Use builderClassName, add test and test protos

gen-tests.gradle.kts

@@ -249,6 +249,7 @@ val generateKotlinBuildersOnlyTests by tasks.creating(JavaExec::class) {
     "--kotlin_out=wire-tests/src/commonTest/proto-kotlin",
     "--kotlin_builders_only",
     "redacted_test_builders_only.proto",
+    "simple_message_builders_only.proto",
   )
 }
 

wire-kotlin-generator/src/main/java/com/squareup/wire/kotlin/KotlinGenerator.kt

@@ -549,7 +549,7 @@ class KotlinGenerator private constructor(
 
     addDefaultFields(type, companionBuilder, nameAllocator)
     addAdapter(type, companionBuilder)
-    if (buildersOnly || javaInterOp) addBuildClosure(type, companionBuilder)
+    if (buildersOnly || javaInterOp) addBuildClosure(type, companionBuilder, builderClassName)
 
     val classBuilder = TypeSpec.classBuilder(className)
       .apply {
@@ -1970,16 +1970,16 @@ class KotlinGenerator private constructor(
     }
   }
 
-  private fun addBuildClosure(type: MessageType, companionBuilder: TypeSpec.Builder) {
+  private fun addBuildClosure(type: MessageType, companionBuilder: TypeSpec.Builder, builderClassName: ClassName) {
     val body = buildCodeBlock {
-      addStatement("val builder = Builder()")
-      addStatement("buildFn(builder)")
+      addStatement("val builder = %T()", builderClassName)
+      addStatement("body(builder)")
       addStatement("return builder.build()")
     }
     val buildFn = FunSpec.builder("build")
-      .addParameter("buildFn",
+      .addParameter("body",
         LambdaTypeName.get(
-          parameters = arrayOf(TypeVariableName("Builder")),
+          parameters = arrayOf(builderClassName),
           returnType = Unit::class.asClassName()
         )
       )

wire-tests/src/commonTest/kotlin/com/squareup/wire/KotlinBuildTest.kt

@@ -0,0 +1,26 @@
+package com.squareup.wire
+
+import com.squareup.wire.protos.kotlin.simple.buildersonly.SimpleMessage
+import kotlin.test.Test
+import kotlin.test.assertEquals
+
+class KotlinBuildTest {
+  @Test fun kotlinBuildEquivalentToBuilderResult() {
+    val kotlinBuildResult = SimpleMessage.build {
+      it.required_int32 = 4
+      it.optional_int32 = 5
+      it.optional_nested_msg = SimpleMessage.NestedMessage.build {
+        it.bb = 100
+      }
+    }
+    val builderResult = SimpleMessage.Builder()
+      .required_int32(4)
+      .optional_int32(5)
+      .optional_nested_msg(SimpleMessage.NestedMessage.Builder()
+        .bb(100)
+        .build()
+      ).build()
+
+    assertEquals(kotlinBuildResult, builderResult)
+  }
+}

wire-tests/src/commonTest/proto-kotlin/com/squareup/wire/protos/kotlin/redacted/buildersonly/NotRedacted.kt

@@ -17,6 +17,7 @@ import kotlin.Boolean
 import kotlin.Int
 import kotlin.Long
 import kotlin.String
+import kotlin.Unit
 import okio.ByteString
 
 public class NotRedacted private constructor(
@@ -148,5 +149,11 @@ public class NotRedacted private constructor(
     }
 
     private const val serialVersionUID: Long = 0L
+
+    public fun build(body: (Builder) -> Unit): NotRedacted {
+      val builder = Builder()
+      body(builder)
+      return builder.build()
+    }
   }
 }

wire-tests/src/commonTest/proto-kotlin/com/squareup/wire/protos/kotlin/redacted/buildersonly/RedactedChild.kt

@@ -17,6 +17,7 @@ import kotlin.Boolean
 import kotlin.Int
 import kotlin.Long
 import kotlin.String
+import kotlin.Unit
 import okio.ByteString
 
 public class RedactedChild private constructor(
@@ -174,5 +175,11 @@ public class RedactedChild private constructor(
     }
 
     private const val serialVersionUID: Long = 0L
+
+    public fun build(body: (Builder) -> Unit): RedactedChild {
+      val builder = Builder()
+      body(builder)
+      return builder.build()
+    }
   }
 }

wire-tests/src/commonTest/proto-kotlin/com/squareup/wire/protos/kotlin/redacted/buildersonly/RedactedCycleA.kt

