Replace YAML anchors with `extends` in `.gitlab-ci.yml`

Description

In 11.3 we are going to release extends keyword support that is an alternative to YAML anchors.

extends is a little more flexible because it uses reverse, recursive, deep merge strategy, unlike anchors.

We should consider refactoring our own .gitlab-ci.yml to use extends instead of YAML anchors, what should hopefully simplify our CI/CD configuration.

What do you think @rymai @meks?

added Quality test labels

added ci-build label

@jlenny we talked about this today!

/cc @godfat

Would be great to do this!

added priority3 label

changed milestone to %11.5

@grzesiek can you help us estimate a rough weight ? maybe 2-3 ?

@meks We don't need to rewrite everything, perhaps most critical / complex parts of the .gitlab-ci.yml. We can start simple, in this case it would be 2 indeed.

That said, I'm a little sad that we don't have specs for .gitlab-ci.yml and an easy way of writing them.

changed weight to 2

mentioned in issue #51598 (closed)

mentioned in issue #51628 (closed)

added severity4 label

Are you guys aware that extends does not merge items? gitlab-runner#3611

@grzesiek I'll suggest postponing this to %11.6.

We backport security fixes for 3 releases, once on %11.6 the last 3 releases will support extends and backporting will be easier.

Sounds good @nolith /cc @meks

added [deprecated] Accepting merge requests label

Cross-posting from omnibus-gitlab#3917 (comment 117604043):

Beware of extends: jobs that are extended inherits the global before_script, and override any script/stage set by a previous extension in contrary to the YAML anchor syntax which doesn't do anything special since it's not a "CI feature".

See the following examples which result in an invalid CI configuration:

• rymai/test-project@651984fc => missing script
• rymai/test-project@0ca20b33 => missing stage
• working example: rymai/test-project@3a694710

Created an issue for these bugs: https://gitlab.com/gitlab-org/gitlab-ce/issues/54111

mentioned in issue #54111 (closed)

I intend to build a public semver versioned library of reusable gitlabci configuration (I already have one internally) but it's depending on this feature shipping. I hope this ships soon - it's going to revolutionize how we use gitlabci.

@ztenerowicz This is an issue about internal .gitlab-ci.yml for GitLab CE and EE. extends is already available in recent versions of GitLab

changed milestone to %12.0

mentioned in issue #60326 (closed)

Milestone %11.9 has expired, this will be rescheduled to the next milestone in active development %11.11. If you think this is incorrect, please feel free to update the milestone to a more appropriate one.

We're also adding missed:11.9

changed milestone to %11.11

added missed:11.9 label

mentioned in issue #63065 (closed)

Milestone %11.11 has expired, this will be rescheduled to the next milestone in active development %12.1. If you think this is incorrect, please feel free to update the milestone to a more appropriate one.

We're also adding missed:11.11

changed milestone to %12.1

added missed:11.11 label

I would like to mention that we now have support for multiple extends and this feature is now much more flexible.

@grzesiek is this already deployed in gitlab.com? There are no changes to the docs I think : https://docs.gitlab.com/ee/ci/yaml/#extends

@pmatos it is, also present in the docs you linked, scroll down.

@grzesiek ah ok, so the new extends features is the extends with multiple parents. It was not clear what was added in the most recent versions.

mentioned in issue #65094 (closed)

changed milestone to %12.2

added missed:12.1 label

marked this issue as related to #65702 (closed)

mentioned in issue #65702 (closed)

assigned to @rymai

mentioned in merge request !31728 (merged)

removed [deprecated] Accepting merge requests label

marked this issue as related to #66547 (moved)

mentioned in issue #63982 (closed)

mentioned in issue #66572 (closed)

mentioned in issue #66594 (closed)

mentioned in issue #66618 (closed)

changed milestone to %12.3

added missed:12.2 label

mentioned in commit 53c39cc1

added to epic &1853