Generate Kotlin-esque build function for using closures rather than B…

…uilders

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-golden-files/src/main/kotlin/squareup/wire/alltypes/AllTypes.kt

@@ -57,6 +57,7 @@ import kotlin.IntArray
 import kotlin.Long
 import kotlin.LongArray
 import kotlin.String
+import kotlin.Unit
 import kotlin.collections.List
 import kotlin.collections.Map
 import kotlin.lazy
@@ -4496,6 +4497,8 @@ public class AllTypes private constructor(
     }
 
     private const val serialVersionUID: Long = 0L
+
+    public inline fun build(body: Builder.() -> Unit): AllTypes = Builder().apply(body).build()
   }
 
   public enum class NestedEnum(
@@ -4629,6 +4632,9 @@ public class AllTypes private constructor(
       }
 
       private const val serialVersionUID: Long = 0L
+
+      public inline fun build(body: Builder.() -> Unit): NestedMessage =
+          Builder().apply(body).build()
     }
   }
 }

wire-golden-files/src/main/kotlin/squareup/wire/boxedoneof/BoxedOneOfs.kt

@@ -151,5 +151,7 @@ public class BoxedOneOfs(
         VALUE_VALUE)
 
     private const val serialVersionUID: Long = 0L
+
+    public inline fun build(body: Builder.() -> Unit): BoxedOneOfs = Builder().apply(body).build()
   }
 }

wire-golden-files/src/main/kotlin/squareup/wire/buildersonly/SomeMessage.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 SomeMessage private constructor(
@@ -123,6 +124,8 @@ public class SomeMessage private constructor(
     }
 
     private const val serialVersionUID: Long = 0L
+
+    public inline fun build(body: Builder.() -> Unit): SomeMessage = Builder().apply(body).build()
   }
 
   public class NestedMessage private constructor(
@@ -230,6 +233,9 @@ public class SomeMessage private constructor(
       }
 
       private const val serialVersionUID: Long = 0L
+
+      public inline fun build(body: Builder.() -> Unit): NestedMessage =
+          Builder().apply(body).build()
     }
   }
 }

wire-gson-support/src/test/java/com/squareup/wire/proto2/dinosaurs/javainteropkotlin/Dinosaur.kt

@@ -21,6 +21,7 @@ import kotlin.Double
 import kotlin.Int
 import kotlin.Long
 import kotlin.String
+import kotlin.Unit
 import kotlin.collections.List
 import okio.ByteString
 
@@ -259,5 +260,7 @@ public class Dinosaur(
     }
 
     private const val serialVersionUID: Long = 0L
+
+    public inline fun build(body: Builder.() -> Unit): Dinosaur = Builder().apply(body).build()
   }
 }

wire-gson-support/src/test/java/squareup/proto2/keywords/KeywordKotlin.kt

@@ -24,6 +24,7 @@ import kotlin.Boolean
 import kotlin.Int
 import kotlin.Long
 import kotlin.String
+import kotlin.Unit
 import kotlin.collections.List
 import kotlin.collections.Map
 import kotlin.lazy
@@ -267,6 +268,8 @@ public class KeywordKotlin(
     }
 
     private const val serialVersionUID: Long = 0L
+
+    public inline fun build(body: Builder.() -> Unit): KeywordKotlin = Builder().apply(body).build()
   }
 
   public enum class KeywordKotlinEnum(

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

@@ -28,10 +28,12 @@ import com.squareup.kotlinpoet.INT
 import com.squareup.kotlinpoet.KModifier
 import com.squareup.kotlinpoet.KModifier.ABSTRACT
 import com.squareup.kotlinpoet.KModifier.CONST
+import com.squareup.kotlinpoet.KModifier.INLINE
 import com.squareup.kotlinpoet.KModifier.OVERRIDE
 import com.squareup.kotlinpoet.KModifier.PRIVATE
 import com.squareup.kotlinpoet.KModifier.PUBLIC
 import com.squareup.kotlinpoet.LONG
+import com.squareup.kotlinpoet.LambdaTypeName
 import com.squareup.kotlinpoet.MemberName
 import com.squareup.kotlinpoet.MemberName.Companion.member
 import com.squareup.kotlinpoet.NOTHING
@@ -548,6 +550,7 @@ class KotlinGenerator private constructor(
 
     addDefaultFields(type, companionBuilder, nameAllocator)
     addAdapter(type, companionBuilder)
+    if (buildersOnly || javaInterOp) addBuildClosure(type, companionBuilder, builderClassName)
 
     val classBuilder = TypeSpec.classBuilder(className)
       .apply {
@@ -1968,6 +1971,22 @@ class KotlinGenerator private constructor(
     }
   }
 
+  private fun addBuildClosure(type: MessageType, companionBuilder: TypeSpec.Builder, builderClassName: ClassName) {
+    val buildFn = FunSpec.builder("build")
+      .addModifiers(INLINE)
+      .addParameter("body",
+        LambdaTypeName.get(
+          receiver = builderClassName,
+          returnType = Unit::class.asClassName()
+        )
+      )
+      .addStatement("return %T().apply(body).build()", builderClassName)
+      .returns(generatedTypeName(type))
+      .build()
+
+    companionBuilder.addFunction(buildFn)
+  }
+
   private fun redactFun(message: MessageType): FunSpec {
     val className = typeToKotlinName.getValue(message.type) as ClassName
     val nameAllocator = nameAllocator(message)

wire-kotlin-generator/src/test/java/com/squareup/wire/kotlin/KotlinGeneratorTest.kt

