Steve Purcell purcell

Automatic python version plus venv

Goal

For easy editor integration and command-line usage, we'd like to be able to specify a Python version per project, with its own virtualenv to isolate its libraries from those of other projects.

We're willing to change $PATH globally once, but not per project. And we'd like to avoid having to run every python command invocation in a special subshell created by a shell wrapper. Instead, simply invoking "python" or "pip" etc. should do the right thing, based on the directory in which it is invoked.

It turns out this is possible!

Keybase proof

I hereby claim:

I am purcell on github.
I am sanityinc (https://keybase.io/sanityinc) on keybase.
I have a public key ASD6Zb31etK_0lSccFnXOXQKEk2S1137StrRR5dfWAn4Jgo

To claim this, I am signing this object:

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	-- Let's say you have a table full of work:

	CREATE TABLE tasks (
	id UUID PRIMARY KEY NOT NULL DEFAULT gen_random_uuid(),
	status TEXT NOT NULL DEFAULT 'pending',
	payload JSON NOT NULL, -- or just have meaningful columns!
	created_at TIMESTAMP NOT NULL DEFAULT NOW()
	);

	(defvar-local flycheck-eglot-current-errors nil)

	(defun flycheck-eglot-report-fn (diags &rest _)
	(setq flycheck-eglot-current-errors
	(mapcar (lambda (diag)
	(save-excursion
	(goto-char (flymake--diag-beg diag))
	(flycheck-error-new-at (line-number-at-pos)
	(1+ (- (point) (line-beginning-position)))
	(pcase (flymake--diag-type diag)

	{-# LANGUAGE BangPatterns #-}
	{-# LANGUAGE DataKinds #-}
	{-# LANGUAGE DeriveDataTypeable #-}
	{-# LANGUAGE DeriveGeneric #-}
	{-# LANGUAGE FlexibleInstances #-}
	{-# LANGUAGE GeneralizedNewtypeDeriving #-}
	{-# LANGUAGE KindSignatures #-}
	{-# LANGUAGE MultiParamTypeClasses #-}
	{-# LANGUAGE OverloadedStrings #-}
	{-# LANGUAGE RankNTypes #-}

	let
	# Assumes niv sources, which should include the repos for
	# nimlsp, ast-pattern-matching and jsonschema.
	sources = import ./nix/sources.nix;
	pkgs = import sources.nixpkgs {};

	unpackedSource = d: d.overrideAttrs (orig: {
	name = "${orig.pname}-source";
	phases = ["unpackPhase" "patchPhase" "installPhase"];
	installPhase = "mkdir $out; cp -aR . $out/.";

	From 96f7801fd773242cb584d68415b6c72b7db1e123 Mon Sep 17 00:00:00 2001
	From: Steve Purcell <steve@sanityinc.com>
	Date: Tue, 11 May 2021 15:10:45 +1200
	Subject: [PATCH] Use upstreamed poetry2nix overrides for hid and pyusb

	---
	nix/sources.json \| 12 ++++++++++++
	shell.nix \| 32 +++++---------------------------
	2 files changed, 17 insertions(+), 27 deletions(-)

	@nix { "action": "setPhase", "phase": "unpackPhase" }
	unpacking sources
	unpacking source archive /nix/store/8lsf1rrc5d3cgn2i1as76l2k3yr16k9r-ocaml-5.0.0.tar.xz
	source root is ocaml-5.0.0
	setting SOURCE_DATE_EPOCH to timestamp 1671176928 of file ocaml-5.0.0/yacc/wstr.c
	@nix { "action": "setPhase", "phase": "patchPhase" }
	patching sources
	@nix { "action": "setPhase", "phase": "updateAutotoolsGnuConfigScriptsPhase" }
	updateAutotoolsGnuConfigScriptsPhase
	Updating Autotools / GNU config script to a newer upstream version: ./build-aux/config.sub

	#!/bin/bash -e

	error_exit() {
	echo "$1" >&2
	exit 1
	}

	usage_exit() {
	cat <<EOF >&2
	Looks up your AWS keys from your 1Password and exports them before running the next command