Add enum-typed flags to Gradle DSL (#162)

featured-gradle-plugin/CLAUDE.md

@@ -13,6 +13,7 @@ featured {
     localFlags {
         boolean("dark_mode", default = false) { category = "UI" }
         int("max_retries", default = 3)
+        enum("checkout_variant", typeFqn = "com.example.CheckoutVariant", default = "LEGACY")
     }
     remoteFlags {
         boolean("promo_banner", default = false) { description = "Show promo banner" }

featured-gradle-plugin/src/main/kotlin/dev/androidbroadcast/featured/gradle/ConfigParamGenerator.kt

@@ -63,10 +63,11 @@ public object ConfigParamGenerator {
     }
 
     private fun LocalFlagEntry.formatDefault(): String =
-        when (type) {
-            "String" -> defaultValue
-            "Long" -> "${defaultValue}L"
-            "Float" -> "${defaultValue}f"
+        when {
+            isEnum -> "$type.$defaultValue"
+            type == "String" -> defaultValue
+            type == "Long" -> "${defaultValue}L"
+            type == "Float" -> "${defaultValue}f"
             else -> defaultValue
         }
 }

featured-gradle-plugin/src/main/kotlin/dev/androidbroadcast/featured/gradle/FlagContainer.kt

@@ -10,6 +10,7 @@ package dev.androidbroadcast.featured.gradle
  *         boolean("dark_mode", default = false) { category = "UI" }
  *         int("retry_count", default = 3)
  *         string("api_base_url", default = "https://example.com")
+ *         enum("checkout_variant", typeFqn = "com.example.CheckoutVariant", default = "LEGACY")
  *     }
  *     remoteFlags {
  *         boolean("promo_banner_enabled", default = false) {
@@ -80,6 +81,29 @@ public class FlagContainer {
         _flags += FlagSpec(key, "\"$default\"", "String").apply(configure)
     }
 
+    /**
+     * Declares an enum-typed feature flag.
+     *
+     * Enum flags are intentionally excluded from R8 `-assumevalues` DCE rules — the value
+     * cannot be assumed at build time (it is resolved at runtime from providers).
+     *
+     * @param key The configuration key string (e.g. `"checkout_variant"`).
+     * @param typeFqn The fully-qualified Kotlin class name of the enum (e.g. `"com.example.CheckoutVariant"`).
+     * @param default The name of the default enum constant (e.g. `"LEGACY"`).
+     * @param configure Optional block to set [FlagSpec.description], [FlagSpec.category], or [FlagSpec.expiresAt].
+     */
+    public fun enum(
+        key: String,
+        typeFqn: String,
+        default: String,
+        configure: FlagSpec.() -> Unit = {},
+    ) {
+        require('.' in typeFqn) {
+            "typeFqn must be a fully-qualified class name (e.g. \"com.example.MyEnum\"), got \"$typeFqn\""
+        }
+        _flags += FlagSpec(key = key, defaultValue = default, type = typeFqn).apply(configure)
+    }
+
     /** Serialises all flags to pipe-delimited descriptors for [ResolveFlagsTask] inputs. */
     internal fun toDescriptors(): List<String> = _flags.map { it.toDescriptor() }
 }

featured-gradle-plugin/src/main/kotlin/dev/androidbroadcast/featured/gradle/FlagEntryUtils.kt

@@ -36,7 +36,7 @@ internal fun String.capitalized(): String = replaceFirstChar { it.uppercase() }
  * Returns the name of the generated `ConfigValues` extension function for this flag.
  *
  * - Boolean flags: `is<Name>Enabled` (e.g. `isDarkModeEnabled`)
- * - All other types: `get<Name>` (e.g. `getMaxRetries`)
+ * - All other types (including enum): `get<Name>` (e.g. `getMaxRetries`, `getCheckoutVariant`)
  */
 internal fun LocalFlagEntry.extensionFunctionName(): String {
     val capitalized = propertyName.capitalized()

featured-gradle-plugin/src/main/kotlin/dev/androidbroadcast/featured/gradle/FlagSpec.kt

