[JExtract/JNI] Fix boolean naming for variables already called isX

Sources/JExtractSwiftLib/Convenience/String+Extensions.swift

@@ -14,8 +14,7 @@
 
 extension String {
 
-  // TODO: naive implementation good enough for our simple case `methodMethodSomething` -> `MethodSomething`
-  var toCamelCase: String {
+  var firstCharacterUppercased: String {
     guard let f = first else {
       return self
     }

Sources/JExtractSwiftLib/ImportedDecls.swift

@@ -160,15 +160,15 @@ extension ImportedFunc {
     let returnsBoolean = self.functionSignature.result.type.asNominalTypeDeclaration?.knownTypeKind == .bool
 
     if !returnsBoolean {
-      return "get\(self.name.toCamelCase)"
+      return "get\(self.name.firstCharacterUppercased)"
     } else if !self.name.hasJavaBooleanNamingConvention {
-      return "is\(self.name.toCamelCase)"
+      return "is\(self.name.firstCharacterUppercased)"
     } else {
-      return self.name.toCamelCase
+      return self.name
     }
   }
 
   var javaSetterName: String {
-    "set\(self.name.toCamelCase)"
+    "set\(self.name.firstCharacterUppercased)"
   }
 }

Tests/JExtractSwiftTests/JNI/JNIVariablesTests.swift

@@ -411,7 +411,7 @@ struct JNIVariablesTests {
   }
 
   @Test
-  func boolean_swiftThunks() throws {
+  func someBoolean_swiftThunks() throws {
     try assertOutput(
       input: membersSource,
       .jni,
@@ -450,4 +450,58 @@ struct JNIVariablesTests {
       ]
     )
   }
+
+  @Test
+  func isBoolean_javaBindings() throws {
+    try assertOutput(
+      input: membersSource,
+      .jni,
+      .java,
+      detectChunkByInitialLines: 8,
+      expectedChunks: [
+      """
+      /**
+      * Downcall to Swift:
+      * {@snippet lang=swift :
+      * public let isBoolean: Bool
+      * }
+      */
+      public boolean isBoolean() {
+        long self$ = this.$memoryAddress();
+        return MyClass.$isBoolean(self$);
+      }
+      """,
+      """
+      private static native boolean $isBoolean(long selfPointer);
+      """,
+      ]
+    )
+  }
+
+  @Test
+  func isBoolean_swiftThunks() throws {
+    try assertOutput(
+      input: membersSource,
+      .jni,
+      .swift,
+      detectChunkByInitialLines: 1,
+      expectedChunks: [
+        """
+        @_cdecl("Java_com_example_swift_MyClass__00024isBoolean__J")
+        func Java_com_example_swift_MyClass__00024isBoolean__J(environment: UnsafeMutablePointer<JNIEnv?>!, thisClass: jclass, selfPointer: jlong) -> jboolean {
+          guard let env$ = environment else {
+            fatalError("Missing JNIEnv in downcall to \\(#function)")
+          }
+          assert(selfPointer != 0, "selfPointer memory address was null")
+          let selfBits$ = Int(Int64(fromJNI: selfPointer, in: env$))
+          guard let self$ = UnsafeMutablePointer<MyClass>(bitPattern: selfBits$) else {
+            fatalError("self memory address was null in call to \\(#function)!")
+          }
+          let result = self$.pointee.isBoolean
+          return result.getJNIValue(in: environment)
+        }
+        """,
+      ]
+    )
+  }
 }