[dwaddle]

Fixes #80

Problem

ParamEscaper.escape_item previously fell through to escape_string when given bytes parameters (such as LargeBinary / BINARY column binds). escape_string attempted item.decode("utf-8"), causing any non-UTF-8 byte sequence (e.g. b'\x00\xff', b'\x80', b'7\xe7\x9f') to raise UnicodeDecodeError.

Solution

• Add ParamEscaper.escape_binary and handle (bytes, bytearray, memoryview) in ParamEscaper.escape_item by emitting unhex('<hex>').
• Add unit tests in tests/unit/test_param_escaper.py covering arbitrary byte sequences (both valid and invalid UTF-8), bytearray, memoryview, and Cursor.mogrify.

Backward Compatibility

100% backward compatible; DatabendDialect uses supports_unicode_binds = True so string binds are passed as str, while bytes binds for BINARY / LargeBinary columns now reliably bind regardless of byte content.

[chatgpt-codex-connector]

Codex Review Summary

This comment shows the latest Codex review activity on this pull request.

Review	Status	Commit	Review trigger
📝 Code Review	✅ Completed 2026-10-17T14:01:57.066589Z	654ab98	PR opened

ℹ️ About Codex in GitHub

Your team has set up Codex to review pull requests in this repo. Reviews are triggered when you

• Open a pull request for review
• Mark a draft as ready
• Comment "@codex review" or "@codex security review".

Codex reacts with 👀 while any review is running, comments if it has suggestions, and reacts with 👍 once all reviews finish with no findings.

[hantmac]

Reviewed the parameter-dispatch path, SQLAlchemy binary bind processors, and Cursor.execute/executemany. No blocking findings. Hex encoding is byte-preserving, avoids UTF-8 decoding, and limits the interpolated payload to hex digits. The new bytes/bytearray/memoryview branch does not affect str parameters.

Validation on Python 3.11 with databend-driver 0.34.2:

• All 11 added tests pass on SQLAlchemy 1.4.54 and 2.0.55.
• Extra deterministic checks pass for 777 bytes-like cases per version, including empty data, all byte values, quote/backslash/percent/NUL bytes, execute, executemany, and LargeBinary/BINARY bind processing.
• Combined with #76: 20 unit tests pass; the two failures (test_view_names and test_columns) also reproduce on unchanged main and are pre-existing.

I approved the pending fork workflows. Package build is green. The fresh CI TEST run fails before pytest: the MinIO download returns HTTP 410, /usr/bin/minio contains the error page, and Databend cannot start its S3 backend (StorageUnavailable / health check reset): https://github.com/databendlabs/databend-sqlalchemy/actions/runs/39038774957 . This is an infrastructure failure, not a binary-parameter test failure. A live-server binary round-trip was not validated in this review; recommend adding that coverage as a follow-up.

Approving and merging this targeted fix. Please address the MinIO/bootstrap CI breakage and stale unit-test expectations separately.