Fix infinite recursion by sniffing the shebang #6711
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When we see `#!/usr/bin/env -S uv run"`, treat the input as a python file to avoid infinite recursion. Tested manually. Fixes #6360
| @@ -882,6 +883,20 @@ impl TryFrom<&ExternalCommand> for RunCommand { | |||
| { | |||
| Ok(Self::PythonGuiScript(target_path, args.to_vec())) | |||
| } else { | |||
| // Sniff the shebang to avoid infinite recursion | |||
| let known_shebang = br"#!/usr/bin/env -S uv run"; | |||
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This wouldn't take into account for cases where e.g. env -S isn't supported (older version of coreutils), where some black magic or custom script (e.g. named uv-run in my case) is used in the shebang.
Also it wouldn't be completely alien to want to hardcode a path to uv instead of relying to env.
In both of these cases the shebang wouldn't match, and this heuristic would not completely fix the infinite recursion issue.
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I also worry this heuristic is too brittle. I'm not sure what the solution is without peeking. Some sort of environment variable?
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My two cents as I'm still discovering and playing with uv, I'd be happy with an alternative entry point (e.g. uv exec) which would only accept files as input.
It seems to me that this whole issue is made complex by uv run also being expected to run 'scripts' declared in pyproject.toml (I think?), and being bent to also work like a standalone script runner.
EDIT: I feel like a CLI flag to force a file to be executed would also be acceptable.
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We also have something like... #3097 — maybe we just need a --script flag here to force us to treat something as a script? We should still have a way to detect recursion and bail instead of looping though.
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(i.e. a UV_INTERNAL__RECURSION variable that we bump on every recursive subprocess and bail after some limit is hit)
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A --script flag plus a UV_INTERNAL_RECURSION for better error reporting would work.
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A more resilient solution would be not running binaries, but only running python scripts and python from uv run, this seems to be done by e.g. bash to avoid infinite recursion.
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I'm pretty unwilling to change that part of the user experience — running binaries from uv run is important. I think a separate command or opt-in to that experience via --script makes the most sense to me.
When we see
#!/usr/bin/env -S uv run", treat the input as a python file to avoid infinite recursion.Tested manually.
Fixes #6360