Unable to use .env variable in functions for database.instance()

[danielluca]

Version info

node: 16.14.0

firebase-functions: 3.18.1

firebase-tools: 10.2.2

firebase-admin: 10.0.2

Test case

const myFunction = functions
  .runWith({
    vpcConnector: 'static-vpc-connector',
    vpcConnectorEgressSettings: 'ALL_TRAFFIC',
  })
  .region('europe-west3')
  .database
  .instance(process.env.MY_INSTANCE)
  .ref('/some/{ref}')
  .onCreate(async (snapshot, context) => {}

Expected behavior

Function should use the .env variable set in .env file.

Actual behavior

If I set the instance without a .env variable, the function can be deployed.
If I set the instance with a .env, I get an error.

Were you able to successfully deploy your functions?

i  functions: cleaning up build files...
Error: There was an error deploying functions

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[taeold]

Other issues that touches on this problem:

firebase/firebase-tools#4361
#1044

Pasting a response I posted in another issue:

As both of you have already found out, we are intentionally not including user-defined environment variables when parsing your source code to discover your functions. This limits their use when compared to functions config.

We are preparing something new that digs into exactly this problem -stay tuned. Until then, I'd suggest that you continue to rely on functions config if need environment-aware logic when deploying your functions.

Since this is a common point of confusion, I'm going to try to consolidate our response in a single issue. Arbitrary going to pick the earliest reported issue (#1044) as our single source of truth. Let's continue our discussion there.

[inlined]

See #1084 for our plans around this area.