move mutex to Job

Makes more sense since it is the data object being modified, and although the synthetic test was passing in prev commit the actual tests w/ data race detector were still tripping.  This suggests multiple RunContext objects are in-use with the same Job, which the test has been updated to represent.

act/model/workflow.go

@@ -11,6 +11,7 @@ import (
 	"slices"
 	"strconv"
 	"strings"
+	"sync"
 
 	"code.forgejo.org/forgejo/runner/v9/act/common"
 	"code.forgejo.org/forgejo/runner/v9/act/schema"
@@ -217,7 +218,9 @@ type Job struct {
 	Uses           string                    `yaml:"uses"`
 	With           map[string]any            `yaml:"with"`
 	RawSecrets     yaml.Node                 `yaml:"secrets"`
-	Result         string
+
+	Result      string
+	ResultMutex sync.Mutex
 }
 
 // Strategy for the job

act/runner/job_executor.go

@@ -164,8 +164,8 @@ func setJobResult(ctx context.Context, info jobInfo, rc *RunContext, success boo
 
 	// As we're reading the matrix build's status (`rc.Run.Job().Result`), it's possible for it change in another
 	// goroutine running `setJobResult` and invoking `.result(...)`. Prevent concurrent execution of `setJobResult`...
-	rc.JobResultMutex.Lock()
-	defer rc.JobResultMutex.Unlock()
+	rc.Run.Job().ResultMutex.Lock()
+	defer rc.Run.Job().ResultMutex.Unlock()
 
 	jobResult := "success"
 	// we have only one result for a whole matrix build, so we need

act/runner/job_executor_test.go

@@ -338,14 +338,26 @@ func TestJobExecutorNewJobExecutor(t *testing.T) {
 
 func TestSetJobResultConcurrency(t *testing.T) {
 	jim := &jobInfoMock{}
-	rc := &RunContext{
+	job := model.Job{
+		Result: "success",
+	}
+	// Distinct RunContext objects are used to replicate realistic setJobResult in matrix build
+	rc1 := &RunContext{
 		Run: &model.Run{
 			JobID: "test",
 			Workflow: &model.Workflow{
 				Jobs: map[string]*model.Job{
-					"test": {
-						Result: "success",
-					},
+					"test": &job,
+				},
+			},
+		},
+	}
+	rc2 := &RunContext{
+		Run: &model.Run{
+			JobID: "test",
+			Workflow: &model.Workflow{
+				Jobs: map[string]*model.Job{
+					"test": &job,
 				},
 			},
 		},
@@ -374,7 +386,7 @@ func TestSetJobResultConcurrency(t *testing.T) {
 		if result == "success" {
 			time.Sleep(1 * time.Second)
 		}
-		rc.Run.Job().Result = result
+		job.Result = result
 		lastResult = result
 	})
 
@@ -383,12 +395,12 @@ func TestSetJobResultConcurrency(t *testing.T) {
 	// Goroutine 1, mark as success:
 	go func() {
 		defer wg.Done()
-		setJobResult(t.Context(), jim, rc, true)
+		setJobResult(t.Context(), jim, rc1, true)
 	}()
 	// Goroutine 2, mark as failure:
 	go func() {
 		defer wg.Done()
-		setJobResult(t.Context(), jim, rc, false)
+		setJobResult(t.Context(), jim, rc2, false)
 	}()
 	wg.Wait()
 

act/runner/run_context.go

@@ -18,7 +18,6 @@ import (
 	"regexp"
 	"runtime"
 	"strings"
-	"sync"
 	"text/template"
 	"time"
 
@@ -57,8 +56,6 @@ type RunContext struct {
 	randomName          string
 	networkName         string
 	networkCreated      bool
-
-	JobResultMutex sync.Mutex
 }
 
 func (rc *RunContext) AddMask(mask string) {