Skip to content

GH-144533: Use wasmtime's --argv0 to auto-discover sysconfig in WASI builds #145328

New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

Sign up for GitHub

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

Merged
savannahostrowski merged 3 commits into from
Feb 28, 2026
Merged

GH-144533: Use wasmtime's --argv0 to auto-discover sysconfig in WASI builds #145328

Show file tree
Hide file tree
Changes from all commits
Commits
Show all changes
3 commits
Select commit Hold shift + click to select a range
0d68ee0
Pass executable to argv0
savannahostrowski Feb 27, 2026
acc0955
📜🤖 Added by blurb_it.
blurb-it[bot] Feb 27, 2026
fdbf6eb
Merge branch 'main' into wasi-argv0
savannahostrowski Feb 28, 2026
File filter

Filter by extension

Filter by extension
Conversations
Failed to load comments.
Loading
Jump to
Jump to file
Failed to load files.
Loading
Diff view
Diff view
1 change: 1 addition & 0 deletions Misc/NEWS.d/next/Build/2026-02-27-18-10-02.gh-issue-144533.21fk9L.rst
View file
Open in desktop
Original file line number Diff line number Diff line change
@@ -0,0 +1 @@
Use wasmtime's ``--argv0`` to auto-discover sysconfig in WASI builds
19 changes: 3 additions & 16 deletions Platforms/WASI/__main__.py
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -317,21 +317,8 @@ def configure_wasi_python(context, working_dir):

wasi_build_dir = working_dir.relative_to(CHECKOUT)

python_build_dir = BUILD_DIR / "build"
lib_dirs = list(python_build_dir.glob("lib.*"))
assert len(lib_dirs) == 1, (
f"Expected a single lib.* directory in {python_build_dir}"
)
lib_dir = os.fsdecode(lib_dirs[0])
python_version = lib_dir.rpartition("-")[-1]
sysconfig_data_dir = (
f"{wasi_build_dir}/build/lib.wasi-wasm32-{python_version}"
)

# Use PYTHONPATH to include sysconfig data which must be anchored to the
# WASI guest's `/` directory.
args = {
"PYTHONPATH": f"/{sysconfig_data_dir}",
"ARGV0": f"/{wasi_build_dir}/python.wasm",
"PYTHON_WASM": working_dir / "python.wasm",
}
# Check dynamically for wasmtime in case it was specified manually via
Expand Down Expand Up @@ -421,8 +408,8 @@ def main():
default_host_triple = config["targets"]["host-triple"]
default_host_runner = (
f"{WASMTIME_HOST_RUNNER_VAR} run "
# For setting PYTHONPATH to the sysconfig data directory.
"--env PYTHONPATH={PYTHONPATH} "
# Set argv0 so that getpath.py can auto-discover the sysconfig data directory
"--argv0 {ARGV0} "
# Map the checkout to / to load the stdlib from /Lib.
f"--dir {os.fsdecode(CHECKOUT)}::/ "
# Flags involving --optimize, --codegen, --debug, --wasm, and --wasi can be kept
Expand Down
Loading