From 6d80c01440f09a094e57ef5837f66f6bb85eb19f Mon Sep 17 00:00:00 2001
From: David Nguyen <87228593+davidnguyen-tech@users.noreply.github.com>
Date: Wed, 11 Feb 2026 12:26:23 +0100
Subject: [PATCH 1/2] Fix maccatalyst native build failure on Xcode 26.2

Use the macOS-equivalent deployment target (14.0) instead of the
Catalyst version (17.0) for CMAKE_OSX_DEPLOYMENT_TARGET. CMake
interprets this value as a macOS min-version since CMAKE_SYSTEM_NAME
is Darwin, and newer clang rejects 17.0 as an invalid macOS version.

The effective Catalyst minimum version is enforced separately via
the -target triple in eng/native/configurecompiler.cmake.
---
 eng/native/build-commons.sh | 8 +++++---
 1 file changed, 5 insertions(+), 3 deletions(-)

diff --git a/eng/native/build-commons.sh b/eng/native/build-commons.sh
index bf86924ac52607..a825c8bd537c36 100755
--- a/eng/native/build-commons.sh
+++ b/eng/native/build-commons.sh
@@ -91,9 +91,11 @@ build_native()
     if [[ "$targetOS" == maccatalyst ]]; then
         cmakeArgs="-C $__RepoRootDir/eng/native/tryrun_ios_tvos.cmake $cmakeArgs"
 
-        # set default macCatalyst deployment target
-        # keep in sync with SetOSTargetMinVersions in the root Directory.Build.props
-        cmakeArgs="-DCMAKE_SYSTEM_NAME=Darwin -DCMAKE_OSX_SYSROOT=macosx -DCMAKE_SYSTEM_VARIANT=maccatalyst -DCMAKE_OSX_DEPLOYMENT_TARGET=17.0 $cmakeArgs"
+        # CMAKE_OSX_DEPLOYMENT_TARGET is set to the macOS equivalent (14.0) of the
+        # Catalyst min version (17.0) so CMake's compiler test emits a valid
+        # -mmacosx-version-min flag. The effective Catalyst min version is enforced
+        # via the -target triple in eng/native/configurecompiler.cmake, not this value.
+        cmakeArgs="-DCMAKE_SYSTEM_NAME=Darwin -DCMAKE_OSX_SYSROOT=macosx -DCMAKE_SYSTEM_VARIANT=maccatalyst -DCMAKE_OSX_DEPLOYMENT_TARGET=14.0 $cmakeArgs"
     fi
 
     if [[ "$targetOS" == android || "$targetOS" == linux-bionic ]]; then

From 9f1bf51971e55a1368d98445a91c418b394c582e Mon Sep 17 00:00:00 2001
From: David Nguyen <87228593+davidnguyen-tech@users.noreply.github.com>
Date: Tue, 17 Feb 2026 13:07:52 +0100
Subject: [PATCH 2/2] Address review notes

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>
---
 eng/native/build-commons.sh        | 11 ++++++-----
 eng/native/configurecompiler.cmake |  2 ++
 2 files changed, 8 insertions(+), 5 deletions(-)

diff --git a/eng/native/build-commons.sh b/eng/native/build-commons.sh
index a825c8bd537c36..09d72c63e6ff70 100755
--- a/eng/native/build-commons.sh
+++ b/eng/native/build-commons.sh
@@ -91,11 +91,12 @@ build_native()
     if [[ "$targetOS" == maccatalyst ]]; then
         cmakeArgs="-C $__RepoRootDir/eng/native/tryrun_ios_tvos.cmake $cmakeArgs"
 
-        # CMAKE_OSX_DEPLOYMENT_TARGET is set to the macOS equivalent (14.0) of the
-        # Catalyst min version (17.0) so CMake's compiler test emits a valid
-        # -mmacosx-version-min flag. The effective Catalyst min version is enforced
-        # via the -target triple in eng/native/configurecompiler.cmake, not this value.
-        cmakeArgs="-DCMAKE_SYSTEM_NAME=Darwin -DCMAKE_OSX_SYSROOT=macosx -DCMAKE_SYSTEM_VARIANT=maccatalyst -DCMAKE_OSX_DEPLOYMENT_TARGET=14.0 $cmakeArgs"
+        # Intentionally do not set CMAKE_OSX_DEPLOYMENT_TARGET for maccatalyst here:
+        # - CMake interprets CMAKE_OSX_DEPLOYMENT_TARGET as a macOS minimum version
+        #   instead of MacCatalyst, causing newer clang to reject it as invalid.
+        # - The effective Catalyst minimum version is enforced via the
+        #   -target *-apple-ios<version>-macabi flag in eng/native/configurecompiler.cmake
+        cmakeArgs="-DCMAKE_SYSTEM_NAME=Darwin -DCMAKE_OSX_SYSROOT=macosx -DCMAKE_SYSTEM_VARIANT=maccatalyst $cmakeArgs"
     fi
 
     if [[ "$targetOS" == android || "$targetOS" == linux-bionic ]]; then
diff --git a/eng/native/configurecompiler.cmake b/eng/native/configurecompiler.cmake
index 6b9ac068fd87c6..474402706f40ff 100644
--- a/eng/native/configurecompiler.cmake
+++ b/eng/native/configurecompiler.cmake
@@ -727,6 +727,8 @@ if (CLR_CMAKE_HOST_UNIX OR CLR_CMAKE_HOST_WASI)
       endif()
     endif()
     add_link_options(${DISABLE_OVERRIDING_MIN_VERSION_ERROR})
+    # Keep the Catalyst version in the -target triples below in sync
+    # with MacCatalystVersionMin in SetOSTargetMinVersions in Directory.Build.props.
     if(CLR_CMAKE_HOST_ARCH_ARM64)
       set(CLR_CMAKE_MACCATALYST_COMPILER_TARGET "arm64-apple-ios17.0-macabi")
       add_link_options(-target ${CLR_CMAKE_MACCATALYST_COMPILER_TARGET})