add undefinedFormatting checker

checkers/rules/rules.go

@@ -717,3 +717,18 @@ func emptyDecl(m dsl.Matcher) {
 	m.Match(`const()`).Report(`empty const() block`)
 	m.Match(`type()`).Report(`empty type() block`)
 }
+
+//doc:summary Detects bad usage of fmt.Errorf
+//doc:tags    diagnostic experimental opinionated
+//doc:before  fmt.Errorf(xs)
+//doc:after   fmt.Errorf("%s", xs)
+func undefinedFormatting(m dsl.Matcher) {
+	m.Match(`fmt.Errorf($f)`).
+		Where(!m["f"].Const).
+		Suggest("errors.New($f)").
+		Report(`use errors.New($f) or fmt.Errorf("%s", $f) instead`)
+
+	m.Match(`fmt.Errorf($f($*args))`).
+		Suggest("errors.New($f($*args))").
+		Report(`use errors.New($f($*args)) or fmt.Errorf("%s",$f($*args)) instead`)
+}

checkers/testdata/undefinedFormatting/negative_tests.go

@@ -0,0 +1,15 @@
+package checker_test
+
+import (
+	"fmt"
+)
+
+var foo = "bar"
+
+func fmtFormatting() {
+	fmt.Errorf("%s", foo)
+	fmt.Errorf("123")
+	fmt.Errorf("%s", fooError())
+}
+
+func fooError() string { return "foo" }

checkers/testdata/undefinedFormatting/positive_tests.go

@@ -0,0 +1,19 @@
+package checker_test
+
+import (
+	"fmt"
+)
+
+func fmtUndefinedFormatting() {
+	foo := "foo happend"
+	fooFunc := func(k string) (string, string) { return "", "123" }
+	var barFunc = func() string { return "123" }
+	/*! use errors.New(foo) or fmt.Errorf("%s", foo) instead */
+	fmt.Errorf(foo)
+
+	/*! use errors.New(fooFunc("123")) or fmt.Errorf("%s", fooFunc("123")) instead */
+	fmt.Errorf(fooFunc("123"))
+
+	/*! use errors.New(barFunc()) or fmt.Errorf("%s", barFunc()) instead */
+	fmt.Errorf(barFunc())
+}

framework/lintmain/internal/hotload/hotload.go

@@ -7,7 +7,7 @@ import (
 	"github.com/go-critic/go-critic/framework/linter"
 )
 
-// CheckersFromDylib loads checkers provided by a dynamic lybrary found under path.
+// CheckersFromDylib loads checkers provided by a dynamic library found under path.
 //
 // The returned info slice must be re-assigned to the original info slice,
 // since there will be new entries there.