fix(gradle-plugin): guard missing autolinked JNI dirs (#56886)

Summary:
Related to #56334.

`GenerateAutolinkingNewArchitecturesFileTask` currently emits unconditional `add_subdirectory(...)` calls for autolinked New Architecture JNI/codegen directories.

During `clean`, Android Studio native model configuration, or other native cleanup/configuration flows, some dependency codegen directories may not exist yet. CMake then fails before clean/configuration can complete:

```text
add_subdirectory given source ".../android/build/generated/source/codegen/jni/"
which is not an existing directory
```

This changes the generated `Android-autolinking.cmake` to:

- initialize `AUTOLINKED_LIBRARIES` as an empty list;
- only call `add_subdirectory(...)` when the native directory exists;
- append each autolinked target only after its directory has been added.

That keeps existing generated JNI directories linked as before while allowing native clean/model configuration to skip directories that have not been generated yet.

## Changelog:

[ANDROID] [FIXED] - Guard missing autolinked JNI directories in generated CMake during native clean/model configuration.

Pull Request resolved: #56886

Test Plan:
```sh
./gradlew -p packages/gradle-plugin :react-native-gradle-plugin:test --tests com.facebook.react.tasks.GenerateAutolinkingNewArchitecturesFileTaskTest
```

Result:

```text
BUILD SUCCESSFUL
```

Reviewed By: christophpurrer

Differential Revision: D105826478

Pulled By: cortinico

fbshipit-source-id: e3a698c2334cc02189eefca21b34a0a0181eb5f3

Author: Phecda

packages/gradle-plugin/react-native-gradle-plugin/src/main/kotlin/com/facebook/react/tasks/GenerateAutolinkingNewArchitecturesFileTask.kt

@@ -61,31 +61,39 @@ abstract class GenerateAutolinkingNewArchitecturesFileTask : DefaultTask() {
             // If user provided a custom cmakeListsPath, let's honor it.
             val nativeFolderPath = sanitizeCmakeListsPath(cmakeListsPath)
             addDirectoryString +=
-                "add_subdirectory(\"$nativeFolderPath\" ${libraryName}_autolinked_build)"
+                """
+                if(EXISTS "$nativeFolderPath")
+                  add_subdirectory("$nativeFolderPath" ${libraryName}_autolinked_build)
+                  list(APPEND AUTOLINKED_LIBRARIES $CODEGEN_LIB_PREFIX${libraryName})
+                else()
+                  message(WARNING "React Native: Skipping autolinked library '$CODEGEN_LIB_PREFIX${libraryName}' because the source directory does not exist: $nativeFolderPath")
+                endif()
+                """
+                    .trimIndent()
           }
           if (cxxModuleCMakeListsPath != null) {
             // If user provided a custom cxxModuleCMakeListsPath, let's honor it.
             val nativeFolderPath = sanitizeCmakeListsPath(cxxModuleCMakeListsPath)
             addDirectoryString +=
-                "\nadd_subdirectory(\"$nativeFolderPath\" ${libraryName}_cxxmodule_autolinked_build)"
+                """
+
+                if(EXISTS "$nativeFolderPath")
+                  add_subdirectory("$nativeFolderPath" ${libraryName}_cxxmodule_autolinked_build)
+                ${
+                    dep.cxxModuleCMakeListsModuleName?.let {
+                      "  list(APPEND AUTOLINKED_LIBRARIES $it)"
+                    } ?: ""
+                }
+                else()
+                  message(WARNING "React Native: Skipping autolinked C++ module '${dep.cxxModuleCMakeListsModuleName ?: libraryName}' because the source directory does not exist: $nativeFolderPath")
+                endif()
+                """
+                    .trimIndent()
           }
           addDirectoryString
         }
 
-    val libraryModules =
-        packages.joinToString("\n  ") { dep ->
-          var autolinkedLibraries = ""
-          if (dep.libraryName != null) {
-            autolinkedLibraries += "$CODEGEN_LIB_PREFIX${dep.libraryName}"
-          }
-          if (dep.cxxModuleCMakeListsModuleName != null) {
-            autolinkedLibraries += "\n${dep.cxxModuleCMakeListsModuleName}"
-          }
-          autolinkedLibraries
-        }
-
     return CMAKE_TEMPLATE.replace("{{ libraryIncludes }}", libraryIncludes)
-        .replace("{{ libraryModules }}", libraryModules)
   }
 
   internal fun generateCppFileContent(
@@ -173,11 +181,9 @@ abstract class GenerateAutolinkingNewArchitecturesFileTask : DefaultTask() {
         # or link against a old prefab target (this is needed for React Native 0.76 on).
         set(REACTNATIVE_MERGED_SO true)
 
-        {{ libraryIncludes }}
+        set(AUTOLINKED_LIBRARIES)
 
-        set(AUTOLINKED_LIBRARIES
-          {{ libraryModules }}
-        )
+        {{ libraryIncludes }}
         """
             .trimIndent()
 

packages/gradle-plugin/react-native-gradle-plugin/src/test/kotlin/com/facebook/react/tasks/GenerateAutolinkingNewArchitecturesFileTaskTest.kt

@@ -128,11 +128,9 @@ class GenerateAutolinkingNewArchitecturesFileTaskTest {
             # or link against a old prefab target (this is needed for React Native 0.76 on).
             set(REACTNATIVE_MERGED_SO true)
 
+            set(AUTOLINKED_LIBRARIES)
 
 
-            set(AUTOLINKED_LIBRARIES
-              
-            )
             """
                 .trimIndent()
         )
@@ -155,15 +153,26 @@ class GenerateAutolinkingNewArchitecturesFileTaskTest {
             # or link against a old prefab target (this is needed for React Native 0.76 on).
             set(REACTNATIVE_MERGED_SO true)
 
-            add_subdirectory("./a/directory/" aPackage_autolinked_build)
-            add_subdirectory("./another/directory/with\ spaces/" anotherPackage_autolinked_build)
-            add_subdirectory("./another/directory/cxx/" anotherPackage_cxxmodule_autolinked_build)
-
-            set(AUTOLINKED_LIBRARIES
-              react_codegen_aPackage
-              react_codegen_anotherPackage
-            another_cxxModule
-            )
+            set(AUTOLINKED_LIBRARIES)
+
+            if(EXISTS "./a/directory/")
+              add_subdirectory("./a/directory/" aPackage_autolinked_build)
+              list(APPEND AUTOLINKED_LIBRARIES react_codegen_aPackage)
+            else()
+              message(WARNING "React Native: Skipping autolinked library 'react_codegen_aPackage' because the source directory does not exist: ./a/directory/")
+            endif()
+            if(EXISTS "./another/directory/with\ spaces/")
+              add_subdirectory("./another/directory/with\ spaces/" anotherPackage_autolinked_build)
+              list(APPEND AUTOLINKED_LIBRARIES react_codegen_anotherPackage)
+            else()
+              message(WARNING "React Native: Skipping autolinked library 'react_codegen_anotherPackage' because the source directory does not exist: ./another/directory/with\ spaces/")
+            endif()
+            if(EXISTS "./another/directory/cxx/")
+              add_subdirectory("./another/directory/cxx/" anotherPackage_cxxmodule_autolinked_build)
+              list(APPEND AUTOLINKED_LIBRARIES another_cxxModule)
+            else()
+              message(WARNING "React Native: Skipping autolinked C++ module 'another_cxxModule' because the source directory does not exist: ./another/directory/cxx/")
+            endif()
             """
                 .trimIndent()
         )