How can I get a reference to a CommitService instance in a pre-receive hook?

[Lon Ingram]

I'm trying to write a ScriptRunner pre-receive hook that rejects merge commits except from master.

I'm able to enumerate the refChanges, but I don't see how to get a reference to a CommitService instance so that I can get the message and parents of each commit.

Here's what I have thus far:

import com.atlassian.stash.commit.Commit
import com.atlassian.stash.commit.CommitService
import com.atlassian.stash.commit.CommitsBetweenRequest
import com.atlassian.stash.hook.HookResponse 
import com.atlassian.stash.repository.RefChange
import com.atlassian.stash.repository.Repository
import com.atlassian.stash.util.Page
import com.atlassian.stash.util.PageRequestImpl
import com.atlassian.stash.util.PageUtils
Repository repository = repository 
Collection<RefChange> refChanges = refChanges
HookResponse hookResponse = hookResponse
for (refChange in refChanges) {
  hookResponse.out().print("from ${refChange.getFromHash()} to ${refChange.getToHash()}\n")
  hookResponse.out().print(">>> ${refChange.getRefId()}\n")
  CommitsBetweenRequest request = new CommitsBetweenRequest.Builder(repository)
      .exclude(refChange.getFromHash())
      .include(refChange.getToHash())
      .build()
  try {
    Page<Commit> commits =
      commitService.getCommitsBetween(request, PageUtils.newRequest(0, 25))
  } catch (e) {
    hookResponse.out().println("DOH: ${e.getMessage()}")
    return false
  }
  for (commit in commits) {
    hookResponse.out().println(">>> ${commit.getMessage()}")
    hookResponse.out().println(">>> parents: ${commit.getParents().length}")
  }
}
return true

EDIT

Well, I can't answer my own question, apparently, but the solution is to use ComponentLocator:

import com.atlassian.sal.api.component.ComponentLocator
import com.atlassian.stash.commit.CommitService


CommitService commitService = ComponentLocator.getComponent(CommitService)

[JamieA · Accepted solution]

The solution is to use ComponentLocator 

You just need to be aware that you will have to modify that import when you come to upgrade to Bitbucket server: https://scriptrunner.adaptavist.com/latest/bitbucket/releases/release-4.1.2.html

There is also a method tacked on to refChanges which will get all the commits:

refChanges.getCommits(repository).each { Commit commit -> ...

[Lon Ingram]

Thanks! That is useful. It would be great to add some documentation about this to https://scriptrunner.adaptavist.com/latest/bitbucket/PreReceiveHooks.html

[JamieA]

Some of the extension methods are doc'd at https://scriptrunner.adaptavist.com/latest/bitbucket/#_condition_methods, unfortunately not that one.