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"
 }