fix(githubreview): 证据的 redacted 与 truncated 标记各自跟随自己的真实工作

internal/githubreview/sanitize.go

@@ -27,7 +27,7 @@ func SanitizeRemoteText(value string, limit int) TextEvidence {
 		limit = MaxTextBytes
 	}
 	originalBytes := len([]byte(value))
-	clean := outputsafe.Sanitize([]byte(value))
+	clean, inputRedacted := outputsafe.SanitizeWithRedaction([]byte(value))
 	clean = remoteImage.ReplaceAllString(clean, "[remote image omitted]")
 	clean = remoteLink.ReplaceAllString(clean, "$1 [remote link omitted]")
 	clean = remoteHTMLTag.ReplaceAllString(clean, "[remote HTML omitted]")
@@ -37,16 +37,17 @@ func SanitizeRemoteText(value string, limit int) TextEvidence {
 	clean = strings.TrimSpace(clean)
 	clean, truncated := truncateUTF8Bytes(clean, limit)
 	redacted := redact.String(clean)
-	if redacted != clean {
+	lateRedacted := redacted != clean
+	if lateRedacted {
 		clean = redacted
 	}
 	// A redaction marker can grow the text. Re-apply the hard byte boundary.
 	clean, secondTruncation := truncateUTF8Bytes(clean, limit)
-	truncated = truncated || secondTruncation || originalBytes > len([]byte(clean))
+	truncated = truncated || secondTruncation
 	sum := Fingerprint("remote-text", clean)
 	return TextEvidence{Text: clean, SHA256: sum, OriginalBytes: originalBytes,
 		StoredBytes: len([]byte(clean)), Truncated: truncated,
-		Redacted: redacted != outputsafe.Sanitize([]byte(value)), Untrusted: true}
+		Redacted: inputRedacted || lateRedacted, Untrusted: true}
 }
 
 func EmptyTextEvidence() TextEvidence {

internal/githubreview/sanitize_test.go

@@ -23,6 +23,47 @@ func TestSanitizeRemoteTextMakesRemoteSyntaxInertAndBounded(t *testing.T) {
 	}
 }
 
+func TestSanitizeRemoteTextRedactedFlagTracksSecretRedaction(t *testing.T) {
+	token := "ghp_abcdefghijklmnopqrstuvwxyz0123456789"
+	for _, test := range []struct {
+		name     string
+		value    string
+		redacted bool
+	}{
+		{name: "token only", value: token, redacted: true},
+		{name: "inert link", value: "see [docs](https://example.com/doc)", redacted: false},
+		{name: "oversized plain text", value: strings.Repeat("a", 200), redacted: false},
+	} {
+		evidence := SanitizeRemoteText(test.value, 100)
+		if evidence.Redacted != test.redacted {
+			t.Errorf("%s: Redacted=%v, want %v (%#v)", test.name, evidence.Redacted, test.redacted, evidence)
+		}
+	}
+	if evidence := SanitizeRemoteText(token, 100); !strings.Contains(evidence.Text, "[REDACTED:github-token]") {
+		t.Fatalf("token evidence lost its redaction marker: %#v", evidence)
+	}
+}
+
+// Masking a credential makes the stored evidence shorter than its input, but no
+// byte bound was applied. OriginalBytes/StoredBytes already carry that difference,
+// so Truncated must stay reserved for the boundary actually being reached — with
+// and without the second pass that re-applies it after a growing marker.
+func TestSanitizeRemoteTextTruncatedFlagTracksTheByteBound(t *testing.T) {
+	token := "ghp_abcdefghijklmnopqrstuvwxyz0123456789"
+	masked := SanitizeRemoteText("github="+token, 4096)
+	if masked.Truncated || !masked.Redacted || masked.StoredBytes >= masked.OriginalBytes {
+		t.Errorf("in-bounds redaction reported truncation: %#v", masked)
+	}
+	bounded := SanitizeRemoteText(strings.Repeat("界", 100), 40)
+	if !bounded.Truncated {
+		t.Errorf("byte bound was not reported: %#v", bounded)
+	}
+	grown := SanitizeRemoteText(strings.Repeat("a", 20)+token+strings.Repeat("b", 20), 40)
+	if !grown.Truncated {
+		t.Errorf("redaction growth past the byte bound was not reported: %#v", grown)
+	}
+}
+
 func TestSanitizeRemoteTextPreservesUTF8Boundary(t *testing.T) {
 	evidence := SanitizeRemoteText(strings.Repeat("界", 10), 10)
 	if !evidence.Truncated || !strings.HasPrefix(strings.Repeat("界", 10), evidence.Text) ||

internal/outputsafe/stream.go

@@ -367,6 +367,15 @@ func (s *Stream) consume(value rune, output *strings.Builder) {
 
 // Sanitize is the one-shot form used for already bounded output.
 func Sanitize(data []byte) string {
+	text, _ := SanitizeWithRedaction(data)
+	return text
+}
+
+// SanitizeWithRedaction is Sanitize plus whether secret redaction changed the
+// text, so callers can tell a redaction apart from control-character removal.
+func SanitizeWithRedaction(data []byte) (string, bool) {
 	stream := &Stream{}
-	return redact.String(stream.Feed(data) + stream.Flush())
+	inert := stream.Feed(data) + stream.Flush()
+	redacted := redact.String(inert)
+	return redacted, redacted != inert
 }

internal/outputsafe/stream_test.go

@@ -31,6 +31,20 @@ func TestSanitizeRemovesC1UnicodeControlsAndRedactsSecrets(t *testing.T) {
 	}
 }
 
+func TestSanitizeWithRedactionSeparatesRedactionFromControlStripping(t *testing.T) {
+	secret := []byte("before\u009b31mafter token=secret-value-1234567890")
+	got, redacted := SanitizeWithRedaction(secret)
+	if !redacted || got != Sanitize(secret) {
+		t.Fatalf("redaction was not reported apart from stripping: %q %v", got, redacted)
+	}
+	// Removing control characters shortens the text but is not a secret redaction.
+	plain := []byte("before\u009b31mafter\u009dtitle")
+	got, redacted = SanitizeWithRedaction(plain)
+	if redacted || got != Sanitize(plain) {
+		t.Fatalf("control stripping must not report redaction: %q %v", got, redacted)
+	}
+}
+
 func TestRedactingStreamCarriesSecretAndPrivateKeyStateAcrossChunks(t *testing.T) {
 	stream := &RedactingStream{}
 	parts := []string{