feat(verifier): encode state.logs for the web host

Claude-Session: https://claude.ai/code/session_01ShuAy8q8ZfPi8KHxwc8JpQ

internal/verifier/marshal.go

@@ -468,19 +468,44 @@ func runtimeMillis(stepTime, runStart time.Time) int64 {
 	return stepTime.Sub(runStart).Milliseconds()
 }
 
+// logFields is the ONE description of a state.logs entry, for the same reason
+// lastActionFields is: the goja host turns it into a JS object (logsArray) and
+// the web host receives the same fields as JSON (EncodeLogs), so a property
+// counting error-level lines cannot read one shape on native and another on web.
+func logFields(entry LogEntry) []actionField {
+	return []actionField{
+		{key: "unixMillis", value: entry.UnixMillis},
+		{key: "level", value: entry.Level},
+		{key: "tag", value: entry.Tag},
+		{key: "message", value: entry.Message},
+	}
+}
+
 func logsArray(runtime *goja.Runtime, logs []LogEntry) *goja.Object {
 	array := runtime.NewArray()
 	for index, entry := range logs {
-		item := runtime.NewObject()
-		_ = item.Set("unixMillis", entry.UnixMillis)
-		_ = item.Set("level", entry.Level)
-		_ = item.Set("tag", entry.Tag)
-		_ = item.Set("message", entry.Message)
-		_ = array.Set(fmt.Sprintf("%d", index), item)
+		_ = array.Set(fmt.Sprintf("%d", index), objectFromFields(runtime, logFields(entry)))
 	}
 	return array
 }
 
+// EncodeLogs renders this step's log entries for the web host, which has no
+// Go-side state object to read: the runner pushes this JSON into the page
+// before each extractor evaluation. No entries encodes as an empty array, the
+// same value the goja host reports for a step whose log fetch found nothing.
+func EncodeLogs(logs []LogEntry) json.RawMessage {
+	var buffer bytes.Buffer
+	buffer.WriteByte('[')
+	for index, entry := range logs {
+		if index > 0 {
+			buffer.WriteByte(',')
+		}
+		buffer.Write(encodeFields(logFields(entry)))
+	}
+	buffer.WriteByte(']')
+	return buffer.Bytes()
+}
+
 func exceptionsArray(runtime *goja.Runtime, exceptions []Exception) *goja.Object {
 	array := runtime.NewArray()
 	for index, exception := range exceptions {

internal/verifier/marshal_test.go

@@ -282,3 +282,50 @@ func TestLastAction_ReportsARelaunchSeparatelyFromTheDispatch(t *testing.T) {
 		})
 	}
 }
+
+// TestLogs_WebJSONMatchesTheGojaObject pins state.logs to ONE shape across the
+// two hosts, for the same reason lastAction is pinned. On web the page's
+// reading of every extractor replaces the host's, so state.logs is whatever
+// EncodeLogs put in the page: a field this side renames or cases differently
+// leaves the default noLogcatErrors counting nothing on web while it counts on
+// native, with nothing reporting that it never saw an entry.
+func TestLogs_WebJSONMatchesTheGojaObject(t *testing.T) {
+	verifier := newVerifier(t)
+	mustLoad(t, verifier, `
+		globalThis.lines = __sanderling__.extract(state => JSON.stringify(state.logs));
+	`)
+
+	for _, testCase := range []struct {
+		name string
+		logs []LogEntry
+	}{
+		{"none", nil},
+		{"empty", []LogEntry{}},
+		{
+			"one error",
+			[]LogEntry{{UnixMillis: 1700000000123, Level: "E", Tag: "console", Message: "boom from the page"}},
+		},
+		{
+			"mixed levels",
+			[]LogEntry{
+				{UnixMillis: 1, Level: "E", Tag: "console", Message: `say "hi" <b> & co`},
+				{UnixMillis: 2, Level: "W", Tag: "AndroidRuntime", Message: "a warning"},
+			},
+		},
+	} {
+		t.Run(testCase.name, func(t *testing.T) {
+			if err := verifier.PushSnapshot(SnapshotInput{
+				Snapshots: Snapshots{},
+				Logs:      testCase.logs,
+			}); err != nil {
+				t.Fatal(err)
+			}
+			handle := verifier.runtime.GlobalObject().Get("lines").ToObject(verifier.runtime)
+			goja := handle.Get("current").String()
+			web := string(EncodeLogs(testCase.logs))
+			if goja != web {
+				t.Errorf("the two hosts disagree on state.logs\n goja: %s\n  web: %s", goja, web)
+			}
+		})
+	}
+}