[MM-63561] - Job server: Fix read after write (#32527)

* fix read after write

* clean up tests

server/channels/jobs/jobs.go

@@ -253,12 +253,7 @@ func (srv *JobServer) RequestCancellation(rctx request.CTX, jobId string) *model
 	}
 	if newJob != nil {
 		if srv.metrics != nil {
-			job, err := srv.GetJob(rctx, jobId)
-			if err != nil {
-				return model.NewAppError("RequestCancellation", "app.job.update.app_error", nil, "", http.StatusInternalServerError).Wrap(err)
-			}
-
-			srv.metrics.DecrementJobActive(job.Type)
+			srv.metrics.DecrementJobActive(newJob.Type)
 		}
 
 		return nil

server/channels/jobs/jobs_test.go

@@ -10,13 +10,11 @@ import (
 	"os"
 	"testing"
 
-	"github.com/stretchr/testify/mock"
 	"github.com/stretchr/testify/require"
 
 	"github.com/mattermost/mattermost/server/public/model"
 	"github.com/mattermost/mattermost/server/public/shared/mlog"
 	"github.com/mattermost/mattermost/server/public/shared/request"
-	"github.com/mattermost/mattermost/server/v8/channels/store"
 	"github.com/mattermost/mattermost/server/v8/channels/store/storetest"
 	"github.com/mattermost/mattermost/server/v8/channels/utils/testutils"
 	"github.com/mattermost/mattermost/server/v8/einterfaces/mocks"
@@ -641,17 +639,9 @@ func TestRequestCancellation(t *testing.T) {
 	t.Run("cancelled, job not found", func(t *testing.T) {
 		jobServer, mockStore, _ := makeJobServer(t)
 
-		job := &model.Job{
-			Id:   "job_id",
-			Type: "job_type",
-		}
-
 		mockStore.JobStore.
 			On("UpdateStatusOptimistically", "job_id", model.JobStatusPending, model.JobStatusCanceled).
-			Return(job, nil)
-		mockStore.JobStore.
-			On("Get", mock.AnythingOfType("*request.Context"), "job_id").
-			Return(nil, &store.ErrNotFound{})
+			Return(nil, errors.New("failed to update Job with id=job_id"))
 
 		err := jobServer.RequestCancellation(ctx, "job_id")
 		expectErrorId(t, "app.job.update.app_error", err)
@@ -668,9 +658,6 @@ func TestRequestCancellation(t *testing.T) {
 		mockStore.JobStore.
 			On("UpdateStatusOptimistically", "job_id", model.JobStatusPending, model.JobStatusCanceled).
 			Return(job, nil)
-		mockStore.JobStore.
-			On("Get", mock.AnythingOfType("*request.Context"), "job_id").
-			Return(job, nil)
 		mockMetrics.On("DecrementJobActive", "job_type")
 
 		err := jobServer.RequestCancellation(ctx, "job_id")