@@ -5,7 +5,8 @@ package dev.androidbroadcast.featured.gradle
  *
  * @property key The configuration key string (e.g. `"dark_mode"`). Acts as the unique identifier.
  * @property defaultValue The default value serialised to a string (e.g. `"false"`, `"42"`).
- * @property type The Kotlin type name: `"Boolean"`, `"Int"`, `"Long"`, `"Float"`, `"Double"`, or `"String"`.
+ * @property type The Kotlin type name: `"Boolean"`, `"Int"`, `"Long"`, `"Float"`, `"Double"`, `"String"`,
+ *   or a fully-qualified enum class name (e.g. `"com.example.CheckoutVariant"`).
  * @property description Optional human-readable description passed to the generated [ConfigParam].
  * @property category Optional grouping label shown in the debug UI.
  * @property expiresAt Optional ISO-8601 date (`"YYYY-MM-DD"`) after which the flag is considered stale.

featured-gradle-plugin/src/main/kotlin/dev/androidbroadcast/featured/gradle/IosConstValGenerator.kt

@@ -15,21 +15,28 @@ private const val HEADER = "// Auto-generated by featured-gradle-plugin — do n
  *
  * String values are wrapped in double-quotes; all other primitive types are emitted
  * verbatim (matching Kotlin literal syntax for Boolean, Int, Long, Double, Float).
+ *
+ * **Enum flags are not supported** — Kotlin `const val` only accepts primitive types
+ * and `String`. Enum entries are silently skipped in both [generate] and [generateExpect].
  */
 public object IosConstValGenerator {
     /**
      * Generates the `iosMain` Kotlin source file containing `actual const val`
      * declarations for every entry in [entries].
      *
-     * Returns a blank string when [entries] is empty.
+     * Enum-typed entries (detected via [LocalFlagEntry.isEnum]) are excluded because
+     * `const val` does not support enum types.
+     *
+     * Returns a blank string when [entries] is empty or all entries are enums.
      */
     public fun generate(entries: List<LocalFlagEntry>): String {
-        if (entries.isEmpty()) return ""
+        val eligible = entries.filterNot { it.isEnum }
+        if (eligible.isEmpty()) return ""
         return buildString {
             appendLine(HEADER)
             appendLine("package $GENERATED_PACKAGE")
             appendLine()
-            entries.forEach { entry ->
+            eligible.forEach { entry ->
                 appendLine(actualDeclaration(entry))
             }
         }
@@ -39,15 +46,19 @@ public object IosConstValGenerator {
      * Generates the `commonMain` Kotlin source file containing `expect val`
      * declarations for every entry in [entries].
      *
-     * Returns a blank string when [entries] is empty.
+     * Enum-typed entries (detected via [LocalFlagEntry.isEnum]) are excluded because
+     * `const val` does not support enum types.
+     *
+     * Returns a blank string when [entries] is empty or all entries are enums.
      */
     public fun generateExpect(entries: List<LocalFlagEntry>): String {
-        if (entries.isEmpty()) return ""
+        val eligible = entries.filterNot { it.isEnum }
+        if (eligible.isEmpty()) return ""
         return buildString {
             appendLine(HEADER)
             appendLine("package $GENERATED_PACKAGE")
             appendLine()
-            entries.forEach { entry ->
+            eligible.forEach { entry ->
                 appendLine("public expect val ${entry.key}: ${entry.type}")
             }
         }

featured-gradle-plugin/src/main/kotlin/dev/androidbroadcast/featured/gradle/LocalFlagEntry.kt

@@ -5,7 +5,8 @@ package dev.androidbroadcast.featured.gradle
  *
  * @property key The configuration key string (e.g. `"dark_mode"`).
  * @property defaultValue The default value as a raw string (e.g. `"false"`, `"42"`).
- * @property type The Kotlin type name: `"Boolean"`, `"Int"`, `"Long"`, `"Float"`, `"Double"`, or `"String"`.
+ * @property type The Kotlin type name: `"Boolean"`, `"Int"`, `"Long"`, `"Float"`, `"Double"`, `"String"`,
+ *   or a fully-qualified enum class name (e.g. `"com.example.CheckoutVariant"`).
  * @property moduleName The Gradle module path that declares this flag (e.g. `":feature:checkout"`).
  * @property propertyName The camelCase property name derived from [key] (e.g. `"darkMode"`).
  * @property flagType Either `"local"` or `"remote"`.
@@ -26,6 +27,17 @@ public data class LocalFlagEntry(
 ) {
     public val isLocal: Boolean get() = flagType == FLAG_TYPE_LOCAL
 
