Deprecated SingletonSupport

release-notes/CREDITS-2.x

@@ -18,6 +18,7 @@ Contributors:
 # 2.17.0 (not yet released)
 
 WrongWrong (@k163377)
+* #758: Deprecated SingletonSupport.
 * #755: Changes in constructor invocation and argument management.
 * #752: Fix KDoc for KotlinModule.
 * #751: Marked useKotlinPropertyNameForGetter as deprecated.

release-notes/VERSION-2.x

@@ -18,6 +18,7 @@ Co-maintainers:
 
 2.17.0 (not yet released)
 
+#758: Deprecated SingletonSupport and related properties to be consistent with KotlinFeature.SingletonSupport.
 #755: Changes in constructor invocation and argument management.
  This change degrades performance in cases where the constructor is called without default arguments, but improves performance in other cases.
 #751: The KotlinModule#useKotlinPropertyNameForGetter property was deprecated because it differed from the name of the KotlinFeature.

src/main/kotlin/com/fasterxml/jackson/module/kotlin/KotlinModule.kt

@@ -25,6 +25,8 @@ fun Class<*>.isKotlinClass(): Boolean = this.isAnnotationPresent(Metadata::class
  *  using the default value provided in Kotlin.
  * @property singletonSupport        Default: DISABLED.  Mode for singleton handling.
  *  See {@link com.fasterxml.jackson.module.kotlin.SingletonSupport label}
+ * @property enabledSingletonSupport Default: false.  A temporary property that is maintained until the return value of `singletonSupport` is changed.
+ *  It will be removed in 2.21.
  * @property strictNullChecks        Default: false.  Whether to check deserialized collections.  With this disabled,
  *  the default, collections which are typed to disallow null members
  *  (e.g. List<String>) may contain null values after deserialization.  Enabling it
@@ -53,6 +55,11 @@ class KotlinModule @Deprecated(
     val nullToEmptyCollection: Boolean = NullToEmptyCollection.enabledByDefault,
     val nullToEmptyMap: Boolean = NullToEmptyMap.enabledByDefault,
     val nullIsSameAsDefault: Boolean = NullIsSameAsDefault.enabledByDefault,
+    @property:Deprecated(
+        level = DeprecationLevel.WARNING,
+        message = "The return value will be Boolean in 2.19. Until then, use enabledSingletonSupport.",
+        replaceWith = ReplaceWith("enabledSingletonSupport")
+    )
     val singletonSupport: SingletonSupport = DISABLED,
     val strictNullChecks: Boolean = StrictNullChecks.enabledByDefault,
     @Deprecated(
@@ -65,6 +72,7 @@ class KotlinModule @Deprecated(
     val useJavaDurationConversion: Boolean = UseJavaDurationConversion.enabledByDefault,
 ) : SimpleModule(KotlinModule::class.java.name, PackageVersion.VERSION) {
     val kotlinPropertyNameAsImplicitName: Boolean get() = useKotlinPropertyNameForGetter
+    val enabledSingletonSupport: Boolean get() = singletonSupport == CANONICALIZE
 
     companion object {
         // Increment when option is added

src/main/kotlin/com/fasterxml/jackson/module/kotlin/SingletonSupport.kt

@@ -3,6 +3,11 @@ package com.fasterxml.jackson.module.kotlin
 /**
  * Special handling for singletons.
  */
+@Deprecated(
+    level = DeprecationLevel.WARNING,
+    message = "It will be removed in 2.19 to unify with KotlinFeature.",
+    replaceWith = ReplaceWith("KotlinFeature.SingletonSupport")
+)
 enum class SingletonSupport {
     // No special handling of singletons (pre-2.10 behavior)
     //      Each time a Singleton object is deserialized a new instance is created.

src/test/kotlin/com/fasterxml/jackson/module/kotlin/KotlinModuleTest.kt

@@ -18,6 +18,7 @@ class KotlinModuleTest {
         assertFalse(module.nullToEmptyMap)
         assertFalse(module.nullIsSameAsDefault)
         assertEquals(SingletonSupport.DISABLED, module.singletonSupport)
+        assertFalse(module.enabledSingletonSupport)
         assertFalse(module.strictNullChecks)
         assertFalse(module.kotlinPropertyNameAsImplicitName)
         assertFalse(module.useJavaDurationConversion)
@@ -41,6 +42,7 @@ class KotlinModuleTest {
         assertTrue(module.nullToEmptyMap)
         assertTrue(module.nullIsSameAsDefault)
         assertEquals(SingletonSupport.CANONICALIZE, module.singletonSupport)
+        assertTrue(module.enabledSingletonSupport)
         assertTrue(module.strictNullChecks)
         assertTrue(module.kotlinPropertyNameAsImplicitName)
         assertTrue(module.useJavaDurationConversion)