From 9af344f4705943571bc0c18e73435b18c4819641 Mon Sep 17 00:00:00 2001
From: lionelhorn <50528276+lionelhorn@users.noreply.github.com>
Date: Sun, 11 Aug 2024 20:20:47 +0200
Subject: [PATCH] fix(type): add scope in setter code to prevent `variable
 already declared` #603 (#606)

- When a tuple definition contained "duplicated" union types like [number|null, number|null], the jitted function couldln't be build as some variable like `oldErrors` were already declared. Probably one block per number|null
---
 packages/type/src/serializer.ts           | 20 ++++---
 packages/type/tests/issues/tuples.spec.ts | 69 +++++++++++++++++++++++
 2 files changed, 80 insertions(+), 9 deletions(-)
 create mode 100644 packages/type/tests/issues/tuples.spec.ts

diff --git a/packages/type/src/serializer.ts b/packages/type/src/serializer.ts
index 4f39d2f78..7b0aee376 100644
--- a/packages/type/src/serializer.ts
+++ b/packages/type/src/serializer.ts
@@ -1792,16 +1792,18 @@ export function handleUnion(type: TypeUnion, state: TemplateState) {
     ` : '';
 
     state.addCodeForSetter(`
-        const oldErrors = state.errors;
-        if (state.errors) state.errors = [];
-
-        //type guard for union
-        if (false) {} ${lines.join(' ')}
-        else {
-            ${handleErrors}
-            ${state.assignValidationError('type', 'No valid union member found. Valid: ' + stringifyResolvedType(type))}
+        {
+            const oldErrors = state.errors;
+            if (state.errors) state.errors = [];
+
+            //type guard for union
+            if (false) {} ${lines.join(' ')}
+            else {
+                ${handleErrors}
+                ${state.assignValidationError('type', 'No valid union member found. Valid: ' + stringifyResolvedType(type))}
+            }
+            state.errors = oldErrors;
         }
-        state.errors = oldErrors;
     `);
 }
 
diff --git a/packages/type/tests/issues/tuples.spec.ts b/packages/type/tests/issues/tuples.spec.ts
new file mode 100644
index 000000000..2b74c8c8c
--- /dev/null
+++ b/packages/type/tests/issues/tuples.spec.ts
@@ -0,0 +1,69 @@
+import { expect, test } from '@jest/globals';
+import { cast, validate } from '@deepkit/type';
+
+test('cast literal obj having typed tuple [number | null, number | null] as nested prop', () => {
+    type MinMax = [number | null, number | null];
+
+    class T {
+        building!: {
+            area: MinMax
+        };
+    }
+
+    // const d = JSON.parse('{"building":{"area":[120,null]}}');
+    const d = {
+        building: {
+            area: [120, null],
+        },
+    };
+
+    const errors = validate<T>(d);
+    expect(errors.length).toBe(0);
+
+    const casted: T = cast<T>(d);
+
+    expect(casted.building.area[0]).toBe(120);
+    expect(casted.building.area[1]).toBe(null);
+});
+
+test('cast literal obj to T containing typed tuple', () => {
+    type SomeData = [string | null, string, string | null];
+
+    class T {
+        tuple!: SomeData;
+    }
+
+    const d = {
+        tuple: [null, 'z', null],
+    };
+
+    const errors = validate<T>(d);
+    expect(errors.length).toBe(0);
+
+    const casted: T = cast<T>(d);
+
+    expect(casted.tuple[0]).toBe(null);
+    expect(casted.tuple[1]).toBe('z');
+    expect(casted.tuple[2]).toBe(null);
+});
+
+test("cast literal obj having typed tuple [number | null, number | null] as nested prop", () => {
+    type MinMax = [min: number | null, max: number | null];
+
+    class T {
+        building?: {
+            area?: MinMax
+        }
+    }
+
+    // const d = JSON.parse('{"building":{"area":[120,null]}}');
+
+    const data: T = cast<T>({
+        building: {
+            area: [120, null]
+        }
+    });
+
+    const errors = validate<T>(data);
+    expect(errors.length).toBe(0);
+});