From 1f82d65ea04134d7182158cf3cc98158b6923f87 Mon Sep 17 00:00:00 2001
From: Timothee Guerin <tiguerin@microsoft.com>
Date: Tue, 11 Jun 2024 15:10:35 -0700
Subject: [PATCH] Do not run decorators on cloned type if the original type
 wasn't finished (#3566)

In the same way we have this logic for `cloneTypeForSymbol`
---
 ...one-type-donot-finish-unfinished-2024-5-11-21-54-41.md | 8 ++++++++
 packages/compiler/src/core/checker.ts                     | 5 ++++-
 2 files changed, 12 insertions(+), 1 deletion(-)
 create mode 100644 .chronus/changes/fix-clone-type-donot-finish-unfinished-2024-5-11-21-54-41.md

diff --git a/.chronus/changes/fix-clone-type-donot-finish-unfinished-2024-5-11-21-54-41.md b/.chronus/changes/fix-clone-type-donot-finish-unfinished-2024-5-11-21-54-41.md
new file mode 100644
index 0000000000..947d8feafe
--- /dev/null
+++ b/.chronus/changes/fix-clone-type-donot-finish-unfinished-2024-5-11-21-54-41.md
@@ -0,0 +1,8 @@
+---
+# Change versionKind to one of: internal, fix, dependencies, feature, deprecation, breaking
+changeKind: fix
+packages:
+  - "@typespec/compiler"
+---
+
+[API] Do not run decorators on cloned type if the original type wasn't finished
diff --git a/packages/compiler/src/core/checker.ts b/packages/compiler/src/core/checker.ts
index 1647ece4e6..17d055307c 100644
--- a/packages/compiler/src/core/checker.ts
+++ b/packages/compiler/src/core/checker.ts
@@ -6512,7 +6512,10 @@ export function createChecker(program: Program): Checker {
    * recursively by the caller.
    */
   function cloneType<T extends Type>(type: T, additionalProps: Partial<T> = {}): T {
-    const clone = finishType(initializeClone(type, additionalProps));
+    let clone = initializeClone(type, additionalProps);
+    if (type.isFinished) {
+      clone = finishType(clone);
+    }
     const projection = projectionsByType.get(type);
     if (projection) {
       projectionsByType.set(clone, projection);