Environment Variable Default Not Working Correctly v1.3.0

[damaestro]

Describe the bug

When using the shell default value syntax, the default is not always interpreted. Oddly, it does work if the source variable name doesn't match the destination variable name.

This works as expected with docker compose.

To Reproduce
Steps to reproduce the behavior:

Dockerfile:

FROM docker.io/library/busybox:latest
CMD ["/bin/sh"]

docker-compose.yaml:

version: '3'
services:
  test:
    build: .
    environment:
      TEST_EXPECT_WORKING: ${TEST_EXPECT_WORKING:-working}
      TEST_EXPECT_EMPTY: ${DOES_NOT_EXIST}
      TEST_EXPECT_ONE: 1
      TEST_ODDLY_WORKING: ${HOW_STRANGE:-working}
    command: ["/bin/sh", "-c", "printenv|grep TEST"]

Expected behavior

TEST_EXPECT_WORKING: ${TEST_EXPECT_WORKING:-working} is a common pattern for allowing user-set environment variables to be passed through, while also setting a default. This is working fine with docker compose.

Actual behavior

TEST_EXPECT_WORKING is set to ${TEST_EXPECT_WORKING:-working} not working or previously set $TEST_EXPECT_WORKING.

Output

Versions:

$ podman-compose version
podman-compose version 1.3.0
podman version 5.3.1

Defaults expected:

$ podman compose run test
TEST_EXPECT_EMPTY=
TEST_ODDLY_WORKING=working
TEST_EXPECT_ONE=1
TEST_EXPECT_WORKING=${TEST_EXPECT_WORKING:-working}

User-set expected:

$ TEST_EXPECT_WORKING='cli-working' podman compose run test
TEST_EXPECT_EMPTY=
TEST_ODDLY_WORKING=working
TEST_EXPECT_ONE=1
TEST_EXPECT_WORKING=cli-working

Environment:

• OS: Linux
• podman version: 5.3.1
• podman compose version: 1.3.0

Additional context

This might have been working previously as I'm just now noticing it.

[damaestro]

I've confirmed this is a bug with podman-compose 1.3.0. The following is working with 1.2.0:

Versions:

$ podman-compose version
podman-compose version 1.2.0
podman version 5.3.1

Defaults expected:

$ podman compose run test
TEST_EXPECT_ONE=1
TEST_EXPECT_WORKING=working
TEST_ODDLY_WORKING=working
TEST_EXPECT_EMPTY=

User-set expected:

$ TEST_EXPECT_WORKING='cli-working' podman compose run test
TEST_EXPECT_ONE=1
TEST_EXPECT_WORKING=cli-working
TEST_ODDLY_WORKING=working
TEST_EXPECT_EMPTY=

[indrat]

Also just ran in to this. The problematic line appears to be: https://github.com/containers/podman-compose/blob/main/podman_compose.py#L273

Removing the update to the subs_dict before the svc_envs are substituted appears to fix this issue for me.

[p12tic]

Fixed in #1110.