From 69d7ed60dab7c75d53692e833e24598b9f4331d2 Mon Sep 17 00:00:00 2001
From: Alexander Tikhonov <fatal1ty.rnd@gmail.com>
Date: Thu, 26 Sep 2024 17:05:19 +0300
Subject: [PATCH] Avoid potential duplications in union unpacker

---
 mashumaro/core/meta/types/unpack.py | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/mashumaro/core/meta/types/unpack.py b/mashumaro/core/meta/types/unpack.py
index 9c040d5..43b8d8d 100644
--- a/mashumaro/core/meta/types/unpack.py
+++ b/mashumaro/core/meta/types/unpack.py
@@ -170,15 +170,19 @@ def get_method_prefix(self) -> str:
 
     def _add_body(self, spec: ValueSpec, lines: CodeLines) -> None:
         ambiguous_unpacker_types = []
+        unpackers = set()
         for type_arg in self.union_args:
             unpacker = UnpackerRegistry.get(
                 spec.copy(type=type_arg, expression="value")
             )
             if type_arg in (bool, str) and unpacker == "value":
                 ambiguous_unpacker_types.append(type_arg)
+            if unpacker in unpackers:
+                continue
             with lines.indent("try:"):
                 lines.append(f"return {unpacker}")
             lines.append("except Exception: pass")
+            unpackers.add(unpacker)
         # if len(ambiguous_unpacker_types) >= 2:
         #     warnings.warn(
         #         f"{type_name(spec.builder.cls)}.{spec.field_ctx.name} "