Extension installation dependencies

[joaomoreno]

We want to support extensions depending on other extensions and having that transitive closure installed when installing the first one. Eg. vscode-go could depend on vscode-go-syntax.

This requires vsce work:

• Figure out a syntax for package.json to indicate extension dependencies: extensionDependencies
• Map dependencies to version properties, queriable from the Marketplace: Add extension dependencies as a version property vscode-vsce#124
  • Property: Microsoft.VisualStudio.Code.ExtensionDependencies

For vscode:

• Figure out extension transitive closure, from version properties.
• Render that in the extension editor. Tracked in Show the user the list of extensions that will be installed #12756
• Figure out how to notify user that more extensions will be installed (Install all, Install this extension only, Cancel)

We're leaving Uninstall out of the story for now.

[joaomoreno]

@seanmcbreen @waderyan fyi

As discussed with @egamma, we're going with an approach in which 100% of this work in on our side. An extension can list other extensions it wants to be installed in the user's machine, when installing itself. As a consequence, this connection won't surface in the Marketplace, only at extension installation time, within VS Code itself.

Any other approach would require cooperation with the Marketplace to create a first class concept of extension dependencies or packs.

[waderyan]

An extension can list other extensions it wants to be installed in the user's machine, when installing itself.

Will this be done in the manifest file or where will it be done?

I am not opposed to the approach, but I can see some benefit to having dependent extensions surface in the Marketplace's UI.

[joaomoreno]

We decided to use the (already existing) extensionDependencies property in package.json. It is a list of extension names.

Going with this decision won't luck us down and will let the Marketplace reflect that data in their UI, if we want to go that way in the future.

[waderyan]

Cool sounds good to me.