perf: migrate bash launcher to hermetic-build by jbedard · Pull Request #1045 · aspect-build/rules_py

jbedard · 2026-05-22T05:58:07Z

Changes are visible to end-users: yes

Searched for relevant documentation and updated as needed: yes
Breaking change (forces users to change their own code or config): no
Suggested release notes appear below: yes

Use https://github.com/hermeticbuild/hermetic-launcher to launch the python toolchain instead of depending on a shell wrapper.

Test plan

Covered by existing test cases
Manual testing

aspect-workflows · 2026-05-22T06:49:30Z

Bazel 8 (Test)

All tests were cache hits

183 tests (100.0%) were fully cached saving 1m 5s.

Bazel 9 (Test)

All tests were cache hits

182 tests (100.0%) were fully cached saving 1m 10s.

Bazel 8 (Test)

e2e

All tests were cache hits

136 tests (100.0%) were fully cached saving 1m 21s.

Bazel 9 (Test)

e2e

All tests were cache hits

131 tests (100.0%) were fully cached saving 1m 1s.

Bazel 8 (Test)

examples/uv_pip_compile

All tests were cache hits

1 test (100.0%) was fully cached saving 444ms.

Buildifier Gazelle

jbedard · 2026-05-22T07:27:10Z

+# Make wheel-declared console scripts reachable via `subprocess.run("name", ...)`.
+_venv_bin = os.path.join(sys.prefix, "bin")
+if _venv_bin not in os.environ.get("PATH", "").split(os.pathsep):
+    os.environ["PATH"] = _venv_bin + os.pathsep + os.environ.get("PATH", "")


Does anyone know of a better way of doing this? Should it be opt-in?

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jbedard · 2026-05-22T17:12:30Z

@@ -1,5 +1,12 @@
 """quasi-public types."""

+PyExecutableInfo = provider(


This replaces the __PEX_PY_BINARY_ENTRYPOINT__ we were inserting into the shell script.

I don't know the history behind py_pex_binary or if this is the ideal solution. @thesayyn?

this should not be needed now that we have b5ecd19

Because we can just use DefaultInfo.executable or something like that?

aspect-workflows · 2026-05-28T17:20:46Z

✨ Aspect Workflows Tasks

📅 Fri May 29 21:53:27 UTC 2026

🔄 2 in progress tasks

🔄 test (test-e2e-bazel-9) · ⏱ 3.3s · 🐙 GitHub Actions · ☑️ Check
💬 Spawning bazel test...
🔄 test (test-root-bazel-9) · ⏱ 3.6s · 🐙 GitHub Actions · ☑️ Check
💬 Spawning bazel test...

❌ 1 failed task

❌ test (test-e2e-bazel-8) · ⏱ 1m 29s · 🐙 GitHub Actions · ☑️ Check
💬 failed in test · Bazel test failed

✅ 4 successful tasks

✅ buildifier · ⏱ 21.7s · 🐙 GitHub Actions · ☑️ Check
💬 Format complete (clean)
✅ gazelle · ⏱ 25.7s · 🐙 GitHub Actions · ☑️ Check
💬 Gazelle complete (clean)
✅ test (test-examples-uv_pip_compile-bazel-8) · ⏱ 27.2s · 🐙 GitHub Actions · ☑️ Check
💬 Bazel test complete (1/1 passed · 1 cached)
✅ test (test-root-bazel-8) · ⏱ 2m 55s · 🐙 GitHub Actions · ☑️ Check
💬 Bazel test complete (184/184 passed · 120 cached)

🔁 Reproduce

❌ test (test-e2e-bazel-8)

aspect test -- \
  @@aspect_rules_py++uv+sdist_build__uv_pyproject_cases__pyahocorasick__2_2_0//:whl \
  //cases/uv-pyproject-cases/pyahocorasick:test

# without Aspect CLI
bazel test -- \
  @@aspect_rules_py++uv+sdist_build__uv_pyproject_cases__pyahocorasick__2_2_0//:whl \
  //cases/uv-pyproject-cases/pyahocorasick:test

_{Install aspect: docs.aspect.build/cli/install}

_{⏱ Last updated Fri May 29 21:56:39 UTC 2026 · 📊 GitHub API quota 263/15,000 (2% used, resets in 31m)}
_{🚀 Powered by Aspect CLI (v2026.22.23) | Aspect Build · X · LinkedIn · YouTube}

github-actions · 2026-05-28T17:22:45Z

py_binary startup benchmark

Version	Mean (ms)	Median (ms)	± stddev	vs BCR	vs main	Build (s)
BCR 1.11.5 (baseline)	330.136	328.383	±6.299	—	—	45.80
HEAD main	135.411	134.753	±2.685	-59.0%	—	15.22
This PR	61.200	59.951	±5.682	-81.5%	-54.8%	12.66

Measured with hyperfine --warmup 5 --runs 50 on Linux
Gate: PR vs HEAD main (threshold: 10%). BCR is shown only as a historical baseline.
Build time: cold bazel build //:bench with isolated output base, no disk cache.

sys.path quality

Version	sys.path entries	distinct site-packages roots
BCR 1.11.5 (baseline)	6	1
HEAD main	7	2
This PR	7	2

sys.path quality measured by bench_syspath inside the assembled venv. Duplicate realpaths indicate symlink redundancy; many distinct site-packages roots suggest an inefficient venv layout.

…uncher native stub Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

…st build compat

jbedard force-pushed the hermetic-build branch from 58bede8 to 6516ca3 Compare May 22, 2026 06:48

jbedard force-pushed the hermetic-build branch 2 times, most recently from 491171d to dbccde5 Compare May 22, 2026 07:11

jbedard commented May 22, 2026

View reviewed changes

jbedard requested review from gregmagolan, thesayyn and xangcastle May 22, 2026 17:06

jbedard marked this pull request as ready for review May 22, 2026 17:07

jbedard requested a review from dzbarsky May 22, 2026 17:07

chatgpt-codex-connector Bot reviewed May 22, 2026

View reviewed changes

Comment thread py/private/py_venv/_virtualenv.py Outdated

jbedard commented May 22, 2026

View reviewed changes

jbedard force-pushed the hermetic-build branch from 5ee55bc to ed4dee2 Compare May 22, 2026 19:12

thesayyn reviewed May 22, 2026

View reviewed changes

Comment thread py/private/py_venv/types.bzl Outdated

jbedard force-pushed the hermetic-build branch 2 times, most recently from b5ecd19 to fe6c33c Compare May 28, 2026 17:20

perf: migrate py_venv_exec launcher from bash template to hermetic_la…

f439e95

…uncher native stub Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

xangcastle force-pushed the hermetic-build branch from e7aa847 to f439e95 Compare May 29, 2026 11:13

fix: benchmark RUNFILES_DIR for native launcher stub and macOS 26 sdi…

91df6c8

…st build compat

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perf: migrate bash launcher to hermetic-build#1045

perf: migrate bash launcher to hermetic-build#1045
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		@@ -1,5 +1,12 @@
		"""quasi-public types."""

		PyExecutableInfo = provider(

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jbedard commented May 22, 2026

Changes are visible to end-users: yes

Test plan

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