InMemoryBackend: deep-copy values on Set/Get to fix data race#807
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…d Set/Get and SetVector/GetVector to prevent data races
Performance
✓ No regressions detected |
📊 Coverage gateThresholds from
✅ Gate passedNo surface regressed past the allowed threshold and the aggregate stayed above the floor. |
📐 Patch coverage gateThreshold: 80% on lines this PR touches vs
✅ Patch gate passedEvery surface whose lines were touched by this PR has patch coverage at or above the threshold. |
… paths Exercises the previously-uncovered branches in deepCopyAny ([]any recursion, []float64 copying, default passthrough) and deepCopyFloat64Slice (nil input handling) to satisfy the patch-coverage gate at 80%. No production code changes.
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🔴 PR-AF Review — Merge Blocked — Must-Fix Found
🚫 Merge blocked. 1 must-fix issue found by automated review.
Automated multi-agent code review · PR-AF built with AgentField
6 findings · 🚫 1 blocking · 💬 5 advisory · 🔴 0 critical · 🟠 6 important · 🔵 0 suggestions · ⚪ 0 nitpicks
PR Overview
Summary
- Recursive
deepCopyAnyformap[string]any,[]any, and[]float64applied onSet,Get,SetVector,GetVector - Callers and the backend never share mutable references, preventing data races
- Verified with
go vetclean andgo test -race ./agent/
Changes
agent/backend/inmemory/inmemory.go— AddeddeepCopyAnyhelper and applied it toSet,Get,SetVector,GetVectoragent/backend/inmemory/inmemory_test.go— Added regression tests that mutate originals and returned values, asserting stored state is unchanged; concurrent access test
Test plan
- Run
go vet ./agent/...— passes clean - Run
go test -race ./agent/...— all tests pass with race detector enabled - Regression tests verify that mutating returned values does not affect stored state and vice versa
- Concurrent access test verifies no data races under parallel reads/writes
Closes #432
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Key Findings
1 issue(s) should be addressed before merge:
- 🟠 Recursive memory copy accepts cyclic caller graphs (
sdk/go/agent/memory.go:361) — The public memory APIs accept caller-provided arbitrary values without validating or bounding object graphs:Memory.Settakesvalue anyand forwards it directly to the backend, while `Memory.SetVe… Gate: PR introduces a deep-copy function that can cause stack overflow on cyclic inputs, a regression from previous behavior.
5 advisory finding(s) surfaced as non-blocking:
- 🟠 Unsupported mutable
anyvalues remain aliased to backend storage (sdk/go/agent/memory.go:374) - 🟠 Preserve nil metadata when copying vector records (
sdk/go/agent/memory.go:482) - 🟠 Get relies on a copier that preserves mutable aliases (
sdk/go/agent/memory.go:440) - 🟠 Preserve typed nil maps when deep-copying memory values (
sdk/go/agent/memory.go:359) - 🟠 Preserve typed nil slices in deepCopyAny (
sdk/go/agent/memory.go:365)
Files with findings: sdk/go/agent/memory.go
All Findings by Severity
🟠 Important (6)
- Unsupported mutable
anyvalues remain aliased to backend storagesdk/go/agent/memory.go:374 - Preserve nil metadata when copying vector records
sdk/go/agent/memory.go:482 - Recursive memory copy accepts cyclic caller graphs
sdk/go/agent/memory.go:361 - Get relies on a copier that preserves mutable aliases
sdk/go/agent/memory.go:440 - Preserve typed nil maps when deep-copying memory values
sdk/go/agent/memory.go:359 - Preserve typed nil slices in deepCopyAny
sdk/go/agent/memory.go:365
Review Process Details
Dimensions Analyzed (2):
- Optional vector metadata must not panic — 2 file(s)
- Mutable dynamic types escaping the deep-copy switch — 840 file(s)
Meta-Dimension Lenses (3):
- Semantic — 3 dimension(s), 93% coverage confidence
- Mechanical — 1 dimension(s), 90% coverage confidence
- Systemic — 2 dimension(s), 91% coverage confidence
Pipeline Stats
| Metric | Value |
|---|---|
| Duration | 765.2s |
| Agent invocations | 24 |
| Coverage iterations | 1 |
| Estimated cost | N/A (provider does not report cost) |
| Budget exhausted | No |
| PR type | bug_fix |
| Complexity | medium |
Review ID: rev_0c5c3b91f197
| dst := make([]float64, len(val)) | ||
| copy(dst, val) | ||
| return dst | ||
| default: |
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Note
Advisory — non-blocking. Safe to merge and address in a follow-up.
