Variable substitution with environment - allow for fallback to default

[dellagustin-sap]

When doing variable substitution with environment (at debugging launch, but could be useful for tasks too - ${env:Name}), I would like to provide a fallback (default) when the environment variable is not set.

As an example, see the variable substitution scheme for Docker Compose: https://docs.docker.com/compose/compose-file/#variable-substitution

• ${VARIABLE:-default} evaluates to default if VARIABLE is unset or empty in the environment.
• ${VARIABLE-default} evaluates to default only if VARIABLE is unset in the environment.

The syntax for VS Code could be ${env:Name:-default} and ${env:Name-default} with the same logic.

VS Code version 1.42.1

[vscodebot]

This feature request is now a candidate for our backlog. The community has 60 days to upvote the issue. If it receives 20 upvotes we will move it to our backlog. If not, we will close it. To learn more about how we handle feature requests, please see our documentation.

Happy Coding!

[dellagustin-sap]

Hooorray, 20 👍
We go to backlog
I wish I had the time to do the contribution myself (assuming I would be smart enough to carry it forward)

[vscodebot]

🙂 This feature request received a sufficient number of community upvotes and we moved it to our backlog. To learn more about how we handle feature requests, please see our documentation.

Happy Coding!

[flying-sheep]

Any way to circumvent this for now? I want to do use XDG basedir spec and prepend something to XDG_DATA_DIRS.

To this end I need to retrieve the value of XDG_DATA_DIRS if it’s set and use a default when it isn’t set, which would look like this:

"env": {
    "XDG_DATA_DIRS": "${workspaceFolder}/something:${env:XDG_DATA_DIRS-/usr/local/share:/usr/share}"
}

There seems to be no way to currently do this in a launch configuration, and falling back to the empty string will break every GUI application launched with that env value set.

[alexr00]

Instead of using env you could write an extension that provides a command and use command input variables