added errorlint

Author: JkLondon

.golangci.yml

@@ -22,8 +22,8 @@ linters:
     - unconvert
     - wastedassign
     - zerologlint
+    - errorlint
   disable:
-    - errorlint #TODO: enable me
     - noctx #TODO: enable me
     - nilerr #TODO: enable me
     - unused #TODO: enable me

mdbx/cursor_test.go

@@ -688,7 +688,7 @@ func TestCursor_Del(t *testing.T) {
 
 		k, v, err = cur.Get(nil, nil, Next)
 		if err != nil {
-			return fmt.Errorf("post-delete: %v", err)
+			return fmt.Errorf("post-delete: %w", err)
 		}
 		item = items[2]
 		if !bytes.Equal(k, []byte(item.k)) {

mdbx/error.go

@@ -8,6 +8,7 @@ package mdbx
 import "C"
 
 import (
+	"errors"
 	"fmt"
 	"os"
 	"syscall"
@@ -26,6 +27,10 @@ func (err *OpError) Error() string {
 	return err.Op + ": " + err.Errno.Error()
 }
 
+func (err *OpError) Is(target error) bool {
+	return errors.Is(err.Errno, target)
+}
+
 // Errno is an error type that represents the (unique) errno values defined by
 // LMDB.  Other errno values (such as EINVAL) are represented with type
 // syscall.Errno.  On Windows, LMDB return codes are translated into portable
@@ -152,3 +157,8 @@ func IsErrnoFn(err error, fn func(error) bool) bool {
 	}
 	return fn(err)
 }
+
+func (e Errno) Is(target error) bool {
+	t, ok := target.(Errno)
+	return ok && t == e
+}

mdbx/error_test.go

@@ -1,6 +1,7 @@
 package mdbx
 
 import (
+	"errors"
 	"fmt"
 	"syscall"
 	"testing"
@@ -36,13 +37,11 @@ func TestErrno(t *testing.T) {
 		t.Errorf("errno(0) != nil: %#v", zeroerr)
 	}
 	syserr := _operrno("testop", int(syscall.EINVAL))
-	//nolint:err113
-	if syserr.(*OpError).Errno != syscall.EINVAL { // fails if error is Errno(syscall.EINVAL)
+	if !errors.Is(syserr, syscall.EINVAL) { // fails if error is Errno(syscall.EINVAL)
 		t.Errorf("errno(syscall.EINVAL) != syscall.EINVAL: %#v", syserr)
 	}
 	mdberr := _operrno("testop", int(KeyExist))
-	//nolint:err113
-	if mdberr.(*OpError).Errno != KeyExist {
+	if !errors.Is(mdberr, KeyExist) {
 		t.Errorf("errno(ErrKeyExist) != ErrKeyExist: %#v", syserr)
 	}
 }

mdbx/mdbx_test.go

@@ -138,7 +138,7 @@ func TestTest1(t *testing.T) {
 		for k, v := range data {
 			err = txn.Put(db, []byte(k), []byte(v), NoOverwrite)
 			if err != nil {
-				return fmt.Errorf("put: %v", err)
+				return fmt.Errorf("put: %w", err)
 			}
 		}
 
@@ -159,7 +159,7 @@ func TestTest1(t *testing.T) {
 		cursor, err := txn.OpenCursor(db)
 		if err != nil {
 			cursor.Close()
-			return fmt.Errorf("cursor: %v", err)
+			return fmt.Errorf("cursor: %w", err)
 		}
 		var bkey, bval []byte
 		var bNumVal int
@@ -169,7 +169,7 @@ func TestTest1(t *testing.T) {
 				break
 			}
 			if err != nil {
-				return fmt.Errorf("cursor get: %v", err)
+				return fmt.Errorf("cursor get: %w", err)
 			}
 			bNumVal++
 			skey := string(bkey)
@@ -191,7 +191,7 @@ func TestTest1(t *testing.T) {
 		cursor.Close()
 		bval, err = txn.Get(db, []byte("Key-0"))
 		if err != nil {
-			return fmt.Errorf("get: %v", err)
+			return fmt.Errorf("get: %w", err)
 		}
 		if string(bval) != "Val-0" {
 			return fmt.Errorf("get: value %q does not match %q", bval, "Val-0")