Extract shared discover plugin logic into the step

[therazix]

This PR extracts some shared behavior (repository fetching, installation of libraries, and application of policies) from individual discover plugins to their parent Discover plugin. The discover step now has control over these individual actions and can, for example, choose when exactly to perform repository fetching and other actions. It also makes some behavior consistent between the two discover plugins. The discover/shell plugin now gains the url-content-type key, which works the same way as in the discover/fmf plugin. Remote repository fetching is now unified for both plugins.

Resolves #4348

Pull Request Checklist

• implement the feature
• write the documentation
• extend the test coverage
• update the specification
• adjust plugin docstring
• modify the json schema
• mention the version
• include a release note

[thrix]

@therazix looks good, I just found one thing via Claude Code Opus 4.5 to review. Can you check on it please?

Nice catch, thanks! I completely missed the duplicate validation. It should be fixed in 562eaa0.

Ty, can we also add tests?

  1. Add test plan in tests/discover/libraries/data/plan.fmf

  /shell:
      summary: "Library installation with shell discover plugin"
      discover:
          how: shell
          tests:
            - name: /certificate-shell
              test: ./certificate.sh
              require:
                - library(openssl/certgen)

  2. Add test phase in tests/discover/libraries/test.sh

  Add this phase before the cleanup:

  rlPhaseStartTest "Shell discover plugin installs libraries"
      rlRun -s "$tmt shell"
      rlAssertGrep "Fetch library 'openssl/certgen'" $rlRun_LOG
  rlPhaseEnd

[thrix]

LGTM after adding tests.

[LecrisUT]

Ty, can we also add tests?

  1. Add test plan in tests/discover/libraries/data/plan.fmf

  /shell:
      summary: "Library installation with shell discover plugin"
      discover:
          how: shell
          tests:
            - name: /certificate-shell
              test: ./certificate.sh
              require:
                - library(openssl/certgen)

Would prefer to keep it similar to file.sh that is already there. It seems that that would require changes on #4427 also because I had an assumption in there which I should be able to relax, but we would need more coverage in /tests/libarires

[LecrisUT]

@therazix do you have a tracker for unifying the rest of these options? I don't see why keep_git_metadata should be only in shell or why the dist_git_* are only in fmf. There is still a lot of other discrepancy that we need to deal with, but just tracking these discrepancies would be helpful.

[thrix]

@therazix do you have a tracker for unifying the rest of these options? I don't see why keep_git_metadata should be only in shell or why the dist_git_* are only in fmf. There is still a lot of other discrepancy that we need to deal with, but just tracking these discrepancies would be helpful.

In that case I would keep it for the next release with an issue

[therazix]

Ty, can we also add tests?

I added a simple test that should cover the keep-git-metadata validation with a remote URL specified in 956203c.

[therazix]

@therazix do you have a tracker for unifying the rest of these options? I don't see why keep_git_metadata should be only in shell or why the dist_git_* are only in fmf. There is still a lot of other discrepancy that we need to deal with, but just tracking these discrepancies would be helpful.

Not yet. I will create an issue that will track the remaining things to improve or refactor. This is the first step. The other things will be addressed in additional PRs.

[skycastlelily]

Other than the nitpick, LGTM

[thrix]

The test issue is a known flake with virtual tests, I will be filing an issue for them