From 436b3140e72b9f24d1e3e5595316867600bc1eb9 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?=E5=AE=8B=E5=AE=B6=E8=B1=AA?= <songjiahao@tongyuan.cc>
Date: Tue, 26 Sep 2023 09:00:30 +0800
Subject: [PATCH] remove method of converting PyObject to Nothing

---
 src/conversions.jl | 11 ++++++++---
 1 file changed, 8 insertions(+), 3 deletions(-)

diff --git a/src/conversions.jl b/src/conversions.jl
index 0226f036..a6f09482 100644
--- a/src/conversions.jl
+++ b/src/conversions.jl
@@ -61,7 +61,8 @@ convert(::Type{T}, po::PyObject) where {T<:Real} =
 convert(::Type{T}, po::PyObject) where T<:Complex =
     T(@pycheck ccall(@pysym(:PyComplex_AsCComplex), Complex{Cdouble}, (PyPtr,), po))
 
-convert(::Type{Nothing}, po::PyObject) = nothing
+# TODO: This method defination causes method invalidations and latency in Julia 1.9.3, https://github.com/JuliaLang/julia/issues/51389
+# convert(::Type{Nothing}, po::PyObject) = nothing
 
 function Base.float(o::PyObject)
     a = PyAny(o)
@@ -771,7 +772,7 @@ end
 macro return_not_None(ex)
     quote
         T = $(esc(ex))
-        if T != Union{}
+        if T !== Union{}
             return T
         end
     end
@@ -829,9 +830,13 @@ function convert(::Type{PyAny}, o::PyObject)
     end
     try
         T = pytype_query(o)
-        if T == PyObject && is_pyjlwrap(o)
+        if T === PyObject && is_pyjlwrap(o)
             return unsafe_pyjlwrap_to_objref(o)
         end
+        if T === Nothing
+            return nothing
+        end
+
         convert(T, o)
     catch
         pyerr_clear() # just in case