From 635f3244bac126235a52eebdb3ec1c2820fd34c9 Mon Sep 17 00:00:00 2001
From: Shawn Yuan <shuaiyuan@microsoft.com>
Date: Fri, 27 Mar 2026 10:03:27 +0800
Subject: [PATCH 1/8] init

Signed-off-by: Shawn Yuan <shuaiyuan@microsoft.com>
---
 .../Microsoft.WSL.Containers.common.targets   | 95 +++++++++++++++++++
 .../build/cmake/wslcConfig.cmake              | 67 +++++++++++++
 .../native/Microsoft.WSL.Containers.targets   | 45 +++++++++
 .../net/Microsoft.WSL.Containers.targets      |  9 ++
 4 files changed, 216 insertions(+)
 create mode 100644 nuget/Microsoft.WSL.Containers/build/cmake/wslcConfig.cmake

diff --git a/nuget/Microsoft.WSL.Containers/build/Microsoft.WSL.Containers.common.targets b/nuget/Microsoft.WSL.Containers/build/Microsoft.WSL.Containers.common.targets
index 2454f2555..3b38dfd05 100644
--- a/nuget/Microsoft.WSL.Containers/build/Microsoft.WSL.Containers.common.targets
+++ b/nuget/Microsoft.WSL.Containers/build/Microsoft.WSL.Containers.common.targets
@@ -7,4 +7,99 @@
     <ItemGroup>
         <ReferenceCopyLocalPaths Include="$(MSBuildThisFileDirectory)..\runtimes\win-$(WSLCSDK_Platform)\wslcsdk.dll" />
     </ItemGroup>
+
+    <!-- ================================================================== -->
+    <!-- Container Image Build Targets                                      -->
+    <!-- ================================================================== -->
+
+    <!-- Default properties -->
+    <PropertyGroup>
+        <WslcImageOutputDir Condition="'$(WslcImageOutputDir)' == ''">$(OutDir)</WslcImageOutputDir>
+        <WslcCliPath Condition="'$(WslcCliPath)' == ''">wslc</WslcCliPath>
+    </PropertyGroup>
+
+    <!-- Default metadata for WslcImage items -->
+    <ItemDefinitionGroup>
+        <WslcImage>
+            <Tag>latest</Tag>
+            <Output>$(WslcImageOutputDir)</Output>
+        </WslcImage>
+    </ItemDefinitionGroup>
+
+    <!-- Check that wslc CLI is installed -->
+    <Target Name="WslcCheckDependencies"
+            BeforeTargets="WslcBuildAllImages"
+            Condition="'@(WslcImage)' != ''">
+
+        <Exec Command="$(WslcCliPath) --version"
+              IgnoreExitCode="true"
+              ConsoleToMSBuild="true"
+              StandardOutputImportance="low"
+              StandardErrorImportance="low">
+            <Output TaskParameter="ExitCode" PropertyName="_WslcExitCode" />
+        </Exec>
+
+        <Error Condition="'$(_WslcExitCode)' != '0'"
+               Code="WSLC0001"
+               Text="The WSLC runtime was not found. Install WSL by running: wsl --install --no-distribution" />
+    </Target>
+
+    <!-- Outer target: dispatch each WslcImage to inner target via MSBuild task -->
+    <Target Name="WslcBuildAllImages"
+            AfterTargets="Build"
+            DependsOnTargets="WslcCheckDependencies"
+            Condition="'@(WslcImage)' != ''">
+
+        <MSBuild Projects="$(MSBuildProjectFullPath)"
+                 Targets="_WslcBuildSingleImage"
