collector: release caller-owned MI destination options (#2601)

Signed-off-by: Jan-Otto Kröpke <mail@jkroepke.de>

pkg/collector/collection.go

@@ -359,7 +359,6 @@ func (c *Collection) initMI() (*mi.Session, error) {
 
 	session, err := newMISession(app, destinationOptions)
 	if err != nil {
-		_ = destinationOptions.Delete()
 		_ = app.Close()
 
 		return nil, err
@@ -370,7 +369,11 @@ func (c *Collection) initMI() (*mi.Session, error) {
 	return session, nil
 }
 
+// newMISession consumes destinationOptions. The session retains its own options;
+// release the caller's options before initMI can close the application on failure.
 func newMISession(app *mi.Application, destinationOptions *mi.DestinationOptions) (*mi.Session, error) {
+	defer func() { _ = destinationOptions.Delete() }()
+
 	if err := destinationOptions.SetLocale(mi.LocaleEnglish); err != nil {
 		return nil, fmt.Errorf("error from set locale: %w", err)
 	}

pkg/collector/mi_options_internal_test.go

@@ -0,0 +1,48 @@
+// SPDX-License-Identifier: Apache-2.0
+//
+// Copyright The Prometheus Authors
+// Licensed 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.
+
+//go:build windows
+
+package collector
+
+import (
+	"testing"
+	"time"
+
+	"github.com/prometheus-community/windows_exporter/internal/mi"
+	"github.com/stretchr/testify/require"
+)
+
+func TestMISessionAfterCallerOptionsDeleted(t *testing.T) {
+	t.Parallel()
+
+	app, err := mi.ApplicationInitialize()
+	require.NoError(t, err)
+	t.Cleanup(func() { require.NoError(t, app.Close()) })
+
+	options, err := app.NewDestinationOptions()
+	require.NoError(t, err)
+	// newMISession releases the original options before returning.
+	session, err := newMISession(app, options)
+	require.NoError(t, err)
+	t.Cleanup(func() { require.NoError(t, session.Close()) })
+
+	query, err := mi.NewQuery("SELECT Caption FROM Win32_OperatingSystem")
+	require.NoError(t, err)
+
+	var operatingSystems []struct{ Caption string }
+	require.NoError(t, session.Query(&operatingSystems, mi.NamespaceRootCIMv2, query, 5*time.Second))
+	require.NotEmpty(t, operatingSystems)
+}