pillar/assignableadapters: clear error strings

for parentassigngrp cycles:

1. create two usb adapters that have each other as parentassigngrp
2. change the parentassignrp of one of the adapters

now the cycle should be gone, but
as the error string for both adapters has been set, it was
not cleared

Signed-off-by: Christoph Ostarek <christoph@zededa.com>

pkg/pillar/types/assignableadapters.go

@@ -410,7 +410,6 @@ func (aa *AssignableAdapters) LookupIoBundleLogicallabel(label string) *IoBundle
 // LookupIoBundleGroup returns an empty slice if not found
 // Returns pointers into aa
 func (aa *AssignableAdapters) LookupIoBundleGroup(group string) []*IoBundle {
-
 	var list []*IoBundle
 	if group == "" {
 		return list
@@ -430,7 +429,6 @@ func (aa *AssignableAdapters) LookupIoBundleGroup(group string) []*IoBundle {
 // a member phylabel, logicallabel, or a group
 // Returns pointers into aa
 func (aa *AssignableAdapters) LookupIoBundleAny(name string) []*IoBundle {
-
 	list := aa.LookupIoBundleGroup(name)
 	if len(list) != 0 {
 		return list
@@ -464,24 +462,39 @@ func (aa *AssignableAdapters) LookupIoBundleIfName(ifname string) *IoBundle {
 func (aa *AssignableAdapters) CheckParentAssigngrp() bool {
 	assigngrp2parent := make(map[string]string)
 
+	ownParentError := "IOBundle cannot be it's own parent"
+	parentAssigngrpMismatchError := "IOBundle with parentassigngrp mismatch found"
+	emptyAssigngrpWithParentError := "IOBundle with empty assigngrp cannot have a parent"
+	cycleDetectedError := "Cycle detected, please check provided parentassigngrp/assigngrp"
+
 	var cycleDetectedAssigngrp string
 	for i := range aa.IoBundleList {
 		ioBundle := &aa.IoBundleList[i]
 
+		for _, errStr := range []string{
+			ownParentError,
+			parentAssigngrpMismatchError,
+			emptyAssigngrpWithParentError,
+			cycleDetectedError,
+		} {
+			if ioBundle.Error == errStr {
+				ioBundle.Error = ""
+			}
+		}
 		if ioBundle.AssignmentGroup == ioBundle.ParentAssignmentGroup && ioBundle.AssignmentGroup != "" {
-			ioBundle.Error = "IOBundle cannot be it's own parent"
+			ioBundle.Error = ownParentError
 			ioBundle.ErrorTime = time.Now()
 			return true
 		}
 		parentassigngrp, ok := assigngrp2parent[ioBundle.AssignmentGroup]
 		if ok && parentassigngrp != ioBundle.ParentAssignmentGroup {
-			ioBundle.Error = "IOBundle with parentassigngrp mismatch found"
+			ioBundle.Error = parentAssigngrpMismatchError
 			ioBundle.ErrorTime = time.Now()
 			return true
 		}
 
 		if ioBundle.AssignmentGroup == "" && ioBundle.ParentAssignmentGroup != "" {
-			ioBundle.Error = "IOBundle with empty assigngrp cannot have a parent"
+			ioBundle.Error = emptyAssigngrpWithParentError
 			ioBundle.ErrorTime = time.Now()
 			return true
 		}
@@ -516,7 +529,7 @@ func (aa *AssignableAdapters) CheckParentAssigngrp() bool {
 	for i := range aa.IoBundleList {
 		ioBundle := &aa.IoBundleList[i]
 		if ioBundle.AssignmentGroup == cycleDetectedAssigngrp {
-			ioBundle.Error = "Cycle detected, please check provided parentassigngrp/assigngrp"
+			ioBundle.Error = cycleDetectedError
 			ioBundle.ErrorTime = time.Now()
 		}
 	}

pkg/pillar/types/assignableadapters_test.go

@@ -500,6 +500,49 @@ func alternativeCheckBadUSBBundlesImpl(bundles []IoBundle) {
 	}
 }
 
+func TestClearingCycleErrors(t *testing.T) {
+	t.Parallel()
+
+	aa := AssignableAdapters{}
+	bundles := make([]IoBundle, 2)
+
+	bundles[0].Phylabel = "usb1"
+	bundles[1].Phylabel = "usb2"
+
+	bundles[0].UsbAddr = "1:1"
+	bundles[1].UsbAddr = "1:2"
+
+	bundles[0].AssignmentGroup = "a1"
+	bundles[1].AssignmentGroup = "a2"
+
+	bundles[0].ParentAssignmentGroup = "a2"
+	bundles[1].ParentAssignmentGroup = "a1"
+
+	aa.IoBundleList = bundles
+
+	aa.CheckParentAssigngrp()
+
+	errFound := func() bool {
+		found := false
+		for _, ioBundle := range aa.IoBundleList {
+			if ioBundle.Error != "" {
+				found = true
+			}
+		}
+		return found
+	}
+
+	if !errFound() {
+		t.Fatalf("no error found although there is a cycle: %+v", aa.IoBundleList)
+	}
+
+	aa.IoBundleList[1].ParentAssignmentGroup = "p2"
+	aa.CheckParentAssigngrp()
+	if errFound() {
+		t.Fatalf("error found although there is no cycle anymore: %+v", aa.IoBundleList)
+	}
+}
+
 func TestClearingUSBCollision(t *testing.T) {
 	t.Parallel()
 	aa := AssignableAdapters{}