From bc5400e8612120d46b2b64d2b6fd8e16acc00b11 Mon Sep 17 00:00:00 2001
From: Rolf Bjarne Kvinge <rolf@xamarin.com>
Date: Fri, 24 Aug 2018 16:23:56 +0200
Subject: [PATCH] [mmp] Show an error if trying to build a 32-bit app with
 Xcode 10. Fixes #4569. (#4684) (#4690)

Fixes https://github.com/xamarin/xamarin-macios/issues/4569.
---
 docs/website/mmp-errors.md    | 12 ++++++++++++
 docs/website/mtouch-errors.md |  2 ++
 tools/mmp/driver.cs           |  6 ++++++
 3 files changed, 20 insertions(+)

diff --git a/docs/website/mmp-errors.md b/docs/website/mmp-errors.md
index c0c832f675..bffa33c982 100644
--- a/docs/website/mmp-errors.md
+++ b/docs/website/mmp-errors.md
@@ -158,6 +158,18 @@ As a last-straw solution, use an older version of Xamarin.Mac that does not requ
 
 <!-- 0136 and 0137 used by mtouch -->
 
+#### MM0138: Building 32-bit apps is not possible when using Xcode 10. Please migrate project to the Unified API.
+
+Xcode 10 does not support building 32-bit applications.
+
+The project must be [migrated to a Unified project](https://docs.microsoft.com/en-us/xamarin/cross-platform/macios/unified/updating-mac-apps) in order to support 64-bit.
+
+#### MM0139: Building 32-bit apps is not possible when using Xcode 10. Please change the architecture in the project's Mac Build options to 'x86_64'.
+
+Xcode 10 does not support building 32-bit applications.
+
+Change the architecture in the project's Mac Build options to 'x86_64' in order to build a 64-bit application.
+
 # MM1xxx: file copy / symlinks (project related)
 
 ### <a name="MM1034">MM1034: Could not create symlink '{file}' -> '{target}': error {number}
diff --git a/docs/website/mtouch-errors.md b/docs/website/mtouch-errors.md
index f1391feada..fcc65a8858 100644
--- a/docs/website/mtouch-errors.md
+++ b/docs/website/mtouch-errors.md
@@ -699,6 +699,8 @@ that can't be found.
 mtouch may in certain cases still find references at a later point, which
 means that if the build otherwise succeeds, this warning can be ignored.
 
+<!-- 0138-0139: used by mmp -->
+
 # MT1xxx: Project related error messages
 
 ### MT10xx: Installer / mtouch
diff --git a/tools/mmp/driver.cs b/tools/mmp/driver.cs
index 277ff4b1a2..8bcd7ea7eb 100644
--- a/tools/mmp/driver.cs
+++ b/tools/mmp/driver.cs
@@ -484,6 +484,12 @@ namespace Xamarin.Bundler {
 			// InitializeCommon needs SdkVersion set to something valid
 			ValidateSDKVersion ();
 
+			if (action != Action.RunRegistrar && XcodeVersion.Major >= 10 && !Is64Bit) {
+				if (IsClassic)
+					throw ErrorHelper.CreateError (138, "Building 32-bit apps is not possible when using Xcode 10. Please migrate project to the Unified API.");
+				throw ErrorHelper.CreateError (139, "Building 32-bit apps is not possible when using Xcode 10. Please change the architecture in the project's Mac Build options to 'x86_64'.");
+			}
+
 			// InitializeCommon needs the current profile
 			if (IsClassic)
 				Profile.Current = new MonoMacProfile ();