Add thread-local namespace for reentrant calls

Author: benoitc

c_src/py_event_loop.c

@@ -55,6 +55,12 @@ ErlNifResourceType *TIMER_RESOURCE_TYPE = NULL;
 static char g_priv_dir[1024] = {0};
 static bool g_priv_dir_set = false;
 
+/**
+ * Thread-local for current event loop namespace during task execution.
+ * This allows reentrant calls (erlang.call -> Python) to use the same namespace.
+ */
+__thread process_namespace_t *tl_current_event_loop_namespace = NULL;
+
 /** Atoms for event loop messages */
 ERL_NIF_TERM ATOM_SELECT;
 ERL_NIF_TERM ATOM_READY_INPUT;
@@ -2736,8 +2742,16 @@ ERL_NIF_TERM nif_process_ready_tasks(ErlNifEnv *env, int argc,
             kwargs = term_to_py(term_env, tuple_elems[5]);
         }
 
+        /* Set current namespace for reentrant calls (erlang.call -> Python) */
+        process_namespace_t *prev_namespace = tl_current_event_loop_namespace;
+        tl_current_event_loop_namespace = ns;
+
         /* Call the function to get coroutine */
         PyObject *coro = PyObject_Call(func, args, kwargs);
+
+        /* Restore previous namespace */
+        tl_current_event_loop_namespace = prev_namespace;
+
         Py_DECREF(func);
         Py_DECREF(args);
         Py_XDECREF(kwargs);

c_src/py_event_loop.h

@@ -387,6 +387,15 @@ extern ErlNifResourceType *FD_RESOURCE_TYPE;
 /** @brief Resource type for timer_resource_t */
 extern ErlNifResourceType *TIMER_RESOURCE_TYPE;
 
+/**
+ * @brief Current event loop namespace for reentrant calls
+ *
+ * Set during task execution in process_ready_tasks. Used by erlang.call()
+ * to access the same namespace when Python calls back to Erlang and
+ * Erlang calls back to Python.
+ */
+extern __thread process_namespace_t *tl_current_event_loop_namespace;
+
 /* ============================================================================
  * Atom Declarations
  * ============================================================================ */

test/py_async_task_SUITE.erl

@@ -36,7 +36,8 @@
     test_process_namespace_exec/1,
     test_process_namespace_eval/1,
     test_process_namespace_async_func/1,
-    test_process_namespace_isolation/1
+    test_process_namespace_isolation/1,
+    test_process_namespace_reentrant/1
 ]).
 
 all() ->
@@ -72,7 +73,8 @@ all() ->
         test_process_namespace_exec,
         test_process_namespace_eval,
         test_process_namespace_async_func,
-        test_process_namespace_isolation
+        test_process_namespace_isolation,
+        test_process_namespace_reentrant
     ].
 
 groups() -> [].
@@ -435,3 +437,37 @@ test_process_namespace_isolation(_Config) ->
         {ok, _} ->
             ct:log("isolation test: parent unexpectedly saw child_var")
     end.
+
+test_process_namespace_reentrant(_Config) ->
+    %% Test that namespace variables are accessible during task execution
+    %% This verifies the thread-local namespace is set correctly
+
+    %% Define a variable and a function that uses it
+    ok = py_event_loop:exec(<<"
+shared_value = 100
+
+def use_shared():
+    # Access shared_value from namespace
+    return shared_value + 23
+">>),
+
+    %% Call the function via create_task - it should access the namespace
+    Ref = py_event_loop:create_task('__main__', use_shared, []),
+    {ok, Result} = py_event_loop:await(Ref, 5000),
+    ct:log("reentrant test: use_shared() returned ~p (expected 123)", [Result]),
+    123 = Result,
+
+    %% Test with a function that modifies namespace
+    ok = py_event_loop:exec(<<"
+def increment_shared():
+    global shared_value
+    shared_value += 1
+    return shared_value
+">>),
+
+    Ref2 = py_event_loop:create_task('__main__', increment_shared, []),
+    {ok, 101} = py_event_loop:await(Ref2, 5000),
+
+    %% Verify the change persists in namespace
+    {ok, 101} = py_event_loop:eval(<<"shared_value">>),
+    ct:log("reentrant test: namespace modifications persist correctly").