fix(environments): pin PythonEnvironment._write_to_file encoding to UTF-8#2827
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…TF-8 PythonEnvironment._write_to_file is the shared helper every concrete PythonEnvironment subclass uses to land an agent-generated script on disk before invoking subprocess. The bare 'open(script_path, "w")' inherits 'locale.getpreferredencoding(False)' — cp1252 on default Windows installs — so the first non-cp1252 character (CJK string literal, emoji, smart quote from copy-pasted documentation, PEP 3131 identifier) raises 'UnicodeEncodeError' mid-write. The script is then partially written, the subprocess runs an invalid file, and the agent sees a syntax error or truncated output instead of the intended behavior. Pin encoding="utf-8" on the open call. Adds source-level regression coverage in test/environments/test_python_environment_utf8.py that runs on every CI lane (no PythonEnvironment subclass extras required) so the kwarg cannot silently regress.
marklysze
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Correct — PythonEnvironment._write_to_file now pins UTF-8. Agent-generated scripts almost always include non-ASCII content (docstrings, string literals, identifiers under PEP 3131), so this fix prevents silent mid-write failures on Windows. LGTM.
marklysze
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Same encoding fix in PythonEnvironment._write_to_file. This is the path that writes agent-generated scripts to disk — agent output reliably contains non-ASCII (comments, string literals, CJK identifiers). Test correctly exercises the cp1252-locale code path. Approved.
This was referenced May 17, 2026
`check-license-headers` pre-commit hook flagged the new test package init as missing the standard SPDX header; add the 2023-2026 ag2 header matching the sibling test file to clear the pre-commit-check / pr-check failures.
Remove regression comment regarding UTF-8 encoding handling in PythonEnvironment._write_to_file.
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Description
PythonEnvironment._write_to_file(autogen/environments/python_environment.py:90) is the shared helper every concretePythonEnvironmentsubclass uses to land an agent-generated script on disk before invokingsubprocess. The bareopen(script_path, "w")inheritslocale.getpreferredencoding(False)— cp1252 on default Windows installs — so the first non-cp1252 character (CJK string literal, emoji, smart quote from copy-pasted documentation, PEP 3131 identifier) raisesUnicodeEncodeErrormid-write. The script is then partially written, the subprocess runs an invalid file, and the agent sees a syntax error or truncated output instead of the intended behavior. Same class of bug as #1731 / PRs #2818 / #2819 / #2825 / #2826.This change pins
encoding="utf-8".Tests
Added
test/environments/test_python_environment_utf8.py— source-level regression check that asserts the kwarg appears on the call site. Runs on every CI lane.Checklist
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