The smolagents bug that made my agent retry the same valid code three times

This is a submission for DEV's Summer Bug Smash: Clear the Lineup powered by Sentry.

Third entry in the DEV x Sentry Bug Smash. Entry 1 was a crash with a confusing message. Entry 2 was a freeze the timeout could not catch. This one is quieter and sneakier: valid Python that the sandbox rejects with an error pointing at the wrong thing entirely.

When the open issues run out, fuzz

By entry 3 every obvious open smolagents bug was already claimed or had a competing PR. So instead of reading the issue tracker I pointed a small fuzzer at the piece of smolagents that runs the most untrusted code: LocalPythonExecutor, the sandbox that executes model-generated Python.

The method is boring and effective: feed it ordinary, valid Python one snippet at a time, and flag anything that raises InterpreterError. Valid Python that the sandbox refuses to run is, by definition, a bug, because the model writes valid Python and expects it to work.