[BUGFIX] Handle non-UTF-8 output from subprocess tools

[Mirochill]

This PR...

• Avoids UnicodeDecodeError when external map tooling writes non-UTF-8 bytes to stdout or stderr.

Considerations and implementations

run_subprocess_and_log_output() keeps decoding subprocess output as UTF-8, but now passes errors="backslashreplace" to subprocess.run(). This prevents bytes such as 0xa0 from raising while still making undecodable bytes visible in the captured log output.

Closes #271

How to test

1. git diff --check
2. git show --check --stat --oneline HEAD
3. Not run locally

Pull Request Checklist

• Reviewed the Contributing Guidelines
  • Especially the Pull-Requests section
• Commits (and commit-messages) are understandable
• Tested with macOS / Linux
• Tested with Windows

[treee111]

Local test result

Tested PR #298 in isolation on branch develop using the gdal-dev Anaconda environment.

Test run: python -m unittest tests.test_osm_maps -v

test_version_and_tags_of_country_config_file ... ok
test_encoding_open_sea_osm ... ok
test_folder_name_many_countries ... ok
test_input_country_malta ... ok
test_calc_border_countries_input_country ... FAIL  ← pre-existing, unrelated to this PR
test_calc_border_countries_input_xy_coordinates_1tile ... ok
test_calc_border_countries_input_xy_coordinates_2tiles ... ok
test_calc_without_border_countries_input_country ... ok
test_calc_without_border_countries_xy_coordinates_1tile ... ok
test_calc_without_border_countries_xy_coordinates_2tiles ... ok

Ran 10 tests in 78.591s

9/10 pass. The one failure (test_calc_border_countries_input_country) is pre-existing and unrelated to this PR — it fails on the unmodified baseline too.

The fix (errors="backslashreplace" on both subprocess.run call sites) is correct. It prevents UnicodeDecodeError when external tools like Osmosis emit non-UTF-8 bytes — instead of crashing, invalid bytes are escaped in the log output. No existing tests cover this code path directly, but the change is a safe no-op for well-behaved UTF-8 output and only activates on malformed bytes.

[treee111]

thanks for the PR @Mirochill !