WIP: Solve stuck pipeline when depending with dag on a manual job

What does this MR do?

Related to: #31264 (closed)

This MR aims to solve the problem that pipelines get stuck when a job needs a manual job.

The idea behind this MR is to make a manual job "blocker" if another job needs it, even the manual job is allow_failure:true.

❗ Of course, legacy tests are failing... ❗

Example 1

test:
  stage: test
  when: manual
  allow_failure: true
  script: exit 1

deploy:
  stage: deploy
  script: exit 0
  needs: [test]

# Current behavior:
# test: manual / stage: skipped
# deploy: created / stage: created
# pipeline: created

# Fixed behavior:
# test: manual / stage: manual
# deploy: created / stage: created
# pipeline: manual

Example 2

build:
  stage: build
  script: exit 0

test:
  stage: test
  when: manual
  allow_failure: true
  script: exit 1

deploy:
  stage: deploy
  script: exit 0
  needs: [test]

# Current behavior:
# build: success / stage: success
# test: manual / stage: skipped
# deploy: created / stage: created
# pipeline: running

# Fixed behavior:
# build: success / stage: success
# test: manual / stage: manual
# deploy: created / stage: created
# pipeline: manual

Screenshots

SQL Query Changes

From:

SELECT "ci_builds"."id",
       "ci_builds"."name",
       "ci_builds"."status",
       "ci_builds"."allow_failure",
       "ci_builds"."stage_idx",
       "ci_builds"."processed",
       "ci_builds"."lock_version"
FROM "ci_builds"
WHERE "ci_builds"."commit_id" = 150901085
  AND ("ci_builds"."retried" = FALSE
       OR "ci_builds"."retried" IS NULL)
ORDER BY "ci_builds"."stage_idx" ASC;

https://explain.depesz.com/s/NoOs

To:

SELECT "ci_builds"."id",
       "ci_builds"."name",
       "ci_builds"."status",
       "ci_builds"."allow_failure",
       "ci_builds"."stage_idx",
       "ci_builds"."processed",
       "ci_builds"."lock_version",

  (SELECT TRUE
   FROM "ci_build_needs"
   WHERE (ci_builds.name = ci_build_needs.name) LIMIT 1) AS has_dag_dependent
FROM "ci_builds"
WHERE "ci_builds"."commit_id" = 150901085
  AND ("ci_builds"."retried" = FALSE
       OR "ci_builds"."retried" IS NULL)
ORDER BY "ci_builds"."stage_idx" ASC;

https://explain.depesz.com/s/SVce

Does this MR meet the acceptance criteria?

Conformity

• Changelog entry
• Documentation (if required)
• Code review guidelines
• Merge request performance guidelines
• Style guides
• Database guides
• Separation of EE specific content

Availability and Testing

• Review and add/update tests for this feature/bug. Consider all test levels. See the Test Planning Process.
• Tested in all supported browsers
• Informed Infrastructure department of a default or new setting change, if applicable per definition of done

Security

If this MR contains changes to processing or storing of credentials or tokens, authorization and authentication methods and other items described in the security review guidelines:

• [-] Label as security and @ mention @gitlab-com/gl-security/appsec
• [-] The MR includes necessary changes to maintain consistency between UI, API, email, or other methods
• [-] Security reports checked/validated by a reviewer from the AppSec team