Release an ask's workspace when its job ends, so a pulled build or check leaves nothing for the sweep (issue 1887 A3go, ADR 0509)

go/buildstep/askrun.go

@@ -29,7 +29,10 @@ type AskSteps struct {
 	// Kept looks up a kept verdict by level and digest (the checker's kept bucket, delivery.KeptKey): whether one is
 	// kept and how many tests it counted. Nil takes none.
 	Kept func(ctx context.Context, level, digest string) (tests int, found bool, err error)
-	Logf func(format string, args ...any)
+	// Release removes a workspace once the ask's steps on it ended (the module's release tool's body); nil leaves it to
+	// the module's sweep.
+	Release func(workspace string) error
+	Logf    func(format string, args ...any)
 }
 
 // RunAsk runs ask's job with steps and answers a delivery.BuildAnswer or a delivery.CheckAnswer.
@@ -92,6 +95,7 @@ func (s AskSteps) build(ctx context.Context, job delivery.BuildJob) (any, error)
 		answer.Toolchain = &tc
 	}
 	var f fetched
+	defer func() { s.release(f.Workspace) }()
 	for _, a := range job.Artifacts {
 		if a.From == "" && f.Workspace == "" {
 			r, got, err := s.fetch(ctx, job.Fetch)
@@ -153,6 +157,7 @@ func (s AskSteps) check(ctx context.Context, job delivery.CheckJob) (any, error)
 	if err != nil {
 		return nil, err
 	}
+	defer s.release(f.Workspace)
 	answer := delivery.CheckAnswer{Fetch: r}
 	if len(f.Conflicts) > 0 {
 		return answer, nil // the asker reads the conflict from the fetch's answer: a verdict, not an error
@@ -240,6 +245,16 @@ func (s AskSteps) check(ctx context.Context, job delivery.CheckJob) (any, error)
 	return answer, nil
 }
 
+// release removes an ask's workspace, saying a failure: the module's sweep removes it later.
+func (s AskSteps) release(workspace string) {
+	if workspace == "" || s.Release == nil {
+		return
+	}
+	if err := s.Release(workspace); err != nil && s.Logf != nil {
+		s.Logf("the workspace %s is left to the sweep: %v", workspace, err)
+	}
+}
+
 // plan digests the level and takes the kept verdicts: the packages left to test, or all when the level runs whole (a
 // try of some tests, or a digest that named nothing).
 func (s AskSteps) plan(ctx context.Context, job delivery.CheckJob, f fetched, withRunner func(map[string]any) map[string]any, answer *delivery.CheckAnswer) ([]string, bool, error) {

go/buildstep/askrun_test.go

@@ -68,7 +68,10 @@ func ask(job any) delivery.StepAsk {
 // fetch, and answers each artifact's digest and reference.
 func TestRunAskBuilds(t *testing.T) {
 	r := &recorder{fetch: map[string]any{"workspace": "/w/1"}}
-	out, err := RunAsk(context.Background(), r.steps(), ask(delivery.BuildJob{Module: "m", Path: "modules/m", Publish: true,
+	steps := r.steps()
+	var released []string
+	steps.Release = func(ws string) error { released = append(released, ws); return nil }
+	out, err := RunAsk(context.Background(), steps, ask(delivery.BuildJob{Module: "m", Path: "modules/m", Publish: true,
 		Fetch:     map[string]any{"repository": "novox/x", "commit": runCommit},
 		Artifacts: []delivery.AskArtifact{{Artifact: "base", From: "registry/b@sha256:00"}, {Artifact: "bundle"}, {Artifact: "lib"}}}))
 	if err != nil {
@@ -82,6 +85,9 @@ build {"artifact":"lib","module":"modules/m","publish":true,"workspace":"/w/1"}`
 	if got != want {
 		t.Fatalf("calls:\n%s\nwant:\n%s", got, want)
 	}
+	if len(released) != 1 || released[0] != "/w/1" {
+		t.Errorf("released %v, want the one workspace", released)
+	}
 	a := out.(delivery.BuildAnswer)
 	if len(a.Artifacts) != 3 || a.Artifacts[1].Reference != "artifact-store://bundle" {
 		t.Fatalf("answer %+v", a)