A7 V-9: a part's first views say its own build (own-build beside their list, kept at start by a process)

Builds: design 47 G §674, §424, §519
Claude-Session: https://claude.ai/code/session_01NcbgfGKaxw984XyAPfLm4h

go/views/ownbuild.go

@@ -0,0 +1,44 @@
+package views
+
+import (
+	"context"
+	"encoding/json"
+	"os"
+
+	"git.novox.be/novox/mesh-sdk/go/process"
+)
+
+// OwnBuildKey is where a process keeps its own build in its state `first-views`, and the field both answers of a part's
+// first views carry beside their list (design 47 G §674, §424, §519): the fingerprint the node-engine composed into
+// the part's environment, or OwnBuildUnknown when it carries none.
+const OwnBuildKey = "own-build"
+
+// OwnBuildUnknown is what a part's first views say of its own build when its environment carries no fingerprint.
+const OwnBuildUnknown = "unknown"
+
+func ownBuildWord(b process.Build) string {
+	if b.Fingerprint == "" {
+		return OwnBuildUnknown
+	}
+	return b.Fingerprint
+}
+
+// ownBuild is the build this reader's bundle was composed with, read from its environment at each answer.
+func (r *Reader) ownBuild() process.Build {
+	getenv := r.Getenv
+	if getenv == nil {
+		getenv = os.Getenv
+	}
+	return process.ReadOwnBuild(getenv)
+}
+
+// KeepOwnBuild writes a process's own build at OwnBuildKey of kv (its state `first-views`) at its start, for its tools
+// bundle's status tool to read (design 47 G §674).
+func KeepOwnBuild(ctx context.Context, kv interface {
+	Put(ctx context.Context, key string, value []byte) (uint64, error)
+}, b process.Build, logf func(string, ...any)) {
+	data, _ := json.Marshal(ownBuildWord(b))
+	if _, err := kv.Put(ctx, OwnBuildKey, data); err != nil && logf != nil {
+		logf("views: the own build is not kept in %s: %v", StatusState, err)
+	}
+}

go/views/process_reader.go

@@ -833,6 +833,7 @@ func (r *ProcessReader) Start(ctx context.Context, js jetstream.JetStream, cred
 	var said func(Status)
 	if status != nil {
 		status.Ready(func(kv jetstream.KeyValue) {
+			KeepOwnBuild(ctx, kv, process.OwnBuild(), r.logf)
 			if err := hearAgain(ctx, kv, r.Followers, r.logf); err != nil {
 				r.logf("views: the hand asks of %s's first views are not heard (%v) until it starts again", r.Module, err)
 			}

go/views/reader.go

@@ -35,10 +35,11 @@ type Reader struct {
 	// Acts records a re-read by hand before it is asked (nil records nothing
 	// and the re-read is refused).
 	Acts HandActs
-	// Now, Bound and Wait are for tests: zero are the clock, Bound and five seconds.
-	Now   func() time.Time
-	Bound time.Duration
-	Wait  time.Duration
+	// Now, Bound, Wait and Getenv are for tests: zero are the clock, Bound, five seconds and os.Getenv.
+	Getenv func(string) string
+	Now    func() time.Time
+	Bound  time.Duration
+	Wait   time.Duration
 
 	mu        sync.Mutex
 	followers map[string]*Follower // by "<owner>.<state>"
@@ -589,7 +590,7 @@ func (r *Reader) Rows(name string, rows func() any) {
 
