test RCTInstance invalidation on RCTHost restart (#37899)

Summary:
Pull Request resolved: https://github.com/facebook/react-native/pull/37899

Changelog: [Internal]

Reviewed By: cipolleschi

Differential Revision: D46547012

fbshipit-source-id: 9b157678c474120aeca3896942e368678cb5b8eb

packages/react-native/ReactCommon/react/bridgeless/iostests/RCTHostTests.mm

@@ -8,6 +8,8 @@
 #import <XCTest/XCTest.h>
 
 #import <RCTTestUtils/ShimRCTInstance.h>
+#import <React/RCTLog.h>
+#import <React/RCTMockDef.h>
 #import <ReactCommon/RCTHermesInstance.h>
 #import <ReactCommon/RCTHost.h>
 #import <ReactCommon/RCTInstance.h>
@@ -15,6 +17,22 @@
 
 #import <OCMock/OCMock.h>
 
+RCT_MOCK_REF(RCTHost, _RCTLogNativeInternal);
+
+RCTLogLevel gLogLevel;
+int gLogCalledTimes = 0;
+NSString *gLogMessage = nil;
+static void RCTLogNativeInternalMock(RCTLogLevel level, const char *fileName, int lineNumber, NSString *format, ...)
+{
+  gLogLevel = level;
+  gLogCalledTimes++;
+
+  va_list args;
+  va_start(args, format);
+  gLogMessage = [[NSString alloc] initWithFormat:format arguments:args];
+  va_end(args);
+}
+
 @interface RCTHostTests : XCTestCase
 @end
 
@@ -43,15 +61,34 @@ static ShimRCTInstance *shimmedRCTInstance;
 - (void)tearDown
 {
   [shimmedRCTInstance reset];
+  gLogCalledTimes = 0;
+  gLogMessage = nil;
 
   [super tearDown];
 }
 
 - (void)testStart
 {
+  RCT_MOCK_SET(RCTHost, _RCTLogNativeInternal, RCTLogNativeInternalMock);
+
+  XCTAssertEqual(shimmedRCTInstance.initCount, 0);
   [_subject start];
   OCMVerify(OCMTimes(1), [_mockHostDelegate hostDidStart:_subject]);
   XCTAssertEqual(shimmedRCTInstance.initCount, 1);
+  XCTAssertEqual(gLogCalledTimes, 0);
+
+  XCTAssertEqual(shimmedRCTInstance.invalidateCount, 0);
+  [_subject start];
+  XCTAssertEqual(shimmedRCTInstance.initCount, 2);
+  XCTAssertEqual(shimmedRCTInstance.invalidateCount, 1);
+  OCMVerify(OCMTimes(2), [_mockHostDelegate hostDidStart:_subject]);
+  XCTAssertEqual(gLogLevel, RCTLogLevelWarning);
+  XCTAssertEqual(gLogCalledTimes, 1);
+  XCTAssertEqualObjects(
+      gLogMessage,
+      @"RCTHost should not be creating a new instance if one already exists. This implies there is a bug with how/when this method is being called.");
+
+  RCT_MOCK_RESET(RCTHost, _RCTLogNativeInternal);
 }
 
 @end

packages/react-native/ReactCommon/react/bridgeless/platform/ios/Core/RCTHost.mm

@@ -15,9 +15,13 @@
 #import <React/RCTFabricSurface.h>
 #import <React/RCTJSThread.h>
 #import <React/RCTLog.h>
+#import <React/RCTMockDef.h>
 #import <React/RCTPerformanceLogger.h>
 #import <React/RCTReloadCommand.h>
 
+RCT_MOCK_DEF(RCTHost, _RCTLogNativeInternal);
+#define _RCTLogNativeInternal RCT_MOCK_USE(RCTHost, _RCTLogNativeInternal)
+
 using namespace facebook::react;
 
 @interface RCTHost () <RCTReloadListener, RCTInstanceDelegate>

packages/react-native/ReactCommon/react/test_utils/ios/Shims/ShimRCTInstance.h

@@ -10,6 +10,7 @@
 @interface ShimRCTInstance : NSObject
 
 @property (assign) int initCount;
+@property (assign) int invalidateCount;
 
 - (void)reset;
 

packages/react-native/ReactCommon/react/test_utils/ios/Shims/ShimRCTInstance.mm

@@ -24,6 +24,7 @@ static __weak ShimRCTInstance *weakShim = nil;
         [ShimRCTInstance class],
         @selector(initWithDelegate:
                   jsEngineInstance:bundleManager:turboModuleManagerDelegate:onInitialBundleLoad:moduleRegistry:));
+    RCTSwizzleInstanceSelector([RCTInstance class], [ShimRCTInstance class], @selector(invalidate));
     weakShim = self;
   }
   return self;
@@ -36,7 +37,9 @@ static __weak ShimRCTInstance *weakShim = nil;
       [ShimRCTInstance class],
       @selector(initWithDelegate:
                 jsEngineInstance:bundleManager:turboModuleManagerDelegate:onInitialBundleLoad:moduleRegistry:));
+  RCTSwizzleInstanceSelector([RCTInstance class], [ShimRCTInstance class], @selector(invalidate));
   _initCount = 0;
+  _invalidateCount = 0;
 }
 
 - (instancetype)initWithDelegate:(id<RCTInstanceDelegate>)delegate
@@ -50,4 +53,9 @@ static __weak ShimRCTInstance *weakShim = nil;
   return self;
 }
 
+- (void)invalidate
+{
+  weakShim.invalidateCount++;
+}
+
 @end