v8.0 module release (#22975)

https://mattermost.atlassian.net/browse/MM-52079

```release-note
We upgrade the module version to 8.0. The new module path is github.com/mattermost-server/server/v8.
```


Co-authored-by: Doug Lauder <wiggin77@warpmail.net>

server/plugin/supervisor_test.go

@@ -0,0 +1,83 @@
+// Copyright (c) 2015-present Mattermost, Inc. All Rights Reserved.
+// See LICENSE.txt for license information.
+
+package plugin
+
+import (
+	"os"
+	"path/filepath"
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+	"github.com/stretchr/testify/require"
+
+	"github.com/mattermost/mattermost-server/server/v8/channels/utils"
+	"github.com/mattermost/mattermost-server/server/v8/model"
+	"github.com/mattermost/mattermost-server/server/v8/platform/shared/mlog"
+)
+
+func TestSupervisor(t *testing.T) {
+	for name, f := range map[string]func(*testing.T){
+		"Supervisor_InvalidExecutablePath":     testSupervisorInvalidExecutablePath,
+		"Supervisor_NonExistentExecutablePath": testSupervisorNonExistentExecutablePath,
+		"Supervisor_StartTimeout":              testSupervisorStartTimeout,
+	} {
+		t.Run(name, f)
+	}
+}
+
+func testSupervisorInvalidExecutablePath(t *testing.T) {
+	dir, err := os.MkdirTemp("", "")
+	require.NoError(t, err)
+	defer os.RemoveAll(dir)
+
+	os.WriteFile(filepath.Join(dir, "plugin.json"), []byte(`{"id": "foo", "server": {"executable": "/foo/../../backend.exe"}}`), 0600)
+
+	bundle := model.BundleInfoForPath(dir)
+	log := mlog.CreateConsoleTestLogger(true, mlog.LvlError)
+	defer log.Shutdown()
+	supervisor, err := newSupervisor(bundle, nil, nil, log, nil)
+	assert.Nil(t, supervisor)
+	assert.Error(t, err)
+}
+
+func testSupervisorNonExistentExecutablePath(t *testing.T) {
+	dir, err := os.MkdirTemp("", "")
+	require.NoError(t, err)
+	defer os.RemoveAll(dir)
+
+	os.WriteFile(filepath.Join(dir, "plugin.json"), []byte(`{"id": "foo", "server": {"executable": "thisfileshouldnotexist"}}`), 0600)
+
+	bundle := model.BundleInfoForPath(dir)
+	log := mlog.CreateConsoleTestLogger(true, mlog.LvlError)
+	defer log.Shutdown()
+	supervisor, err := newSupervisor(bundle, nil, nil, log, nil)
+	require.Error(t, err)
+	require.Nil(t, supervisor)
+}
+
+// If plugin development goes really wrong, let's make sure plugin activation won't block forever.
+func testSupervisorStartTimeout(t *testing.T) {
+	dir, err := os.MkdirTemp("", "")
+	require.NoError(t, err)
+	defer os.RemoveAll(dir)
+
+	backend := filepath.Join(dir, "backend.exe")
+	utils.CompileGo(t, `
+		package main
+
+		func main() {
+			for {
+			}
+		}
+	`, backend)
+
+	os.WriteFile(filepath.Join(dir, "plugin.json"), []byte(`{"id": "foo", "server": {"executable": "backend.exe"}}`), 0600)
+
+	bundle := model.BundleInfoForPath(dir)
+	log := mlog.CreateConsoleTestLogger(true, mlog.LvlError)
+	defer log.Shutdown()
+	supervisor, err := newSupervisor(bundle, nil, nil, log, nil)
+	require.Error(t, err)
+	require.Nil(t, supervisor)
+}