 // firstViews is what `<prefix>_first_views` answers: the views' statuses and each list added by Rows.
 func (r *Reader) firstViews() map[string]any {
-	out := map[string]any{"views": r.Statuses()}
+	out := map[string]any{"views": r.Statuses(), OwnBuildKey: ownBuildWord(r.ownBuild())}
 	r.mu.Lock()
 	rows := maps.Clone(r.rows)
 	r.mu.Unlock()

go/views/status.go

@@ -125,7 +125,7 @@ func StatusTools(reader, read, again string, st keptStatus, acts HandActs, now f
 				}
 				out := []Status{}
 				for _, k := range keys {
-					if strings.HasPrefix(k, "again.") {
+					if strings.HasPrefix(k, "again.") || k == OwnBuildKey {
 						continue
 					}
 					e, err := st.Get(k)
@@ -137,7 +137,14 @@ func StatusTools(reader, read, again string, st keptStatus, acts HandActs, now f
 						out = append(out, s)
 					}
 				}
-				return map[string]any{"first-views": out}, nil
+				own := OwnBuildUnknown
+				if e, err := st.Get(OwnBuildKey); err == nil && e != nil {
+					var w string
+					if json.Unmarshal(e.Value, &w) == nil && strings.TrimSpace(w) != "" {
+						own = w
+					}
+				}
+				return map[string]any{"first-views": out, OwnBuildKey: own}, nil
 			}},
 		{Name: again,
 			Description: fmt.Sprintf("Ask %s's first view of an owner's state again now, by hand (a hand act, its caller and why kept in "+

go/views/views_test.go

@@ -5,6 +5,7 @@ import (
 	"encoding/json"
 	"errors"
 	"fmt"
+	"maps"
 	"reflect"
 	"runtime"
 	"slices"
@@ -1234,3 +1235,49 @@ func TestViews(t *testing.T) {
 	t.Run("Views", subViews)
 	t.Run("StdioWriterPublishesAndListensThroughTheModulesOwnPlumbing", subStdioWriterPublishesAndListensThroughTheModulesOwnPlumbing)
 }
+
+type putRecorder struct{ puts map[string][]byte }
+
+func (p *putRecorder) Put(_ context.Context, key string, value []byte) (uint64, error) {
+	p.puts[key] = value
+	return 1, nil
+}
+
+// statusWith is a state `first-views` holding the given values.
+type statusWith map[string][]byte
+
+func (s statusWith) Keys() ([]string, error) { return slices.Collect(maps.Keys(s)), nil }
+func (s statusWith) Get(k string) (*stdio.StateEntry, error) {
+	if v, ok := s[k]; ok {
+		return &stdio.StateEntry{Value: v}, nil
+	}
+	return nil, nil
+}
+func (statusWith) Put(string, any) (uint64, error) { return 0, errors.New("read only") }
+
+// design 47 G §674: both answers of a part's first views say its own build beside their list.
+func TestFirstViewsSayTheOwnBuild(t *testing.T) {
+	for name, c := range map[string]struct{ env, want string }{"a fingerprint": {"abc123", "abc123"}, "none": {"", "unknown"}} {
+		getenv := func(string) string { return c.env }
+		// the bundle reader's answer
+		r := &Reader{Module: "m", Getenv: getenv}
+		got, _ := r.Tools("m")[0].Run(nil)
+		if v := got.(map[string]any)[OwnBuildKey]; v != c.want {
+			t.Errorf("%s: the bundle reader's first views say %v, want %s", name, v, c.want)
+		}
+		// the process writes it at its start, and its status tool reads it
+		rec := &putRecorder{puts: map[string][]byte{}}
+		KeepOwnBuild(context.Background(), rec, process.ReadOwnBuild(getenv), nil)
+		st := statusWith{OwnBuildKey: rec.puts[OwnBuildKey]}
+		read, err := StatusTools("m", "m_first_views", "m_first_view_again", st, nil, time.Now)[0].Run(nil)
+		m := read.(map[string]any)
+		if err != nil || m[OwnBuildKey] != c.want || len(m["first-views"].([]Status)) != 0 {
+			t.Errorf("%s: the status tool says %v, %v, want %s", name, m, err, c.want)
+		}
+	}
+	// a process that kept nothing yet says unknown
+	read, _ := StatusTools("m", "r", "a", statusWith{}, nil, time.Now)[0].Run(nil)
+	if read.(map[string]any)[OwnBuildKey] != "unknown" {
+		t.Errorf("nothing kept: %v", read)
+	}
+}