Fix iOS markdown style metadata warnings

Resolve markdown UITextView styles to plain React Native text styles before crossing the third-party boundary. react-native-uitextview flattens parent and child styles internally, so Unistyles metadata must not be carried into that handoff.

packages/app/src/components/markdown-text-style.test.ts

@@ -0,0 +1,32 @@
+import { describe, expect, it } from "vitest";
+import { StyleSheet, type TextStyle } from "react-native";
+import { resolvePlainMarkdownTextStyle } from "@/components/markdown-text-style";
+
+function unistylesStyle(id: string, style: Record<string, unknown>) {
+  return {
+    ...style,
+    [`unistyles_${id}`]: { id },
+  };
+}
+
+function uiTextViewFlatten(rootStyle: TextStyle, style: TextStyle): Record<string, unknown> {
+  // react-native-uitextview/src/util.ts:8 flattens [rootStyle, style]
+  // before passing the result to its native View-backed components.
+  return { ...(StyleSheet.flatten([rootStyle, style]) as Record<string, unknown>) };
+}
+
+function unistylesMetadataKeys(style: Record<string, unknown>) {
+  return Object.keys(style).filter((key) => key.startsWith("unistyles_"));
+}
+
+describe("resolvePlainMarkdownTextStyle", () => {
+  it("keeps UITextView from collapsing parent and child Unistyles styles into one native View style object", () => {
+    const merged = uiTextViewFlatten(
+      resolvePlainMarkdownTextStyle(unistylesStyle("paragraph", { color: "#111" })),
+      resolvePlainMarkdownTextStyle(unistylesStyle("text", { fontWeight: "600" })),
+    );
+
+    expect(unistylesMetadataKeys(merged)).toHaveLength(0);
+    expect(merged).toMatchObject({ color: "#111", fontWeight: "600" });
+  });
+});

packages/app/src/components/markdown-text-style.ts

@@ -0,0 +1,25 @@
+import { StyleSheet, type StyleProp, type TextStyle } from "react-native";
+
+export function resolvePlainMarkdownTextStyle(style: StyleProp<TextStyle>): TextStyle {
+  return stripUnistylesMetadata(StyleSheet.flatten(style) ?? {});
+}
+
+function stripUnistylesMetadata(style: TextStyle): TextStyle {
+  // iOS markdown text goes through react-native-uitextview. That library
+  // inherits text styles by flattening [parentStyle, childStyle] before handing
+  // the result to native View-backed components. If both entries are Unistyles
+  // styles, flattening preserves both `unistyles_*` metadata keys in one object,
+  // and Unistyles correctly warns that the style should have stayed array-shaped.
+  //
+  // `UITextView` is a third-party boundary, not a Unistyles-tracked component in
+  // our ownership model. Resolve the concrete style values before crossing that
+  // boundary and drop only Unistyles' private tracking metadata. This preserves
+  // iOS paragraph/spanning text selection while avoiding the metadata merge.
+  const plainStyle: Record<string, unknown> = { ...style };
+  for (const key of Object.keys(plainStyle)) {
+    if (key.startsWith("unistyles_")) {
+      delete plainStyle[key];
+    }
+  }
+  return plainStyle as TextStyle;
+}

packages/app/src/components/markdown-text.ios.tsx

@@ -1,6 +1,7 @@
 import { useMemo, type ReactNode } from "react";
 import { View, type StyleProp, type TextProps, type TextStyle, type ViewStyle } from "react-native";
 import { UITextView } from "react-native-uitextview";
+import { resolvePlainMarkdownTextStyle } from "@/components/markdown-text-style";
 
 interface MarkdownTextSpanProps {
   style?: StyleProp<TextStyle>;
@@ -26,11 +27,13 @@ export function MarkdownTextSpan({
   onPress,
   accessibilityRole,
 }: MarkdownTextSpanProps) {
+  const plainStyle = useMemo(() => resolvePlainMarkdownTextStyle(style), [style]);
+
   return (
     <UITextView
       uiTextView
       selectable
-      style={style}
+      style={plainStyle}
       onPress={onPress}
       accessibilityRole={accessibilityRole}
     >
@@ -59,7 +62,11 @@ export function MarkdownParagraphView({
   children,
 }: MarkdownParagraphViewProps) {
   const textStyle = useMemo(
-    () => [paragraphStyle, MARKDOWN_PARAGRAPH_RESET] as StyleProp<TextStyle>,
+    () =>
+      resolvePlainMarkdownTextStyle([
+        paragraphStyle,
+        MARKDOWN_PARAGRAPH_RESET,
+      ] as StyleProp<TextStyle>),
     [paragraphStyle],
   );
   const viewStyle = useMemo(() => [paragraphStyle, MARKDOWN_PARAGRAPH_RESET], [paragraphStyle]);