use-errors-new: disable for Go 1.26 (#1697)

Author: alexandear

RULES_DESCRIPTIONS.md

@@ -1708,6 +1708,9 @@ _Configuration_: N/A
 
 _Description_: This rule identifies calls to `fmt.Errorf` that can be safely replaced by, the more efficient, `errors.New`.
 
+_Note_: This rule is irrelevant for Go 1.26+.
+For unformatted strings, `fmt.Errorf("x")` generally [matches](https://go.dev/doc/go1.26#fmtpkgfmt) the allocations for `errors.New("x")`.
+
 _Configuration_: N/A
 
 ## use-fmt-print

lint/package.go

@@ -44,6 +44,8 @@ var (
 	Go124 = goversion.Must(goversion.NewVersion("1.24"))
 	// Go125 is a constant representing the Go version 1.25.
 	Go125 = goversion.Must(goversion.NewVersion("1.25"))
+	// Go126 is a constant representing the Go version 1.26.
+	Go126 = goversion.Must(goversion.NewVersion("1.26"))
 )
 
 // Files return package's files.

rule/use_errors_new.go

@@ -12,6 +12,11 @@ type UseErrorsNewRule struct{}
 
 // Apply applies the rule to given file.
 func (*UseErrorsNewRule) Apply(file *lint.File, _ lint.Arguments) []lint.Failure {
+	if file.Pkg.IsAtLeastGoVersion(lint.Go126) {
+		// For unformatted strings in Go 1.26, fmt.Errorf matches the behavior of errors.New, so we can skip the analysis.
+		return nil
+	}
+
 	var failures []lint.Failure
 
 	walker := lintFmtErrorf{

test/use_errors_new_test.go

@@ -8,4 +8,5 @@ import (
 
 func TestUseErrorsNew(t *testing.T) {
 	testRule(t, "use_errors_new", &rule.UseErrorsNewRule{})
+	testRule(t, "go1.26/use_errors_new", &rule.UseErrorsNewRule{})
 }

testdata/go1.26/go.mod

@@ -0,0 +1,3 @@
+module github.com/mgechev/revive/testdata
+
+go 1.26

testdata/go1.26/use_errors_new.go

@@ -0,0 +1,12 @@
+package pkg
+
+import "fmt"
+
+func errorsNew() (int, error) {
+	fmt.Errorf("repo cannot be nil")
+	errs := append(errs, fmt.Errorf("commit cannot be nil"))
+	fmt.Errorf("unable to load base repo: %w", err)
+	fmt.Errorf("Failed to get full commit id for origin/%s: %w", pr.BaseBranch, err)
+
+	return 0, fmt.Errorf(msg + "something")
+}