direct: Fix cycle error message (#3469)

Author: denik

acceptance/bundle/resource_deps/loop_jobs/out.deploy.direct-exp.txt

@@ -1,5 +1,5 @@
 Uploading bundle files to /Workspace/Users/[USERNAME]/.bundle/test-bundle/default/files...
-Error: cycle detected: jobs.bar refers to jobs.foo via ${resources.jobs.bar.id} which refers to jobs.bar via ${resources.jobs.foo.id}
+Error: cycle detected: jobs.foo refers to jobs.bar via ${resources.jobs.bar.id} which refers to jobs.foo via ${resources.jobs.foo.id}
 
 
 Exit code (musterr): 1

acceptance/bundle/resource_deps/loop_jobs/out.plan.direct-exp.txt

@@ -1,4 +1,4 @@
-Error: cycle detected: jobs.bar refers to jobs.foo via ${resources.jobs.bar.id} which refers to jobs.bar via ${resources.jobs.foo.id}
+Error: cycle detected: jobs.foo refers to jobs.bar via ${resources.jobs.bar.id} which refers to jobs.foo via ${resources.jobs.foo.id}
 
 
 Exit code (musterr): 1

libs/dagrun/dagrun.go

@@ -65,16 +65,16 @@ func (e *CycleError[N]) Error() string {
 		return fmt.Sprintf("cycle detected: %v refers to itself via %s", e.Nodes[0], e.Edges[0])
 	}
 
-	// Build "A refers to B via E1" pieces for every edge except the closing one.
+	// Build "to refers to from via edge" pieces for every edge except the closing one.
 	var parts []string
 	for i := 1; i < len(e.Nodes); i++ {
-		parts = append(parts, fmt.Sprintf("%v refers to %v via %s", e.Nodes[i-1], e.Nodes[i], e.Edges[i-1]))
+		parts = append(parts, fmt.Sprintf("%v refers to %v via %s", e.Nodes[i], e.Nodes[i-1], e.Edges[i-1]))
 	}
 
 	return fmt.Sprintf(
 		"cycle detected: %s which refers to %v via %s",
 		strings.Join(parts, " "),
-		e.Nodes[0],
+		e.Nodes[len(e.Nodes)-1],
 		e.Edges[len(e.Edges)-1],
 	)
 }

libs/dagrun/dagrun_test.go

@@ -77,7 +77,7 @@ func TestRun_VariousGraphsAndPools(t *testing.T) {
 				{"A", "B", "${A.id}"},
 				{"B", "A", "${B.id}"},
 			},
-			cycle: "cycle detected: A refers to B via ${A.id} which refers to A via ${B.id}",
+			cycle: "cycle detected: B refers to A via ${A.id} which refers to B via ${B.id}",
 		},
 		{
 			name: "three-node cycle",
@@ -86,7 +86,7 @@ func TestRun_VariousGraphsAndPools(t *testing.T) {
 				{"Y", "Z", "e2"},
 				{"Z", "X", "e3"},
 			},
-			cycle: "cycle detected: X refers to Y via e1 Y refers to Z via e2 which refers to X via e3",
+			cycle: "cycle detected: Y refers to X via e1 Z refers to Y via e2 which refers to Z via e3",
 		},
 		{
 			name:         "downstream runs with failed dependency",