Why non-blocking: The PR adds partial deep copy, improving thread safety; the remaining aliasing is a pre-existing issue and not a regression that breaks production functionality.
Unsupported mutable any values remain aliased to backend storage
🟠 IMPORTANT · confidence 99%
Deep-copy all mutable any values in deepCopyAny or reject unsupported types. Currently the default branch returns []byte, []string, map[string]string, pointers, and nested unsupported mutable values by reference, allowing callers to modify backend state outside of b.mu after a Set or Get, breaking the thread-safety guarantee.
Evidence
Step 1:
NewMemory(nil)selectsNewInMemoryBackend, andMemory.Set/ScopedMemory.Setforward their unrestrictedvalue anyargument toInMemoryBackend.Set.
Step 2:SetassignsdeepCopyAny(value)tob.data[ck][key].
Step 3: for[]byte,[]string,map[string]string, pointers, and all other unmatched dynamic types,deepCopyAnyreaches thedefaultbranch and returns the original reference unchanged (lines 374-375). A nested[]byte, for example, reaches that same branch through the recursivemap[string]any/[]anyhandling.
Step 4:Getinvokes the same helper on the stored value and returns that same reference again. Mutating either the post-Set input or the returned value therefore mutatesb.dataoutsideb.mu, producing state corruption and race-detector failures under concurrent access.
💡 Suggested Fix
Define and enforce a complete ownership contract: either deep-copy all supported mutable shapes (including []byte, typed slices/maps, pointers and nested values—likely with a carefully bounded reflection-based copier), or reject unsupported mutable values instead of silently retaining aliases. Add Set-input and Get-return mutation tests for []byte, []string, map[string]string, pointer-containing values, and each nested beneath map[string]any / []any, exercising both NewMemory(nil) and scoped facades under -race.
Runtime ownership behavior · confidence 99%
🤖 Reviewed by AgentField PR-AF
| embedding: embedding, | ||
| metadata: metadata, | ||
| embedding: deepCopyFloat64Slice(embedding), | ||
| metadata: deepCopyAny(metadata).(map[string]any), |
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Note
Advisory — non-blocking. Safe to merge and address in a follow-up.
Why non-blocking: Behavioral change from nil to empty map has no demonstrated production impact or breach of explicit public API contract.
Preserve nil metadata when copying vector records
🟠 IMPORTANT · confidence 99%
Return nil explicitly when metadata is nil in SetVector and GetVector to prevent the copy path from silently converting it to an empty map.
deepCopyAny boxes a nil map[string]any as a typed value, so its map branch runs and creates an empty map instead of preserving nil. This breaks the optional-metadata contract: callers can no longer distinguish absent metadata from an intentionally supplied empty object.
Evidence
Step 1: A caller invokes
NewMemory(nil).SetVector(ctx, key, embedding, nil)(orInMemoryBackend.SetVector(..., nil)); both public forwarding paths pass themap[string]anyargument unchanged toInMemoryBackend.SetVector.
Step 2:SetVectorpasses its statically typed nilmetadataparameter todeepCopyAnyat line 482.
Step 3: The dynamic type ismap[string]any, sodeepCopyAnyenters the map branch at lines 358-363 and callsmake(map[string]any, len(val)), producing a non-nil empty map rather than preserving nil.
Step 4:GetVectorrepeats that copy at line 500 and returns{}. A direct/default-backend round-trip test expecting successful storage andnilretrieval failed for untyped nil and typed nil metadata, reportingmetadata=map[string]interface {}{};the prior implementation stored and returned the original nil map.
