====== rules ======


[[https://docs.gitlab.com/ee/ci/yaml/#rulesif|rules:if]]
<code>
Use rules:if clauses to specify when to add a job to a pipeline:

    If an if statement is true, add the job to the pipeline.
    If an if statement is true, but it’s combined with when: never, do not add the job to the pipeline.
    If no if statements are true, do not add the job to the pipeline. 
</code>

[[https://docs.gitlab.com/ee/ci/yaml/#ruleschanges|rules:changes]]

===== conditional variables =====

<code yaml>
build:
  rules:
    - if: $CI_COMMIT_REF_NAME == $CI_DEFAULT_BRANCH
      variables:
        CCACHE_DISABLE: 1
    - if: $CI_COMMIT_TAG
      variables:
        CCACHE_DISABLE: 1
</code>

  * [[https://docs.gitlab.com/ee/ci/caching/index.html#use-a-variable-to-control-a-jobs-cache-policy|Use a variable to control a job’s cache policy]]
  * [[https://gitlab.com/gitlab-org/gitlab/-/issues/270415#note_1050526105|Support `cache` policies for job `rules`]]


<code yaml>
workflow:
  rules:
    - if: $CI_COMMIT_REF_NAME == $CI_DEFAULT_BRANCH
      variables:
        CCACHE_DISABLE: 1
        CACHE_CCACHE_POLICY: pull
    - if: $CI_COMMIT_TAG
      variables:
        CCACHE_DISABLE: 1
        CACHE_CCACHE_POLICY: pull
    - when: always

.ccache: &cache-ccache
  key: cache-ccache
  paths:
    - .ccache
  policy: ${CACHE_CCACHE_POLICY}


.build-target:
  cache:
    - <<: *cache-ccache

</code>

===== negate glob? =====

How to negate ''rules:changes'' pattern?

Not possible. ''rules:changes'' takes glob patterns and they are inclusive only.
You have to specify all paths/patterns to match one by one.

BUT:

Glob patterns are interpreted with Ruby’s [[https://docs.ruby-lang.org/en/master/File.html#method-c-fnmatch|File.fnmatch]] with the [[https://docs.ruby-lang.org/en/master/File/Constants.html#module-File::Constants-label-Filename+Globbing+Constants+-28File-3A-3AFNM_-2A-29|flags]] ''File::FNM_PATHNAME | File::FNM_DOTMATCH | File::FNM_EXTGLOB''. 

Ruby's fnmatch is used to handle patterns. It doesn't support ''!'' character.

To write rule to do not match changes in <code>src/**/*</code> directory but matches ''s'', ''sr'', ''src2'':
<code yaml>
rules:
  - changes:
    - "{[^s]*,s,s[^r]*,sr,sr[^c]*,src?*}/**/*"
    - "*"
</code>

Note: second pattern ''*'' is for match any file (but not directory!)
More, to exclude ''src/'' and ''doc/'':

<code yaml>
  rules:
    - changes:
        - "{[^s^d]*,s,d,s[^r]*,d[^o],sr,do,sr[^c]*,do[^c]*,src?*,doc?*}/**/*"
        - "*"
</code>

More about:
  * [[https://stackoverflow.com/questions/69905938/is-there-a-way-to-write-a-glob-pattern-that-matches-all-files-except-those-in-a|Is there a way to write a glob pattern that matches all files except those in a folder?]]
  * [[https://stackoverflow.com/questions/73228188/gitlab-ci-cd-ruleschanges-negate-glob/73229777#73229777|gitlab CI/CD rules:changes negate glob]]