dev: Add missing pre-commit executable warning to the venv installer (#…

…204)

Running the pre-commit hooks locally eliminates the need to rebase onto
changes that the pre-commit-ci bot commits. This makes the PR process
smoother for contributors. But in case someone can't install or build
the pre-commit binary, this warning is not fatal to the venv installer.

Co-authored-by: Thomas Duvernay <td75013@hotmail.fr>

tools/venv_install.sh

@@ -41,6 +41,10 @@ if [ $# -eq 0 ]; then  # first install
         warn "Python 3.10+ is required"; exit 1; }
     $PYTHON_BINARY -m venv .venv-"${PWD##*/}"
     upgrade
+    2>/dev/null 1>&2 command -v pre-commit || {
+        warn "Skipping installation of pre-commit hooks, which requires the pre-commit command.";
+        warn "To install them later, run `pre-commit install` in the local PyDRex clone."
+    }
     2>/dev/null 1>&2 command -v pre-commit && pre-commit install
     echo "/.venv-${PWD##*/}" >>.git/info/exclude
     echo "/requirements.txt" >>.git/info/exclude