[Alpenj]

Description

On Windows, --batch and --checkpoint do not agree on the file encoding:

• --batch files are opened with click.open_file(path), so they are read with the locale encoding (the ANSI code page on Windows, such as cp1252 or cp949).
• The --checkpoint file is written with click.open_file(path, mode='a') (locale encoding) in run_query(), but replay_checkpoint_file() reads it back with encoding='utf-8'.

So on Windows, a UTF-8 batch file with any non-ASCII text fails to load or is read garbled, a statement with a character outside the code page cannot be written to the checkpoint, and --resume cannot read back a checkpoint that holds a non-ASCII statement. On Linux and macOS the locale encoding is usually UTF-8, so the problem does not show there.

Reproduction with the same open() calls, Python 3.14 on Windows with the cp949 code page:

locale encoding: cp949
batch read: UnicodeDecodeError 'cp949' codec can't decode byte 0xe2 in position 16: illegal multibyte sequence
checkpoint write: UnicodeEncodeError 'cp949' codec can't encode character '\u2728' in position 15: illegal multibyte sequence
checkpoint replay: UnicodeDecodeError 'utf-8' codec can't decode byte 0xc7 in position 23: invalid continuation byte

(The batch file is select 'Łukasz ✨';. The last line is a Korean statement written to the checkpoint with the locale encoding and read back as UTF-8, as --resume does.)

This change:

• reads --batch files as UTF-8. Standard input (--batch -) is left as before, so click still picks the console encoding.
• writes the --checkpoint file as UTF-8, which matches how replay_checkpoint_file() reads it.

Tests:

• test_main_batch_without_progress_bar_reads_utf8_batch_and_checkpoint and test_main_batch_with_progress_bar_reads_utf8_batch use a UTF-8 batch file with Łukasz ✨.
• test_run_query_writes_checkpoint_as_utf8 checks that the checkpoint is written as UTF-8.
• The click.open_file fakes in test_main_modes_batch.py now accept keyword arguments.

On Windows 11 (cp949), Python 3.14, uv run pytest mycli_test/pytests/test_main_modes_batch.py mycli_test/pytests/test_client_query.py: before the fix, the 3 new tests fail (3 failed, 74 passed, 6 skipped); with the fix, 77 passed, 6 skipped.

Checklist

• I added this contribution to the changelog.md file.
• I added my name to the mycli/AUTHORS.txt file (or it's already there).
• To lint and format the code, I ran

  uv run ruff check && uv run ruff format && uv run mypy --install-types .

  ruff check and ruff format --check pass. mypy on the changed files reports the same 4 errors before and after the change; they are Windows-only (pwd and os.getuid are missing there) and in other files.

[rolandwalker]

Hi! Thanks! We love better Windows support!

[rolandwalker]

Released in https://github.com/dbcli/mycli/releases/tag/v2.31.0 !