From 279d773fdc32b8bbc2a9b9698f5f344f6029f9e9 Mon Sep 17 00:00:00 2001
From: Milos Kotlar <kotlarmilos@gmail.com>
Date: Tue, 30 Jun 2026 16:58:04 +0200
Subject: [PATCH] Build mobile inner TFMs as CoreCLR in Mono host builds

Scope UseMonoRuntime so the multi-targeted libraries' mobile target
frameworks build as CoreCLR even when the runtime is built with a
Mono-based SDK (e.g. the source-build Mono validation leg), where they
would otherwise inherit UseMonoRuntime=true and trip the SDK's
mobile-on-Mono check.

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>
---
 Directory.Build.props | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/Directory.Build.props b/Directory.Build.props
index e9d93efb2aecfa..632b96c5194242 100644
--- a/Directory.Build.props
+++ b/Directory.Build.props
@@ -238,6 +238,9 @@
 
     <!-- this property is used by the SDK to pull in mono-based runtime packs -->
     <UseMonoRuntime Condition="'$(UseMonoRuntime)' == '' and '$(RuntimeFlavor)' == 'Mono'">true</UseMonoRuntime>
+    <UseMonoRuntime Condition="'$(UseMonoRuntime)' == 'true' and '$(TargetsMobile)' != 'true' and (
+        $(TargetFramework.EndsWith('-android')) or $(TargetFramework.EndsWith('-ios')) or
+        $(TargetFramework.EndsWith('-tvos')) or $(TargetFramework.EndsWith('-maccatalyst')))">false</UseMonoRuntime>
 
     <!-- For enabling the use of XUnitLogChecker in coreclr and libraries test runs. -->
     <!-- TODO: Enable XUnitLogChecker for NativeAOT tests https://github.com/dotnet/runtime/issues/94722 -->