From 305ebfbe65babb51a172498a37bb4c6c9d79a472 Mon Sep 17 00:00:00 2001
From: Sanjay Ramchandani <65647041+sanjaygrr@users.noreply.github.com>
Date: Wed, 4 Nov 2026 19:38:13 -0300
Subject: [PATCH] Pass out=None with where= for masked arrays to silence numpy
 warning

---
 gsw/_utilities.py | 8 +++++++-
 1 file changed, 7 insertions(+), 1 deletion(-)

diff --git a/gsw/_utilities.py b/gsw/_utilities.py
index f508699..ca1b429 100644
--- a/gsw/_utilities.py
+++ b/gsw/_utilities.py
@@ -51,7 +51,13 @@ def wrapper(*args, **kwargs):
             )
         where = ~mask
 
-        new_kwargs = {"where": where}
+        # Values under the mask are left uninitialized, which is fine for masked
+        # arrays; passing out=None explicitly avoids numpy's "'where' used
+        # without 'out'" warning. Multi-output ufuncs need one None per output.
+        nout = len(f.types[0].split("->")[1]) if hasattr(f, "types") else 1
+        out = None if nout == 1 else (None,) * nout
+
+        new_kwargs = {"where": where, "out": out}
         new_kwargs.update(
             **kwargs
         )  # Allow user override of the where kwarg if they passed it in.