[Bug]: Cannot use literal `${x}` in environment variable files

[lukpsaxo]

Self-service

• [ ] I'd be willing to implement a fix

Describe the bug

If your env variable needs to have a value with ${} in it, yarn will error:

Usage Error: Environment variable not found (endpoint)

To reproduce

create a env file with:

CYPRESS_DOWNLOAD_PATH_TEMPLATE="${endpoint}/${platform}-${arch}/cypress.zip"

Environment

windows

Additional context

the problem is here:

https://github.com/yarnpkg/berry/blob/10d16c36653713dae4c4347394cd80b7c2015412/packages/yarnpkg-core/sources/miscUtils.ts#L470

I think it just needs a negative look behind for an escaping \ - which would match the behaviour of npm and setting variables in npmrc.

[clemyan]

Can you expand your reproduction? It is unclear where you put that line and what command(s) you are running when the bug occurs.

FWIW, I tried and failed to reproduce:

PS> yarn init -2
PS> echo 'CYPRESS_DOWNLOAD_PATH_TEMPLATE="${endpoint}/${platform}-${arch}/cypress.zip"' > .env.yarn
PS> $env:endpoint = "http://localhost"; $env:platform="win32"; $env:arch="x64";
PS> yarn node -p 'process.env.CYPRESS_DOWNLOAD_PATH_TEMPLATE'
http://localhost/win32-x64/cypress.zip

[lukpsaxo]

@clemyan thanks for your response, I can see I am not clear.

Cypress actually expands those variables itself - so I don't want yarn to expand them, I want to be able to escape it so yarn leaves it alone.

repro:

yarn init -2
echo 'CYPRESS_DOWNLOAD_PATH_TEMPLATE="${endpoint}/${platform}-${arch}/cypress.zip"' > .env.yarn
yarn node -p 'process.env.CYPRESS_DOWNLOAD_PATH_TEMPLATE'

and I guess you could change the repro to this:

yarn init -2
echo 'CYPRESS_DOWNLOAD_PATH_TEMPLATE="\${endpoint}/\${platform}-\${arch}/cypress.zip"' > .env.yarn
yarn node -p 'process.env.CYPRESS_DOWNLOAD_PATH_TEMPLATE'

where the $ is escaped, but yarn still tries to expand the variables.

https://docs.cypress.io/guides/references/advanced-installation#Download-path-template

[clemyan]

I see, you want a literal ${x} in your variable

Maybe we should follow dotenv-expand's expansion logic.