Exclude documentation and .github from CI triggers

[Copilot]

Context

CI pipelines trigger full test runs for changes to documentation and Copilot instruction files (.github/), wasting resources on non-build file changes.

Changes Made

.vsts-dotnet-ci.yml

• Added paths.exclude filters to both trigger and pr sections for documentation/* and .github/*
• Converts simple branch list to structured format required for path filtering:

trigger:
  branches:
    include:
    - main
    - exp/*
    - vs*
  paths:
    exclude:
    - documentation/*
    - .github/*

azure-pipelines/check-documentation-only-change.yml

• Expanded PowerShell pattern matching to recognize .github/* files as non-build files:

$isNonBuildFile = ($file -match "^documentation/") -or ($file -match "^\.github/")

• Preserves onlyDocChanged variable name for backward compatibility with 84+ downstream references

Testing

Validated PowerShell logic handles all scenarios: documentation-only, .github-only, mixed non-build files, and code file inclusions.

Notes

Pipeline will no longer trigger for documentation/Copilot changes. Safety net still protects mixed-commit scenarios.

Original prompt

Problem

Azure DevOps test jobs trigger and run for a long time even when only non-build files like Copilot instructions (.github/) or documentation (documentation/) are changed. This wastes CI resources.

Solution

Make two changes:

1. Add paths.exclude to the CI and PR triggers in .vsts-dotnet-ci.yml

The file currently has a simple trigger with no path filters:

trigger:
- main
- exp/*
- vs*

Change this to use paths.exclude so the pipeline doesn't even start for non-build file changes:

trigger:
  branches:
    include:
    - main
    - exp/*
    - vs*
  paths:
    exclude:
    - documentation/*
    - .github/*

pr:
  paths:
    exclude:
    - documentation/*
    - .github/*

This is a GitHub-hosted repo, so both trigger: and pr: support YAML paths filters.

2. Expand azure-pipelines/check-documentation-only-change.yml to also recognize .github/ files

The current check only recognizes files under documentation/:

$isUnderDocumentation = $file -match "^documentation/"

Update this to also treat .github/ files as non-build changes, so that even in mixed-commit scenarios, the safety net correctly identifies non-build-only changes. Change the variable name and match to something like:

$isNonBuildFile = ($file -match "^documentation/") -or ($file -match "^\.github/")
if(!$isNonBuildFile)

Make sure the output variable name (onlyDocChanged) stays the same so all downstream references continue to work.

Context

• PR Expand test instructions into their own file #13212 adds Copilot test instruction files under .github/ — this is the kind of change that should not trigger full test runs.
• The repo's CI pipeline is at .vsts-dotnet-ci.yml.
• The documentation-only check template is at azure-pipelines/check-documentation-only-change.yml.
• Many jobs reference the onlyDocChanged variable — do NOT rename it.

This pull request was created from Copilot chat.

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[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.