node-tools/internal/launch/launch.go

@@ -345,6 +345,7 @@ func Start(module, entry string, env []string, mesh Bus, logf func(string, ...an
 					go func(m message) {
 						var result any = map[string]any{}
 						var err error
+						asked := time.Now()
 						switch m.Method {
 						case "mesh/publish":
 							err = mesh.Publish(m.Params)
@@ -479,6 +480,14 @@ func Start(module, entry string, env []string, mesh Bus, logf func(string, ...an
 							}
 							return
 						}
+						// A state or log operation the bus refused or let time out reaches a caller as a call that
+						// does not answer: say it here, with how long it took, so the next hang is readable.
+						// A lost compare-and-set is the normal answer of two writers to one key, retried by its caller: not said.
+						if err != nil && errorCode(err) != CodeChanged && (strings.HasPrefix(m.Method, "mesh/state.") ||
+							strings.HasPrefix(m.Method, "mesh/log.") || busStateCalls[m.Method]) {
+							logf("[mesh-tools] %s's bundle asked %s and it failed after %s: %v", module, m.Method,
+								time.Since(asked).Round(time.Millisecond), err)
+						}
 						if len(m.ID) == 0 {
 							return
 						}

node-tools/internal/launch/state_failed_test.go

@@ -0,0 +1,75 @@
+package launch
+
+import (
+	"encoding/json"
+	"errors"
+	"fmt"
+	"os"
+	"path/filepath"
+	"strings"
+	"testing"
+	"time"
+)
+
+// changedError is a lost compare-and-set as the bus answers it: told by its code (novox/hq ADR 0259).
+type changedError struct{}
+
+func (changedError) Error() string  { return "the key changed since revision 3" }
+func (changedError) ErrorCode() int { return CodeChanged }
+
+// refusingState answers the state "lost" with a lost compare-and-set and every other state with a time-out.
+type refusingState struct{ subscribing }
+
+func (*refusingState) State(_ string, params json.RawMessage) (json.RawMessage, error) {
+	if strings.Contains(string(params), `"state":"lost"`) {
+		return nil, changedError{}
+	}
+	return nil, errors.New("the bus did not answer in 10s")
+}
+
+// A bundle that asks the runtime for the state "lost" once it is started, and for the state "copied" once that is
+// answered, so the first answer's handling has ended before the second is asked.
+const askingBundle = `#!/bin/sh
+while IFS= read -r line; do
+  id=$(printf '%s' "$line" | sed -n 's/.*"id":\([0-9]*\)[,}].*/\1/p')
+  case "$line" in
+    *'"method":"initialize"'*) printf '{"jsonrpc":"2.0","id":%s,"result":{}}\n' "$id" ;;
+    *'"method":"tools/list"'*) printf '{"jsonrpc":"2.0","id":%s,"result":{"tools":[]}}\n' "$id"
+       printf '{"jsonrpc":"2.0","id":"q1","method":"mesh/state.update","params":{"state":"lost","key":"k"}}\n' ;;
+    *'"id":"q1"'*) printf '{"jsonrpc":"2.0","id":"q2","method":"mesh/state.get","params":{"state":"copied","key":"k"}}\n' ;;
+  esac
+done
+`
+
+// A state operation the bus refuses or lets time out is said in the runtime's log with its method, its bundle and its
+// time (issue 1966: a hand-act seat whose calls hung said nothing); a lost compare-and-set, asked first, is not.
+func TestAFailedStateOperationIsSaidInTheRuntimesLog(t *testing.T) {
+	dir := t.TempDir()
+	entry := filepath.Join(dir, "bundle")
+	if err := os.WriteFile(entry, []byte(askingBundle), 0o755); err != nil {
+		t.Fatal(err)
+	}
+	said := make(chan string, 16)
+	logf := func(f string, a ...any) { said <- fmt.Sprintf(f, a...) }
+	l, err := Start("asker", entry, os.Environ(), &refusingState{}, logf)
+	if err != nil {
+		t.Fatal(err)
+	}
+	t.Cleanup(l.Stop)
+	var heard []string
+	timeout := time.After(5 * time.Second)
+	for {
+		select {
+		case line := <-said:
+			heard = append(heard, line)
+			if strings.Contains(line, "mesh/state.update") {
+				t.Fatalf("a lost compare-and-set was said as a failure: %q", line)
+			}
+			if strings.Contains(line, "asker's bundle asked mesh/state.get and it failed after") && strings.Contains(line, "did not answer in 10s") {
+				return
+			}
+		case <-timeout:
+			t.Fatalf("the failed state operation was not said; the log: %v", heard)
+		}
+	}
+}