+    /**
+     * Returns `true` when this flag's type is an enum (i.e. a fully-qualified class name
+     * containing a `.`) rather than a built-in Kotlin primitive or `String`.
+     *
+     * Enum flags require special handling in code generators:
+     * - ProGuard `-assumevalues` rules are skipped (enum values are not assumable at build time).
+     * - iOS `const val` generation is skipped (`const` only supports primitive types and `String`).
+     * - The generated `ConfigParam` default expression uses `TypeFqn.CONSTANT_NAME` syntax.
+     */
+    public val isEnum: Boolean get() = '.' in type
+
     /**
      * Returns the Kotlin reference used in the generated `FlagRegistry.register(...)` call.
      *

featured-gradle-plugin/src/main/kotlin/dev/androidbroadcast/featured/gradle/ProguardRulesGenerator.kt

@@ -18,6 +18,10 @@ package dev.androidbroadcast.featured.gradle
  * cannot be assumed at build time.
  *
  * Supported return types: `boolean`, `int`, `long`, `float`, `double`, `java.lang.String`.
+ *
+ * **Enum flags are intentionally excluded** — their runtime values are resolved from providers
+ * and cannot be assumed at build time (see issue #162). [jvmType] returns `null` for any
+ * unrecognised type (including enum FQNs), which causes those entries to be filtered out.
  */
 public object ProguardRulesGenerator {
     private const val PACKAGE = "dev.androidbroadcast.featured.generated"

featured-gradle-plugin/src/test/fixtures/android-project/build.gradle.kts

@@ -25,5 +25,6 @@ android {
 featured {
     localFlags {
         boolean("dark_mode", default = false)
+        enum("checkout_variant", typeFqn = "dev.androidbroadcast.featured.testapp.CheckoutVariant", default = "LEGACY")
     }
 }

featured-gradle-plugin/src/test/fixtures/android-project/src/main/kotlin/dev/androidbroadcast/featured/testapp/CheckoutVariant.kt

@@ -0,0 +1,6 @@
+package dev.androidbroadcast.featured.testapp
+
+enum class CheckoutVariant {
+    LEGACY,
+    NEW,
+}

featured-gradle-plugin/src/test/kotlin/dev/androidbroadcast/featured/gradle/ConfigParamGeneratorTest.kt

@@ -129,6 +129,29 @@ class ConfigParamGeneratorTest {
         assertContains(local, "Auto-generated by Featured Gradle Plugin")
     }
 
+    // ── enum flags ────────────────────────────────────────────────────────────
+
+    @Test
+    fun `generates enum ConfigParam with fqn type argument`() {
+        val entries = listOf(localEntry("checkout_variant", "LEGACY", "com.example.CheckoutVariant"))
+        val (local, _) = ConfigParamGenerator.generate(entries)
+        assertContains(local, "ConfigParam<com.example.CheckoutVariant>")
+    }
+
+    @Test
+    fun `enum default value uses fqn dot constant syntax`() {
+        val entries = listOf(localEntry("checkout_variant", "LEGACY", "com.example.CheckoutVariant"))
+        val (local, _) = ConfigParamGenerator.generate(entries)
+        assertContains(local, "defaultValue = com.example.CheckoutVariant.LEGACY")
+    }
+
+    @Test
+    fun `enum flag is included in local object`() {
+        val entries = listOf(localEntry("checkout_variant", "LEGACY", "com.example.CheckoutVariant"))
+        val (local, _) = ConfigParamGenerator.generate(entries)
+        assertContains(local, "val checkoutVariant = ConfigParam<com.example.CheckoutVariant>")
+    }
+
     // ── helpers ───────────────────────────────────────────────────────────────
 
     private fun localEntry(

featured-gradle-plugin/src/test/kotlin/dev/androidbroadcast/featured/gradle/ExtensionFunctionGeneratorTest.kt