@@ -1960,6 +1960,32 @@ class KotlinGeneratorTest {
     assertThat(code).doesNotContain("InnerMessage public constructor(")
   }
 
+  @Test
+  fun buildersOnlyOrJavaInteropGeneratesKotlinBuildClosure() {
+    val schema = buildSchema {
+      add(
+        "message.proto".toPath(),
+        """
+        |syntax = "proto2";
+        |message SomeMessage {
+        |  optional string a = 1;
+        |  optional string b = 2;
+        |}
+        |
+        """.trimMargin(),
+      )
+    }
+    val code = KotlinWithProfilesGenerator(schema)
+      .generateKotlin("SomeMessage", buildersOnly = false, javaInterop = false)
+    assertThat(code).doesNotContain("inline fun build(body: Builder.() -> Unit): SomeMessage")
+    val buildersOnlyCode = KotlinWithProfilesGenerator(schema)
+      .generateKotlin("SomeMessage", buildersOnly = true)
+    assertThat(buildersOnlyCode).contains("inline fun build(body: Builder.() -> Unit): SomeMessage")
+    val javaInteropCode = KotlinWithProfilesGenerator(schema)
+      .generateKotlin("SomeMessage", javaInterop = true)
+    assertThat(javaInteropCode).contains("inline fun build(body: Builder.() -> Unit): SomeMessage")
+  }
+
   @Test
   fun javaInteropAndBuildersOnly() {
     val schema = buildSchema {

wire-moshi-adapter/src/test/java/com/squareup/wire/proto2/dinosaurs/javainteropkotlin/Dinosaur.kt

@@ -21,6 +21,7 @@ import kotlin.Double
 import kotlin.Int
 import kotlin.Long
 import kotlin.String
+import kotlin.Unit
 import kotlin.collections.List
 import okio.ByteString
 
@@ -259,5 +260,7 @@ public class Dinosaur(
     }
 
     private const val serialVersionUID: Long = 0L
+
+    public inline fun build(body: Builder.() -> Unit): Dinosaur = Builder().apply(body).build()
   }
 }

wire-moshi-adapter/src/test/java/com/squareup/wire/proto2/person/javainteropkotlin/Person.kt

@@ -24,6 +24,7 @@ import kotlin.Boolean
 import kotlin.Int
 import kotlin.Long
 import kotlin.String
+import kotlin.Unit
 import kotlin.collections.List
 import okio.ByteString
 
@@ -249,6 +250,8 @@ public class Person(
     }
 
     private const val serialVersionUID: Long = 0L
+
+    public inline fun build(body: Builder.() -> Unit): Person = Builder().apply(body).build()
   }
 
   /**
@@ -439,6 +442,8 @@ public class Person(
       }
 
       private const val serialVersionUID: Long = 0L
+
+      public inline fun build(body: Builder.() -> Unit): PhoneNumber = Builder().apply(body).build()
     }
   }
 }

wire-moshi-adapter/src/test/java/squareup/proto2/keywords/KeywordKotlin.kt

@@ -24,6 +24,7 @@ import kotlin.Boolean
 import kotlin.Int
 import kotlin.Long
 import kotlin.String
+import kotlin.Unit
 import kotlin.collections.List
 import kotlin.collections.Map
 import kotlin.lazy
@@ -267,6 +268,8 @@ public class KeywordKotlin(
     }
 
     private const val serialVersionUID: Long = 0L
+
+    public inline fun build(body: Builder.() -> Unit): KeywordKotlin = Builder().apply(body).build()
   }
 
   public enum class KeywordKotlinEnum(

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

@@ -0,0 +1,43 @@
+/*
+ * Copyright (C) 2018 Square, Inc.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      https://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+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 bb = 100
+
+    val kotlinBuildResult = SimpleMessage.build {
+      required_int32 = 4
+      optional_int32 = 5
+      optional_nested_msg = SimpleMessage.NestedMessage.build {
+        this.bb = bb
+      }
+    }
+    val builderResult = SimpleMessage.Builder()
+      .required_int32(4)
+      .optional_int32(5)
+      .optional_nested_msg(SimpleMessage.NestedMessage.Builder()
+        .bb(bb)
+        .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 +149,7 @@ public class NotRedacted private constructor(
     }
 
     private const val serialVersionUID: Long = 0L
+
+    public inline fun build(body: Builder.() -> Unit): NotRedacted = Builder().apply(body).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 +175,7 @@ public class RedactedChild private constructor(
     }
 
     private const val serialVersionUID: Long = 0L
+
+    public inline fun build(body: Builder.() -> Unit): RedactedChild = Builder().apply(body).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 +125,8 @@ public class RedactedCycleA private constructor(
     }
 
     private const val serialVersionUID: Long = 0L
+
+    public inline fun build(body: Builder.() -> Unit): RedactedCycleA =
+        Builder().apply(body).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 +125,8 @@ public class RedactedCycleB private constructor(
     }
 
     private const val serialVersionUID: Long = 0L
+
+    public inline fun build(body: Builder.() -> Unit): RedactedCycleB =
+        Builder().apply(body).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 +151,8 @@ public class RedactedExtension private constructor(
     }
 
     private const val serialVersionUID: Long = 0L
+
+    public inline fun build(body: Builder.() -> Unit): RedactedExtension =
+        Builder().apply(body).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 +203,8 @@ public class RedactedFields private constructor(
     }
 
     private const val serialVersionUID: Long = 0L
+
+    public inline fun build(body: Builder.() -> Unit): RedactedFields =
+        Builder().apply(body).build()
   }
 }