fix: nativewind broken by import source being overwritten in default case

.changeset/rude-icons-fail.md

@@ -0,0 +1,5 @@
+---
+"@callstack/repack": patch
+---
+
+Fix nativewind issue caused by jsx import source being overwritten to undefined when using babel-swc-loader

apps/tester-app/ios/Podfile.lock

@@ -1,6 +1,6 @@
 PODS:
   - boost (1.84.0)
-  - callstack-repack (5.2.0):
+  - callstack-repack (5.2.2):
     - boost
     - DoubleConversion
     - fast_float
@@ -2930,7 +2930,7 @@ EXTERNAL SOURCES:
 
 SPEC CHECKSUMS:
   boost: 7e761d76ca2ce687f7cc98e698152abd03a18f90
-  callstack-repack: 9c91d2c48b139e38919c656474f43ab0494b4c21
+  callstack-repack: c874fe60c49dcf3067bca0627b7ace673589737c
   DoubleConversion: cb417026b2400c8f53ae97020b2be961b59470cb
   fast_float: b32c788ed9c6a8c584d114d0047beda9664e7cc6
   FBLazyVector: a867936a67af0d09c37935a1b900a1a3c795b6d1
@@ -3011,7 +3011,7 @@ SPEC CHECKSUMS:
   RNWorklets: 20451b83d42e7509f43599b405993e57e3a038af
   SocketRocket: d4aabe649be1e368d1318fdf28a022d714d65748
   SwiftyRSA: 8c6dd1ea7db1b8dc4fb517a202f88bb1354bc2c6
-  Yoga: 00013dd9cde63a2d98e8002fcc4f5ddb66c10782
+  Yoga: b01392348aeea02064c21a2762a42893d82b60a7
 
 PODFILE CHECKSUM: 6d7cbe03444d5e87210979fb32a0eca299d758fe
 

packages/repack/src/loaders/babelSwcLoader/__tests__/__snapshots__/babelSwcLoader.test.ts.snap

@@ -37,8 +37,8 @@ exports[`partitionTransforms only custom transforms are excluded from included s
       },
       "transform": {
         "react": {
-          "importSource": undefined,
-          "runtime": undefined,
+          "importSource": "react",
+          "runtime": "automatic",
           "useBuiltins": true,
         },
       },

packages/repack/src/loaders/babelSwcLoader/__tests__/swc.test.ts

@@ -175,6 +175,90 @@ describe('swc transforms support detection', () => {
       );
     });
 
+    it('should apply default react transform when plugin has no react transform options', () => {
+      const inputConfig: SwcLoaderOptions = {
+        jsc: {
+          transform: { react: {} },
+        },
+      };
+      const { swcConfig } = getSupportedSwcCustomTransforms(
+        [['transform-react-jsx', {}]],
+        inputConfig
+      );
+
+      expect(swcConfig.jsc?.transform?.react).toEqual({
+        runtime: 'automatic',
+        importSource: 'react',
+      });
+    });
+
+    it('should preserve existing react transform config when plugin has none', () => {
+      const inputConfig: SwcLoaderOptions = {
+        jsc: {
+          transform: {
+            react: { runtime: 'automatic', importSource: 'nativewind' },
+          },
+        },
+      };
+      const { swcConfig } = getSupportedSwcCustomTransforms(
+        [['transform-react-jsx', {}]],
+        inputConfig
+      );
+
+      expect(swcConfig.jsc?.transform?.react).toEqual({
+        runtime: 'automatic',
+        importSource: 'nativewind',
+      });
+    });
+
+    it('should use plugin importSource option for react transform', () => {
+      const inputConfig: SwcLoaderOptions = {
+        jsc: {
+          transform: {
+            react: {},
+          },
+        },
+      };
+      const { swcConfig } = getSupportedSwcCustomTransforms(
+        [
+          [
+            'transform-react-jsx',
+            { runtime: 'automatic', importSource: 'nativewind' },
+          ],
+        ],
+        inputConfig
+      );
+
+      expect(swcConfig.jsc?.transform?.react).toEqual({
+        runtime: 'automatic',
+        importSource: 'nativewind',
+      });
+    });
+
+    it('should use plugin importSource option for react transform and override existing importSource', () => {
+      const inputConfig: SwcLoaderOptions = {
+        jsc: {
+          transform: {
+            react: { importSource: 'preact' },
+          },
+        },
+      };
+      const { swcConfig } = getSupportedSwcCustomTransforms(
+        [
+          [
+            'transform-react-jsx',
+            { runtime: 'automatic', importSource: 'nativewind' },
+          ],
+        ],
+        inputConfig
+      );
+
+      expect(swcConfig.jsc?.transform?.react).toEqual({
+        runtime: 'automatic',
+        importSource: 'nativewind',
+      });
+    });
+
     it('configures modules commonjs options based on provided config (snapshot)', () => {
       const inputConfig: SwcLoaderOptions = {};
       const { swcConfig } = getSupportedSwcCustomTransforms(

packages/repack/src/loaders/babelSwcLoader/swc.ts

@@ -77,9 +77,7 @@ function getTransformReactDevelopmentConfig(
 
 function getTransformReactRuntimeConfig(
   swcConfig: SwcLoaderOptions,
-  reactRuntimeConfig: Record<string, any> = {
-    runtime: 'automatic',
-  }
+  reactRuntimeConfig: Record<string, any> = {}
 ): SwcLoaderOptions {
   return {
     ...swcConfig,
@@ -89,8 +87,14 @@ function getTransformReactRuntimeConfig(
         ...swcConfig.jsc?.transform,
         react: {
           ...swcConfig.jsc?.transform?.react,
-          runtime: reactRuntimeConfig.runtime,
-          importSource: reactRuntimeConfig.importSource,
+          runtime:
+            reactRuntimeConfig.runtime ??
+            swcConfig.jsc?.transform?.react?.runtime ??
+            'automatic',
+          importSource:
+            reactRuntimeConfig.importSource ??
+            swcConfig.jsc?.transform?.react?.importSource ??
+            'react',
         },
       },
     },