@@ -78,6 +78,23 @@ class ExtensionFunctionGeneratorTest {
         assertContains(source, "fun ConfigValues.getApiUrl(): String")
     }
 
+    // ── local enum flag ───────────────────────────────────────────────────────
+
+    @Test
+    fun `generates get… extension for local enum flag`() {
+        val entries = listOf(localEntry("checkout_variant", "com.example.CheckoutVariant"))
+        val source = ExtensionFunctionGenerator.generate(entries, modulePath)
+        assertContains(source, "fun ConfigValues.getCheckoutVariant(): com.example.CheckoutVariant")
+        assertContains(source, "getValue(GeneratedLocalFlags.checkoutVariant).value")
+    }
+
+    @Test
+    fun `enum extension uses get… prefix, not is…Enabled`() {
+        val entries = listOf(localEntry("checkout_variant", "com.example.CheckoutVariant"))
+        val source = ExtensionFunctionGenerator.generate(entries, modulePath)
+        assertFalse(source.contains("isCheckoutVariantEnabled"), "Enum flag must not use is…Enabled naming")
+    }
+
     // ── remote flag ───────────────────────────────────────────────────────────
 
     @Test

featured-gradle-plugin/src/test/kotlin/dev/androidbroadcast/featured/gradle/FeaturedPluginIntegrationTest.kt

@@ -100,7 +100,8 @@ class FeaturedPluginIntegrationTest {
 
     /**
      * Asserts that [content] contains a well-formed `-assumevalues` block targeting the
-     * extensions class for the root module (`:`) and the `dark_mode` boolean flag.
+     * extensions class for the root module (`:`) and the `dark_mode` boolean flag,
+     * and that the enum flag `checkout_variant` is NOT present in the rules.
      *
      * Expected output (from [ProguardRulesGenerator]):
      * ```proguard
@@ -111,6 +112,9 @@ class FeaturedPluginIntegrationTest {
      *
      * The root module path `:` produces the identifier `Root` via [String.modulePathToIdentifier],
      * so the JVM class name is `FeaturedRoot_FlagExtensionsKt`.
+     *
+     * Enum flags (`checkout_variant`) must not appear in `-assumevalues` rules — their values
+     * are resolved at runtime from providers and cannot be assumed at build time (issue #162).
      */
     private fun assertContainsAssumevaluesBlock(content: String) {
         assertTrue(
@@ -121,6 +125,10 @@ class FeaturedPluginIntegrationTest {
             content.contains("boolean $IS_DARK_MODE_ENABLED($CONFIG_VALUES_FQN) return false;"),
             "Expected 'boolean $IS_DARK_MODE_ENABLED($CONFIG_VALUES_FQN) return false;' in rules\nActual content:\n$content",
         )
+        assertTrue(
+            !content.contains("checkoutVariant"),
+            "Enum flag 'checkout_variant' must not appear in -assumevalues rules\nActual content:\n$content",
+        )
     }
 
     // ── Helpers ───────────────────────────────────────────────────────────────

featured-gradle-plugin/src/test/kotlin/dev/androidbroadcast/featured/gradle/FlagContainerTest.kt

