Python: preserve dict subclasses in workflow checkpoints - #8519
Open
Manohar Paturi (ManoharPaturi) wants to merge 1 commit into
Open
Manohar Paturi (ManoharPaturi) wants to merge 1 commit into
Manohar Paturi (ManoharPaturi) wants to merge 1 commit into
Conversation
encode_checkpoint_value used isinstance checks for dict and list, so dict subclasses (defaultdict, Counter, OrderedDict) nested in checkpoint state were silently flattened to plain dicts on save. The save-time validation passed because decoding still succeeded, but restored workflows got a plain dict: a defaultdict access pattern like state["missing"].append(x) then raises KeyError on resume, and Counter/OrderedDict types are lost. Only plain dict/list values now take the JSON path; subclasses are pickled like tuples and sets already were, preserving type and behavior through the round trip. collections.Counter joins OrderedDict, defaultdict, and deque in the built-in restricted-unpickler allowlist so the common stdlib dict subclasses restore under restricted decoding too.
Manohar Paturi (ManoharPaturi)
deployed
to
github-app-auth
September 18, 2026 12:28 — with 
GitHub Actions
Active
GitHub Actions
Active
Manohar Paturi (ManoharPaturi)
deployed
to
github-app-auth
September 18, 2026 12:28 — with
GitHub Actions
Active
GitHub Actions
Active
agent-framework-automation
Bot
added
the
python
Manohar Paturi (ManoharPaturi)
deployed
to
github-app-auth
September 18, 2026 12:29 — with
GitHub Actions
Active
GitHub Actions
Active
Manohar Paturi (ManoharPaturi)
deployed
to
github-app-auth
September 18, 2026 12:29 — with
GitHub Actions
Active
GitHub Actions
Active
This file contains hidden or bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
Sign up for free
to join this conversation on GitHub.
Already have an account?
Sign in to comment
Add this suggestion to a batch that can be applied as a single commit.This suggestion is invalid because no changes were made to the code.Suggestions cannot be applied while the pull request is closed.Suggestions cannot be applied while viewing a subset of changes.Only one suggestion per line can be applied in a batch.Add this suggestion to a batch that can be applied as a single commit.Applying suggestions on deleted lines is not supported.You must change the existing code in this line in order to create a valid suggestion.Outdated suggestions cannot be applied.This suggestion has been applied or marked resolved.Suggestions cannot be applied from pending reviews.Suggestions cannot be applied on multi-line comments.Suggestions cannot be applied while the pull request is queued to merge.Suggestion cannot be applied right now. Please check back later.
Motivation & Context
Fixes #8517. checkpoint encode/decode reconstructed every mapping as a plain dict, so defaultdict/Counter/OrderedDict in workflow state lost their type across a save/load and resumed workflows broke.
Description & Review Guide
Related Issue
Fixes #8517
Contribution Checklist