Is it possible the nested use of !reference in gitlab-ci.yml? - reference

Question

rules.yml
.rules:
default:
- .gitlab-ci.yml
- Makefile
- VERSION
a_pybuild_deps:
- !reference [.rules, default]
- foo/a/**
b_pybuild_deps:
- !reference [.rules, default]
- foo/b/**
It works if I am simply referring to default:
gitlab-ci.yml
include:
- local: "./rules.yml"
a_pybuild:
...
stage: py_build
script:
...
only:
changes: !reference [.rules, default]
But I want to do the following:
gitlab-ci.yml
include:
- local: "./rules.yml"
a_pybuild:
...
stage: py_build
script:
...
only:
changes: !reference [.rules, a_pybuild_deps]
b_pybuild:
...
stage: py_build
script:
...
only:
changes: !reference [.rules, b_pybuild_deps]
Like this I will get a lint error: jobs:a_pybuild:only changes should be an array of string
I understand the problem, but is there any proper way to apply this?

Answer 1

As of GitLab 14.8, you can use nested !references up to 10 levels deep, but only for script:, before_script: and after_script:.
Nesting of !reference is not allowed in other keys, like only: which is why you get this error.
In versions of GitLab prior to 14.8, nested !references are prohibited entirely.
In your situation, you would simply have to manually duplicate your default rules into a_pybuild_deps and b_pybuild_deps or omit the default rules from those keys entirely and !reference both the default and respective pybuild keys in the job.
This is probably the most flexible and DRY way to do it is to use rules: instead of only: and arrange your rules like so:
# rules.yml
.rules:
default:
changes:
- .gitlab-ci.yml
- Makefile
- VERSION
a_pybuild_deps:
changes:
- foo/a/**
b_pybuild_deps:
changes:
- foo/b/**
#.gitlab-ci.yml
include:
- local: "./rules.yml"
a_pybuild:
script: '...'
rules:
- !reference [.rules, default]
- !reference [.rules, a_pybuild_deps]
b_pybuild:
script: '...'
rules:
- !reference [.rules, default]
- !reference [.rules, b_pybuild_deps]