+                 Properties="Configuration=$(Configuration);Platform=$(Platform);_WslcName=%(WslcImage.Identity);_WslcTag=%(WslcImage.Tag);_WslcDockerfile=%(WslcImage.Dockerfile);_WslcContext=%(WslcImage.Context);_WslcSources=%(WslcImage.Sources);_WslcOutput=%(WslcImage.Output)" />
+    </Target>
+
+    <!-- Collect source files for incremental check (wildcards only expand in ItemGroup Include) -->
+    <Target Name="_WslcCollectSources" BeforeTargets="_WslcBuildSingleImage">
+        <ItemGroup>
+            <_WslcSourceFiles Include="$(_WslcDockerfile);$(_WslcSources)" />
+        </ItemGroup>
+    </Target>
+
+    <!-- Inner target: build a single image with incremental check -->
+    <Target Name="_WslcBuildSingleImage"
+            DependsOnTargets="_WslcCollectSources"
+            Inputs="@(_WslcSourceFiles)"
+            Outputs="$(IntDir)wslc_$(_WslcName).marker">
+
+        <MakeDir Directories="$(IntDir);$(_WslcOutput)" />
+
+        <Message Importance="high"
+                 Text="WSLC: Building image '$(_WslcName):$(_WslcTag)'..." />
+
+        <Exec Command="$(WslcCliPath) image build -t &quot;$(_WslcName):$(_WslcTag)&quot; -f &quot;$(_WslcDockerfile)&quot; &quot;$(_WslcContext)&quot;"
+              ConsoleToMSBuild="true" />
+
+        <Message Importance="high"
+                 Text="WSLC: Saving image '$(_WslcName):$(_WslcTag)' to $(_WslcOutput)\$(_WslcName).tar..." />
+
+        <Exec Command="$(WslcCliPath) image save &quot;$(_WslcName):$(_WslcTag)&quot; -o &quot;$(_WslcOutput)\$(_WslcName).tar&quot;"
+              ConsoleToMSBuild="true" />
+
+        <!-- Save image ID for efficient check-then-load at runtime -->
+        <Exec Command="$(WslcCliPath) image inspect &quot;$(_WslcName):$(_WslcTag)&quot; --format {{.Id}} &gt; &quot;$(_WslcOutput)\$(_WslcName).id&quot;"
+              IgnoreStandardErrorWarningFormat="true" />
+
+        <Touch Files="$(IntDir)wslc_$(_WslcName).marker" AlwaysCreate="true" />
+
+        <Message Importance="high"
+                 Text="WSLC: [$(_WslcName)] Image built and saved successfully." />
+    </Target>
+
+    <!-- Clean container artifacts -->
+    <Target Name="WslcClean"
+            AfterTargets="Clean"
+            Condition="'@(WslcImage)' != ''">
+
+        <Delete Files="%(WslcImage.Output)\%(WslcImage.Identity).tar" />
+        <Delete Files="%(WslcImage.Output)\%(WslcImage.Identity).id" />
+        <Delete Files="$(IntDir)wslc_%(WslcImage.Identity).marker" />
+    </Target>
+
 </Project>
\ No newline at end of file
diff --git a/nuget/Microsoft.WSL.Containers/build/cmake/wslcConfig.cmake b/nuget/Microsoft.WSL.Containers/build/cmake/wslcConfig.cmake
new file mode 100644
index 000000000..f64db3609
--- /dev/null
+++ b/nuget/Microsoft.WSL.Containers/build/cmake/wslcConfig.cmake
@@ -0,0 +1,67 @@
+# wslcConfig.cmake - Container image build support for CMake
+#
+# Provides the wslc_add_image() function for declaring container image
+# build targets with incremental rebuild support.
