last linter fixes

.github/workflows/lint.yml

@@ -19,7 +19,6 @@ jobs:
         uses: golangci/golangci-lint-action@v3
         with:
           version: latest
-          args: --timeout 5m --verbose -D unused
           skip-cache: false
           skip-pkg-cache: false
           skip-build-cache: false

.golangci.yml

@@ -1,20 +0,0 @@
-issues:
-        max-same-issues: 0
-        exclude-use-default: false
-linters:
-        enable:
-        - whitespace
-        - gosec
-        - gci
-        - misspell
-        - gomnd
-        - gofmt
-        - goimports
-        - lll
-        - golint
-        - gocyclo
-        disable:
-        - unused
-linters-settings:
-        lll:
-                line-length: 100

tree.go

@@ -1555,7 +1555,7 @@ func (t *Tree) PrintGraphvizFirstNLevels(fromRoot []byte, untilLvl int) error {
 	}
 	w := bytes.NewBufferString("")
 	if _, err := fmt.Fprintf(w,
-		"--------\nGraphviz of the Tree with Root "+hex.EncodeToString(fromRoot)+":\n"); err != nil {
+		"--------\nGraphviz of the Tree with Root %s:\n", hex.EncodeToString(fromRoot)); err != nil {
 		return err
 	}
 	err := t.GraphvizFirstNLevels(w, fromRoot, untilLvl)
@@ -1564,7 +1564,7 @@ func (t *Tree) PrintGraphvizFirstNLevels(fromRoot []byte, untilLvl int) error {
 		return err
 	}
 	if _, err := fmt.Fprintf(w,
-		"End of Graphviz of the Tree with Root "+hex.EncodeToString(fromRoot)+"\n--------\n"); err != nil {
+		"End of Graphviz of the Tree with Root %s\n--------\n", hex.EncodeToString(fromRoot)); err != nil {
 		return err
 	}
 

vt.go

@@ -625,7 +625,7 @@ func (n *node) computeHashes(currLvl, maxLvl int, p *params, pairs [][2][]byte)
 	return pairs, nil
 }
 
-//nolint:all
+//nolint:unused
 func (t *vt) graphviz(w io.Writer) error {
 	if _, err := fmt.Fprintf(w, `digraph hierarchy {
 node [fontname=Monospace,fontsize=10,shape=box]
@@ -641,7 +641,7 @@ node [fontname=Monospace,fontsize=10,shape=box]
 	return nil
 }
 
-//nolint:all
+//nolint:unused
 func (n *node) graphviz(w io.Writer, p *params, nEmpties int) (int, error) {
 	if n == nil {
 		return nEmpties, nil
@@ -720,7 +720,7 @@ func (n *node) graphviz(w io.Writer, p *params, nEmpties int) (int, error) {
 	return nEmpties, nil
 }
 
-//nolint:all
+//nolint:unused
 func (t *vt) printGraphviz() error {
 	w := bytes.NewBufferString("")
 	if _, err := fmt.Fprintf(w,