fix(memory): replace deprecated datetime.utcnow() with timezone-aware alternative

[MeloMei]

Summary

Replace all datetime.utcnow() calls in the memory module with
datetime.now(timezone.utc).replace(tzinfo=None), eliminating
DeprecationWarning on Python 3.12+.

Motivation

datetime.utcnow() is deprecated since Python 3.12
(docs)
and scheduled for removal. It creates naive datetimes that are
indistinguishable from local time, which can cause subtle bugs
when mixed with timezone-aware datetimes.

The qdrant_edge_storage.py backend already uses the recommended
pattern datetime.now(timezone.utc).replace(tzinfo=None). This PR
aligns the remaining memory module files with that convention.

Changes

• memory/types.py — MemoryRecord.created_at and last_accessed
  default factories; compute_composite_score() age calculation
• memory/unified_memory.py — update_record() timestamp
• memory/encoding_flow.py — execute_plans() timestamp
• memory/storage/lancedb_storage.py — schema placeholder,
  _row_to_record() fallback, touch_records() timestamp

All replacements use .replace(tzinfo=None) to preserve the existing
naive-datetime contract across the codebase.

Tests

Existing memory tests pass. The 4 pre-existing failures on Windows
(lancedb network guard, qdrant os.kill compat) are unrelated.

uv run pytest lib/crewai/tests/memory/ -x -q
# 13 passed, 4 failed (pre-existing)

Notes

• This PR only addresses memory/ module. Other modules may also
  contain utcnow() calls — those can be handled in follow-up PRs.
• Test files also emit the same DeprecationWarning; updating tests
  is left for a separate PR to keep this change focused.

Note: This PR was authored with AI assistance. Please apply the llm-generated label per CONTRIBUTING.md.

Summary by CodeRabbit

• Refactor
  • Standardized timestamp handling across the memory system by introducing a centralized time utility function. All timestamp generation now uses a consistent approach, improving code maintainability and reducing redundancy.

[coderabbitai]

No actionable comments were generated in the recent review. 🎉

ℹ️ Recent review info

⚙️ Run configuration

Configuration used: Organization UI

Review profile: CHILL

Plan: Pro Plus

Run ID: 5fe687b7-f23a-4476-aa5d-87c8c628751e

📥 Commits

Reviewing files that changed from the base of the PR and between c6f7f4b and 1365253.

📒 Files selected for processing (4)

• lib/crewai/src/crewai/memory/encoding_flow.py
• lib/crewai/src/crewai/memory/storage/lancedb_storage.py
• lib/crewai/src/crewai/memory/types.py
• lib/crewai/src/crewai/memory/unified_memory.py

🚧 Files skipped from review as they are similar to previous changes (3)

• lib/crewai/src/crewai/memory/storage/lancedb_storage.py
• lib/crewai/src/crewai/memory/types.py
• lib/crewai/src/crewai/memory/encoding_flow.py

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📝 Walkthrough

Walkthrough

Across four memory module files, all datetime.utcnow() calls are replaced with a shared _utc_now() helper that returns datetime.now(timezone.utc).replace(tzinfo=None). The change affects MemoryRecord field defaults, the compute_composite_score recency calculation, LanceDB storage schema rows and touch_records, execute_plans update timestamps, and Memory.update() last_accessed assignment.

Changes

UTC Timestamp Standardization

Layer / File(s)	Summary
Central _utc_now() helper and MemoryRecord defaults lib/crewai/src/crewai/memory/types.py	Introduces _utc_now() helper that returns naive UTC datetimes. Updates MemoryRecord.created_at and last_accessed default factories, and compute_composite_score recency calculation to use the helper.
LanceDB storage schema and datetime parsing lib/crewai/src/crewai/memory/storage/lancedb_storage.py	LanceDBStorage imports timezone and _utc_now, updates schema placeholder rows to use a single now timestamp for both created_at and last_accessed, normalizes datetime inputs in _parse_dt to naive UTC, and updates touch_records to use the helper.
Encoding flow timestamp generation lib/crewai/src/crewai/memory/encoding_flow.py	execute_plans removes direct datetime import and switches to _utc_now() for generating now timestamps when updating MemoryRecord objects.
Unified memory last_accessed update lib/crewai/src/crewai/memory/unified_memory.py	Memory.update() imports _utc_now and switches from datetime.utcnow() to the helper when setting record last_accessed timestamps.

Estimated code review effort

🎯 2 (Simple) | ⏱️ ~10 minutes

🚥 Pre-merge checks | ✅ 5

✅ Passed checks (5 passed)

Check name	Status	Explanation
Description Check	✅ Passed	Check skipped - CodeRabbit’s high-level summary is enabled.
Title check	✅ Passed	The title accurately describes the main change: replacing deprecated datetime.utcnow() calls with a timezone-aware alternative, which is the core objective reflected in all four modified files.
Docstring Coverage	✅ Passed	Docstring coverage is 87.50% which is sufficient. The required threshold is 80.00%.
Linked Issues check	✅ Passed	Check skipped because no linked issues were found for this pull request.
Out of Scope Changes check	✅ Passed	Check skipped because no linked issues were found for this pull request.

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[Copilot]

Pull request overview

Note

Copilot was unable to run its full agentic suite in this review.

This PR updates how “now” timestamps are generated across the memory subsystem, switching from datetime.utcnow() to datetime.now(timezone.utc) (while still persisting naive UTC datetimes).

Changes:

• Replaces datetime.utcnow() usages with datetime.now(timezone.utc).replace(tzinfo=None) in multiple modules.
• Updates default timestamp factories for MemoryRecord fields to use the new approach.
• Updates recency scoring and storage “touch” timestamps to use the new approach.

Reviewed changes

Copilot reviewed 4 out of 4 changed files in this pull request and generated 3 comments.

File	Description
lib/crewai/src/crewai/memory/unified_memory.py	Updates record update timestamp generation to use timezone-based now() then strip tzinfo.
lib/crewai/src/crewai/memory/types.py	Updates model timestamp defaults and recency scoring to use the new “UTC now” approach.
lib/crewai/src/crewai/memory/storage/lancedb_storage.py	Updates storage-layer created/last_accessed timestamps and fallback datetime parsing default.
lib/crewai/src/crewai/memory/encoding_flow.py	Updates plan execution timestamp generation to use the new “UTC now” approach.

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