Avoid deprecated iOS tag lookup for chart commands (PRO-4970)

README.md

@@ -5,20 +5,25 @@
 
 ### Native command dispatch
 
-On Android, imperative chart commands use `codegenNativeCommands` with the
+On Android and iOS, imperative chart commands use `codegenNativeCommands` with the
 current native host ref. Keep this path ref-based: converting the ref with
 `findNodeHandle` and calling `UIManager.dispatchViewManagerCommand` sends Fabric
-through `findShadowNodeByTag_DEPRECATED`. React Native 0.85.3's default lookup can
-race native tree teardown (PRO-4970). Ref-based dispatch avoids that lookup for
-chart commands without changing global React Native feature flags.
-
-iOS retains its existing numeric command mapping. Both paths check the current
-ref at call time and ignore commands after detachment. The native command names,
-argument order and payloads are unchanged.
+through `findShadowNodeByTag_DEPRECATED`. That lookup walks the whole shadow tree
+on the JS thread and can race concurrent commits and native tree teardown
+(PRO-4970); React Native only fixes it behind the
+`fixFindShadowNodeByTagRaceCondition` flag, which is off by default. Ref-based
+dispatch avoids the lookup for chart commands without changing global React
+Native feature flags.
+
+On iOS the view is a legacy view manager running through Fabric's interop layer,
+which resolves a command by its method name and prepends the view tag itself, so
+the native `RCT_EXTERN_METHOD` signatures are unchanged. Both platforms check the
+current ref at call time and ignore commands after detachment. The native command
+names, argument order and payloads are unchanged.
 
 Run `yarn test` (Node 22+) for command routing, payload, detachment and independent
 chart checks. These tests mock the native bridge; they do **not** prove the
-intermittent Android SIGSEGV is resolved. Validate a mobile build containing this
+intermittent Android or iOS SIGSEGV is resolved. Validate a mobile build containing this
 package with repeated interval changes (including 3D → weekly), market and engine
 switches, reconnects, background/foreground and idle runs, collecting native logs.
 

index.js

@@ -1,5 +1,5 @@
 import React, { forwardRef, useImperativeHandle, useRef } from 'react';
-import { requireNativeComponent, UIManager, findNodeHandle, Platform } from 'react-native';
+import { requireNativeComponent } from 'react-native';
 import codegenNativeCommands from 'react-native/Libraries/Utilities/codegenNativeCommands';
 
 const NativeRNKLineView = requireNativeComponent('RNKLineView');
@@ -26,20 +26,11 @@ const RNKLineView = forwardRef((props, ref) => {
     const view = nativeRef.current;
     if (!view) return detachedResult;
 
-    if (Platform.OS === 'android') {
-      // Dispatch through the host ref. Numeric tags force Fabric through
-      // findShadowNodeByTag_DEPRECATED, whose RN 0.85 lookup can race teardown.
-      return Commands[name](view, ...args);
-    }
-
-    // Preserve iOS's exported numeric command mapping.
-    const nodeHandle = findNodeHandle(view);
-    if (!nodeHandle) return detachedResult;
-    return UIManager.dispatchViewManagerCommand(
-      nodeHandle,
-      UIManager.getViewManagerConfig('RNKLineView').Commands[name],
-      args
-    );
+    // Dispatch through the host ref on every platform. Numeric tags force Fabric
+    // through findShadowNodeByTag_DEPRECATED, whose tree walk can race concurrent
+    // commits and native tree teardown (PRO-4970). iOS's legacy view manager
+    // interop resolves these commands by method name.
+    return Commands[name](view, ...args);
   };
 
   useImperativeHandle(ref, () => ({

tests/commands.test.cjs

@@ -60,18 +60,12 @@ for (const platform of ['android', 'ios']) {
       const payload = { time: 123, close: 42 };
       const args = name.startsWith('get') ? [] : [payload];
       api[name](...args);
-      if (platform === 'android') {
-        assert.equal(calls.length, 1);
-        assert.equal(calls[0][0], 'host');
-        assert.equal(calls[0][1], host);
-        assert.equal(calls[0][2], name);
-      } else {
-        assert.equal(calls.length, 2);
-        assert.equal(calls[0][0], 'lookup');
-        assert.equal(calls[1][0], 'legacy');
-        assert.equal(calls[1][1], host.tag);
-        assert.equal(calls[1][2], ids[name]);
-      }
+      // Both platforms must use the host ref: a numeric tag would send Fabric
+      // through findShadowNodeByTag_DEPRECATED.
+      assert.equal(calls.length, 1);
+      assert.equal(calls[0][0], 'host');
+      assert.equal(calls[0][1], host);
+      assert.equal(calls[0][2], name);
       const sent = calls.at(-1)[3];
       assert.equal(sent.length, args.length);
       if (args.length) assert.equal(sent[0], payload);
@@ -95,6 +89,13 @@ for (const platform of ['android', 'ios']) {
     api.updateLastCandlestick({ close: 12 });
     assert.equal(calls[0][1], replacement);
   });
+
+  test(`${platform}: no command resolves a numeric tag or uses the legacy dispatcher`, async () => {
+    const { api, calls } = await mount(platform);
+    for (const name of names) api[name]({ time: 123 });
+    assert.equal(calls.length, names.length);
+    assert.ok(calls.every(([kind]) => kind === 'host'));
+  });
 }
 
 test('independent charts dispatch to their own native refs', async () => {