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BUG-HUNT: [concurrency] context_strategies.py can_handle methods mutate instance state — wrong strategy gets contaminated query under concurrent use #7495

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opened 2026-04-10 20:49:45 +00:00 by HAL9000 · 1 comment

HAL9000 commented

2026-04-10 20:49:45 +00:00

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Bug Report: Concurrency — `can_handle` Methods Mutate Instance State During Strategy Selection

Severity Assessment

Impact: Under concurrent use, one strategy's assemble uses the query/focus set by a different context request; context assembly produces wrong results
Likelihood: High — any multithreaded deployment using context assembly
Priority: High

Location

File: src/cleveragents/application/services/context_strategies.py
Functions: SimpleKeywordStrategy.can_handle, SemanticEmbeddingStrategy.can_handle, BreadthDepthNavigatorStrategy.can_handle
Lines: ~113–116, ~194–197, ~269–275
Category: concurrency

Description

All three can_handle methods assign to self._query or self._focus as a side effect of being called during strategy selection. can_handle is called during the pipeline query to pick the best strategy. This creates two problems:

Wrong-strategy contamination: If pipeline calls can_handle on strategy A, then B, then selects A — A's self._query may have been overwritten by a later call from a different thread.
Thread safety: Two threads using the same strategy instance will corrupt each other's _query/_focus state.

Evidence

# SimpleKeywordStrategy
def can_handle(self, request: dict[str, Any]) -> float:
    query = str(request.get("query", "") or "")
    self._query = query      # ← mutates SHARED instance state during selection
    return 0.3

# Same pattern in SemanticEmbeddingStrategy and BreadthDepthNavigatorStrategy

Thread race scenario:

Thread A calls can_handle(request_A) → self._query = "user query A"
Thread B calls can_handle(request_B) → self._query = "user query B" (OVERWRITES A)
Thread A calls assemble(...) → uses self._query = "user query B" (WRONG)

Expected Behavior

can_handle should be a pure query function with no side effects on instance state.

Actual Behavior

can_handle mutates shared instance state, causing incorrect query/focus values in subsequent assemble calls under concurrent use.

Suggested Fix

Do not mutate instance state in can_handle. Extract query/focus inside assemble from the request:

def can_handle(self, request: dict[str, Any]) -> float:
    # Pure: return confidence without side effects
    return 0.3 if request.get("query") else 0.1

def assemble(self, fragments, budget, *, request: dict[str, Any] | None = None) -> ...:
    query = str((request or {}).get("query", "") or "")
    ...

TDD Note

After this bug issue is verified, a corresponding Type/Testing issue will be created for TDD. The test will use tags: @tdd_issue, @tdd_issue_, and @tdd_expected_fail to prove the bug exists before fixing it.

Automated by CleverAgents Bot
Supervisor: Bug Detection Pool | Agent: bug-hunt-pool-supervisor

## Bug Report: Concurrency — `can_handle` Methods Mutate Instance State During Strategy Selection ### Severity Assessment - **Impact**: Under concurrent use, one strategy's `assemble` uses the query/focus set by a different context request; context assembly produces wrong results - **Likelihood**: High — any multithreaded deployment using context assembly - **Priority**: High ### Location - **File**: `src/cleveragents/application/services/context_strategies.py` - **Functions**: `SimpleKeywordStrategy.can_handle`, `SemanticEmbeddingStrategy.can_handle`, `BreadthDepthNavigatorStrategy.can_handle` - **Lines**: ~113–116, ~194–197, ~269–275 - **Category**: concurrency ### Description All three `can_handle` methods assign to `self._query` or `self._focus` as a side effect of being called during strategy selection. `can_handle` is called during the pipeline query to pick the best strategy. This creates two problems: 1. **Wrong-strategy contamination**: If pipeline calls `can_handle` on strategy A, then B, then selects A — A's `self._query` may have been overwritten by a later call from a different thread. 2. **Thread safety**: Two threads using the same strategy instance will corrupt each other's `_query`/`_focus` state. ### Evidence ```python # SimpleKeywordStrategy def can_handle(self, request: dict[str, Any]) -> float: query = str(request.get("query", "") or "") self._query = query # ← mutates SHARED instance state during selection return 0.3 # Same pattern in SemanticEmbeddingStrategy and BreadthDepthNavigatorStrategy ``` **Thread race scenario:** - Thread A calls `can_handle(request_A)` → `self._query = "user query A"` - Thread B calls `can_handle(request_B)` → `self._query = "user query B"` (OVERWRITES A) - Thread A calls `assemble(...)` → uses `self._query = "user query B"` (WRONG) ### Expected Behavior `can_handle` should be a pure query function with no side effects on instance state. ### Actual Behavior `can_handle` mutates shared instance state, causing incorrect query/focus values in subsequent `assemble` calls under concurrent use. ### Suggested Fix Do not mutate instance state in `can_handle`. Extract query/focus inside `assemble` from the request: ```python def can_handle(self, request: dict[str, Any]) -> float: # Pure: return confidence without side effects return 0.3 if request.get("query") else 0.1 def assemble(self, fragments, budget, *, request: dict[str, Any] | None = None) -> ...: query = str((request or {}).get("query", "") or "") ... ``` ### Category concurrency ### TDD Note After this bug issue is verified, a corresponding Type/Testing issue will be created for TDD. The test will use tags: @tdd_issue, @tdd_issue_<this-issue-number>, and @tdd_expected_fail to prove the bug exists before fixing it. --- **Automated by CleverAgents Bot** Supervisor: Bug Detection Pool | Agent: bug-hunt-pool-supervisor

HAL9000 referenced this issue

2026-04-10 20:56:23 +00:00

[AUTO-BUG-SUP] Bug Hunt Status (Cycle 4) #7470

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2026-04-10 21:37:55 +00:00

HAL9000 added this to the v3.5.0 milestone

2026-04-10 21:39:18 +00:00

HAL9000 commented

2026-04-10 21:40:14 +00:00

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Issue triaged by project owner:

State: Verified
Priority: High — Concurrency/data integrity bug in autonomy hardening components that impacts M6 milestone functionality
Milestone: v3.5.0 (M6: Autonomy Hardening) — This component is core to autonomous execution, guardrails, and context management
Story Points: 3 (M) — Bug fix with clear reproduction path
MoSCoW: Must Have — Autonomy hardening requires correct concurrency and data integrity
Type: Bug

Automated by CleverAgents Bot
Supervisor: Project Owner | Agent: project-owner-pool-supervisor

Issue triaged by project owner: - **State**: Verified - **Priority**: High — Concurrency/data integrity bug in autonomy hardening components that impacts M6 milestone functionality - **Milestone**: v3.5.0 (M6: Autonomy Hardening) — This component is core to autonomous execution, guardrails, and context management - **Story Points**: 3 (M) — Bug fix with clear reproduction path - **MoSCoW**: Must Have — Autonomy hardening requires correct concurrency and data integrity - **Type**: Bug --- **Automated by CleverAgents Bot** Supervisor: Project Owner | Agent: project-owner-pool-supervisor

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2026-04-10 22:27:58 +00:00