fallback-venv

Fallback Venv (Shared Disk / Foreign-Owned Checkout)

Use this when source setup.csh (or setup.sh) fails because:

• The repo directory is owned by another user (drwxr-s---), so .venv/ cannot be created in-tree, or
• Your $HOME is over quota and pip install aborts with OSError: [Errno 122] Disk quota exceeded, or
• git pull in setup.csh fails with Permission denied on .git/FETCH_HEAD.

make check / make ci still need pytest, ruff, mypy, etc. The fix is a venv on a writable, roomy filesystem (/tmp on the build host) — not in $HOME and not in the repo.

Detection (tcsh — PRIMARY)

# 1. Repo writable by me?
ls -ld $cwd                          # look for group/other write perms
# 2. Home quota OK?
df -h ~                              # check Avail
# 3. /tmp roomy?
df -h /tmp                           # need ~1 GB free

If repo is foreign-owned OR home is tight, skip setup.csh and use the steps below.

Procedure (tcsh)

# Pick the project's required interpreter. For Chopper:
set PY = /usr/intel/bin/python3.13.2
set VENV = /tmp/chopper_venv_${USER}

# Wipe any half-built venv from a previous failed run
rm -rf $VENV

# Create + activate
$PY -m venv $VENV
source $VENV/bin/activate.csh
rehash                               # tcsh: refresh command hash so pytest/ruff resolve

# Install dev extras from the repo (editable)
cd /path/to/chopper
pip install -e ".[dev]"

# Verify
which pytest ruff mypy               # all three must resolve under $VENV/bin

Procedure (bash/zsh fallback)

PY=/usr/intel/bin/python3.13.2
VENV=/tmp/chopper_venv_$USER
rm -rf "$VENV"
"$PY" -m venv "$VENV"
source "$VENV/bin/activate"
cd /path/to/chopper
pip install -e ".[dev]"
which pytest ruff mypy

Run the Gate

cd /path/to/chopper
make ci |& tail -200                 # tcsh uses |& not 2>&1 |
echo "exit=$status"

A clean run ends with ============================ N passed in Xs ============================ and exit=0.

Re-Activation in Later Sessions

The venv persists at /tmp/chopper_venv_${USER} until the host reboots or /tmp is reaped. On a new shell:

source /tmp/chopper_venv_${USER}/bin/activate.csh
rehash

If activate.csh is missing, the venv was reaped — recreate it with the procedure above.

Gotchas

• tcsh redirection: use cmd |& tail (not cmd 2>&1 | tail). Plain >& works, 2>&1 does not.
• rehash is required in tcsh after creating or activating a venv, or which pytest will report Command not found. even though it exists in $PATH.
• Do not edit setup.csh to point at /tmp — the script is shared infrastructure for the repo owner. The fallback venv is a per-user workaround that lives outside the repo.
• Do not commit anything from this procedure. It produces no repo changes; it only enables the gate to run.
• If pip install still fails on /tmp (rare), check df -h /tmp and try /tmp/$USER/chopper_venv on a different shared scratch disk.

When to Tell the User

Mention it once, briefly, when reporting test results — so they know why the standard source setup.csh path was skipped. Example:

Used a fallback venv at /tmp/chopper_venv_${USER} because the checkout is owned by another user and setup.csh couldn't create .venv in-tree.