@@ -16,6 +16,7 @@ import kotlin.Boolean
 import kotlin.Int
 import kotlin.Long
 import kotlin.String
+import kotlin.Unit
 import okio.ByteString
 
 public class RedactedCycleA private constructor(
@@ -124,5 +125,11 @@ public class RedactedCycleA private constructor(
     }
 
     private const val serialVersionUID: Long = 0L
+
+    public fun build(body: (Builder) -> Unit): RedactedCycleA {
+      val builder = Builder()
+      body(builder)
+      return builder.build()
+    }
   }
 }

wire-tests/src/commonTest/proto-kotlin/com/squareup/wire/protos/kotlin/redacted/buildersonly/RedactedCycleB.kt

@@ -16,6 +16,7 @@ import kotlin.Boolean
 import kotlin.Int
 import kotlin.Long
 import kotlin.String
+import kotlin.Unit
 import okio.ByteString
 
 public class RedactedCycleB private constructor(
@@ -124,5 +125,11 @@ public class RedactedCycleB private constructor(
     }
 
     private const val serialVersionUID: Long = 0L
+
+    public fun build(body: (Builder) -> Unit): RedactedCycleB {
+      val builder = Builder()
+      body(builder)
+      return builder.build()
+    }
   }
 }

wire-tests/src/commonTest/proto-kotlin/com/squareup/wire/protos/kotlin/redacted/buildersonly/RedactedExtension.kt

@@ -17,6 +17,7 @@ import kotlin.Boolean
 import kotlin.Int
 import kotlin.Long
 import kotlin.String
+import kotlin.Unit
 import okio.ByteString
 
 public class RedactedExtension private constructor(
@@ -150,5 +151,11 @@ public class RedactedExtension private constructor(
     }
 
     private const val serialVersionUID: Long = 0L
+
+    public fun build(body: (Builder) -> Unit): RedactedExtension {
+      val builder = Builder()
+      body(builder)
+      return builder.build()
+    }
   }
 }

wire-tests/src/commonTest/proto-kotlin/com/squareup/wire/protos/kotlin/redacted/buildersonly/RedactedFields.kt

@@ -17,6 +17,7 @@ import kotlin.Boolean
 import kotlin.Int
 import kotlin.Long
 import kotlin.String
+import kotlin.Unit
 import okio.ByteString
 
 public class RedactedFields private constructor(
@@ -202,5 +203,11 @@ public class RedactedFields private constructor(
     }
 
     private const val serialVersionUID: Long = 0L
+
+    public fun build(body: (Builder) -> Unit): RedactedFields {
+      val builder = Builder()
+      body(builder)
+      return builder.build()
+    }
   }
 }

wire-tests/src/commonTest/proto-kotlin/com/squareup/wire/protos/kotlin/redacted/buildersonly/RedactedRepeated.kt

@@ -19,6 +19,7 @@ import kotlin.Boolean
 import kotlin.Int
 import kotlin.Long
 import kotlin.String
+import kotlin.Unit
 import kotlin.collections.List
 import okio.ByteString
 
@@ -168,5 +169,11 @@ public class RedactedRepeated private constructor(
     }
 
     private const val serialVersionUID: Long = 0L
+
+    public fun build(body: (Builder) -> Unit): RedactedRepeated {
+      val builder = Builder()
+      body(builder)
+      return builder.build()
+    }
   }
 }

wire-tests/src/commonTest/proto-kotlin/com/squareup/wire/protos/kotlin/redacted/buildersonly/RedactedRequired.kt

@@ -16,6 +16,7 @@ import kotlin.Boolean
 import kotlin.Int
 import kotlin.Long
 import kotlin.String
+import kotlin.Unit
 import kotlin.UnsupportedOperationException
 import okio.ByteString
 
@@ -124,5 +125,11 @@ public class RedactedRequired private constructor(
     }
 
     private const val serialVersionUID: Long = 0L
+
+    public fun build(body: (Builder) -> Unit): RedactedRequired {
+      val builder = Builder()
+      body(builder)
+      return builder.build()
+    }
   }
 }