Merge pull request 'The seed leaves a module as it runs today when it is held, failed or at an old-form build, and the modules held only behind it too (issue 1126)' (#127) from fix/1126-seed-oldbuild into main

go/compose/composed.go

@@ -318,6 +318,15 @@ func Stub(m catalogue.Manifest) catalogue.Manifest {
 		m.OwnsPaths = catalogue.DeclaredPaths(m)
 	}
 	m.Build = nil
+	// Nor is a template its build kept for its own files handed: a stub carries none of them (issue 1126: novox's node
+	// refused "postgres: its build kept a template for consumers, which it does not declare" with postgres held). Its
+	// items stay, and the templates they render through: a held module's contributions to other modules' collections
+	// (seat contributions, shell blocks, seat data) still reach their collectors.
+	if m.Handed != nil {
+		h := *m.Handed
+		h.Templates = nil
+		m.Handed = &h
+	}
 	var dirs []map[string]any
 	for _, r := range m.Resources {
 		if r["type"] == "directory" {

go/compose/frombus/answer.go

@@ -209,21 +209,59 @@ func Answer(ctx context.Context, r Reader, mesh Mesh, s Scope, fps map[string]st
 	return a
 }
 
-// heldAsToday moves each refusal of a module the node holds today (Scope.HeldToday) into Held: the candidate holds it as
-// the node does, which is no change (issue 1126: a seed reproduces today, and today holds it too).
-func heldAsToday(a *delivery.CandidateAnswer, today []string) {
+// heldBehind is why a module is held with a held one it reads (composeEach's dependents).
+func heldBehind(m string) string {
+	return "it reads what " + m + " contributes or listens on, and " + m + " is held"
+}
+
+// behind is the held module a refusal's words say it is held behind, or "".
+func behind(why string) string {
+	rest, ok := strings.CutPrefix(why, "it reads what ")
+	if !ok {
+		return ""
+	}
+	m, _, ok := strings.Cut(rest, " contributes or listens on, and ")
+	if !ok || why != heldBehind(m) {
+		return ""
+	}
+	return m
+}
+
+// heldAsToday moves into Held each refusal of a module the node keeps today as it runs (Scope.HeldToday, with how:
+// held, failed, running a build of the old form), and of each module held only behind one of those: the candidate keeps
+// them as the node does, which is no change (issue 1126: a seed reproduces today, and today keeps them so). Each says
+// how it stands today (ModuleRefused.Today).
+func heldAsToday(a *delivery.CandidateAnswer, today map[string]string) {
 	if len(today) == 0 {
 		return
 	}
-	kept := a.Refusals[:0]
-	for _, r := range a.Refusals {
-		if slices.Contains(today, r.Module) {
-			a.Held = append(a.Held, r)
-		} else {
-			kept = append(kept, r)
+	how := map[string]string{}
+	for m, w := range today {
+		how[m] = w
+	}
+	for moved := true; moved; {
+		moved = false
+		kept := a.Refusals[:0]
+		for _, r := range a.Refusals {
+			w, keep := how[r.Module]
+			if !keep {
+				if m := behind(r.Why); m != "" {
+					if _, behindKept := how[m]; behindKept {
+						w, keep = "held behind "+m, true
+					}
+				}
+			}
+			if keep {
+				r.Today = w
+				how[r.Module] = w
+				a.Held = append(a.Held, r)
+				moved = true
+			} else {
+				kept = append(kept, r)
+			}
 		}
+		a.Refusals = kept
 	}
-	a.Refusals = kept
 	if len(a.Refusals) == 0 {
 		a.Refusals = nil
 	}
@@ -313,7 +351,7 @@ func composeEach(in compose.Input, node string, fps map[string]string, applied b
 		// What the others read of its manifest (what it contributes, what it listens on) is its new manifest's, not
 		// necessarily the build's that runs: what reads it is held with it (review of the apply, round 2).
 		for _, r := range dependents(in, node, src[m], failed) {
-			hold(r, "it reads what "+m+" contributes or listens on, and "+m+" is held", false)
+			hold(r, heldBehind(m), false)
 		}
 	}
 	for _, m := range sortedKeys(failed) {

