Bind trusted task approval to exact producer facts and lifetime

Assistant: codex
Assistant-Model: gpt-6-astra
Assistant-Session: 01a140c4-354a-7823-8f0d-8f717397f786

internal/emission/delivery.go

@@ -112,7 +112,9 @@ func (o *Outbox) nextEntry() (entry, int64, error) {
 		return entry{}, 0, err
 	}
 	var e entry
-	if err := json.Unmarshal(line, &e); err != nil {
+	decoder := json.NewDecoder(bytes.NewReader(line))
+	decoder.UseNumber()
+	if err := decoder.Decode(&e); err != nil {
 		return entry{}, 0, err
 	}
 	if e.Seq != o.cursor.Seq+1 || e.Event.Source != o.source {

internal/emission/numeric_replay_test.go

@@ -0,0 +1,53 @@
+package emission
+
+import (
+	"bytes"
+	"crypto/ed25519"
+	"encoding/json"
+	"github.com/netkingdom/access-engine/internal/sign"
+	"github.com/netkingdom/access-engine/pkg/api"
+	"testing"
+)
+
+func TestOutboxReplayPreservesProducerNumericSignature(t *testing.T) {
+	folder := t.TempDir()
+	outbox, err := Open(folder, "synthetic-source")
+	if err != nil {
+		t.Fatal(err)
+	}
+	key := ed25519.NewKeyFromSeed(bytes.Repeat([]byte{21}, 32))
+	envelope := api.DecisionEnvelope{ID: "decision:synthetic-numeric", Effect: api.DecisionEffectDeny, Resource: api.ResourceRef{ID: "synthetic", Type: "tenant", System: "tenant-engine"}}
+	envelope.Binding = &api.DecisionBinding{Context: map[string]any{"float": json.Number("1.0"), "negative_zero": json.Number("-0.0"), "integer": json.Number("9007199254740993"), "exponent": json.Number("1e-07")}}
+	if err := sign.Sign(&envelope, key, "synthetic-numeric"); err != nil {
+		t.Fatal(err)
+	}
+	if err := outbox.Append(envelope); err != nil {
+		t.Fatal(err)
+	}
+	outbox.Close()
+	outbox, err = Open(folder, "synthetic-source")
+	if err != nil {
+		t.Fatal(err)
+	}
+	defer outbox.Close()
+	entry, _, err := outbox.nextEntry()
+	if err != nil {
+		t.Fatal(err)
+	}
+	wire, err := json.Marshal(entry.Event.Data)
+	if err != nil {
+		t.Fatal(err)
+	}
+	replayed, err := sign.DecodeEnvelope(wire)
+	if err != nil {
+		t.Fatal(err)
+	}
+	if err := sign.Verify(replayed, map[string]ed25519.PublicKey{"synthetic-numeric": key.Public().(ed25519.PublicKey)}); err != nil {
+		t.Fatal(err)
+	}
+	before, _ := sign.CanonicalBytes(envelope)
+	after, _ := sign.CanonicalBytes(replayed)
+	if !bytes.Equal(before, after) {
+		t.Fatal("replayed signed bytes changed")
+	}
+}

internal/emission/outbox.go

@@ -136,7 +136,9 @@ func (o *Outbox) load() error {
 			return os.Truncate(o.path, o.size)
 		}
 		var e entry
-		if err := json.Unmarshal(data[good:good+end], &e); err != nil {
+		decoder := json.NewDecoder(bytes.NewReader(data[good : good+end]))
+		decoder.UseNumber()
+		if err := decoder.Decode(&e); err != nil {
 			return fmt.Errorf("outbox line %d is corrupt: %w", line, err)
 		}
 		if e.Seq != o.seq+1 || e.Event.Source != o.source {