From ea3bac6b9eb38aac94d086630b9815bfca7197fd Mon Sep 17 00:00:00 2001
From: Simon Willison <swillison@gmail.com>
Date: Mon, 1 Jun 2026 20:34:44 -0700
Subject: [PATCH 1/2] Release 0.1a0

---
 pyproject.toml | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/pyproject.toml b/pyproject.toml
index 821a04b..f13a7d6 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -1,6 +1,6 @@
 [project]
 name = "micropython-wasm"
-version = "0.1"
+version = "0.1a0"
 description = "MicroPython packaged in WASM for wasmtime"
 readme = "README.md"
 requires-python = ">=3.10"

From 0a1bc63eb50bc9b0bba71515d2933b43fc3b2412 Mon Sep 17 00:00:00 2001
From: Simon Willison <swillison@gmail.com>
Date: Mon, 1 Jun 2026 20:40:57 -0700
Subject: [PATCH 2/2] Trying out a fix for Python 3.11 in CI, refs #3

---
 .github/workflows/publish.yml    |  3 ++-
 .github/workflows/test.yml       |  3 ++-
 README.md                        |  2 +-
 micropython_wasm/__init__.py     | 44 +++++++++++++++++++-------------
 tests/test_persistent_session.py | 12 +++++++++
 5 files changed, 43 insertions(+), 21 deletions(-)

diff --git a/.github/workflows/publish.yml b/.github/workflows/publish.yml
index a93b5ee..cb8443b 100644
--- a/.github/workflows/publish.yml
+++ b/.github/workflows/publish.yml
@@ -10,6 +10,8 @@ permissions:
 jobs:
   test:
     runs-on: ubuntu-latest
+    env:
+      RUST_BACKTRACE: "1"
     strategy:
       matrix:
         python-version: ["3.10", "3.11", "3.12", "3.13", "3.14"]
@@ -65,4 +67,3 @@ jobs:
         path: dist/
     - name: Publish to PyPI
       uses: pypa/gh-action-pypi-publish@release/v1
-
diff --git a/.github/workflows/test.yml b/.github/workflows/test.yml
index 3eb8719..b1c7334 100644
--- a/.github/workflows/test.yml
+++ b/.github/workflows/test.yml
@@ -8,6 +8,8 @@ permissions:
 jobs:
   test:
     runs-on: ubuntu-latest
+    env:
+      RUST_BACKTRACE: "1"
     strategy:
       matrix:
         python-version: ["3.10", "3.11", "3.12", "3.13", "3.14"]
@@ -25,4 +27,3 @@ jobs:
     - name: Run tests
       run: |
         python -m pytest
-
diff --git a/README.md b/README.md
index af75cfe..51c1125 100644
--- a/README.md
+++ b/README.md
@@ -700,7 +700,7 @@ skipped, but package/build-script tests still run.
 Current local result:
 
 ```text
-52 passed
+53 passed
 ```
 
 To test a custom artifact manually:
diff --git a/micropython_wasm/__init__.py b/micropython_wasm/__init__.py
index 7f2ca21..b0ef9a2 100644
--- a/micropython_wasm/__init__.py
+++ b/micropython_wasm/__init__.py
@@ -336,7 +336,7 @@ def close(self) -> None:
         if self._started:
             self._request_queue.put({"op": "close"})
         if self._thread is not None:
-            self._thread.join(timeout=1.0)
+            self._thread.join()
 
     def __enter__(self) -> MicroPythonSession:
         if self._closed:
@@ -449,23 +449,30 @@ def capture_stderr(data: bytes) -> None:
         _define_host_call(linker, store, host_functions, Func, FuncType, ValType)
 
         try:
-            module = Module.from_file(engine, str(self.wasm_path))
-            instance = linker.instantiate(store, module)
-            start = instance.exports(store).get("_start")
-            if start is None:
-                raise MicroPythonWasmError("WASI module does not export _start")
-            if not isinstance(start, Func):
-                raise MicroPythonWasmError("WASI module _start export is not callable")
-            start(store)
-        except ExitTrap as exc:
-            if getattr(exc, "code", 0) not in (0, None):
-                raise MicroPythonWasmError(
-                    f"guest exited with code {exc.code}"
-                ) from exc
-        except Trap as exc:
-            raise MicroPythonWasmError(f"guest trapped: {exc}") from exc
-        except WasmtimeError as exc:
-            raise MicroPythonWasmError(f"wasmtime error: {exc}") from exc
+            try:
+                module = Module.from_file(engine, str(self.wasm_path))
+                instance = linker.instantiate(store, module)
+                start = instance.exports(store).get("_start")
+                if start is None:
+                    raise MicroPythonWasmError("WASI module does not export _start")
+                if not isinstance(start, Func):
+                    raise MicroPythonWasmError(
+                        "WASI module _start export is not callable"
+                    )
+                start(store)
+            except ExitTrap as exc:
+                if getattr(exc, "code", 0) not in (0, None):
+                    raise MicroPythonWasmError(
+                        f"guest exited with code {exc.code}"
+                    ) from exc
+            except Trap as exc:
+                raise MicroPythonWasmError(f"guest trapped: {exc}") from exc
+            except WasmtimeError as exc:
+                raise MicroPythonWasmError(f"wasmtime error: {exc}") from exc
+        finally:
+            with self._callback_lock:
+                self._store = None
+                self._thread_host_functions = None
 
     def _session_next(self) -> dict[str, object]:
         request = self._request_queue.get()
@@ -634,6 +641,7 @@ def capture_stderr(data: bytes) -> None:
     finally:
         if timer is not None:
             timer.cancel()
+            timer.join()
 
     return RunResult(
         stdout="".join(stdout_parts),
diff --git a/tests/test_persistent_session.py b/tests/test_persistent_session.py
index 368af2a..bb05fdf 100644
--- a/tests/test_persistent_session.py
+++ b/tests/test_persistent_session.py
@@ -120,3 +120,15 @@ def test_persistent_session_close_is_idempotent():
 
     with pytest.raises(MicroPythonSessionClosed):
         session.run("print(1)")
+
+
+def test_persistent_session_close_releases_thread_resources():
+    session = MicroPythonSession()
+    session.run("print(1)")
+
+    session.close()
+
+    assert session._thread is not None
+    assert not session._thread.is_alive()
+    assert session._store is None
+    assert session._thread_host_functions is None