From 0d4f8efff29cfc0360fe7e1e71f67801fca8aef0 Mon Sep 17 00:00:00 2001
From: Jonas Lagoni <jonas-lt@live.dk>
Date: Tue, 7 May 2024 09:17:02 +0200
Subject: [PATCH] fix!: add unique union types for Python (#1982)

---
 docs/migrations/version-3-to-4.md             |  4 +++
 src/generators/python/PythonConstrainer.ts    |  3 ++-
 .../python/PythonConstrainer.spec.ts          | 25 ++++++++++++++++++-
 test/runtime/runtime-python.spec.ts           |  4 +--
 test/runtime/runtime-python/tests/__init__.py |  7 ++++++
 .../runtime-python/{test => tests}/main.py    |  6 ++---
 6 files changed, 41 insertions(+), 8 deletions(-)
 create mode 100644 test/runtime/runtime-python/tests/__init__.py
 rename test/runtime/runtime-python/{test => tests}/main.py (89%)

diff --git a/docs/migrations/version-3-to-4.md b/docs/migrations/version-3-to-4.md
index 525b445ba1..e21906dd62 100644
--- a/docs/migrations/version-3-to-4.md
+++ b/docs/migrations/version-3-to-4.md
@@ -95,6 +95,10 @@ Console.WriteLine(dateTime2);
 
 Models are aiming to be >= v3.7 compliant.
 
+### Unique types in unions
+
+In v4, unions types are rendered unique, meaning you will never see `str | str` but just `str`.
+
 ### Pydantic now follows v2 instead of v1
 
 Reference: https://docs.pydantic.dev/2.6/migration/
diff --git a/src/generators/python/PythonConstrainer.ts b/src/generators/python/PythonConstrainer.ts
index 1b74ba522b..6d1a872ec6 100644
--- a/src/generators/python/PythonConstrainer.ts
+++ b/src/generators/python/PythonConstrainer.ts
@@ -50,7 +50,8 @@ export const PythonDefaultTypeMapping: PythonTypeMapping = {
     const unionTypes = constrainedModel.union.map((unionModel) => {
       return unionModel.type;
     });
-    return unionTypes.join(' | ');
+    const uniqueSet = new Set(unionTypes);
+    return [...uniqueSet].join(' | ');
   },
   Dictionary({ constrainedModel }): string {
     return `dict[${constrainedModel.key.type}, ${constrainedModel.value.type}]`;
diff --git a/test/generators/python/PythonConstrainer.spec.ts b/test/generators/python/PythonConstrainer.spec.ts
index a53b0bb9c3..a032f7f322 100644
--- a/test/generators/python/PythonConstrainer.spec.ts
+++ b/test/generators/python/PythonConstrainer.spec.ts
@@ -199,6 +199,29 @@ describe('PythonConstrainer', () => {
       expect(type).toEqual('str');
     });
     test('should render multiple types', () => {
+      const unionModel1 = new ConstrainedStringModel(
+        'test',
+        undefined,
+        {},
+        'str'
+      );
+      const unionModel2 = new ConstrainedStringModel(
+        'test',
+        undefined,
+        {},
+        'str2'
+      );
+      const model = new ConstrainedUnionModel('test', undefined, {}, '', [
+        unionModel1,
+        unionModel2
+      ]);
+      const type = PythonDefaultTypeMapping.Union({
+        constrainedModel: model,
+        ...defaultOptions
+      });
+      expect(type).toEqual('str | str2');
+    });
+    test('should render unique types', () => {
       const unionModel1 = new ConstrainedStringModel(
         'test',
         undefined,
@@ -219,7 +242,7 @@ describe('PythonConstrainer', () => {
         constrainedModel: model,
         ...defaultOptions
       });
-      expect(type).toEqual('str | str');
+      expect(type).toEqual('str');
     });
   });
 
diff --git a/test/runtime/runtime-python.spec.ts b/test/runtime/runtime-python.spec.ts
index a290ab32de..f23a4bc22a 100644
--- a/test/runtime/runtime-python.spec.ts
+++ b/test/runtime/runtime-python.spec.ts
@@ -9,8 +9,8 @@ test("Python runtime testing", async () => {
 
     const compileCommand = `cd ${path.resolve(
         __dirname,
-        "./runtime-python/test/"
-    )} && python3 main.py`;
+        "./runtime-python"
+    )} && python3 -m unittest discover ./tests`;
     await execCommand(compileCommand,true);
   
 });
\ No newline at end of file
diff --git a/test/runtime/runtime-python/tests/__init__.py b/test/runtime/runtime-python/tests/__init__.py
new file mode 100644
index 0000000000..51b46a879f
--- /dev/null
+++ b/test/runtime/runtime-python/tests/__init__.py
@@ -0,0 +1,7 @@
+import os
+import sys
+PROJECT_PATH = os.getcwd()
+SOURCE_PATH = os.path.join(
+    PROJECT_PATH, "src"
+)
+sys.path.append(SOURCE_PATH)
\ No newline at end of file
diff --git a/test/runtime/runtime-python/test/main.py b/test/runtime/runtime-python/tests/main.py
similarity index 89%
rename from test/runtime/runtime-python/test/main.py
rename to test/runtime/runtime-python/tests/main.py
index fb98a0a351..49121eeb80 100644
--- a/test/runtime/runtime-python/test/main.py
+++ b/test/runtime/runtime-python/tests/main.py
@@ -1,8 +1,6 @@
 import unittest
-import sys
-sys.path.insert(1, '../src/main/')
-from Address import Address
-from NestedObject import NestedObject
+from src.main.Address import Address
+from src.main.NestedObject import NestedObject
 import json
     
 class TestAddress(unittest.TestCase):