[data race] SimpleManager

[liran-funaro]

This is an apparent race that appears only in tests. Not a real issue.

SimpleManager waitingTXs Counter

Location

• Read: service/coordinator/dependencygraph/manager_test.go:382 (test goroutine)
• Write: service/coordinator/dependencygraph/simple.go:178 (processing goroutine)

Root Cause

The SimpleManager.waitingTXs integer field is accessed concurrently without synchronization:

Writer (simple.go:178):

func (m *SimpleManager) processValidatedBatch(val validatedBatch) TxNodeBatch {
    m.waitingTXs -= val.txCount  // ← WRITE (line 178)
    // ...
}

Reader (manager_test.go:382):

func getWaitingTXs(t *testing.T, m any) int {
    switch mt := m.(type) {
    case *SimpleManager:
        return mt.waitingTXs  // ← READ (line 382)
    // ...
    }
}

Problem

1. The processValidatedBatch() method runs in the taskProcessing() goroutine (goroutine 215)
2. The test's ensureWaitingTXsLimit() polls waitingTXs via require.EventuallyWithT() (goroutine 587)
3. Plain integer reads/writes are not atomic in Go - concurrent access without synchronization is a data race
4. The field is also modified in processTxBatch() (line 156: m.waitingTXs += len(batch))

Impact

• Test flakiness with incorrect values read
• Race detector failures
• Potential for reading partially written values on some architectures

---

Fix: SimpleManager waitingTXs

Use atomic operations:

type SimpleManager struct {
    // ...
    waitingTXs atomic.Int32  // Change from int to atomic.Int32
}

// In production code:
m.waitingTXs.Add(-int32(val.txCount))
m.waitingTXs.Add(int32(len(batch)))

// In test code:
return int(mt.waitingTXs.Load())

---

• detected by [CI] Enable race detection for unit tests in CI #442

==================
  WARNING: DATA RACE
  Read at 0x00c000475528 by goroutine 587:
    github.com/hyperledger/fabric-x-committer/service/coordinator/dependencygraph.getWaitingTXs()
        /home/runner/work/fabric-x-committer/fabric-x-committer/service/coordinator/dependencygraph/manager_test.go:382 +0x78
    github.com/hyperledger/fabric-x-committer/service/coordinator/dependencygraph.ensureWaitingTXsLimit.func1()
        /home/runner/work/fabric-x-committer/fabric-x-committer/service/coordinator/dependencygraph/manager_test.go:364 +0x5e
    github.com/stretchr/testify/assert.EventuallyWithT.func1()
        /home/runner/go/pkg/mod/github.com/stretchr/testify@v1.11.1/assert/assertions.go:2096 +0xb3
  
  Previous write at 0x00c000475528 by goroutine 215:
    github.com/hyperledger/fabric-x-committer/service/coordinator/dependencygraph.(*SimpleManager).processValidatedBatch()
        /home/runner/work/fabric-x-committer/fabric-x-committer/service/coordinator/dependencygraph/simple.go:178 +0xc4
    github.com/hyperledger/fabric-x-committer/service/coordinator/dependencygraph.(*SimpleManager).taskProcessing()
        /home/runner/work/fabric-x-committer/fabric-x-committer/service/coordinator/dependencygraph/simple.go:144 +0x5ca
    github.com/hyperledger/fabric-x-committer/service/coordinator/dependencygraph.(*SimpleManager).Run.func3()
        /home/runner/work/fabric-x-committer/fabric-x-committer/service/coordinator/dependencygraph/simple.go:79 +0xad
  
  Goroutine 587 (running) created at:
    github.com/stretchr/testify/assert.EventuallyWithT()
        /home/runner/go/pkg/mod/github.com/stretchr/testify@v1.11.1/assert/assertions.go:2108 +0x278
    github.com/stretchr/testify/require.EventuallyWithT()
        /home/runner/go/pkg/mod/github.com/stretchr/testify@v1.11.1/require/require.go:440 +0xd1
    github.com/hyperledger/fabric-x-committer/service/coordinator/dependencygraph.ensureWaitingTXsLimit()
        /home/runner/work/fabric-x-committer/fabric-x-committer/service/coordinator/dependencygraph/manager_test.go:363 +0x12a
    github.com/hyperledger/fabric-x-committer/service/coordinator/dependencygraph.TestDependencyGraphManager.func2()
        /home/runner/work/fabric-x-committer/fabric-x-committer/service/coordinator/dependencygraph/manager_test.go:356 +0x30a8
    testing.tRunner()
        /opt/hostedtoolcache/go/1.26.1/x64/src/testing/testing.go:2036 +0x21c
    testing.(*T).Run.gowrap1()
        /opt/hostedtoolcache/go/1.26.1/x64/src/testing/testing.go:2101 +0x38
  
  Goroutine 215 (running) created at:
    github.com/hyperledger/fabric-x-committer/service/coordinator/dependencygraph.(*SimpleManager).Run()
        /home/runner/work/fabric-x-committer/fabric-x-committer/service/coordinator/dependencygraph/simple.go:77 +0x3a4
    github.com/hyperledger/fabric-x-committer/service/coordinator/dependencygraph.startManager.func1()
        /home/runner/work/fabric-x-committer/fabric-x-committer/service/coordinator/dependencygraph/manager_test.go:417 +0x50
    github.com/hyperledger/fabric-x-committer/utils/test.RunServiceForTest.func1()
        /home/runner/work/fabric-x-committer/fabric-x-committer/utils/test/utils.go:205 +0x11e
    sync.(*WaitGroup).Go.func1()
        /opt/hostedtoolcache/go/1.26.1/x64/src/sync/waitgroup.go:258 +0x5d
  ==================