From a5b867ba5beba35aec9b65cd11a1c9850af1acd3 Mon Sep 17 00:00:00 2001
From: Alexander Wang <alex@terrastruct.com>
Date: Wed, 2 Aug 2023 19:44:36 -0700
Subject: [PATCH] fix race

---
 d2renderers/d2fonts/d2fonts.go | 7 +++++++
 1 file changed, 7 insertions(+)

diff --git a/d2renderers/d2fonts/d2fonts.go b/d2renderers/d2fonts/d2fonts.go
index 1a552dc32..51704db23 100644
--- a/d2renderers/d2fonts/d2fonts.go
+++ b/d2renderers/d2fonts/d2fonts.go
@@ -9,6 +9,7 @@ import (
 	"encoding/base64"
 	"fmt"
 	"strings"
+	"sync"
 
 	"oss.terrastruct.com/d2/lib/font"
 	fontlib "oss.terrastruct.com/d2/lib/font"
@@ -41,6 +42,8 @@ func (f Font) GetEncodedSubset(corpus string) string {
 		}
 	}
 
+	FontFamiliesMu.Lock()
+	defer FontFamiliesMu.Unlock()
 	fontBuf := make([]byte, len(FontFaces[f]))
 	copy(fontBuf, FontFaces[f])
 	fontBuf = font.UTF8CutFont(fontBuf, uniqueChars)
@@ -96,6 +99,8 @@ var FontFamilies = []FontFamily{
 	HandDrawn,
 }
 
+var FontFamiliesMu sync.Mutex
+
 //go:embed encoded/SourceSansPro-Regular.txt
 var sourceSansProRegularBase64 string
 
@@ -309,6 +314,8 @@ func AddFontStyle(font Font, style FontStyle, ttf []byte) error {
 }
 
 func AddFontFamily(name string, regularTTF, italicTTF, boldTTF, semiboldTTF []byte) (*FontFamily, error) {
+	FontFamiliesMu.Lock()
+	defer FontFamiliesMu.Unlock()
 	customFontFamily := FontFamily(name)
 
 	regularFont := Font{