F3: mesh-build-go and mesh-build-node follow the drops other holders write, and a module with no watch says so (ADR 0664 §4, issue 1748 review 1)

Claude-Session: https://claude.ai/code/session_01JG73KEq4zoDfM9WtYpcQgZ

modules/mesh-build-go/buildstep/pull_drop.go

@@ -90,6 +90,7 @@ func (p *Puller) Drop(id, by, why string) error {
 // the pull then refuses a dropped ask but cannot end a running one.
 func (p *Puller) watchDrops() {
 	if p.WatchPauses == nil {
+		p.logf("no watch of the drops in the pauses of %s is set: a dropped ask that runs here is not ended, only refused when it is pulled", p.Node)
 		return
 	}
 	err := p.WatchPauses(sdkstep.DroppedPrefix+"**", func(ch stdio.StateChange) error {

modules/mesh-build-go/buildstep/pull_seat_test.go

@@ -132,6 +132,12 @@ func TestADroppedAskIsRefusedAtPullAndARunningOneIsEnded(t *testing.T) {
 	fresh, _ := json.Marshal(nodebuildgo.Drop{V: int64(sdkstep.Version), Why: "fresh", At: ptr(time.Now())})
 	kv.put(sdkstep.DropKey("old"), json.RawMessage(old))
 	kv.put(sdkstep.DropKey("fresh"), json.RawMessage(fresh))
+	// Review 1: a module that sets no watch of the drops says so (a dropped ask running here is then not ended).
+	var said []string
+	(&Puller{Node: "shanks", Logf: func(f string, a ...any) { said = append(said, fmt.Sprintf(f, a...)) }}).watchDrops()
+	if len(said) != 1 || !strings.Contains(said[0], "no watch of the drops") {
+		t.Errorf("a puller with no watch said %q", said)
+	}
 	p := &Puller{Load: kv.load, ForgetPause: kv.forget, PauseKeys: kv.keys}
 	p.sweepDropped()
 	if keys, _ := kv.keys(); len(keys) != 1 || keys[0] != sdkstep.DropKey("fresh") {

modules/mesh-build-go/cmd/mesh-build-go/main.go

@@ -45,6 +45,7 @@ func main() {
 		Pauses:              stdio.State(sdkstep.PausesState).Put,
 		ReadPauses:          readOf(stdio.State(sdkstep.PausesState)),
 		ForgetPause:         stdio.State(sdkstep.PausesState).Delete,
+		WatchPauses:         stdio.State(sdkstep.PausesState).Watch,
 		ReadToolchainsState: readOf(stdio.State(seat.StateToolchains)),
 		Ctx:                 ctx,
 		Say:                 logf,

modules/mesh-build-go/cmd/mesh-build-go/module_test.go

@@ -4,6 +4,7 @@ import (
 	"context"
 	"encoding/json"
 	"errors"
+	"os"
 	"strings"
 	"sync"
 	"testing"
@@ -198,3 +199,15 @@ func TestParseGoVersion(t *testing.T) {
 		t.Errorf("accepted a text that is not `go version`'s")
 	}
 }
+
+// ADR 0664 §4 (issue 1748, review 1): the module follows the drops other holders write in the shared pauses state, or a drop
+// served by another node would never end a step running here. main wires the watch.
+func TestMainWiresTheWatchOfTheDrops(t *testing.T) {
+	raw, err := os.ReadFile("main.go")
+	if err != nil {
+		t.Fatal(err)
+	}
+	if !strings.Contains(string(raw), "WatchPauses:") {
+		t.Error("main.go does not set Module.WatchPauses: a drop written by another holder would not end a running step")
+	}
+}

modules/mesh-build-node/cmd/mesh-build-node/main.go

@@ -51,6 +51,7 @@ func main() {
 		Pauses:              stdio.State(sdkstep.PausesState).Put,
 		ReadPauses:          readOf(stdio.State(sdkstep.PausesState)),
 		ForgetPause:         stdio.State(sdkstep.PausesState).Delete,
+		WatchPauses:         stdio.State(sdkstep.PausesState).Watch,
 		ReadToolchainsState: readOf(stdio.State(seat.StateToolchains)),
 		Work:                WorkDir,
 		Run:                 dforgekey.ExecRunnerClean(0),

modules/mesh-build-node/cmd/mesh-build-node/module_test.go

@@ -228,3 +228,15 @@ func TestParseNodeVersion(t *testing.T) {
 		t.Errorf("accepted a text that is not `node --version`'s")
 	}
 }
+
+// ADR 0664 §4 (issue 1748, review 1): the module follows the drops other holders write in the shared pauses state, or a drop
+// served by another node would never end a step running here. main wires the watch.
+func TestMainWiresTheWatchOfTheDrops(t *testing.T) {
+	raw, err := os.ReadFile("main.go")
+	if err != nil {
+		t.Fatal(err)
+	}
+	if !strings.Contains(string(raw), "WatchPauses:") {
+		t.Error("main.go does not set Module.WatchPauses: a drop written by another holder would not end a running step")
+	}
+}