Add @Json.ignore (#1417)

* Default Json.name to an unset value

* Promote shared transient tests to DualKotlinTest

* Add new ignore property to Json

* Support it in ClassJsonAdapter

* Mention no enum/record support

* Support in KotlinJsonAdapter

* Rework code gen API to know of "ignored"

* Support in apt code gen

* Support in KSP

* Update old non-working transient example test

* Synthetic holders

* Use field on both

kotlin/tests/extra-moshi-test-module/build.gradle.kts

@@ -17,3 +17,7 @@
 plugins {
   kotlin("jvm")
 }
+
+dependencies {
+  implementation(project(":moshi"))
+}

kotlin/tests/extra-moshi-test-module/src/main/kotlin/com/squareup/moshi/kotlin/codegen/test/extra/AbstractClassInModuleA.kt

@@ -15,10 +15,14 @@
  */
 package com.squareup.moshi.kotlin.codegen.test.extra
 
+import com.squareup.moshi.Json
+
 public abstract class AbstractClassInModuleA {
-  // Transients to ensure processor sees them across module boundaries since @Transient is
-  // SOURCE-only
-  // TODO uncomment these when https://github.com/google/ksp/issues/710 is fixed
-//  @Transient private lateinit var lateinitTransient: String
-//  @Transient private var regularTransient: String = "regularTransient"
+  // Ignored to ensure processor sees them across module boundaries.
+  // @Transient doesn't work for this case because it's source-only and jvm modifiers aren't currently visible in KSP.
+
+  // Note that we target the field because otherwise it is stored on the synthetic holder method for
+  // annotations, which isn't visible from kapt
+  @field:Json(ignore = true) private lateinit var lateinitIgnored: String
+  @field:Json(ignore = true) private var regularIgnored: String = "regularIgnored"
 }

kotlin/tests/src/test/kotlin/com/squareup/moshi/kotlin/DualKotlinTest.kt

@@ -625,6 +625,124 @@ class DualKotlinTest {
   data class IntersectionTypes<E>(
     val value: E
   ) where E : Enum<E>, E : IntersectionTypeInterface<E>
+
+  @Test fun transientConstructorParameter() {
+    val moshi = Moshi.Builder().add(KotlinJsonAdapterFactory()).build()
+    val jsonAdapter = moshi.adapter<TransientConstructorParameter>()
+
+    val encoded = TransientConstructorParameter(3, 5)
+    assertThat(jsonAdapter.toJson(encoded)).isEqualTo("""{"b":5}""")
+
+    val decoded = jsonAdapter.fromJson("""{"a":4,"b":6}""")!!
+    assertThat(decoded.a).isEqualTo(-1)
+    assertThat(decoded.b).isEqualTo(6)
+  }
+
+  class TransientConstructorParameter(@Transient var a: Int = -1, var b: Int = -1)
+
+  @Test fun multipleTransientConstructorParameters() {
+    val moshi = Moshi.Builder().add(KotlinJsonAdapterFactory()).build()
+    val jsonAdapter = moshi.adapter(MultipleTransientConstructorParameters::class.java)
+
+    val encoded = MultipleTransientConstructorParameters(3, 5, 7)
+    assertThat(jsonAdapter.toJson(encoded)).isEqualTo("""{"b":5}""")
+
+    val decoded = jsonAdapter.fromJson("""{"a":4,"b":6}""")!!
+    assertThat(decoded.a).isEqualTo(-1)
+    assertThat(decoded.b).isEqualTo(6)
+    assertThat(decoded.c).isEqualTo(-1)
+  }
+
+  class MultipleTransientConstructorParameters(@Transient var a: Int = -1, var b: Int = -1, @Transient var c: Int = -1)
+
+  @Test fun transientProperty() {
+    val moshi = Moshi.Builder().add(KotlinJsonAdapterFactory()).build()
+    val jsonAdapter = moshi.adapter<TransientProperty>()
+
+    val encoded = TransientProperty()
+    encoded.a = 3
+    encoded.setB(4)
+    encoded.c = 5
+    assertThat(jsonAdapter.toJson(encoded)).isEqualTo("""{"c":5}""")
+
+    val decoded = jsonAdapter.fromJson("""{"a":4,"b":5,"c":6}""")!!
+    assertThat(decoded.a).isEqualTo(-1)
+    assertThat(decoded.getB()).isEqualTo(-1)
+    assertThat(decoded.c).isEqualTo(6)
+  }
+
+  class TransientProperty {
+    @Transient var a: Int = -1
+    @Transient private var b: Int = -1
+    var c: Int = -1
+
+    fun getB() = b
+
+    fun setB(b: Int) {
+      this.b = b
+    }
+  }
+
+  @Test fun ignoredConstructorParameter() {
+    val moshi = Moshi.Builder().add(KotlinJsonAdapterFactory()).build()
+    val jsonAdapter = moshi.adapter<IgnoredConstructorParameter>()
+
+    val encoded = IgnoredConstructorParameter(3, 5)
+    assertThat(jsonAdapter.toJson(encoded)).isEqualTo("""{"b":5}""")
+
+    val decoded = jsonAdapter.fromJson("""{"a":4,"b":6}""")!!
+    assertThat(decoded.a).isEqualTo(-1)
+    assertThat(decoded.b).isEqualTo(6)
+  }
+
+  class IgnoredConstructorParameter(@Json(ignore = true) var a: Int = -1, var b: Int = -1)
+
+  @Test fun multipleIgnoredConstructorParameters() {
+    val moshi = Moshi.Builder().add(KotlinJsonAdapterFactory()).build()
+    val jsonAdapter = moshi.adapter(MultipleIgnoredConstructorParameters::class.java)
+
+    val encoded = MultipleIgnoredConstructorParameters(3, 5, 7)
+    assertThat(jsonAdapter.toJson(encoded)).isEqualTo("""{"b":5}""")
+
+    val decoded = jsonAdapter.fromJson("""{"a":4,"b":6}""")!!
+    assertThat(decoded.a).isEqualTo(-1)
+    assertThat(decoded.b).isEqualTo(6)
+    assertThat(decoded.c).isEqualTo(-1)
+  }
+
+  class MultipleIgnoredConstructorParameters(
+    @Json(ignore = true) var a: Int = -1,
+    var b: Int = -1,
+    @Json(ignore = true) var c: Int = -1
+  )
+
+  @Test fun ignoredProperty() {
+    val moshi = Moshi.Builder().add(KotlinJsonAdapterFactory()).build()
+    val jsonAdapter = moshi.adapter<IgnoredProperty>()
+
+    val encoded = IgnoredProperty()
+    encoded.a = 3
+    encoded.setB(4)
+    encoded.c = 5
+    assertThat(jsonAdapter.toJson(encoded)).isEqualTo("""{"c":5}""")
+
+    val decoded = jsonAdapter.fromJson("""{"a":4,"b":5,"c":6}""")!!
+    assertThat(decoded.a).isEqualTo(-1)
+    assertThat(decoded.getB()).isEqualTo(-1)
+    assertThat(decoded.c).isEqualTo(6)
+  }
+
+  class IgnoredProperty {
+    @Json(ignore = true) var a: Int = -1
+    @Json(ignore = true) private var b: Int = -1
+    var c: Int = -1
+
+    fun getB() = b
+
+    fun setB(b: Int) {
+      this.b = b
+    }
+  }
 }
 
