Change shebangs with Tools/scripts/pathfix.py?

[hroncok]

There is a script in /usr/lib64/python3.6/Tools/scripts/pathfix.py that changes shebangs. We may want to:

• recommend that in the shebang sections of this guide
• use it automagically in rpm builds to fix shebangs? (with similar logic to pybytecompile script)

I'm opening this here, because of the first above point. If we say we want to use this automatically, we can discuss this in some ML.

Example usage:

%install
...
%{python3_sitearch}/Tools/scripts/pathfix.py -i "%{__python3} -s" -p %{buildroot}%{_bindir}/*

Note: A small problem with this script is that it only converts files where the name matches r'^[a-zA-Z0-9_]+\.py$' when called on directory, but you can call it directly on files.

[hroncok]

@encukou @torsava bump?

[encukou]

I think we should package this properly – into /usr/bin as part of python3-devel – and then recommend it. The %{python3_sitearch}/Tools/scripts directory is horrible and I'd like to get rid of it eventually.
If we run this automatically, we need to be really careful about the shebangs it generates: the -s will not combine cleanly with other options.

[torsava]

Is the file name limit a bug or a feature? I'd fix it before we recommend it.

[encukou]

@torsava, I think adding a CLI option to act on all files (or all executable files?) would have a good chance of being accepted ustream.
See issue10140 and python/cpython@7cd94b8 for a similar change.

[torsava]

So, do we want to act on all files with the extension .py, or all executable files that have the word python in the shebang line?

I'm more inclined towards the first.

[encukou]

On further thought, for Fedora the tool might be OK as it is. Files in /usr/lib should not be executable and should not have shebangs anyway. And files in /usr/bin don't need the directory traversal.

(Also, setuptools gives correct shebangs anyway – this is only for other buildsystems.)

[torsava]

On further thought, for Fedora the tool might be OK as it is. Files in /usr/lib should not be executable and should not have shebangs anyway. And files in /usr/bin don't need the directory traversal.

So we advise to do ... pathfix.py -i .... %{_bindir}/* ? That does sound alright.

[hroncok]

I think we should package this properly – into /usr/bin as part of python3-devel – and then recommend it. The %{python3_sitearch}/Tools/scripts directory is horrible and I'd like to get rid of it eventually.

That of course was my intention as well.

[hroncok]

I'll craft a pull-request for python3.spec. What executable name? /usr/bin/pathfix (that one seems to be free in Fedora)?

[hroncok]

I went with /usr/bin/pathfix for now: https://src.fedoraproject.org/rpms/python3/pull-request/13

[igor-raits]

@hroncok I'm kinda reluctant requiring python3-devel in buildroot just to change shebang..

[hroncok]

Well since this was originally opened for Python only (unlike rpm-software-management/rpm#344), it wasn't a problem for me. Feel free to go with Shell instead.

[hroncok]

We gonna need this anyway to get rid of /usr/bin/python, unless you want rpm-software-management/rpm#344 to have language specific hacks.