Fix tests for cargo stress on free-threaded build (#4469)

* make it possible to run test_bad_datetime_module_panic under 'cargo stress'

* weaken assertions in tests of the pending decrefs pool on free-threaded builds

* use the tempfile crate to create a temporary directory

Cargo.toml

@@ -61,6 +61,7 @@ serde = { version = "1.0", features = ["derive"] }
 serde_json = "1.0.61"
 rayon = "1.6.1"
 futures = "0.3.28"
+tempfile = "3.12.0"
 
 [build-dependencies]
 pyo3-build-config = { path = "pyo3-build-config", version = "=0.23.0-dev", features = ["resolve-config"] }

src/gil.rs

@@ -447,7 +447,9 @@ mod tests {
             .contains(&unsafe { NonNull::new_unchecked(obj.as_ptr()) })
     }
 
-    #[cfg(not(pyo3_disable_reference_pool))]
+    // with no GIL, threads can empty the POOL at any time, so this
+    // function does not test anything meaningful
+    #[cfg(not(any(pyo3_disable_reference_pool, Py_GIL_DISABLED)))]
     fn pool_dec_refs_contains(obj: &PyObject) -> bool {
         POOL.pending_decrefs
             .lock()
@@ -471,7 +473,7 @@ mod tests {
             drop(reference);
 
             assert_eq!(obj.get_refcnt(py), 1);
-            #[cfg(not(pyo3_disable_reference_pool))]
+            #[cfg(not(any(pyo3_disable_reference_pool)))]
             assert!(pool_dec_refs_does_not_contain(&obj));
         });
     }
@@ -493,12 +495,18 @@ mod tests {
             // The reference count should not have changed (the GIL has always
             // been held by this thread), it is remembered to release later.
             assert_eq!(obj.get_refcnt(py), 2);
+            #[cfg(not(Py_GIL_DISABLED))]
             assert!(pool_dec_refs_contains(&obj));
             obj
         });
 
         // Next time the GIL is acquired, the reference is released
+        #[allow(unused)]
         Python::with_gil(|py| {
+            // with no GIL, another thread could still be processing
+            // DECREFs after releasing the lock on the POOL, so the
+            // refcnt could still be 2 when this assert happens
+            #[cfg(not(Py_GIL_DISABLED))]
             assert_eq!(obj.get_refcnt(py), 1);
             assert!(pool_dec_refs_does_not_contain(&obj));
         });
@@ -641,13 +649,15 @@ mod tests {
             // For GILGuard::acquire
 
             POOL.register_decref(NonNull::new(obj.clone_ref(py).into_ptr()).unwrap());
+            #[cfg(not(Py_GIL_DISABLED))]
             assert!(pool_dec_refs_contains(&obj));
             let _guard = GILGuard::acquire();
             assert!(pool_dec_refs_does_not_contain(&obj));
 
             // For GILGuard::assume
 
             POOL.register_decref(NonNull::new(obj.clone_ref(py).into_ptr()).unwrap());
+            #[cfg(not(Py_GIL_DISABLED))]
             assert!(pool_dec_refs_contains(&obj));
             let _guard2 = unsafe { GILGuard::assume() };
             assert!(pool_dec_refs_does_not_contain(&obj));

tests/test_datetime_import.rs

@@ -1,26 +1,28 @@
 #![cfg(not(Py_LIMITED_API))]
 
 use pyo3::{prelude::*, types::PyDate};
+use tempfile::Builder;
 
 #[test]
 #[should_panic(expected = "module 'datetime' has no attribute 'datetime_CAPI'")]
 fn test_bad_datetime_module_panic() {
     // Create an empty temporary directory
     // with an empty "datetime" module which we'll put on the sys.path
-    let tmpdir = std::env::temp_dir();
-    let tmpdir = tmpdir.join("pyo3_test_date_check");
-    let _ = std::fs::remove_dir_all(&tmpdir);
-    std::fs::create_dir(&tmpdir).unwrap();
-    std::fs::File::create(tmpdir.join("datetime.py")).unwrap();
+    let tmpdir = Builder::new()
+        .prefix("pyo3_test_data_check")
+        .tempdir()
+        .unwrap();
+    std::fs::File::create(tmpdir.path().join("datetime.py")).unwrap();
 
     Python::with_gil(|py: Python<'_>| {
         let sys = py.import("sys").unwrap();
         sys.getattr("path")
             .unwrap()
-            .call_method1("insert", (0, tmpdir))
+            .call_method1("insert", (0, tmpdir.path()))
             .unwrap();
 
         // This should panic because the "datetime" module is empty
         PyDate::new(py, 2018, 1, 1).unwrap();
     });
+    tmpdir.close().unwrap();
 }