(tvm-ffi) branch main updated: [FIX] Build dlpack exchange test in a per-test tmp dir to avoid JIT lock hang (#677)

[tqchen]

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tqchen pushed a commit to branch main
in repository https://gitbox.apache.org/repos/asf/tvm-ffi.git


The following commit(s) were added to refs/heads/main by this push:
     new 0ec8dc8b [FIX] Build dlpack exchange test in a per-test tmp dir to 
avoid JIT lock hang (#677)
0ec8dc8b is described below

commit 0ec8dc8befe3c77742cf8c42181d6e3950aa66f0
Author: Yong Wu <yongc...@gmail.com>
AuthorDate: Mon Jul 20 15:18:10 2026 -0700

    [FIX] Build dlpack exchange test in a per-test tmp dir to avoid JIT lock 
hang (#677)
    
    Fixes https://github.com/apache/tvm-ffi/issues/641
    
    ### root cause
    The test JIT-compiles a C++ snippet with torch's
    `cpp_extension.load_inline`, which by default builds into the shared
    `~/.cache/torch_extensions` cache, serialized by torch's `FileBaton`:
    - `try_acquire()` creates an ordinary lock **file** (`os.open`
    `O_CREAT|O_EXCL`).
    - `wait()` spins on `os.path.exists(lock)` with **no timeout** and no
    staleness check.
    - `release()` (which deletes the file) only runs on the normal path.
    
    If a build is killed mid-compile — e.g. a CI time limit sends SIGTERM —
    the lock file is left behind. On CI where that cache sits on a
    persistent shared filesystem, every subsequent run then waits on the
    orphaned lock **forever**.
    
    ### Fix
    Pass `build_directory=tmp_path` to `load_inline` so each run builds in a
    fresh, unique directory. The baton lock is always fresh, so a killed
    prior run can no longer poison later runs, and the test no longer uses
    (or can be poisoned by) any shared cache — independent of the
    filesystem.
---
 tests/python/test_dlpack_exchange_api.py | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/tests/python/test_dlpack_exchange_api.py 
b/tests/python/test_dlpack_exchange_api.py
index f37e3b98..4d837ba5 100644
--- a/tests/python/test_dlpack_exchange_api.py
+++ b/tests/python/test_dlpack_exchange_api.py
@@ -20,6 +20,7 @@ from __future__ import annotations
 
 import ctypes
 import sys
+from pathlib import Path
 
 import pytest
 
@@ -41,7 +42,7 @@ _has_gpu = torch is not None and torch.cuda.is_available()
 
 
 @pytest.mark.skipif(not _has_dlpack_api, reason="PyTorch DLPack Exchange API 
not available")
-def test_dlpack_exchange_api() -> None:
+def test_dlpack_exchange_api(tmp_path: Path) -> None:
     # xfail the test on windows platform, it seems to be a bug in torch 
extension building on windows
     if sys.platform.startswith("win"):
         pytest.xfail("DLPack Exchange API test is known to fail on Windows 
platform")
@@ -210,6 +211,7 @@ def test_dlpack_exchange_api() -> None:
         cpp_sources=[source],
         functions=["test_dlpack_api"],
         extra_include_paths=include_paths,
+        build_directory=str(tmp_path),
     )
 
     # Run the comprehensive test