 typealias TypeAlias = Int

kotlin/tests/src/test/kotlin/com/squareup/moshi/kotlin/reflect/KotlinJsonAdapterTest.kt

@@ -278,35 +278,6 @@ class KotlinJsonAdapterTest {
     var b: Int = -1
   }
 
-  @Test fun transientConstructorParameter() {
-    val moshi = Moshi.Builder().add(KotlinJsonAdapterFactory()).build()
-    val jsonAdapter = moshi.adapter<TransientConstructorParameter>()
-
-    val encoded = TransientConstructorParameter(3, 5)
-    assertThat(jsonAdapter.toJson(encoded)).isEqualTo("""{"b":5}""")
-
-    val decoded = jsonAdapter.fromJson("""{"a":4,"b":6}""")!!
-    assertThat(decoded.a).isEqualTo(-1)
-    assertThat(decoded.b).isEqualTo(6)
-  }
-
-  class TransientConstructorParameter(@Transient var a: Int = -1, var b: Int = -1)
-
-  @Test fun multipleTransientConstructorParameters() {
-    val moshi = Moshi.Builder().add(KotlinJsonAdapterFactory()).build()
-    val jsonAdapter = moshi.adapter(MultipleTransientConstructorParameters::class.java)
-
-    val encoded = MultipleTransientConstructorParameters(3, 5, 7)
-    assertThat(jsonAdapter.toJson(encoded)).isEqualTo("""{"b":5}""")
-
-    val decoded = jsonAdapter.fromJson("""{"a":4,"b":6}""")!!
-    assertThat(decoded.a).isEqualTo(-1)
-    assertThat(decoded.b).isEqualTo(6)
-    assertThat(decoded.c).isEqualTo(-1)
-  }
-
-  class MultipleTransientConstructorParameters(@Transient var a: Int = -1, var b: Int = -1, @Transient var c: Int = -1)
-
   @Test fun requiredTransientConstructorParameterFails() {
     val moshi = Moshi.Builder().add(KotlinJsonAdapterFactory()).build()
     try {
@@ -323,34 +294,22 @@ class KotlinJsonAdapterTest {
 
   class RequiredTransientConstructorParameter(@Transient var a: Int)
 
-  @Test fun transientProperty() {
+  @Test fun requiredIgnoredConstructorParameterFails() {
     val moshi = Moshi.Builder().add(KotlinJsonAdapterFactory()).build()
-    val jsonAdapter = moshi.adapter<TransientProperty>()
-
-    val encoded = TransientProperty()
-    encoded.a = 3
-    encoded.setB(4)
-    encoded.c = 5
-    assertThat(jsonAdapter.toJson(encoded)).isEqualTo("""{"c":5}""")
-
-    val decoded = jsonAdapter.fromJson("""{"a":4,"b":5,"c":6}""")!!
-    assertThat(decoded.a).isEqualTo(-1)
-    assertThat(decoded.getB()).isEqualTo(-1)
-    assertThat(decoded.c).isEqualTo(6)
-  }
-
-  class TransientProperty {
-    @Transient var a: Int = -1
-    @Transient private var b: Int = -1
-    var c: Int = -1
-
-    fun getB() = b
-
-    fun setB(b: Int) {
-      this.b = b
+    try {
+      moshi.adapter<RequiredIgnoredConstructorParameter>()
+      fail()
+    } catch (expected: IllegalArgumentException) {
+      assertThat(expected).hasMessageThat().isEqualTo(
+        "No default value for ignored constructor parameter #0 " +
+          "a of fun <init>(kotlin.Int): " +
+          "com.squareup.moshi.kotlin.reflect.KotlinJsonAdapterTest.RequiredIgnoredConstructorParameter"
+      )
     }
   }
 
+  class RequiredIgnoredConstructorParameter(@Json(ignore = true) var a: Int)
+
   @Test fun constructorParametersAndPropertiesWithSameNamesMustHaveSameTypes() {
     val moshi = Moshi.Builder().add(KotlinJsonAdapterFactory()).build()
     try {