From d8a25501691bb03ea0d4ae7032d20c4fb88229ce Mon Sep 17 00:00:00 2001
From: Evgeny Demchenko <v1mpire@icloud.com>
Date: Fri, 23 May 2025 08:15:21 +0300
Subject: [PATCH] gh-134451: Converted `asyncio.tools.CycleFoundException` from
 dataclass to a regular exception type. (GH-134513) (cherry picked from commit
 f9324cb3cb4d9bb9f0aef2e48b8afa895bde4b0d)

Co-authored-by: Evgeny Demchenko <v1mpire@icloud.com>
---
 Lib/asyncio/tools.py                                 | 12 +++++++++---
 .../2025-05-22-14-12-53.gh-issue-134451.M1rD-j.rst   |  1 +
 2 files changed, 10 insertions(+), 3 deletions(-)
 create mode 100644 Misc/NEWS.d/next/Library/2025-05-22-14-12-53.gh-issue-134451.M1rD-j.rst

diff --git a/Lib/asyncio/tools.py b/Lib/asyncio/tools.py
index bf1cb5e64cbfbe..b2da7d2f6ba10c 100644
--- a/Lib/asyncio/tools.py
+++ b/Lib/asyncio/tools.py
@@ -13,11 +13,17 @@ class NodeType(Enum):
     TASK = 2
 
 
-@dataclass(frozen=True)
 class CycleFoundException(Exception):
     """Raised when there is a cycle when drawing the call tree."""
-    cycles: list[list[int]]
-    id2name: dict[int, str]
+    def __init__(
+            self,
+            cycles: list[list[int]],
+            id2name: dict[int, str],
+        ) -> None:
+        super().__init__(cycles, id2name)
+        self.cycles = cycles
+        self.id2name = id2name
+
 
 
 # ─── indexing helpers ───────────────────────────────────────────
diff --git a/Misc/NEWS.d/next/Library/2025-05-22-14-12-53.gh-issue-134451.M1rD-j.rst b/Misc/NEWS.d/next/Library/2025-05-22-14-12-53.gh-issue-134451.M1rD-j.rst
new file mode 100644
index 00000000000000..3c8339f8842254
--- /dev/null
+++ b/Misc/NEWS.d/next/Library/2025-05-22-14-12-53.gh-issue-134451.M1rD-j.rst
@@ -0,0 +1 @@
+Converted ``asyncio.tools.CycleFoundException`` from dataclass to a regular exception type.