Instructions for GitHub Copilot

How to edit Dockerfiles and READMEs

Dockerfiles and READMEs are generated from templates using Cottle.
Dockerfile templates are located in the eng/dockerfile-templates directory
README templates are located in the eng/readme-templates directory.
Do not edit the Dockerfiles in src/ directly.
To generate Dockerfiles from templates, run pwsh ./eng/dockerfile-templates/Get-GeneratedDockerfiles.ps1.
Do not edit *README*.md files directly.
To generate READMEs, run pwsh ./eng/readme-templates/Get-GeneratedReadmes.ps1.
Use the dockerfile-and-readme-templating skill when modifying their Cottle templates.

manifest.json describes the Dockerfiles in this repo and how they should be built, tagged, and published.
manifest.versions.json contains product version information used by the Dockerfile templates. It is typically updated using the eng/update-dependencies tool.

Only build and test images that were changed.
When changing many images, just build and test a single combination of .NET version and OS as a sanity check.
To build Dockerfiles, run pwsh ./build-and-test.ps1 -mode 'Build' -paths '*glob*pattern*'. For example, to build all .NET 9.0 Ubuntu Noble images, run ./build-and-test.ps1 -paths '*9.0*noble*'.
To run image tests, run pwsh ./tests/run-tests.ps1 -paths '*glob*pattern*'.
To run only the pre-build validation tests, run pwsh ./tests/run-tests.ps1 -paths '*' -TestCategories @('pre-build').

Use the porting-changes skill to port or backport changes between branches.
Use the resolving-conflicts skill when a merge or cherry-pick has conflicts.
Use the merge-main-to-nightly skill when asked to merge main into nightly after a release.