Rust-clippy: Clippy Python scripts portablility

[mati865]

Currently all Python scripts in this repository use shebang #!/usr/bin/env python.

The problem

This is bad because python means default system Python which is Python 3 for Arch and scripts don't work.
Other distributions are going to follow it sooner or later because Python 2 won't be maintained since 2020, for an example: Fedora proposal. Also many distributions like Ubuntu, OpenSUSE, Fedora want to ship only with Python 3 preinstalled.

Behaviour on different platforms

I've checked many Linux distributions and all of them had python2, python2.7, python3, python3.X (X differs based on the version).
All I know about OSX is it doesn't have python2 but has python2.7, it would be great if somebody could reply with list of all variants.
MSYS2 (aka windows-gnu) does it just like Linux, no idea about windows-msvc (does #!/usr/bin/env even work there?).

Possible solutions

1. Use #!/usr/bin/env python2; probably would work everywhere (sometimes it's not installed but available in repo) but note that, Python 2 is almost dead already.
2. Port scrips to Python 3; I have no idea about OSX and MSVC, should work everywhere else.
3. RIIR; everything will work on every supported platform, it's win-win but takes more effort.

cc no idea

[llogiq]

Alternative: Port the scripts to Rust.

[oli-obk]

RIIR all the things

[mati865]

I feel so dump I haven't thought about it earlier.
Edited OP.

[mikerite]

How would option 3 work? Would you create a utility binary crate or somehow use a Rust build script?

[oli-obk]

Yea, just add a crate and maybe a bat and an sh script for convenient invocation together with a .rustup file pointing to stable so the utils aren't rebuilt whenever nightly is bumped

[phansch]

I guess portability is a good reason to use Rust here. Another good thing about using Rust would be that we can add some unit tests to these scripts. The scripts are somewhat complicated already. I remember that the update_lints script had issues before and there are no tests that prevent those issues from appearing again.

[phansch]

I would be happy to work on this, actually.

@oli-obk Did you mean the rust-toolchain file instead of .rustup?

[oli-obk]

yes

[llogiq]

I have looked a bit into this during my ongoing vacation and I believe this could even be written without using regex so a simple .rs file that implements all the functions would work good enough.

[phansch]

@llogiq Were you thinking of using Clippys lint registry to do it without Regex? I have a basic version that uses regex now, and it seems simple enough to continue.

[llogiq]

No, just str::split and friends. But using regex is fine, too.

[phansch]

Quick summary of what's left to do for update_lints.py:

• [x] Handle -c/--check flag, and use it in CI
• [x] Generate the pub mod xxx section (gen_mods in update_lints.py)
• [x] Generate the module::lint_name section (gen_group in update_lints.py)
• [x] Generate the deprecated lints section (gen_deprecated in update_lints.py)

There's also export.py and lintlib.py which need to be rewritten, too.

[mati865]

I think this is done.

[ThibsG]

Actually I am not sure it is totally done, unless these two rewriting have been dropped or done by other means?

There's also export.py and lintlib.py which need to be rewritten, too.

[mati865]

They seem to be used only on the CI so there is no portability issue for the developers.

[llogiq]

True, we don't have a clippy_dev subcommand to create the lints.json yet, right? lintlib shouldn't be needed anymore AFAIR.