Fix allowGlobalAutomatic mode for interfaces (#466)

Author: madsodgaard

Sources/JExtractSwiftLib/JNI/JNISwift2JavaGenerator+JavaBindingsPrinting.swift

@@ -424,7 +424,11 @@ extension JNISwift2JavaGenerator {
     )
   }
 
-  private func printJavaBindingWrapperMethod(_ printer: inout CodePrinter, _ decl: ImportedFunc, signaturesOnly: Bool) {
+  private func printJavaBindingWrapperMethod(
+    _ printer: inout CodePrinter,
+    _ decl: ImportedFunc,
+    signaturesOnly: Bool
+  ) {
     guard let translatedDecl = translatedDecl(for: decl) else {
       fatalError("Decl was not translated, \(decl)")
     }
@@ -470,6 +474,13 @@ extension JNISwift2JavaGenerator {
       if let importedFunc {
         printDeclDocumentation(&printer, importedFunc)
       }
+      var modifiers = modifiers
+
+      // If we are a protocol, we emit this as default method
+      if importedFunc?.parentType?.asNominalTypeDeclaration?.kind == .protocol {
+        modifiers.insert("default", at: 1)
+      }
+
       printer.printBraceBlock("\(annotationsStr)\(modifiers.joined(separator: " ")) \(resultType) \(translatedDecl.name)(\(parametersStr))\(throwsClause)") { printer in
         let globalArenaName = "SwiftMemoryManagement.GLOBAL_SWIFT_JAVA_ARENA"
         let arguments = translatedDecl.translatedFunctionSignature.parameters.map(\.parameter.name) + [globalArenaName]

Tests/JExtractSwiftTests/MemoryManagementModeTests.swift

@@ -74,4 +74,34 @@ struct MemoryManagementModeTests {
       ]
     )
   }
+
+  @Test
+  func allowGlobalAutomatic_protocol() throws {
+    var config = Configuration()
+    config.memoryManagementMode = .allowGlobalAutomatic
+
+    try assertOutput(
+      input:
+        """
+        public class MyClass {}
+        
+        public protocol MyProtocol {
+          public func f() -> MyClass
+        }
+        """,
+      config: config,
+      .jni, .java,
+      detectChunkByInitialLines: 1,
+      expectedChunks: [
+        """
+        public default MyClass f() {
+          return f(SwiftMemoryManagement.GLOBAL_SWIFT_JAVA_ARENA);
+        }
+        """,
+        """
+        public MyClass f(SwiftArena swiftArena$);
+        """
+      ]
+    )
+  }
 }