1 files changed, 102 insertions, 0 deletions
diff --git a/vendor/github.com/mgechev/revive/rule/unused-param.go b/vendor/github.com/mgechev/revive/rule/unused-param.go
new file mode 100644
index 0000000000..60df908d3d
--- /dev/null
+++ b/vendor/github.com/mgechev/revive/rule/unused-param.go
@@ -0,0 +1,102 @@
+package rule
+
+import (
+	"fmt"
+	"go/ast"
+
+	"github.com/mgechev/revive/lint"
+)
+
+// UnusedParamRule lints unused params in functions.
+type UnusedParamRule struct{}
+
+// Apply applies the rule to given file.
+func (r *UnusedParamRule) Apply(file *lint.File, _ lint.Arguments) []lint.Failure {
+	var failures []lint.Failure
+
+	onFailure := func(failure lint.Failure) {
+		failures = append(failures, failure)
+	}
+
+	w := lintUnusedParamRule{onFailure: onFailure}
+
+	ast.Walk(w, file.AST)
+
+	return failures
+}
+
+// Name returns the rule name.
+func (r *UnusedParamRule) Name() string {
+	return "unused-parameter"
+}
+
+type lintUnusedParamRule struct {
+	onFailure func(lint.Failure)
+}
+
+func (w lintUnusedParamRule) Visit(node ast.Node) ast.Visitor {
+	switch n := node.(type) {
+	case *ast.FuncDecl:
+		params := retrieveNamedParams(n.Type.Params)
+		if len(params) < 1 {
+			return nil // skip, func without parameters
+		}
+
+		if n.Body == nil {
+			return nil // skip, is a function prototype
+		}
+
+		// inspect the func body looking for references to parameters
+		fselect := func(n ast.Node) bool {
+			ident, isAnID := n.(*ast.Ident)
+
+			if !isAnID {
+				return false
+			}
+
+			_, isAParam := params[ident.Obj]
+			if isAParam {
+				params[ident.Obj] = false // mark as used
+			}
+
+			return false
+		}
+		_ = pick(n.Body, fselect, nil)
+
+		for _, p := range n.Type.Params.List {
+			for _, n := range p.Names {
+				if params[n.Obj] {
+					w.onFailure(lint.Failure{
+						Confidence: 1,
+						Node:       n,
+						Category:   "bad practice",
+						Failure:    fmt.Sprintf("parameter '%s' seems to be unused, consider removing or renaming it as _", n.Name),
+					})
+				}
+			}
+		}
+
+		return nil // full method body already inspected
+	}
+
+	return w
+}
+
+func retrieveNamedParams(params *ast.FieldList) map[*ast.Object]bool {
+	result := map[*ast.Object]bool{}
+	if params.List == nil {
+		return result
+	}
+
+	for _, p := range params.List {
+		for _, n := range p.Names {
+			if n.Name == "_" {
+				continue
+			}
+
+			result[n.Obj] = true
+		}
+	}
+
+	return result
+}