From e407006e03ff082a3d6547a7d11b23f81ef2b6c8 Mon Sep 17 00:00:00 2001
From: premultiply <4681172+premultiply@users.noreply.github.com>
Date: Mon, 1 Jun 2026 15:07:10 +0200
Subject: [PATCH] OCPP: clear stale transaction state on Available status
 (#30247)

---
 charger/ocpp/connector_core.go | 11 +++++
 charger/ocpp/connector_test.go | 84 ++++++++++++++++++++++++++++++++++
 2 files changed, 95 insertions(+)

diff --git a/charger/ocpp/connector_core.go b/charger/ocpp/connector_core.go
index a780357e6..15d45e7f2 100644
--- a/charger/ocpp/connector_core.go
+++ b/charger/ocpp/connector_core.go
@@ -28,15 +28,26 @@ func (conn *Connector) OnStatusNotification(request *core.StatusNotificationRequ
 	conn.mu.Lock()
 	defer conn.mu.Unlock()
 
+	var applied bool
 	if conn.status == nil {
 		conn.status = request
 		close(conn.statusC) // signal initial status received
+		applied = true
 	} else if request.Timestamp == nil || conn.timestampValid(request.Timestamp.Time) {
 		conn.status = request
+		applied = true
 	} else {
 		conn.log.TRACE.Printf("ignoring status: %s < %s", request.Timestamp.Time, conn.status.Timestamp)
 	}
 
+	// Available means cable unplugged and any prior transaction is stale
+	if applied && request.Status == core.ChargePointStatusAvailable && conn.txnId != 0 {
+		conn.log.DEBUG.Printf("clearing stale transaction %d on Available status", conn.txnId)
+		conn.txnId = 0
+		conn.idTag = ""
+		conn.assumeMeterStopped()
+	}
+
 	if conn.isWaitingForAuth() {
 		if conn.remoteIdTag != "" {
 			// dispatch asynchronously: RemoteStartTransactionRequest issues a
diff --git a/charger/ocpp/connector_test.go b/charger/ocpp/connector_test.go
index 459c612ce..83f7fa922 100644
--- a/charger/ocpp/connector_test.go
+++ b/charger/ocpp/connector_test.go
@@ -7,6 +7,7 @@ import (
 	"github.com/benbjohnson/clock"
 	"github.com/evcc-io/evcc/api"
 	"github.com/evcc-io/evcc/util"
+	"github.com/lorenzodonini/ocpp-go/ocpp1.6/core"
 	"github.com/lorenzodonini/ocpp-go/ocpp1.6/types"
 	"github.com/stretchr/testify/suite"
 )
@@ -152,6 +153,89 @@ func (suite *connTestSuite) TestConnectorMeasurementsRunningTxn() {
 	suite.NoError(err, "Voltages")
 }
 
+// TestOnStatusNotificationClearsStaleTxn ensures that a transaction left over
+// from a previous session (e.g. because the charger never sent StopTransaction,
+// like the Zaptec Go 2 in local OCPP mode) is cleared when the connector
+// returns to Available, so the next Preparing can trigger RemoteStartTransaction.
+func (suite *connTestSuite) TestOnStatusNotificationClearsStaleTxn() {
+	suite.conn.remoteIdTag = "evcc"
+	suite.conn.txnId = 42
+	suite.conn.idTag = "stale"
+
+	_, err := suite.conn.OnStatusNotification(&core.StatusNotificationRequest{
+		ConnectorId: 1,
+		Status:      core.ChargePointStatusAvailable,
+		ErrorCode:   core.NoError,
+		Timestamp:   types.NewDateTime(suite.clock.Now()),
+	})
+	suite.NoError(err)
+	suite.Equal(0, suite.conn.txnId, "txnId should be cleared on Available")
+	suite.Equal("", suite.conn.idTag, "idTag should be cleared on Available")
+
+	// next Preparing notification must now satisfy NeedsAuthentication
+	_, err = suite.conn.OnStatusNotification(&core.StatusNotificationRequest{
+		ConnectorId: 1,
+		Status:      core.ChargePointStatusPreparing,
+		ErrorCode:   core.NoError,
+		Timestamp:   types.NewDateTime(suite.clock.Now().Add(time.Second)),
+	})
+	suite.NoError(err)
+	suite.True(suite.conn.NeedsAuthentication(), "Preparing after Available should require authentication")
+}
+
+// TestOnStatusNotificationKeepsActiveTxn ensures that an active transaction is
+// not cleared by transient status notifications other than Available.
+func (suite *connTestSuite) TestOnStatusNotificationKeepsActiveTxn() {
+	suite.conn.txnId = 42
+	suite.conn.idTag = "active"
+
+	for _, status := range []core.ChargePointStatus{
+		core.ChargePointStatusCharging,
+		core.ChargePointStatusSuspendedEV,
+		core.ChargePointStatusSuspendedEVSE,
+		core.ChargePointStatusFinishing,
+	} {
+		_, err := suite.conn.OnStatusNotification(&core.StatusNotificationRequest{
+			ConnectorId: 1,
+			Status:      status,
+			ErrorCode:   core.NoError,
+			Timestamp:   types.NewDateTime(suite.clock.Now()),
+		})
+		suite.NoError(err)
+		suite.Equalf(42, suite.conn.txnId, "txnId must survive %s", status)
+		suite.Equalf("active", suite.conn.idTag, "idTag must survive %s", status)
+		suite.clock.Add(time.Second)
+	}
+}
+
+// TestOnStatusNotificationKeepsTxnOnIgnoredAvailable ensures we do not clear
+// transaction state when an Available notification is rejected due to an
+// outdated timestamp (i.e. the cached status remains the current one).
+func (suite *connTestSuite) TestOnStatusNotificationKeepsTxnOnIgnoredAvailable() {
+	// prime with a recent Charging status
+	_, err := suite.conn.OnStatusNotification(&core.StatusNotificationRequest{
+		ConnectorId: 1,
+		Status:      core.ChargePointStatusCharging,
+		ErrorCode:   core.NoError,
+		Timestamp:   types.NewDateTime(suite.clock.Now()),
+	})
+	suite.NoError(err)
+	suite.conn.txnId = 42
+	suite.conn.idTag = "active"
+
+	// out-of-order Available with an older timestamp must be ignored
+	// and must not clear the running transaction
+	_, err = suite.conn.OnStatusNotification(&core.StatusNotificationRequest{
+		ConnectorId: 1,
+		Status:      core.ChargePointStatusAvailable,
+		ErrorCode:   core.NoError,
+		Timestamp:   types.NewDateTime(suite.clock.Now().Add(-time.Minute)),
+	})
+	suite.NoError(err)
+	suite.Equal(42, suite.conn.txnId, "txnId must survive ignored Available")
+	suite.Equal("active", suite.conn.idTag, "idTag must survive ignored Available")
+}
+
 func (suite *connTestSuite) TestOnStopTransactionResetsReportedPower() {
 	suite.conn.meterUpdated = suite.clock.Now()