petab1to2 writes an empty condition table if there are no condition-specific changes #552

If the v1 condition table doesn't set anything (e.g. only a conditionId column, or all values NaN), petab1to2 / petab_files_1to2 still writes a v2 conditions.tsv that contains only the header (conditionId targetId targetValue) and lists it in condition_files in the generated problem.yaml.

Since condition_files is optional in PEtab v2, the file and the YAML entry should be omitted in this case.

v1v2_condition_df already returns an empty data frame for this case (petab/v2/petab1to2.py). petab_files_1to2 writes it regardless and keeps condition_files from the converted YAML. Skipping the write and removing the file from new_yaml_config.condition_files when the converted table is empty should be sufficient. Since #547, ProblemConfig.to_yaml then also drops the empty condition_files entry.

🤖 Drafted with AI assistance (Claude Code)