support for removing source branch on GitLab merge requests

Author: Ender Tunc

modules/core/src/main/scala/org/scalasteward/core/application/Cli.scala

@@ -280,8 +280,16 @@ object Cli {
       "When set, the number of required reviewers for a merge request will be set to this number (non-negative integer).  Is only used in the context of gitlab-merge-when-pipeline-succeeds being enabled, and requires that the configured access token have the appropriate privileges.  Also requires a Gitlab Premium subscription."
     ).validate("Required reviewers must be non-negative")(_ >= 0).orNone
 
+  private val gitlabRemoveSourceBranch: Opts[Boolean] =
+    flag(
+      "gitlab-remove-source-branch",
+      "Flag indicating if a merge request should remove the source branch when merging."
+    ).orFalse
+
   private val gitLabCfg: Opts[GitLabCfg] =
-    (gitlabMergeWhenPipelineSucceeds, gitlabRequiredReviewers).mapN(GitLabCfg.apply)
+    (gitlabMergeWhenPipelineSucceeds, gitlabRequiredReviewers, gitlabRemoveSourceBranch).mapN(
+      GitLabCfg.apply
+    )
 
   private val githubAppId: Opts[Long] =
     option[Long](

modules/core/src/main/scala/org/scalasteward/core/application/Config.scala

@@ -158,7 +158,8 @@ object Config {
 
   final case class GitLabCfg(
       mergeWhenPipelineSucceeds: Boolean,
-      requiredReviewers: Option[Int]
+      requiredReviewers: Option[Int],
+      removeSourceBranch: Boolean
   ) extends ForgeSpecificCfg
 
   final case class GiteaCfg(

modules/core/src/main/scala/org/scalasteward/core/forge/gitlab/GitLabApiAlg.scala

@@ -40,6 +40,7 @@ final private[gitlab] case class MergeRequestPayload(
     assignee_ids: Option[List[Int]],
     reviewer_ids: Option[List[Int]],
     target_project_id: Long,
+    remove_source_branch: Boolean,
     source_branch: String,
     target_branch: Branch
 )
@@ -49,7 +50,8 @@ private[gitlab] object MergeRequestPayload {
       id: String,
       projectId: Long,
       data: NewPullRequestData,
-      usernamesToUserIdsMapping: Map[String, Int]
+      usernamesToUserIdsMapping: Map[String, Int],
+      removeSourceBranch: Boolean
   ): MergeRequestPayload = {
     val assignees = data.assignees.flatMap(usernamesToUserIdsMapping.get)
     val reviewers = data.reviewers.flatMap(usernamesToUserIdsMapping.get)
@@ -61,6 +63,7 @@ private[gitlab] object MergeRequestPayload {
       reviewer_ids = Option.when(reviewers.nonEmpty)(reviewers),
       labels = Option.when(data.labels.nonEmpty)(data.labels),
       target_project_id = projectId,
+      remove_source_branch = removeSourceBranch,
       source_branch = data.head,
       target_branch = data.base
     )
@@ -188,7 +191,8 @@ final class GitLabApiAlg[F[_]: Parallel](
         id = url.encodedProjectId(targetRepo),
         projectId = projectId.id,
         data = data,
-        usernamesToUserIdsMapping = usernameMapping
+        usernamesToUserIdsMapping = usernameMapping,
+        removeSourceBranch = gitLabCfg.removeSourceBranch
       )
       res <- client.postWithBody[MergeRequestOut, MergeRequestPayload](
         uri = url.mergeRequest(targetRepo),