Development Instructions for the PowerShell Extension

Development Setup

Fork and clone the vscode-powershell repository.
Fork and clone the PowerShell Editor Services (PSES) repository.

The vscode-powershell folder and the PowerShellEditorServices folder should be next to each other on the file system. Code in vscode-powershell looks for PSES at ../PowerShellEditorServices if you're building locally so PSES must be in that location.
Follow the development instructions for PowerShell Editor Services. You will need to complete this step before proceeding.
Install Node.js 18.x or higher.
Install Visual Studio Code. Open the multi-root workspace file in this repo, extension-dev.code-workspace.

This has a set of recommended extensions to install and provides tasks. The ESLint formatter will require you to install ESLint globally, using npm install -g eslint. Otherwise VS Code will erroneously complain that it isn't able to use it to format TypeScript files.

Tracking Upstream Dependencies

As a VS Code extension, we first rely on the engine field of package.json to state the lowest version of VS Code we support.

When our engine field is updated the development dependency @types/vscode must be updated to match. Note that it uses ~ (not ^) so as to accept new patches with npm update but not new minor versions. Then we check that version of VS Code's own package.json file for their electron dependency. The major version of Electron will tell us which Node.js is included, which dictates which version of Node.js the extension is eventually run with. This lets us finally update our @types/node development dependency to match, our developer machines if necessary, and the CI and OneBranch pipeline tasks.

Building the Code

From Visual Studio Code

Press Ctrl+P and type task build. Explore the other provided tasks for helpful commands.

From a PowerShell prompt

Invoke-Build Build

Explore the vscode-powershell.build.ps1 file for other build targets.

Launching the extension

To debug the extension use one of the provided Launch Extension debug configurations (remember to rebuild first). You can simultaneously use the Attach to Editor Services configuration to attach the .NET debugger to the PowerShell process running the server. Try the powershell.developer.editorServicesWaitForDebugger setting to attach before startup.

Contributing Snippets

For more information on contributing snippets please read our snippet requirements.

Creating a Release

These are the current steps for creating a release for both the editor services and the extension. Azure DevOps access is restricted to Microsoft employees and is used to sign and validate the produced binaries before publishing on behalf of Microsoft. Assume origin is GitHub and ado is Azure DevOps.

cd ./PowerShellEditorServices
git checkout -B release
./tools/updateVersion.ps1 -Version "4.0.0" -Changes "Major release!"
git push --force-with-lease origin
git push ado HEAD:main

cd ../vscode-powershell
git checkout -B release
./tools/updateVersion.ps1 -Version "2024.4.0" -Changes "Major release!"
git push --force-with-lease origin
git push ado HEAD:main

Amend changelogs as necessary.
Push release branches to GitHub and to Azure DevOps main branch.
Download and test assets!
Publish draft releases and merge (don't squash!) branches.
Permit pipeline to publish to marketplace.

If rolling from pre-release to release, do not change the version of PowerShell Editor Services between a pre-release and the subsequent release! We only need to release the extension.

The Azure DevOps pipelines have to build off main branch for reasons, but we still want to use PRs. Hence pushing release to main and then merging (not squashing nor rebasing) those PRs so the commit stays the same.

Versioning

For both our repositories we use Git tags in the form vX.Y.Z to mark the releases in the codebase. We use the GitHub Release feature to create these tags. The ephemeral branch release is used in the process of creating a release for each repository, primarily for the Pull Requests and for Azure DevOps triggers. Once the release PRs are merged, the branch is deleted until used again to prepare the next release. This branch does not mark any specific release, that is the point of the tags.

For PowerShellEditor Services, we simply follow semantic versioning, e.g. vX.Y.Z. We do not release previews frequently because this dependency is not generally used directly: it's a library consumed by other projects which themselves use pre-releases for beta testing.

For the VS Code PowerShell Extension, our version follows vYYYY.X.Z, that is: current year, minor version, and patch version. This is not semantic versioning because of issues with how the VS Code marketplace and extension hosting API itself uses our version number. We do not release on a chronological schedule: we release based on completed work. For historical reasons we are stuck with the major version being year.

Before releasing a stable version (a release) we should almost always first release a preview of the same code, which is a pre-release. The exception to this is hotfix releases where we need to push only bug fixes out as soon as possible, and these should be built off the last release's codebase (found from the Git tag). The pre-release is uploaded to the marketplace using the --pre-release flag given to vsce (the CLI tool used to do so). The previous separate "PowerShell Preview" extension has been deprecated in favor of using the marketplace's support for pre-releases on the one-and-only extension.

Because the marketplace does not actually understand Semantic Versioning pre-release tags (the -preview suffix), the patch numbers need to increment continuously, but we append -preview to our version in the changelog and Git tags. When multiple pre-releases are needed, the patch version is incremented (again because the marketplace ignores the pre-release tag, we can't do -alpha, -beta etc.). The preview field in the extension's manifest (the package.json file) is always false, even for pre-releases, because the marketplace takes the information from the latest release inclusive of pre-releases, hence it was causing the one-and-only extension to look like it was in preview. This is also why the icon no longer changes to the PowerShell Preview icon for pre-releases. When they support pre-releases better (ideally that means supporting the pre-release tags in full) we can revisit this.

Furthermore, for releases, the minor version must be even (like 0, 2, etc.) and for pre-releases it must be odd (like 1, 3, etc.), and an upcoming release's version must be n-1 of the pre-release which previews it. That is, release v2024.0.0 is previewed in the pre-release v2024.1.0-preview. This scheme is designed such that the "newest" (by version) release is always a pre-release, so that the VS Code marketplace always shows a pre-release option. When we previously did this the other way around (incrementing the release as n+1 to the pre-release), every time we released, the pre-release option (dropdown) in the marketplace would unfortunately disappear.

For example, the date is August 23, 2023. The last release was in June, and its version was v2023.6.0. Some significant work has been completed and we want to release the extension, so the next release will be v2023.8.0 (the minor version is n+2 because it must remain even, it only coincidentally matches the month). That means first we create a pre-release with version v2023.9.0-preview (the minor version is n+1 of the upcoming release, and -preview was appended). After publishing, some issues were identified and we decided we needed a second pre-release. Its version is v2023.9.1-preview. User feedback hopefully indicates that the pre-release is working well, so to create a release we will use the same code (but with an updated changelog etc.) and use version v2023.8.0, the next release since v2023.6.0. The version of PowerShell Editor Services may update between pre-releases or releases, but must not change between a pre-release and its subsequent release, as they should use the same code (which includes dependencies).