Compiler-enforce interfaces cannot extend ZiplineScoped (#785)

Closes: #775
cashapp · Dec 21, 2022 · 3ace68d · 3ace68d
1 parent 3c1943b
commit 3ace68d
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Showing 4 changed files with 33 additions and 1 deletion.
diff --git a/zipline-kotlin-plugin/src/main/kotlin/app/cash/zipline/kotlin/ZiplineApis.kt b/zipline-kotlin-plugin/src/main/kotlin/app/cash/zipline/kotlin/ZiplineApis.kt
@@ -39,6 +39,7 @@ internal class ZiplineApis(
   private val serializersModuleFqName = serializationModulesFqName.child("SerializersModule")
   private val ziplineFqName = packageFqName.child("Zipline")
   private val outboundServiceFqName = bridgeFqName.child("OutboundService")
+  val ziplineScopedFqName = packageFqName.child("ZiplineScoped")
   val ziplineServiceFqName = packageFqName.child("ZiplineService")
   private val ziplineServiceSerializerFunctionFqName =
     packageFqName.child("ziplineServiceSerializer")

diff --git a/...ine-kotlin-plugin/src/main/kotlin/app/cash/zipline/kotlin/ZiplineIrGenerationExtension.kt b/...ine-kotlin-plugin/src/main/kotlin/app/cash/zipline/kotlin/ZiplineIrGenerationExtension.kt
@@ -25,6 +25,7 @@ import org.jetbrains.kotlin.ir.declarations.IrModuleFragment
 import org.jetbrains.kotlin.ir.expressions.IrCall
 import org.jetbrains.kotlin.ir.expressions.IrExpression
 import org.jetbrains.kotlin.ir.types.classFqName
+import org.jetbrains.kotlin.ir.util.fqNameWhenAvailable
 import org.jetbrains.kotlin.ir.util.isInterface
 
 class ZiplineIrGenerationExtension(
@@ -38,6 +39,16 @@ class ZiplineIrGenerationExtension(
         val declaration = super.visitClassNew(declaration) as IrClass
 
         try {
+          if (declaration.isInterface &&
+            declaration.superTypes.any { it.classFqName == ziplineApis.ziplineScopedFqName }
+          ) {
+            throw ZiplineCompilationException(
+              element = declaration,
+              message = "Only classes may implement ZiplineScoped, but" +
+                " ${declaration.fqNameWhenAvailable} is an interface",
+            )
+          }
+
           if (declaration.isInterface &&
             declaration.superTypes.any { it.classFqName == ziplineApis.ziplineServiceFqName }
           ) {

diff --git a/...ne-kotlin-plugin/tests/src/test/kotlin/app/cash/zipline/kotlin/ZiplineKotlinPluginTest.kt b/...ne-kotlin-plugin/tests/src/test/kotlin/app/cash/zipline/kotlin/ZiplineKotlinPluginTest.kt
@@ -345,6 +345,26 @@ class ZiplineKotlinPluginTest {
     assertThat(adapterClass).isNotNull()
     assertThat(adapterClass.interfaces).asList().containsExactly(KSerializer::class.java)
   }
+
+  @Test
+  fun `interfaces cannot extend ZiplineScoped`() {
+    val result = compile(
+      sourceFile = SourceFile.kotlin(
+        "main.kt",
+        """
+        package app.cash.zipline.testing
+
+        import app.cash.zipline.ZiplineScoped
+
+        interface SomeInterface : ZiplineScoped
+        """
+      )
+    )
+    assertEquals(KotlinCompilation.ExitCode.COMPILATION_ERROR, result.exitCode, result.messages)
+    assertThat(result.messages)
+      .contains("(5, 1): Only classes may implement ZiplineScoped, but " +
+        "app.cash.zipline.testing.SomeInterface is an interface")
+  }
 }
 
 fun compile(

diff --git a/zipline/src/commonMain/kotlin/app/cash/zipline/internal/bridge/throwables.kt b/zipline/src/commonMain/kotlin/app/cash/zipline/internal/bridge/throwables.kt
@@ -33,7 +33,7 @@ internal expect fun toInboundThrowable(
  * Serialize a [Throwable] in two parts:
  *
  *  * A list of types in preference-order. We'll only need one type in almost all cases, but if we
- *    want to introduce new throwable subtypes in the future this enables backwards=compatibility.
+ *    want to introduce new throwable subtypes in the future this enables backwards-compatibility.
  *
  *  * The throwable message and stacktrace, all together. This may be prefixed with the name
  *    of the throwable class.