODEOWNERS

If the pipeline is “classic” (UI-defined) instead of YAML

In Pipeline → Edit → Triggers, add a Path filter exclusion for:

• /.github/CODEOWNERS

Notes / gotchas

• If your repo has multiple pipelines, you must apply the exclusion to each one that shouldn’t run.
• If you want to exclude all CODEOWNERS files (some repos have multiple), you can broaden to:
  • .github/CODEOWNERS
  • CODEOWNERS (root) if applicable

If you point me at the specific AzDO pipeline YAML path(s) used by msbuild (or paste the current trigger: / pr: sections), I can rewrite the exact snippet to match what’s already there (e.g., existing branch filters, batching, etc.).

User: investigate and apply this to all pipelines in the dotnet/msbuidl repo

Assistant: I can’t apply changes yet because (1) you didn’t explicitly ask for a PR, and (2) I need the exact repo name confirmed: you wrote dotnet/msbuidl (typo) but earlier provided dotnet/msbuild.

If you want me to investigate all Azure Pipelines YAMLs in dotnet/msbuild and then apply the .github/CODEOWNERS path exclusion everywhere, tell me one of the following:

1. “Yes—open a PR in dotnet/msbuild” (and which base branch, if not default), or
2. “Just report findings, no code changes.”

Once confirmed, I will:

• locate every azure-pipelines*.yml (and any YAML templates that define trigger: / pr:),
• list which pipelines currently trigger on CODEOWNERS-only changes,
• update each pipeline to exclude .github/CODEOWNERS from both trigger and pr (where present),
  -...

This pull request was created from Copilot chat.

[dotnet-policy-service]

Hello @copilot, I noticed that you’re changing an .swr file or any file under src/Package/MSBuild.VSSetup.. Please make sure to validate this change by an experimental VS insertion. This is accomplished by pushing to an exp/* branch, which requires write permissions to this repo.

[rainersigwald]

I don't think we can do this, because we have a required check that the PR builds pass. Won't this result in PRs stuck on that check without ever triggering a build? @copilot