Bug: Using same field in both --groupby and --deferred-fields causes undefined behavior

[bosd]

Description

When the same field is specified in both --groupby and --deferred-fields, the import produces undefined behavior where Pass 2 parent_id resolution fails silently.

Steps to Reproduce

odoo-data-flow import \
  --file data/res_partner.csv \
  --model res.partner \
  --deferred-fields parent_id/id \
  --groupby parent_id/id

Expected Behavior

Either:

1. Raise an error/warning when conflicting flags are detected
2. Auto-remove the field from groupby when it's in deferred-fields

Actual Behavior

• Pass 1 ignores parent_id/id (correctly deferred)
• But --groupby parent_id/id tries to batch records by a field that isn't being imported
• Pass 2 fails to resolve parent_id relationships

Impact

Parent/child relationships (like res.partner contacts under companies) are not established, causing data integrity issues.

Workaround

Remove --groupby when using --deferred-fields for the same field.

Environment

• odoo-data-flow version: latest
• Odoo version: 18.0