Add documentation on using typealias for means of global configuration

Also add tests on various `@Serializable` applications

Apply suggestions from code review

Co-authored-by: Vsevolod Tolstopyatov <qwwdfsad@gmail.com>

1 files changed, 94 insertions, 0 deletions

diff --git a/formats/json-tests/commonTest/src/kotlinx/serialization/SerializableOnPropertyTypeAndTypealiasTest.kt b/formats/json-tests/commonTest/src/kotlinx/serialization/SerializableOnPropertyTypeAndTypealiasTest.kt
new file mode 100644
index 00000000..d6f14bd9
--- /dev/null
+++ b/formats/json-tests/commonTest/src/kotlinx/serialization/SerializableOnPropertyTypeAndTypealiasTest.kt
@@ -0,0 +1,94 @@
+package kotlinx.serialization
+
+import kotlinx.serialization.descriptors.*
+import kotlinx.serialization.encoding.*
+import kotlinx.serialization.json.*
+import kotlin.test.*
+
+@Serializable
+data class WithDefault(val s: String)
+
+@Serializable(SerializerA::class)
+data class WithoutDefault(val s: String)
+
+object SerializerA : KSerializer<WithoutDefault> {
+    override val descriptor: SerialDescriptor
+        get() = PrimitiveSerialDescriptor("Bruh", PrimitiveKind.STRING)
+
+    override fun serialize(encoder: Encoder, value: WithoutDefault) {
+        encoder.encodeString(value.s)
+    }
+
+    override fun deserialize(decoder: Decoder): WithoutDefault {
+        return WithoutDefault(decoder.decodeString())
+    }
+}
+
+object SerializerB : KSerializer<WithoutDefault> {
+    override val descriptor: SerialDescriptor
+        get() = PrimitiveSerialDescriptor("Bruh", PrimitiveKind.STRING)
+
+    override fun serialize(encoder: Encoder, value: WithoutDefault) {
+        encoder.encodeString(value.s + "#")
+    }
+
+    override fun deserialize(decoder: Decoder): WithoutDefault {
+        return WithoutDefault(decoder.decodeString().removeSuffix("#"))
+    }
+}
+
+object SerializerC : KSerializer<WithDefault> {
+    override val descriptor: SerialDescriptor
+        get() = PrimitiveSerialDescriptor("Bruh", PrimitiveKind.STRING)
+
+    override fun serialize(encoder: Encoder, value: WithDefault) {
+        encoder.encodeString(value.s + "#")
+    }
+
+    override fun deserialize(decoder: Decoder): WithDefault {
+        return WithDefault(decoder.decodeString().removeSuffix("#"))
+    }
+}
+
+typealias WithoutDefaultAlias = @Serializable(SerializerB::class) WithoutDefault
+typealias WithDefaultAlias = @Serializable(SerializerC::class) WithDefault
+
+@Serializable
+data class TesterWithoutDefault(
+    val b1: WithoutDefault,
+    @Serializable(SerializerB::class) val b2: WithoutDefault,
+    val b3: @Serializable(SerializerB::class) WithoutDefault,
+    val b4: WithoutDefaultAlias
+)
+
+@Serializable
+data class TesterWithDefault(
+    val b1: WithDefault,
+    @Serializable(SerializerC::class) val b2: WithDefault,
+    val b3: @Serializable(SerializerC::class) WithDefault,
+    val b4: WithDefaultAlias
+)
+
+class SerializableOnPropertyTypeAndTypealiasTest : JsonTestBase() {
+
+    @Test
+    fun testWithDefault() {
+        val t = TesterWithDefault(WithDefault("a"), WithDefault("b"), WithDefault("c"), WithDefault("d"))
+        assertJsonFormAndRestored(
+            TesterWithDefault.serializer(),
+            t,
+            """{"b1":{"s":"a"},"b2":"b#","b3":"c#","b4":"d#"}"""
+        )
+    }
+
+    @Test
+    @Ignore // TODO: Unignore in 1.8.20 (#1895)
+    fun testWithoutDefault() {
+        val t = TesterWithoutDefault(WithoutDefault("a"), WithoutDefault("b"), WithoutDefault("c"), WithoutDefault("d"))
+        assertJsonFormAndRestored(
+            TesterWithoutDefault.serializer(),
+            t,
+            """{"b1":"a","b2":"b#","b3":"c#","b4":"d#"}"""
+        )
+    }
+}