From 3680e12dc854564fd548f022c8c24069695eb874 Mon Sep 17 00:00:00 2001
From: Paul Hebble <pjhebble@gmail.com>
Date: Mon, 27 Jul 2020 19:14:50 +0000
Subject: [PATCH] Better message when ZipFile.TestArchive throws
 NotSupportedException

---
 Core/Net/NetFileCache.cs | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/Core/Net/NetFileCache.cs b/Core/Net/NetFileCache.cs
index 68faaf8e4d..87a2360660 100644
--- a/Core/Net/NetFileCache.cs
+++ b/Core/Net/NetFileCache.cs
@@ -467,6 +467,12 @@ public static bool ZipValid(string filename, out string invalidReason)
                 invalidReason = ex.Message;
                 return false;
             }
+            catch (NotSupportedException nse) when (Platform.IsMono)
+            {
+                // SharpZipLib throws this if your locale isn't installed on Mono
+                invalidReason = $"{nse.Message}\r\n\r\nInstall the `mono-complete` package or equivalent for your operating system.";
+                return false;
+            }
         }
 
         /// <summary>