fix(flow): report missing persistence state

[Ultronen]

Related issue

Fixes #7220

Summary

• distinguish an absent Flow state from a state that only lacks a persistence ID
• preserve the existing error normalization for malformed state objects and backend failures
• add regression coverage for absent, null, and missing-ID state validation paths

Verification

• Tests added or updated for the changed behavior

• Relevant tests and quality checks pass locally

• uv run pytest lib/crewai/tests/test_flow_persistence.py -q (18 passed)

• uv run ruff check lib/crewai/src/crewai/flow/persistence/decorators.py lib/crewai/tests/test_flow_persistence.py

• uv run ruff format --check lib/crewai/src/crewai/flow/persistence/decorators.py lib/crewai/tests/test_flow_persistence.py

• uv run mypy lib/ (905 source files)

Additional context

The regression test failed on the previous implementation with the missing-state message rewritten as the missing-ID message. No public API or persistence format changes are included.

This PR was created with Codex assistance. GitHub does not allow external contributors to apply the required llm-generated label; maintainers, please add it.

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Reviewing files that changed from the base of the PR and between 73b4061 and 0035ec2.

📒 Files selected for processing (1)

• lib/crewai/tests/test_flow_persistence.py

🚧 Files skipped from review as they are similar to previous changes (1)

• lib/crewai/tests/test_flow_persistence.py

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📝 Walkthrough

Walkthrough

Changes

Flow state validation

Layer / File(s)	Summary
Route specific persistence validation errors lib/crewai/src/crewai/flow/persistence/decorators.py, lib/crewai/tests/test_flow_persistence.py	persist_state uses a private exception to distinguish missing flow state from missing state IDs. Parametrized tests verify the expected ValueError messages for missing, None, and empty-dict state.

Merge Risk: ⚪ Minimal · up to 0035e

The change narrowly improves reporting for absent or incomplete persistence state while preserving existing error handling, with regression coverage included; no actionable merge-blocking risk remains beyond normal checks and review.

🚥 Pre-merge checks | ✅ 4 | ❌ 1

❌ Failed checks (1 warning)

Check name	Status	Explanation	Resolution
Docstring Coverage	⚠️ Warning	Docstring coverage is 75.00% which is insufficient. The required threshold is 80.00%. Docstring coverage is scoped to functions touched by this diff. Analyzed 4 functions across 2 files.	Write docstrings for the functions missing them to satisfy the coverage threshold.

✅ Passed checks (4 passed)

Check name	Status	Explanation
Linked Issues check	✅ Passed	The changes satisfy issue #7220. They distinguish absent or null state from state without an ID, retain existing error handling, and add regression coverage for the required validation paths.
Out of Scope Changes check	✅ Passed	The changes are limited to the persistence decorator and its targeted regression tests. No unrelated code, API, or persistence-format changes are included.
Title check	✅ Passed	The title clearly and concisely describes the primary change: reporting missing persistence state in flow persistence.
Description check	✅ Passed	The description includes the required related issue, summary, verification details, test results, and additional context. It directly matches the pull request objectives.

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Actionable comments posted: 1

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Inline comments:
In `@lib/crewai/tests/test_flow_persistence.py`:
- Around line 25-27: Extend the parameterized persistence test cases to include
SimpleNamespace() without a state attribute, and assert the existing "Flow
instance has no state" error. Keep the current None and empty-dictionary cases
unchanged.

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ℹ️ Review info

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Configuration used: Organization UI

Review profile: CHILL

Plan: Team

Run ID: cff04c0c-1a91-4768-8bdb-23f6abb6e0dd

📥 Commits

Reviewing files that changed from the base of the PR and between 3d72c70 and 73b4061.

📒 Files selected for processing (2)

• lib/crewai/src/crewai/flow/persistence/decorators.py
• lib/crewai/tests/test_flow_persistence.py

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