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# frozen_string_literal: true
module MergeRequests
class MergeabilityCheckService < ::BaseService
include Gitlab::Utils::StrongMemoize
include Gitlab::ExclusiveLeaseHelpers
delegate :project, to: :@merge_request
delegate :repository, to: :project
def initialize(merge_request)
@merge_request = merge_request
end
# Updates the MR merge_status. Whenever it switches to a can_be_merged state,
# the merge-ref is refreshed.
#
# recheck - When given, it'll enforce a merge-ref refresh if the current merge_status is
# can_be_merged or cannot_be_merged and merge-ref is outdated.
# Given MergeRequests::RefreshService is called async, it might happen that the target
# branch gets updated, but the MergeRequest#merge_status lags behind. So in scenarios
# where we need the current state of the merge ref in repository, the `recheck`
# argument is required.
#
# retry_lease - Concurrent calls wait for at least 10 seconds until the
# lease is granted (other process finishes running). Returns an error
# ServiceResponse if the lease is not granted during this time.
#
# Returns a ServiceResponse indicating merge_status is/became can_be_merged
# and the merge-ref is synced. Success in case of being/becoming mergeable,
# error otherwise.
def execute(recheck: false, retry_lease: true)
return ServiceResponse.error(message: 'Invalid argument') unless merge_request
return ServiceResponse.error(message: 'Unsupported operation') if Gitlab::Database.read_only?
return check_mergeability(recheck) unless merge_ref_auto_sync_lock_enabled?
in_write_lock(retry_lease: retry_lease) do |retried|
# When multiple calls are waiting for the same lock (retry_lease),
# it's possible that when granted, the MR status was already updated for
# that object, therefore we reset if there was a lease retry.
merge_request.reset if retried
check_mergeability(recheck)
end
rescue FailedToObtainLockError => error
ServiceResponse.error(message: error.message)
end
private
attr_reader :merge_request
def check_mergeability(recheck)
recheck! if recheck
update_merge_status
unless merge_request.can_be_merged?
return ServiceResponse.error(message: 'Merge request is not mergeable')
end
unless merge_ref_auto_sync_enabled?
return ServiceResponse.error(message: 'Merge ref is outdated due to disabled feature')
end
unless payload.fetch(:merge_ref_head)
return ServiceResponse.error(message: 'Merge ref cannot be updated')
end
ServiceResponse.success(payload: payload)
end
# It's possible for this service to send concurrent requests to Gitaly in order
# to "git update-ref" the same ref. Therefore we handle a light exclusive
# lease here.
#
def in_write_lock(retry_lease:, &block)
lease_key = "mergeability_check:#{merge_request.id}"
lease_opts = {
ttl: 1.minute,
retries: retry_lease ? 10 : 0,
sleep_sec: retry_lease ? 1.second : 0
}
in_lock(lease_key, lease_opts, &block)
end
def payload
strong_memoize(:payload) do
{
merge_ref_head: merge_ref_head_payload
}
end
end
def merge_ref_head_payload
commit = merge_request.merge_ref_head
return unless commit
target_id, source_id = commit.parent_ids
{
commit_id: commit.id,
source_id: source_id,
target_id: target_id
}
end
def update_merge_status
return unless merge_request.recheck_merge_status?
if can_git_merge? && merge_to_ref
merge_request.mark_as_mergeable
else
merge_request.mark_as_unmergeable
end
end
def recheck!
if !merge_request.recheck_merge_status? && outdated_merge_ref?
merge_request.mark_as_unchecked
end
end
# Checks if the existing merge-ref is synced with the target branch.
#
# Returns true if the merge-ref does not exists or is out of sync.
def outdated_merge_ref?
return false unless merge_ref_auto_sync_enabled?
return false unless merge_request.open?
return true unless ref_head = merge_request.merge_ref_head
return true unless target_sha = merge_request.target_branch_sha
return true unless source_sha = merge_request.source_branch_sha
ref_head.parent_ids != [target_sha, source_sha]
end
def can_git_merge?
!merge_request.broken? && repository.can_be_merged?(merge_request.diff_head_sha, merge_request.target_branch)
end
def merge_to_ref
return true unless merge_ref_auto_sync_enabled?
result = MergeRequests::MergeToRefService.new(project, merge_request.author).execute(merge_request)
result[:status] == :success
end
def merge_ref_auto_sync_enabled?
Feature.enabled?(:merge_ref_auto_sync, project, default_enabled: true)
end
def merge_ref_auto_sync_lock_enabled?
Feature.enabled?(:merge_ref_auto_sync_lock, project, default_enabled: true)
end
end
end
|
