verify-dockerfile: does not recognize default parameter substitution

[Dentrax]

Description

Minimal reproduce:

• Set the $BUILDPLATFORM env to arm/v7.

Happy-path test case:

FROM --platform=${BUILDPLATFORM} golang:1.16.3-alpine3.13 AS builder

• Unset the $BUILDPLATFORM env.

Failing test case:

FROM --platform=${BUILDPLATFORM:-linux/amd64} golang:1.16.3-alpine3.13 AS builder

i.e.:

{
	name:         "digest-platform",
	fileContents: `FROM --platform=${BUILDPLATFORM:-linux/amd64} golang:1.16.3-alpine3.13 AS builder`,
	expected:     []string{"golang:1.16.3-alpine3.13"},
},

getImageFromLine() function returns --platform= instead of --platform=linux/amd64

P.S: This is a limitation of os.ExpandEnv functions. Go currently does not support this feature. We may need to use a custom framework to make a workaround to fix this.

cc: @developer-guy

[github-actions]

This issue is stale because it has been open 60 days with no activity. Remove stale label or comment or this will be closed in 5 days.

[github-actions]

This issue is stale because it has been open 60 days with no activity. Remove stale label or comment or this will be closed in 5 days.

[github-actions]

This issue was closed because it has been stalled for 5 days with no activity.