From 9652c89d5acde3f3f0be15c2b0522f22f8863581 Mon Sep 17 00:00:00 2001
From: nstarman <nstarman@users.noreply.github.com>
Date: Thu, 29 Feb 2024 11:57:46 -0500
Subject: [PATCH] feat: avoid copies when constructing self

Signed-off-by: nstarman <nstarman@users.noreply.github.com>
---
 src/vector/_base.py | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/src/vector/_base.py b/src/vector/_base.py
index ebfa930e..da87b9c8 100644
--- a/src/vector/_base.py
+++ b/src/vector/_base.py
@@ -582,6 +582,10 @@ def constructor(  # noqa: D417
         msg = f"Cannot construct {cls} from {type(obj)}."
         raise TypeError(msg)
 
+    # avoid copying if the types are the same
+    if type(obj) is cls:
+        return obj
+
     return cls(**dict(dataclass_items(obj)))