From 9767ab35ec1a5495f0f9a46ef2c483c76b93e32d Mon Sep 17 00:00:00 2001
From: JamesWrigley <james@puiterwijk.org>
Date: Fri, 17 May 2024 14:05:14 +0200
Subject: [PATCH] Make Socket hold a reference to its Context

This prevents the `Context` from being garbage collected while the `Socket` is
still alive, otherwise the `Socket` would be closed by the `Context`'s finalizer
while the `Socket` is potentially still in use.
---
 src/socket.jl    |  3 ++-
 test/runtests.jl | 16 ++++++++++++++++
 2 files changed, 18 insertions(+), 1 deletion(-)

diff --git a/src/socket.jl b/src/socket.jl
index 4680b16..3501761 100644
--- a/src/socket.jl
+++ b/src/socket.jl
@@ -19,6 +19,7 @@ Do-block constructor.
 """
 mutable struct Socket
     data::Ptr{Cvoid}
+    context::Context
     pollfd::FDWatcher
 
     """
@@ -31,7 +32,7 @@ mutable struct Socket
         if p == C_NULL
             throw(StateError(jl_zmq_error_str()))
         end
-        socket = new(p)
+        socket = new(p, ctx)
         setfield!(socket, :pollfd, FDWatcher(fd(socket), #=readable=#true, #=writable=#false))
         finalizer(close, socket)
         push!(getfield(ctx, :sockets), WeakRef(socket))
diff --git a/test/runtests.jl b/test/runtests.jl
index f07d174..d7274f3 100644
--- a/test/runtests.jl
+++ b/test/runtests.jl
@@ -13,7 +13,23 @@ using ZMQ, Test
 	@test_throws StateError Socket(ctx, PUB)
 end
 
+# This test is in its own function to keep it simple and try to trick Julia into
+# thinking it can safely GC the Context.
+function context_gc_test()
+    ctx = Context()
+    s = Socket(ctx, PUB)
+
+    # Force garbage collection to attempt to delete ctx
+    GC.gc()
+
+    # But it shouldn't be garbage collected since the socket should have a
+    # reference to it, so the socket should still be open.
+    @test isopen(s)
+end
+
 @testset "ZMQ sockets" begin
+    context_gc_test()
+
 	s=Socket(PUB)
 	@test s isa Socket
 	ZMQ.close(s)