Raise error when template variable is unset

[jerkstorecaller]

I started from the recipe example and renamed image to image_name_ext4, but forgot to change the .image before the printf. End-result? The variable is set to WARNING_UNSET.

$ cat test.yaml
{{- $architecture := or .architecture "amd64" -}}
{{- $suite := or .suite "buster" -}}
{{- $type := or .type "min" -}}
{{- $image_name_ext4 := or .image (printf "WARNING_UNSET_%s_%s.ext4" $suite $architecture) -}}
architecture: {{ $architecture }}
actions:
  - action: run
    chroot: false
    description: Checking image name
    command: echo {{ $image_name_ext4 }}

$ debos --print-recipe --dry-run -t "image_name_ext4":"image_1.1.ext4" test.yaml
2022/07/23 14:34:30 Recipe '/home/user/dev/test.yaml':
2022/07/23 14:34:30 architecture: amd64
actions:
  - action: run
    chroot: false
    description: Checking image name
    command: echo WARNING_UNSET_buster_amd64.ext4
2022/07/23 14:34:30 ==== Recipe done (Dry run) ====

This syntax is confusing to me. I feel like image_name_ext4 should either be empty/unset because I set a different hidden variable called image to WARNING_UNSET, or throw an error.

[obbardc]

@jerkstorecaller can you please move your nice to haves into new issues? Those two are indeed things which I'd like to add :-)

As for this issue, I wonder if really we should title it Raise error when template variable is unset ? Would that be a satisfying solution here?

[jerkstorecaller]

Done!

#430
#431

For this issue, it's actually two issues in one (sorry I was just giving general feedback).

1. Raise error when template variable is unset
2. Warn or raise an error when syntax is invalid , eg writing }} at the end of a line instead of -}}. Silently dropping the line is the issue.

I can refactor this into 2 issues if you want.

[obbardc]

That'd be great -please keep this issue for the unset variable warning

[jerkstorecaller]

Done. New ticket: #432

Will now refactor this OP.