go/compose/frombus/answer_rows_test.go

@@ -93,17 +93,25 @@ func answerNamesEveryRefusalAndLeavesAnOldBuildToTheNode(t *testing.T) {
 	}
 	// Issue 1126: a module the node holds today that the candidate holds too is held as today, no refusal: with every
 	// refused module held today the verdict is no refusal, and each is named under Held.
-	today := Answer(ctx, b, Mesh{}, Scope{Node: "n1", Placements: given(b), HeldToday: []string{"api", "spiegel", "web"}},
+	today := Answer(ctx, b, Mesh{}, Scope{Node: "n1", Placements: given(b), HeldToday: map[string]string{"api": "held", "spiegel": "held", "web": "held"}},
 		map[string]string{"lemurs": fp("e"), "web": fp("1"), "api": fp("2"), "spiegel": fp("3")}, nil, "p-h1", 3)
 	if today.Verdict == delivery.CandidateRefused || len(today.Refusals) != 0 || len(today.Held) != 3 || today.Held[0].Why == "" {
 		t.Errorf("held as today: %+v", today)
 	}
 	// A refused module the node does not hold today stays a refusal: holding only api today leaves spiegel and web refused.
-	part := Answer(ctx, b, Mesh{}, Scope{Node: "n1", Placements: given(b), HeldToday: []string{"api"}},
+	part := Answer(ctx, b, Mesh{}, Scope{Node: "n1", Placements: given(b), HeldToday: map[string]string{"api": "held"}},
 		map[string]string{"lemurs": fp("e"), "web": fp("1"), "api": fp("2"), "spiegel": fp("3")}, nil, "p-h1", 3)
 	if part.Verdict != delivery.CandidateRefused || len(part.Refusals) != 2 || len(part.Held) != 1 || part.Held[0].Module != "api" {
 		t.Errorf("held as today in part: %+v", part)
 	}
+	// A module held only behind one kept today is kept as today too, saying behind which (novox's mailu behind de-spiegel).
+	if a := (delivery.CandidateAnswer{Refusals: []delivery.ModuleRefused{{Module: "de-spiegel", Why: "a value is unset"},
+		{Module: "mailu", Why: heldBehind("de-spiegel")}, {Module: "proxy", Why: heldBehind("mailu")}, {Module: "web", Why: "no build"}}}); true {
+		heldAsToday(&a, map[string]string{"de-spiegel": "runs a build of the old form"})
+		if len(a.Refusals) != 1 || a.Refusals[0].Module != "web" || len(a.Held) != 3 || a.Held[2].Today != "held behind mailu" {
+			t.Errorf("held behind a module kept today: %+v", a)
+		}
+	}
 
 	// The fold: spiegel runs inside the node's own composition at a build of the old form. Its resources are carried as
 	// they run, each after the one it runs after: the node's own is the one it runs, and the node composes itself.
@@ -286,6 +294,31 @@ func answerNamesEveryRefusalAndLeavesAnOldBuildToTheNode(t *testing.T) {
 	if got, want := catalogue.DeclaredPaths(compose.Carried(f1, "f1-circuits", &f1runs)), catalogue.DeclaredPaths(f1); !reflect.DeepEqual(got, want) {
 		t.Errorf("f1-circuits carried owns %v, want what the controller composes from its manifest, %v", got, want)
 	}
+	// Issue 1126: a held module hands no template its build kept for a file it no longer carries (novox's node:
+	// "postgres: its build kept a template for consumers"), but keeps its items and their templates, so what it
+	// contributes to other modules' collections still reaches them.
+	for _, row := range []struct {
+		name   string
+		handed *catalogue.Handed
+		items  []catalogue.Item
+	}{
+		{"templates and items", &catalogue.Handed{Templates: map[string]string{"consumers": "files/consumers.json"},
+			Items: map[string]string{"routes": "files/routes.tmpl"}}, []catalogue.Item{{Collection: "routes", Content: "x"}}},
+		{"items alone", nil, []catalogue.Item{{Collection: "routes", Content: "x"}}},
+	} {
+		kept := f1
+		kept.Handed, kept.Items = row.handed, row.items
+		st := compose.Stub(kept)
+		if st.Handed != nil && st.Handed.Templates != nil {
+			t.Errorf("%s: a stub hands templates %v", row.name, st.Handed.Templates)
+		}
+		if !reflect.DeepEqual(st.Items, row.items) {
+			t.Errorf("%s: a stub collects %+v, want its items %+v", row.name, st.Items, row.items)
+		}
+		if row.handed != nil && (st.Handed == nil || !reflect.DeepEqual(st.Handed.Items, row.handed.Items) || row.handed.Templates == nil) {
+			t.Errorf("%s: a stub hands item templates %+v, want %v and its manifest untouched", row.name, st.Handed, row.handed.Items)
+		}
+	}
 	var k1, k2 any
 	_ = json.Unmarshal(keptComposed, &k1)
 	_ = json.Unmarshal(keptFile, &k2)

