chore: Simplify to_dict, from_dict with default (de-)serialization of objects

[julian-risch]

Related Issues

• fixes Simplify to_dict, from_dict with default (de-)serialization of init parameter objects that define to_dict, from_dict #10433

Proposed Changes:

How did you test it?

Notes for the reviewer

Simplifying AzureOpenAIResponsesChatGenerator to_dict
The only other class that I see could be updated is the AzureOpenAIResponsesChatGenerator but I decided against it. The current version makes it easier to understand in one location of the code how AzureOpenAIResponsesChatGenerator's Secret is serialized instead of spreading it across the AzureOpenAIResponsesChatGenerator class and the default_to_dict logic.

        # API key can be a secret or a callable
        serialized_api_key = (
            serialize_callable(self.api_key)
            if callable(self.api_key)
            else self.api_key.to_dict()
            if isinstance(self.api_key, Secret)
            else None
        )

We could do sth like

serialize_callable(self.api_key) if callable(self.api_key) else self.api_key

Happy to discuss.

Deprecating deserialize_document_store_in_init_params_inplace
deserialize_document_store_in_init_params_inplace is no longer used in Haystack and it also isn't used in any of the deepset maintained integrations in haystack-core-integrations. It would be still a breaking change to remove it, so we could deprecate it now and then remove it entirely in a later version of Haystack. If we decide to do that, I can open a separate PR. Happy to discuss this too.

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.

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1 Skipped Deployment

Project	Deployment	Review	Updated (UTC)
haystack-docs	Ignored	Preview	Jan 23, 2026 1:58pm

[coveralls]

Pull Request Test Coverage Report for Build 21288641956

Details

• 0 of 0 changed or added relevant lines in 0 files are covered.
• 17 unchanged lines in 4 files lost coverage.
• Overall coverage decreased (-0.01%) to 92.445%

---

Files with Coverage Reduction	New Missed Lines	%
components/retrievers/filter_retriever.py	1	95.45%
components/retrievers/in_memory/bm25_retriever.py	2	95.83%
components/retrievers/sentence_window_retriever.py	6	93.88%
components/retrievers/in_memory/embedding_retriever.py	8	75.47%

Totals
Change from base Build 21284971239:	-0.01%
Covered Lines:	14756
Relevant Lines:	15962

---

💛 - Coveralls

[anakin87]

I left two comments.

On the other points you brought up:

• Ok with keeping AzureOpenAIResponsesChatGenerator as is
• Let's deprecate deserialize_document_store_in_init_params_inplace as you suggest

[anakin87]

Looks good!