Merge 'ads-lost-err'

Conflicts:
	config.go

config.go

@@ -53,6 +53,7 @@ var allRules = append([]lint.Rule{
 	&rule.ModifiesParamRule{},
 	&rule.DeepExitRule{},
 	&rule.ADSPrintRule{},
+	&rule.ADSLostErrRule{},
 }, defaultRules...)
 
 var allFormatters = []lint.Formatter{

fixtures/ads-lost-err.go

@@ -0,0 +1,9 @@
+package fixtures
+
+import "errors"
+
+func foo(a, b, c, d int) {
+	errors.New("aaa")
+	errors.New(errors.InternalError, errors.MessageOption("nice error message "+err.Error())) // MATCH /original error is lost, consider using errors.NewFromError/
+	errors.MessageOption("nice error message " + err.Error())
+}

rule/ads-lost-err.go

@@ -0,0 +1,95 @@
+package rule
+
+import (
+	"go/ast"
+
+	"github.com/mgechev/revive/lint"
+)
+
+// ADSLostErrRule lints program exit at functions other than main or init.
+type ADSLostErrRule struct{}
+
+// Apply applies the rule to given file.
+func (r *ADSLostErrRule) Apply(file *lint.File, arguments lint.Arguments) []lint.Failure {
+	var failures []lint.Failure
+	onFailure := func(failure lint.Failure) {
+		failures = append(failures, failure)
+	}
+
+	w := lintLostErr{onFailure, "errors", "New"}
+	ast.Walk(w, file.AST)
+	return failures
+}
+
+// Name returns the rule name.
+func (r *ADSLostErrRule) Name() string {
+	return "ads-lost-err"
+}
+
+type lintLostErr struct {
+	onFailure  func(lint.Failure)
+	targetPkg  string
+	targetFunc string
+}
+
+func (w lintLostErr) Visit(node ast.Node) ast.Visitor {
+	ce, ok := node.(*ast.CallExpr)
+	if !ok {
+		return w
+	}
+
+	pkg, fn := getPkgFunc(ce)
+
+	if pkg == w.targetPkg && fn == w.targetFunc {
+		if pkg == "errors" && fn == "New" {
+			w.targetFunc = "MessageOption"
+			return w
+		}
+
+		s := searchErr{&w, ce}
+		for _, exp := range ce.Args {
+			ast.Walk(s, exp)
+		}
+
+		w.targetFunc = "New"
+	}
+
+	return w
+}
+
+type searchErr struct {
+	w  *lintLostErr
+	fc *ast.CallExpr
+}
+
+func (s searchErr) Visit(node ast.Node) ast.Visitor {
+
+	id, ok := node.(*ast.Ident)
+	if !ok {
+		return s
+	}
+	if id.Name == "err" {
+		s.w.onFailure(lint.Failure{
+			Confidence: 0.8,
+			Node:       s.fc,
+			Category:   "bad practice",
+			Failure:    "original error is lost, consider using errors.NewFromError",
+		})
+
+	}
+
+	return s
+}
+
+func getPkgFunc(ce *ast.CallExpr) (string, string) {
+	fc, ok := ce.Fun.(*ast.SelectorExpr)
+	if !ok {
+		return "", ""
+	}
+	id, ok := fc.X.(*ast.Ident)
+	if !ok {
+		return "", ""
+	}
+
+	return id.Name, fc.Sel.Name
+}

test/ads-lost-err_test.go

@@ -0,0 +1,11 @@
+package test
+
+import (
+	"testing"
+
+	"github.com/mgechev/revive/rule"
+)
+
+func TestADSLostErr(t *testing.T) {
+	testRule(t, "ads-lost-err", &rule.ADSLostErrRule{})
+}