merge_into_manifest: remove canceling of pipelines

The canceling was required when a reintegration was necessary before merging. The instant merge afterwards deleted the integration branch, so the pipeline on the branch would fail, because repo cannot checkout the code anymore. With minimal-manifest!126 we started checking out code using refs/pipelines/<id> instead of explicit branch/tag names. This ref still exists when the branch is already deleted (see https://docs.gitlab.com/ce/ci/pipelines/#ref-specs-for-runners), so the pipeline canceling is not necessary anymore.

merge_into_manifest.py

@@ -100,30 +100,6 @@ def merge_into_manifest(manifest_project, master_branch, project, commit):
 
     print("Successfully merged")
 
-    # Check if there is a running pipeline on the integration branch and cancel it.
-    # This happens when a reintegration was necessary before merging. The instant
-    # merge afterwards deletes the integration branch, so the pipeline on the branch
-    # will fail, because repo cannot checkout the code anymore. In order not to
-    # confuse people, we better cancel it. Since there is a pipeline running on the
-    # master after merging, we don't need the branch results anyway.
-    try:
-        pipelines = manifest_project.pipelines.list(
-            sha=manifest_revision,
-            ref=integration_branch,
-            retry_transient_errors=True,
-        )
-    except GitlabGetError:
-        print("WARNING: could not list pipelines for project '%s'" % project.name)
-    if pipelines:
-        pipeline = pipelines[0]
-        if pipeline.status in common.pending_states:
-            pipeline.cancel()
-            print(
-                "Cancelling running pipeline for integration branch '%s':"
-                % integration_branch
-            )
-            print(pipeline.web_url)
-
     return manifest_revision