go/compose/frombus/frombus.go

@@ -134,10 +134,10 @@ type Scope struct {
 	Placements map[string]*delivery.Placement
 	InOwn      []string
 	Running    []delivery.Composed
-	// HeldToday is, in an answer, the modules the node holds today ("node" for its own composition): their have's phase
-	// is held, or they are held inside its own composition. A candidate that holds one too holds it as today, which is
-	// said under CandidateAnswer.Held and is no refusal (issue 1126).
-	HeldToday []string
+	// HeldToday is, in an answer, the modules the node keeps today as they run ("node" for its own composition), each with
+	// how ("held", "failed", "runs a build of the old form"): a candidate that cannot compose one, or holds one only
+	// behind one of them, keeps it as today, which is said under CandidateAnswer.Held and is no refusal (issue 1126).
+	HeldToday map[string]string
 	// SameValue, in an answer, says whether two sealed values open to the same value (the node opens them with its own
 	// key), so a differing resource shows a value sealed again as such (delivery.CompareComposedWith). Nil shows them
 	// as differing.

go/compose/judge/judge.go

@@ -258,9 +258,13 @@ func Brief(p delivery.PlacementProposal, v delivery.PlacementVerdict) string {
 		if held := v.Answers[n].Held; len(held) > 0 {
 			var names []string
 			for _, h := range held {
-				names = append(names, h.Module)
+				today := h.Today
+				if today == "" {
+					today = "held"
+				}
+				names = append(names, h.Module+" ("+today+")")
 			}
-			fmt.Fprintf(&b, "; stays held as today: %s", strings.Join(names, ", "))
+			fmt.Fprintf(&b, "; stays as today: %s", strings.Join(names, ", "))
 		}
 	}
 	return b.String()

go/compose/judge/judge_test.go

@@ -79,7 +79,7 @@ func TestJudge(t *testing.T) {
 				t.Errorf("the difference is named %q", got)
 			}
 		}
-		if strings.HasPrefix(row.name, "a module held as today") && !strings.Contains(Brief(q, v), "stays held as today: spiegel") {
+		if strings.HasPrefix(row.name, "a module held as today") && !strings.Contains(Brief(q, v), "stays as today: spiegel (held)") {
 			t.Errorf("%s: the brief does not show it: %s", row.name, Brief(q, v))
 		}
 		if row.marked != "" && (!slices.Contains(v.Unintended["anchor"], row.marked) || !strings.Contains(Brief(q, v), "not computed: "+row.marked)) {

go/delivery/placement_candidate.go

@@ -190,10 +190,13 @@ type ModuleAdded struct {
 	Unissued []string `json:"unissued,omitempty"`
 }
 
-// ModuleRefused is a value missing for a module the node runs, in the words the composition stood in for it with.
+// ModuleRefused is a value missing for a module the node runs, in the words the composition stood in for it with. Today,
+// in CandidateAnswer.Held, is how the node keeps it today (held, failed, runs a build of the old form, held behind
+// another), which the candidate keeps.
 type ModuleRefused struct {
 	Module string `json:"module"`
 	Why    string `json:"why"`
+	Today  string `json:"today,omitempty"`
 }
 
 // VerdictOf is the verdict of an answer's lists: refused on any refusal, differs on any difference, addition or