T-6: the tool runner reads a sent object by its reference, under the bus state capability

mesh/objects.sent-get reads a sender's sent store only; refused: a state's objects, a reference that is none, an object over a bundle's channel.

Builds: design 47 G §347, §59, §462

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

node-tools/internal/bus/sent.go

@@ -0,0 +1,55 @@
+package bus
+
+import (
+	"context"
+	"errors"
+	"fmt"
+	"strings"
+
+	"git.novox.be/novox/mesh-sdk/go/buscalls"
+	"git.novox.be/novox/mesh-sdk/go/catalogue"
+	"git.novox.be/novox/mesh-sdk/go/stateobjects"
+	"github.com/nats-io/nats.go/jetstream"
+)
+
+// SentGet reads one object of a sender's store of sent objects by the reference that carried it (ADR 0666 §16): the
+// store is the sender's `<module>_sent-objects`, and no other — a state's objects are reached through their owner's
+// bindings alone. It reads as this connection's account, which the bus lets read a sender's sent store only where the
+// grants part granted it, from the manifests' callers and consumers; a refusal says the store.
+func (c *Conn) SentGet(r buscalls.ObjectsSentGetRequest) (*buscalls.ObjectData, error) {
+	ref := stateobjects.Ref{Store: r.Store, Object: r.Object, Size: r.Size, Digest: r.Digest, Form: stateobjects.FormVersion}
+	if _, ok := stateobjects.ReadRef(stateobjects.Wrap(ref)); !ok {
+		return nil, errors.New("a sent object is named by the reference's store, object, size and sha256, as the reply or event carried them")
+	}
+	if !strings.HasSuffix(r.Store, catalogue.BusNameSeparator+catalogue.SentObjectsLocal) {
+		return nil, fmt.Errorf("%s is no sent store (a module's is `<module>%s%s`): only a sent object is read by its reference",
+			r.Store, catalogue.BusNameSeparator, catalogue.SentObjectsLocal)
+	}
+	if r.Size > stateobjects.BundleObjectMost {
+		return nil, fmt.Errorf("the sent object %s is %d bytes and a bundle's runtime channel carries at most %d: it is not read "+
+			"through a bundle", r.Object, r.Size, stateobjects.BundleObjectMost)
+	}
+	js, err := c.jetStream()
+	if err != nil {
+		return nil, err
+	}
+	ctx, cancel := context.WithTimeout(context.Background(), StateTimeout)
+	defer cancel()
+	obs, err := js.ObjectStore(ctx, r.Store)
+	if err != nil {
+		return nil, fmt.Errorf("the sent store %s cannot be read as %s: it is not on the bus, or the bus grants this account no "+
+			"read of it (the manifests' callers and consumers are granted): %w", r.Store, c.cred.Module, err)
+	}
+	info, err := obs.GetInfo(ctx, r.Object)
+	if errors.Is(err, jetstream.ErrObjectNotFound) {
+		return nil, fmt.Errorf("the sent object %s is not in %s: it is kept 7 days, then expires", r.Object, r.Store)
+	}
+	if err != nil {
+		return nil, fmt.Errorf("the sent object %s of %s: %w", r.Object, r.Store, err)
+	}
+	data, err := obs.GetBytes(ctx, r.Object)
+	if err != nil {
+		return nil, fmt.Errorf("the sent object %s of %s: %w", r.Object, r.Store, err)
+	}
+	return &buscalls.ObjectData{Info: objectInfoOf(info), Data: data}, nil
+}

node-tools/internal/bus/sent_test.go

@@ -0,0 +1,30 @@
+package bus
+
+import (
+	"strings"
+	"testing"
+
+	"git.novox.be/novox/mesh-sdk/go/buscalls"
+	"git.novox.be/novox/mesh-sdk/go/stateobjects"
+)
+
+// Design 47 G §347, §59, §462: a sent object is read by the reference that carried it, from a sender's sent store only; a
+// state's objects, a reference that is none and an object too large for a bundle's channel are refused before the bus is asked.
+func TestSentGetRefusesWhatIsNoSentObjectsReference(t *testing.T) {
+	digest := "aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa"
+	big := int64(stateobjects.BundleObjectMost) + 1
+	for _, c := range []struct {
+		name string
+		req  buscalls.ObjectsSentGetRequest
+		want string
+	}{
+		{"no digest", buscalls.ObjectsSentGetRequest{Store: "m_sent-objects", Object: "o", Size: 3}, "named by the reference"},
+		{"a state's objects", buscalls.ObjectsSentGetRequest{Store: "m_asks-objects", Object: "o", Size: 3, Digest: digest}, "no sent store"},
+		{"over the channel", buscalls.ObjectsSentGetRequest{Store: "m_sent-objects", Object: "o", Size: big, Digest: digest}, "not read through a bundle"},
+	} {
+		_, err := (&Conn{}).SentGet(c.req)
+		if err == nil || !strings.Contains(err.Error(), c.want) {
+			t.Errorf("%s: got %v, want an error containing %q", c.name, err, c.want)
+		}
+	}
+}