fbuild-2.1.18 broken: wheel script missing exec bit + 'Operation not permitted' on every build

[zackees]

Regression in fbuild-2.1.18

PyPI: https://pypi.org/project/fbuild/2.1.18/ (released 2026-04-19T02:46:32 UTC)

Two distinct breakages observed on ubuntu-latest (GitHub Actions):

1. Wheel's fbuild console-script missing exec bit

After pip install fbuild==2.1.18:

$ fbuild --version
/opt/hostedtoolcache/Python/3.12.13/x64/bin/fbuild: Permission denied

The installed console-script at .../bin/fbuild has no execute bit. Workaround: chmod +x $(which fbuild).

2. Every build fails with "Operation not permitted (os error 1)"

With fbuild-2.1.18 in a FastLED .venv, compiling ANY sketch for uno (AVR) yields:

   0.00 =   BUILDING uno   =
build error: build failed: io error: Operation not permitted (os error 1)

❌ Compilation failed (fbuild) [0.0s]

Happens for every one of the 83 FastLED examples tried. Failure is immediate (0.0s wall time — fbuild doesn't even get to invoke the toolchain).

Observed in: https://github.com/FastLED/fbuild/actions/runs/24619508294 (step Phase - compile examples).

Working version

fbuild-2.1.16 (released 2026-04-17T20:43:36): compiles succeed normally on the same workflow. Iteration 0 of our benchmark ran against 2.1.16 and produced a full pass in 148s compile / 198s total.

Repro

1. pip install fbuild==2.1.18 → observe Esp32-s3 PSRAM use #1.
2. cd FastLED && ./install && ./compile --no-interactive --no-parallel uno Blink → observe cdc on boot warning #2.

Impact

Blocks every CI run that invokes fbuild after 2026-04-19T02:46Z until rolled back.

Related

• [META] Fastest possible FastLED examples CI rebuild — profile + benchmark #112 — CI benchmark hit this on iteration 1.