TeamCity / Bitbucket Server pull request with multiple VCS roots

Question

I am using TeamCity Enterprise 2021.2 (build 99542) and Bitbucket Server v7.14.0. I have a build configuration in Teamcity with 3 VCS roots: Repo1, Repo2, and Repo3. Each repo has a "main" branch, which is the default branch for all 3 repos. Repo 1 and 2 have a branch called "feature1".

If I set the branch specification in all 3 repos to refs/heads/* and set up a VCS trigger to Repo1 with the filter as +:* the desired behavior is achieved. A build is triggered when a change is made to feature1 in Repo1, and the build checks out feature1 on both Repo1 and Repo2, while main is checked out on repo3.

The problem is that I only want to trigger a build when a pull request is created or updated in Repo1. So, I use the Pull Request build feature to trigger with any pull request in Repo1, and set the branch specification in Repo1 to refs/heads/main (so duplicate builds aren't triggered) This results in almost the desired behavior.

I create a PR for feature 1 in Repo1 in bitbucket. And a build is triggered. The problem is that feature1 is only checked out in Repo1 but NOT Repo2. Is there any way to configure a VCS root for Repo2 to check out the same branch that is being used on Repo1 while builds are being triggered by PRs to Repo1?

I suspect the problem is related to some of the TeamCity build configuration variables. In the first case with the expected behavior, teamcity.build.branch is set to refs/heads/feature1. yay. In the second case, teamcity.build.branch is set to pull-requests/## while teamcity.pullRequest.source.branch is set to feature1.

Answer 1

It is not even a problem of variables, but a problem of the build (logical) branch.

If you are using the Pull Requests build feature it (internally) expands the branch spec of the VCS root in the context of your build configuration with patterns that include refs/pull-requests/123/from kind of branches provided by Bitbucket Server for pull requests. So the logical branch name for the build becomes pull-requests/123, not a source branch of the pull request. As other repos do not have such pull requests in them, for them default VCS branches are selected. Which is in most cases ok, as such things as multi-repo pull requests are not supported by any VCS hosting. Not in my knowledge at least. In our opinion in most cases the following improvement could be useful for many users: to fall back to a VCS branches that match the target branch of the pull request instead of the default branch of the VCS root. This is to be discussed if such feature requests appear.

Anyway your case is different and it seems you want to use source branches in all three repos. If the following feature request is fulfilled it may satisfy your needs: https://youtrack.jetbrains.com/issue/TW-70491 We are currently working on it and it may appear as an experimental feature in one of our bugfix releases soon and as a proper feature in the next feature release this year. Please follow that issue to keep updated.

Cheers, Anton