@@ -101,4 +101,42 @@ class FlagContainerTest {
     fun `empty container has no flags`() {
         assertTrue(FlagContainer().flags.isEmpty())
     }
+
+    @Test
+    fun `enum flag stores fully-qualified type name`() {
+        val container =
+            FlagContainer().apply {
+                enum("checkout_variant", typeFqn = "com.example.CheckoutVariant", default = "LEGACY")
+            }
+        val flag = container.flags.single()
+        assertEquals("checkout_variant", flag.key)
+        assertEquals("com.example.CheckoutVariant", flag.type)
+        assertEquals("LEGACY", flag.defaultValue)
+    }
+
+    @Test
+    fun `enum flag configure block sets description and category`() {
+        val container =
+            FlagContainer().apply {
+                enum("checkout_variant", typeFqn = "com.example.CheckoutVariant", default = "LEGACY") {
+                    description = "Checkout flow variant"
+                    category = "Checkout"
+                }
+            }
+        val flag = container.flags.single()
+        assertEquals("Checkout flow variant", flag.description)
+        assertEquals("Checkout", flag.category)
+    }
+
+    @Test
+    fun `enum flag descriptor contains type fqn and default constant`() {
+        val container =
+            FlagContainer().apply {
+                enum("checkout_variant", typeFqn = "com.example.CheckoutVariant", default = "LEGACY")
+            }
+        val descriptor = container.toDescriptors().single()
+        assertContains(descriptor, "checkout_variant")
+        assertContains(descriptor, "com.example.CheckoutVariant")
+        assertContains(descriptor, "LEGACY")
+    }
 }

featured-gradle-plugin/src/test/kotlin/dev/androidbroadcast/featured/gradle/IosConstValGeneratorTest.kt

@@ -2,6 +2,7 @@ package dev.androidbroadcast.featured.gradle
 
 import kotlin.test.Test
 import kotlin.test.assertContains
+import kotlin.test.assertFalse
 import kotlin.test.assertTrue
 
 class IosConstValGeneratorTest {
@@ -163,4 +164,70 @@ class IosConstValGeneratorTest {
         val result = IosConstValGenerator.generateExpect(emptyList())
         assertTrue(result.isBlank(), "Expected blank output for empty entries, got: '$result'")
     }
+
+    // ── enum flag exclusion ───────────────────────────────────────────────────
+
+    @Test
+    fun `generate skips enum-typed entries`() {
+        val entries =
+            listOf(
+                LocalFlagEntry(key = "dark_mode", defaultValue = "false", type = "Boolean", moduleName = ":app"),
+                LocalFlagEntry(
+                    key = "checkout_variant",
+                    defaultValue = "LEGACY",
+                    type = "com.example.CheckoutVariant",
+                    moduleName = ":app",
+                ),
+            )
+        val result = IosConstValGenerator.generate(entries)
+        assertContains(result, "public actual const val dark_mode: Boolean = false")
+        assertFalse(result.contains("checkout_variant"), "Enum flags must not appear in iOS const val output")
+    }
+
+    @Test
+    fun `generate returns blank when only enum entries are present`() {
+        val entries =
+            listOf(
+                LocalFlagEntry(
+                    key = "checkout_variant",
+                    defaultValue = "LEGACY",
+                    type = "com.example.CheckoutVariant",
+                    moduleName = ":app",
+                ),
+            )
+        val result = IosConstValGenerator.generate(entries)
+        assertTrue(result.isBlank(), "Expected blank output when all entries are enums, got: '$result'")
+    }
+
+    @Test
+    fun `generateExpect skips enum-typed entries`() {
+        val entries =
+            listOf(
+                LocalFlagEntry(key = "dark_mode", defaultValue = "false", type = "Boolean", moduleName = ":app"),
+                LocalFlagEntry(
+                    key = "checkout_variant",
+                    defaultValue = "LEGACY",
+                    type = "com.example.CheckoutVariant",
+                    moduleName = ":app",
+                ),
+            )
+        val result = IosConstValGenerator.generateExpect(entries)
+        assertContains(result, "public expect val dark_mode: Boolean")
+        assertFalse(result.contains("checkout_variant"), "Enum flags must not appear in iOS expect declarations")
+    }
+
+    @Test
+    fun `generateExpect returns blank when only enum entries are present`() {
+        val entries =
+            listOf(
+                LocalFlagEntry(
+                    key = "checkout_variant",
+                    defaultValue = "LEGACY",
+                    type = "com.example.CheckoutVariant",
+                    moduleName = ":app",
+                ),
+            )
+        val result = IosConstValGenerator.generateExpect(entries)
+        assertTrue(result.isBlank(), "Expected blank output when all entries are enums, got: '$result'")
+    }
 }