Merge branch 'undo-revert-of-4892' into 'master'

Revert "Revert "Merge branch '18193-developers-can-merge' into 'master'""

## What does this MR do?

Reverts the revert of !4892 which lacked an EE MR at the time. This has been done in gitlab-org/gitlab-ee!564.

## What are the relevant issue numbers?

Closes #19872.

See merge request !5310

5 files changed, 9 insertions, 6 deletions

diff --git a/app/services/commits/change_service.rb b/app/services/commits/change_service.rb
index c578097376a..ed73d8cb8c2 100644
--- a/app/services/commits/change_service.rb
+++ b/app/services/commits/change_service.rb
@@ -23,7 +23,7 @@ module Commits
     private
 
     def check_push_permissions
-      allowed = ::Gitlab::GitAccess.new(current_user, project, 'web').can_push_to_branch?(@target_branch)
+      allowed = ::Gitlab::UserAccess.new(current_user, project: project).can_push_to_branch?(@target_branch)
 
       unless allowed
         raise ValidationError.new('You are not allowed to push into this branch')
@@ -31,7 +31,7 @@ module Commits
 
       true
     end
-    
+
     def create_target_branch(new_branch)
       # Temporary branch exists and contains the change commit
       return success if repository.find_branch(new_branch)
diff --git a/app/services/files/base_service.rb b/app/services/files/base_service.rb
index 37c5e321b39..55da949f56a 100644
--- a/app/services/files/base_service.rb
+++ b/app/services/files/base_service.rb
@@ -42,7 +42,7 @@ module Files
     end
 
     def validate
-      allowed = ::Gitlab::GitAccess.new(current_user, project, 'web').can_push_to_branch?(@target_branch)
+      allowed = ::Gitlab::UserAccess.new(current_user, project: project).can_push_to_branch?(@target_branch)
 
       unless allowed
         raise_error("You are not allowed to push into this branch")
diff --git a/app/services/git_push_service.rb b/app/services/git_push_service.rb
index a886f35981f..e02b50ff9a2 100644
--- a/app/services/git_push_service.rb
+++ b/app/services/git_push_service.rb
@@ -89,7 +89,8 @@ class GitPushService < BaseService
     # Set protection on the default branch if configured
     if current_application_settings.default_branch_protection != PROTECTION_NONE
       developers_can_push = current_application_settings.default_branch_protection == PROTECTION_DEV_CAN_PUSH ? true : false
-      @project.protected_branches.create({ name: @project.default_branch, developers_can_push: developers_can_push })
+      developers_can_merge = current_application_settings.default_branch_protection == PROTECTION_DEV_CAN_MERGE ? true : false
+      @project.protected_branches.create({ name: @project.default_branch, developers_can_push: developers_can_push, developers_can_merge: developers_can_merge })
     end
   end
 
diff --git a/app/services/merge_requests/merge_service.rb b/app/services/merge_requests/merge_service.rb
index f1b1d90c457..0dac0614141 100644
--- a/app/services/merge_requests/merge_service.rb
+++ b/app/services/merge_requests/merge_service.rb
@@ -34,7 +34,7 @@ module MergeRequests
         committer: committer
       }
 
-      commit_id = repository.merge(current_user, merge_request.diff_head_sha, merge_request.target_branch, options)
+      commit_id = repository.merge(current_user, merge_request, options)
       merge_request.update(merge_commit_sha: commit_id)
     rescue GitHooksService::PreReceiveError => e
       merge_request.update(merge_error: e.message)
@@ -43,6 +43,8 @@ module MergeRequests
       merge_request.update(merge_error: "Something went wrong during merge")
       Rails.logger.error(e.message)
       false
+    ensure
+      merge_request.update(in_progress_merge_commit_sha: nil)
     end
 
     def after_merge
diff --git a/app/services/merge_requests/refresh_service.rb b/app/services/merge_requests/refresh_service.rb
index b11ecd97a57..1daf6bbf553 100644
--- a/app/services/merge_requests/refresh_service.rb
+++ b/app/services/merge_requests/refresh_service.rb
@@ -48,7 +48,7 @@ module MergeRequests
     end
 
     def force_push?
-      Gitlab::ForcePushCheck.force_push?(@project, @oldrev, @newrev)
+      Gitlab::Checks::ForcePush.force_push?(@project, @oldrev, @newrev)
     end
 
     # Refresh merge request diff if we push to source or target branch of merge request