Fix URL re-encoding for square brackets

core/urlutil.go

@@ -3,9 +3,15 @@ package core
 import (
 	"fmt"
 	"net/url"
+	"strings"
 )
 
+// ReencodeURL re-encodes URLs for RFC3986 compliance; as CurseForge URLs aren't properly encoded
 func ReencodeURL(u string) (string, error) {
+	// Go's URL library isn't entirely RFC3986 compliant :(
+	// Manually replace [ and ] with %5B and %5D
+	u = strings.ReplaceAll(u, "[", "%5B")
+	u = strings.ReplaceAll(u, "]", "%5D")
 	parsed, err := url.Parse(u)
 	if err != nil {
 		return "", fmt.Errorf("failed to parse url: %s, %v", u, err)