Add performant error-wrapping utility function (#6665)

* Add performant error-wrapping utility function

* Fix go vet error

lib/go-util/error.go

@@ -0,0 +1,43 @@
+package util
+
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements.  See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership.  The ASF licenses this file
+ * to you under the Apache License, Version 2.0 (the
+ * "License"); you may not use this file except in compliance
+ * with the License.  You may obtain a copy of the License at
+ *
+ *   http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing,
+ * software distributed under the License is distributed on an
+ * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+ * KIND, either express or implied.  See the License for the
+ * specific language governing permissions and limitations
+ * under the License.
+ */
+
+type wrapped struct {
+	context  string
+	original error
+}
+
+func (w *wrapped) Error() string {
+	return w.context + ": " + w.original.Error()
+}
+
+func (w *wrapped) Unwrap() error {
+	return w.original
+}
+
+// WrapError wraps an error in a context for that error. This allows comparison
+// of errors using errors.Is. This is much faster than fmt.Errorf, so it should
+// be preferred wherever that performance impact is considered significant.
+func WrapError(context string, e error) error {
+	return &wrapped{
+		context:  context,
+		original: e,
+	}
+}

lib/go-util/error_test.go

@@ -0,0 +1,74 @@
+package util
+
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements.  See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership.  The ASF licenses this file
+ * to you under the Apache License, Version 2.0 (the
+ * "License"); you may not use this file except in compliance
+ * with the License.  You may obtain a copy of the License at
+ *
+ *   http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing,
+ * software distributed under the License is distributed on an
+ * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+ * KIND, either express or implied.  See the License for the
+ * specific language governing permissions and limitations
+ * under the License.
+ */
+
+import (
+	"database/sql"
+	"errors"
+	"fmt"
+	"testing"
+)
+
+func ExampleWrapError() {
+	err := WrapError("querying for cdns", sql.ErrNoRows)
+	fmt.Println(err)
+	fmt.Println(err == sql.ErrNoRows, errors.Is(err, sql.ErrNoRows))
+	// Output: querying for cdns: sql: no rows in result set
+	// false true
+}
+
+func BenchmarkErrorStringConcatenation(b *testing.B) {
+	for i := 0; i < b.N; i++ {
+		_ = errors.New("querying for cdns: " + sql.ErrNoRows.Error())
+	}
+}
+
+func BenchmarkErrorWrapping(b *testing.B) {
+	for i := 0; i < b.N; i++ {
+		WrapError("querying for cdns", sql.ErrNoRows)
+	}
+}
+
+func BenchmarkErrorf(b *testing.B) {
+	for i := 0; i < b.N; i++ {
+		_ = fmt.Errorf("querying for cdns: %w", sql.ErrNoRows)
+	}
+}
+
+func BenchmarkNestedWraps(b *testing.B) {
+	var err error = sql.ErrNoRows
+	for i := 0; i < b.N; i++ {
+		err = WrapError("querying for cdns", err)
+	}
+}
+
+func BenchmarkNestedStringConcatenations(b *testing.B) {
+	var err error = sql.ErrNoRows
+	for i := 0; i < b.N; i++ {
+		err = errors.New("querying for cdns: " + err.Error())
+	}
+}
+
+func BenchmarkNestedErrorf(b *testing.B) {
+	var err error = sql.ErrNoRows
+	for i := 0; i < b.N; i++ {
+		err = fmt.Errorf("querying for cdns: %w", err)
+	}
+}