fix: import decimal module

- import it in base interpreter
- stops the issue of crashing when imported

examples/import_decimal.py

@@ -0,0 +1,19 @@
+"""
+Import decimal module.
+
+Causes problems if the module is not first imported in the main interpreter.
+"""
+
+from decimal import Decimal
+
+
+def test_import_first():
+    import decimal
+
+    assert Decimal(0) == decimal.Decimal(0)
+
+
+def test_import_again():
+    import decimal
+
+    assert Decimal(0) == decimal.Decimal(0)

src/python.rs

@@ -49,6 +49,11 @@ impl Interpreter {
       ffi::Py_InitializeFromConfig(ptr::from_mut(config.assume_init_mut()));
     }
 
+    // The decimal module crashes the interpreter if it is initialised multiple times
+    // If not initialised in the base interpreter, if a subinterpreter imports it it will crash
+    // TODO: when decimal works properly remove this hack
+    execute_string(c"import decimal").unwrap();
+
     let main_thread_state = unsafe { ffi::PyThreadState_Swap(ptr::null_mut()) };
 
     Self {

src/tests.rs

@@ -157,3 +157,11 @@ fn captures_stdout() {
     "hello world\ninto stderr"
   );
 }
+
+#[test]
+fn import_decimal_module() {
+  let results = run_tests!("./examples/import_decimal.py");
+
+  assert_eq!(results.len(), 2);
+  assert!(results.iter().all(|x| x.outcome == Outcome::Pass));
+}