[Bug]: Env vars interpolation is broken

[Kocal]

Description

Hi :)

Today I've upgraded from v4.0.0-beta.264 to v4.0.0-beta.290, and my apps could not be deployed due to env vars not being interpolated anymore.

Given the following env vars:

DATABASE_URL=postgres://$POSTGRES_USER:$POSTGRES_PASSWORD@database:5432/$POSTGRES_DB?sslmode=disable&charset=utf8&serverVersion=16.2
POSTGRES_USER=user
POSTGRES_PASSWORD=password
POSTGRES_DB=db

If I run printenv in the PHP container for v4.0.0-beta.264, I see DATABASE_URL being correctly interpolated:

DATABASE_URL=postgres://user:password@database:5432/db?sslmode=disable&charset=utf8&serverVersion=16.2

But if I do the same for v4.0.0-beta.290, I see DATABASE_URL being wrongly interpolated:

DATABASE_URL=postgres://:@database:5432/?sslmode=disable&charset=utf8&serverVersion=16.2

Minimal Reproduction (if possible, example repository)

• Create a new project and environment
• Create an env var
• Create an env var that use the other
• Deploy
• printenv in the container, and see the 2nd env var is not correctly interpolated

Exception or Error

No response

Version

v4.0.0-beta.290

[Achder]

I have a similar issue.
I use this in my code:

But it's not interpolating, it's just printing $SOURCE_COMMIT

[lorenzomigliorero]

Same issue; the env variables seem to be handled as a Literal in all cases.

[madebylydia]

This is also reproducible with a Docker Compose file.
Reproduction can be done using the following file: https://github.com/madebylydia/docker-files/blob/1d979fccbee5b4a9f237bf085ce681dde8e531b6/Netdata/compose.yml