💡 Suggested Fix
Preserve nil explicitly before copying vector metadata (for example, use a deepCopyMetadata helper that returns nil when metadata == nil), on both insertion and retrieval. Add direct InMemoryBackend and default NewMemory(nil) round-trip tests for untyped nil and var metadata map[string]any, asserting found, no error/panic, and nil metadata.
Optional vector metadata preservation · confidence 99%
🤖 Reviewed by AgentField PR-AF
| case map[string]any: | ||
| m := make(map[string]any, len(val)) | ||
| for k, vv := range val { | ||
| m[k] = deepCopyAny(vv) |
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Caution
Must-fix before merge. PR introduces a deep-copy function that can cause stack overflow on cyclic inputs, a regression from previous behavior.
Recursive memory copy accepts cyclic caller graphs
🟠 IMPORTANT · confidence 99%
Add cycle detection to deepCopyAny to prevent stack overflow from cyclic maps/slices. The public Memory.Set and SetVector accept arbitrary any and map[string]any values, which are passed to deepCopyAny without bounds. A cyclic input (e.g., a map containing itself) causes infinite recursion, exhausting the stack while holding the backend lock.
Evidence
Producer/API end:
func (m *Memory) Set(ctx context.Context, key string, value any) error(sdk/go/agent/memory.go:79) returnsm.backend.Set(ScopeSession, scopeID, key, value)(line 85);func (m *Memory) SetVector(ctx context.Context, key string, embedding []float64, metadata map[string]any) error(line 148) returnsm.backend.SetVector(ScopeSession, scopeID, key, embedding, metadata)(line 154). The default backend is selected byif backend == nil { backend = NewInMemoryBackend() }(lines 71-74), and it callsdeepCopyAny(value)inSet(line 423) anddeepCopyAny(metadata)inSetVector(line 482). Changed copier end:case map[string]any:allocates a map then runsfor k, vv := range val { m[k] = deepCopyAny(vv) }(lines 358-362);case []any:likewise runsfor i, elem := range val { s[i] = deepCopyAny(elem) }(lines 364-368). Neither branch detects revisited maps/slices or limits recursion.
💡 Suggested Fix
Track visited map/slice identities during copying and either preserve cycles safely or return an error for cyclic input. Thread that error through Set, Get, SetVector, and GetVector; alternatively reject cyclic/deeply nested graphs at the public API boundary with a documented depth limit.
Consistency Verifier · confidence 99%
🤖 Reviewed by AgentField PR-AF
| if !found { | ||
| return nil, false, nil | ||
| } | ||
| return deepCopyAny(val), true, nil |
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Note
Advisory — non-blocking. Safe to merge and address in a follow-up.
Why non-blocking: The finding describes a potential data race due to incomplete deep copy, but does not demonstrate a concrete impact on data integrity, security, or public API that would warrant blocking the merge.
Make deepCopyAny deep-copy every mutable type that Set accepts, not just map[string]any, []any, and []float64.
🟠 IMPORTANT · confidence 98%
When deepCopyAny encounters a map[string]string, []byte, pointer, or any other mutable type, the default case returns the value unchanged (sdk/go/agent/memory.go:374-375). The same incomplete copier is used by Get after acquiring the read lock, so callers receive an alias directly into b.data and can mutate it outside the lock, breaking consistency.
Evidence
Writer:
b.data[ck][key] = deepCopyAny(value)(sdk/go/agent/memory.go:423). Copy fallback:default:\n\t\treturn v(sdk/go/agent/memory.go:374-375). Changed reader:return deepCopyAny(val), true, nil(sdk/go/agent/memory.go:440), after acquiringb.mu.RLock()at line 429.
Consistency Verifier · confidence 98%
🤖 Reviewed by AgentField PR-AF
| func deepCopyAny(v any) any { | ||
| switch val := v.(type) { | ||
| case map[string]any: | ||
| m := make(map[string]any, len(val)) |
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Note
Advisory — non-blocking. Safe to merge and address in a follow-up.
