[JK] Portable/Relocatable Python Linking

[jaswanthikolla]

What's the Issue?
Python binary is compiled with rpath that's /opt/hostedtoolcache/Python. Now, latest github runners define RUNNER_TOOL_CACHE/AGENT_TOOLSDIRECTORY differently than /opt/hostedtoolcache and that installs python at /home/runner/_work/_tool/Python/. So, with this, there are 2 issues.

1. sudo python --version doesn't work ( See Error section) because most systems's doesn't allow passing LD_LIBRARY_PATH due to security issues.
2. python --version doesn't work without setting environment variable LD_LIBRARY_PATH

output of ldd :

runner@arss-runner-xxxx-runner-5jvhz:~/_work/_tool/Python/3.12.3/x64/bin$ ldd python3
	linux-vdso.so.1 (0x00007ffceb776000)
	libpython3.12.so.1.0 => not found
	libc.so.6 => /lib/x86_64-linux-gnu/libc.so.6 (0x00007f7ccc75c000)
	/lib64/ld-linux-x86-64.so.2 (0x00007f7ccc991000)

Error:

python: error while loading shared libraries: libpython3.9.so.1.0: 
cannot open shared object file: No such file or directory

Solution:

$ORIGIN is used to as reference to the binary path. So, we can use rpath that references relative path instead of absolute compile time path. With this relative path, Python binaries become relocatable.

Change:

• --rpath changed to -rpath as it's the standard documented one.
• Use $ORIGIN instead of absolute path

How this is tested?

• I've also written a dockerfile to test this solution. Dockerfile moves the python installation from one location to another, and verifies it.
• New Unit test / PR checks added.

Why bother about this issue?
LD_LIBRARY_PATH can't be used with sudo python due to security concerns. But, more details are here actions/setup-python#871

[mayeut]

I think this might fail on macOS.
@jaswanthikolla, can you run the full build in your fork to make sure this passes ?
It might save some time if it requires some modifications before maintainers validate the workflow / review the PR.

It might only fail when using a version not using the universal2 installer so worth checking a build of python < 3.11

[jaswanthikolla]

This is Ubuntu/Linux Specific code, So this test doesn't get executed for macOS. May be, I can simplify by removing powershell code and write bash instead.

[mayeut]

It does fail on macOS which is an UNIX (it's UNIX specific code, not Linux): https://github.com/mayeut/python-versions/actions/runs/11766830107/job/32774981352

[klalumiere]

Thanks!

[navarro967]

Builds working on my forks thanks to this PR.

[jaswanthikolla]

Any update on this PR? Can it be reviewed and merged?

[WTPOptAxe]

Just adding a +1 here. This is a real issue for many users, @jaswanthikolla has put in the work to resolve it for many use cases, and it's been going stale for 5 months.