feat: Add default (de-)serialization for ComponentDevice

[julian-risch]

Related Issues

• fixes Handle (de-)serialization of ComponentDevice in default_from_dict, default_to_dict automatically #10412

Proposed Changes:

• Extend default_to_dict so that we call to_dict() for any init parameters that are of type ComponentDevice
• Extend default_from_dict so that we call ComponentDevice.from_dict for any dict values that have single or multiple as value of field type and a device string or a device_map dict
• Added tests to verify that the automatic ComponentDevice handling works through component_to_dict/component_from_dict, which internally use default_to_dict/default_from_dict

How did you test it?

Notes for the reviewer

Once this PR is merged I am happy to do a follow up PR that makes use of these changes in all ready-made components in Haystack that use ComponentDevice. I will simplify the to_dict and from_dict methods.

Checklist

• I have read the contributors guidelines and the code of conduct.
• I have updated the related issue with new insights and changes.
• I have added unit tests and updated the docstrings.
• I've used one of the conventional commit types for my PR title: fix:, feat:, build:, chore:, ci:, docs:, style:, refactor:, perf:, test: and added ! in case the PR includes breaking changes.
• I have documented my code.
• I have added a release note file, following the contributors guidelines.
• I have run pre-commit hooks and fixed any issue.

[vercel]

The latest updates on your projects. Learn more about Vercel for GitHub.

Project	Deployment	Review	Updated (UTC)
haystack-docs	Ready	Preview, Comment	Jan 21, 2026 2:02pm

[anakin87]

Looks good