Now that JENKINS-63069 has been fixed, this JENKINS-63033 is the only known issue blocking our migration from Bitbucket Branch Source Plugin.

Lightweight checkout in Bitbucket Branch Source Plugin was requested in JENKINS-42518 and implemented in PR#78. The diffstat was:

58      0       src/main/java/com/cloudbees/jenkins/plugins/bitbucket/Utils.java
23      1       src/main/java/com/cloudbees/jenkins/plugins/bitbucket/api/BitbucketApi.java
57      5       src/main/java/com/cloudbees/jenkins/plugins/bitbucket/client/BitbucketCloudApiClient.java
82      0       src/main/java/com/cloudbees/jenkins/plugins/bitbucket/client/repository/BitbucketRepositorySource.java
104     0       src/main/java/com/cloudbees/jenkins/plugins/bitbucket/filesystem/BitbucketSCMFile.java
147     0       src/main/java/com/cloudbees/jenkins/plugins/bitbucket/filesystem/BitbucketSCMFileSystem.java
81      10      src/main/java/com/cloudbees/jenkins/plugins/bitbucket/server/client/BitbucketServerAPIClient.java
4       0       src/main/java/com/cloudbees/jenkins/plugins/bitbucket/server/client/BitbucketServerApiFactory.java

The main thing seems to be class BitbucketSCMFileSystem (source, Javadoc), which extends SCMFileSystem (source, Javadoc). In contrast, the source code of Bitbucket Server Integration never mentions SCMFileSystem.

From SCM API Implementation Guide, I get the impression that SCMProbe (source, Javadoc) is an alternative to SCMFileSystem. Because the source code of Bitbucket Branch Source Plugin does not mention SCMProbe, I think Bitbucket Server Integration need not implement that.

The BitbucketServerAPIClient.getFileContent method in Bitbucket Branch Source Plugin uses the "/rest/api/1.0/projects/{owner}/repos/{repo}/browse{/path*}{?at}" (REST API doc) URI template and apparently supports UTF-8 text files only. I wonder why that was chosen instead of "/rest/api/1.0/projects/{owner}/repos/{repo}/raw{/path*}{?at}" (REST API doc), which would respond with an octet stream.

Will this ticket cover lightweight checkout for pull requests, too? See also: JENKINS-60342

This would just bring the same capability that the Bitbucket Branch Source plugin already has. Lightweight checkout for the result of merging a pull request no longer works in the Bitbucket Branch Source plugin used with Bitbucket Server (JENKINS-61493), and the Bitbucket Server Integration plugin would then have the same restriction.

I am spiking this ticket at the moment. For anyone watching/waiting on this ticket, are you interested in this feature for pipeline jobs (as opposed to Multibranch Pipeline jobs)? I have been spiking the solution and am not confident a functionally complete solution is possible given how pipeline jobs are implemented, so we're considering just releasing support for Multibranch for now. If anyone is interested in this for pipeline specifically, please file a separate ticket.
EDIT: After a bit more investigation I've confirmed it's impossible for every case, but we can do pipeline so long as the branch selector points to a single branch (no wildcards/selectors)- it appears this is what the GitSCM implementation does so we'll follow suit.

mhenschke_atlassian, what do you mean with "spiking"? I imagine it is not "5. (figuratively, journalism) To discard; to decide not to publish or make public."

kon quite the opposite! I meant spike in the sense of minimal prototyping.

what is the aftermath of the issue? Hard to see it clearly here.

Does this issue have been resolved now?

Because we still meet this issue in Bitbucket 7.21.x