From e4efa40ba08ca82d10673e0a9f46f2a2e530bc83 Mon Sep 17 00:00:00 2001
From: Bryan Andrews <Bryan1041@users.noreply.github.com>
Date: Wed, 13 Jul 2022 12:34:41 -0400
Subject: [PATCH] Add mutex to ensure struct gets initialized once

---
 depguard.go | 12 ++++++++++++
 1 file changed, 12 insertions(+)

diff --git a/depguard.go b/depguard.go
index b727549..d7011cd 100644
--- a/depguard.go
+++ b/depguard.go
@@ -7,6 +7,7 @@ import (
 	"path"
 	"sort"
 	"strings"
+	"sync"
 
 	"github.com/gobwas/glob"
 	"golang.org/x/tools/go/loader"
@@ -61,6 +62,9 @@ type Depguard struct {
 	globIgnoreFileRules   []negatableGlob
 
 	prefixRoot []string
+
+	isInitialized      bool
+	isInitializedMutex sync.Mutex
 }
 
 // Run checks for dependencies given the program and validates them against
@@ -102,6 +106,13 @@ func (dg *Depguard) Run(config *loader.Config, prog *loader.Program) ([]*Issue,
 }
 
 func (dg *Depguard) initialize(config *loader.Config, prog *loader.Program) error {
+	dg.isInitializedMutex.Lock()
+	defer dg.isInitializedMutex.Unlock()
+
+	if dg.isInitialized {
+		return nil
+	}
+
 	// parse ordinary guarded packages
 	for _, pkg := range dg.Packages {
 		if strings.ContainsAny(pkg, "!?*[]{}") {
@@ -168,6 +179,7 @@ func (dg *Depguard) initialize(config *loader.Config, prog *loader.Program) erro
 		}
 	}
 
+	dg.isInitialized = true
 	return nil
 }