Why non-blocking: 行为差异不导致数据丢失、安全漏洞或破坏性契约，且未展示立即生产影响。
Preserve typed nil maps when deep-copying memory values
🟠 IMPORTANT · confidence 98%
Return nil when deep-copying a nil map to preserve typed nilness.
In-memory backend deep-copies values on Set/Get, turning a typed nil map into an allocated empty map. The control-plane backend round-trips through JSON, which preserves nil as null, so Get returns nil. This mismatch means backend choice changes the observable value of a nil map after Set/Get.
Evidence
Changed location, sdk/go/agent/memory.go:358-363:
case map[string]any: m := make(map[string]any, len(val)); ... return m(a nil map has len 0 and becomes non-nil). In-memory Set/Get use that copy at memory.go:423 (b.data[ck][key] = deepCopyAny(value)) and 440 (return deepCopyAny(val), true, nil); vector metadata does likewise at 482 and 500. Other backend, sdk/go/agent/control_plane_memory_backend.go:54-59 sends"data": valuethroughjsonReader, while lines 194-200 sends"metadata": metadata;jsonReadercallsjson.Marshal(v)at lines 406-409.GetVectordecodes intoMetadata map[string]anyand returnsres.Metadataat lines 248-262, preserving JSON null as nil.
💡 Suggested Fix
Preserve nilness before allocating: in the map[string]any branch, return nil when val == nil; otherwise allocate and recursively copy. Add round-trip tests for nil generic map values and nil vector metadata, including parity with the control-plane backend.
Consistency Verifier · confidence 98%
🤖 Reviewed by AgentField PR-AF
| } | ||
| return m | ||
| case []any: | ||
| s := make([]any, len(val)) |
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Note
Advisory — non-blocking. Safe to merge and address in a follow-up.
Why non-blocking: No concrete evidence of broken public API contract or user impact.
In deepCopyAny, return typed nil slices for []any and []float64 when val is nil, to preserve nilness.
🟠 IMPORTANT · confidence 98%
Calling make on a nil slice produces a non-nil empty slice, so deepCopyAny returns a non-nil zero-length slice where a typed nil was originally stored. This changes JSON serialization from null to [] and causes the in-memory backend to behave differently from the control-plane backend, which preserves nilness over the wire.
Evidence
Changed code, sdk/go/agent/memory.go:364-373:
case []any: s := make([]any, len(val)) ... return sandcase []float64: dst := make([]float64, len(val)); copy(dst, val); return dst;makewith a zero length produces a non-nil empty slice even whenvalis nil. The generic API passes the original value into the backend (func (m *Memory) Set(... value any) error { ... return m.backend.Set(..., value) }, lines 78-86) and returns the backend value unchanged (val, _, err := m.backend.Get(...); return val, err, lines 88-98). The distributed serializer constructs its request with"data": value(sdk/go/agent/control_plane_memory_backend.go:54-59) and callsjson.Marshal(v)(lines 406-411), for which nil slices encode asnullwhile non-nil empty slices encode as[].
💡 Suggested Fix
Preserve nilness before allocation: in each []any and []float64 case, return a typed nil slice when val == nil; otherwise allocate and copy. Add Set/Get round-trip tests for typed nil []any and []float64, including their JSON representation if backend consistency is required.
Consistency Verifier · confidence 98%
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Realigns embedded mirrors with skills/ sources inherited from the main merge so skillkit drift tests pass branch-locally. Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
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Summary
deepCopyAnyformap[string]any,[]any, and[]float64applied onSet,Get,SetVector,GetVectorgo vetclean andgo test -race ./agent/Changes
agent/backend/inmemory/inmemory.go— AddeddeepCopyAnyhelper and applied it toSet,Get,SetVector,GetVectoragent/backend/inmemory/inmemory_test.go— Added regression tests that mutate originals and returned values, asserting stored state is unchanged; concurrent access testTest plan
go vet ./agent/...— passes cleango test -race ./agent/...— all tests pass with race detector enabledCloses #432
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