+#
+# Usage:
+#   list(APPEND CMAKE_MODULE_PATH "<nuget>/build/cmake")
+#   find_package(wslc REQUIRED)
+#
+#   wslc_add_image(
+#       NAME        my-server
+#       DOCKERFILE  container/Dockerfile
+#       CONTEXT     container/
+#       SOURCES     container/src/*.cpp container/src/*.h
+#       TAG         latest
+#       OUTPUT      ${CMAKE_BINARY_DIR}/images
+#   )
+
+function(wslc_add_image)
+    cmake_parse_arguments(
+        PARSE_ARGV 0 ARG
+        ""                                      # options (none)
+        "NAME;TAG;DOCKERFILE;CONTEXT;OUTPUT"     # one-value keywords
+        "SOURCES"                                # multi-value keywords
+    )
+
+    # Validate required arguments
+    if(NOT ARG_NAME)
+        message(FATAL_ERROR "wslc_add_image: NAME is required")
+    endif()
+    if(NOT ARG_DOCKERFILE)
+        message(FATAL_ERROR "wslc_add_image: DOCKERFILE is required")
+    endif()
+    if(NOT ARG_CONTEXT)
+        message(FATAL_ERROR "wslc_add_image: CONTEXT is required")
+    endif()
+
+    # Defaults
+    if(NOT ARG_TAG)
+        set(ARG_TAG "latest")
+    endif()
+    if(NOT ARG_OUTPUT)
+        set(ARG_OUTPUT "${CMAKE_CURRENT_BINARY_DIR}")
+    endif()
+
+    set(_image_ref "${ARG_NAME}:${ARG_TAG}")
+    set(_tar_output "${ARG_OUTPUT}/${ARG_NAME}.tar")
+    set(_id_output "${ARG_OUTPUT}/${ARG_NAME}.id")
+    set(_marker "${CMAKE_CURRENT_BINARY_DIR}/wslc_${ARG_NAME}.marker")
+
+    # Resolve source globs to file lists
+    file(GLOB_RECURSE _resolved_sources ${ARG_SOURCES})
+
+    add_custom_command(
+        OUTPUT "${_marker}"
+        COMMAND wslc image build -t "${_image_ref}" -f "${ARG_DOCKERFILE}" "${ARG_CONTEXT}"
+        COMMAND wslc image save "${_image_ref}" -o "${_tar_output}"
+        COMMAND ${CMAKE_COMMAND} -E touch "${_marker}"
+        DEPENDS ${_resolved_sources} "${ARG_DOCKERFILE}"
+        COMMENT "WSLC: Building image '${_image_ref}'..."
+        VERBATIM
+    )
+
+    add_custom_target(wslc_image_${ARG_NAME} ALL
+        DEPENDS "${_marker}"
+    )
+endfunction()
diff --git a/nuget/Microsoft.WSL.Containers/build/native/Microsoft.WSL.Containers.targets b/nuget/Microsoft.WSL.Containers/build/native/Microsoft.WSL.Containers.targets
index 09823c7b0..abf5db776 100644
--- a/nuget/Microsoft.WSL.Containers/build/native/Microsoft.WSL.Containers.targets
+++ b/nuget/Microsoft.WSL.Containers/build/native/Microsoft.WSL.Containers.targets
@@ -23,4 +23,49 @@
     </ItemDefinitionGroup>
 
     <Import Project="$(MSBuildThisFileDirectory)..\Microsoft.WSL.Containers.common.targets" />
+
+    <!-- ================================================================== -->
+    <!-- C++ specific: Write .tlog files for VS Fast Up-to-Date Check       -->
+    <!-- ================================================================== -->
+
+    <Target Name="_WslcWriteAllTlogs"
+            AfterTargets="WslcBuildAllImages"
+            Condition="'@(WslcImage)' != '' AND '$(TLogLocation)' != ''">
+
+        <MSBuild Projects="$(MSBuildProjectFullPath)"
+                 Targets="_WslcWriteSingleTlog"
+                 Properties="Configuration=$(Configuration);Platform=$(Platform);_WslcName=%(WslcImage.Identity);_WslcDockerfile=%(WslcImage.Dockerfile);_WslcSources=%(WslcImage.Sources);_WslcOutput=%(WslcImage.Output);_WslcTlogDir=$(TLogLocation)" />
+    </Target>
+
+    <Target Name="_WslcWriteSingleTlog">
+        <ItemGroup>
+            <_WslcTlogInputs Include="$(_WslcDockerfile);$(_WslcSources)" />
+        </ItemGroup>
+
+        <PropertyGroup>
+            <_WslcDockerfileFullPath>$([System.IO.Path]::GetFullPath('$(_WslcDockerfile)'))</_WslcDockerfileFullPath>
+            <_WslcMarkerFullPath>$([System.IO.Path]::GetFullPath('$(IntDir)wslc_$(_WslcName).marker'))</_WslcMarkerFullPath>
+        </PropertyGroup>
+
+        <WriteLinesToFile
+            File="$(_WslcTlogDir)wslc.$(_WslcName).read.1.tlog"
+            Lines="^$(_WslcDockerfileFullPath);@(_WslcTlogInputs->'%(FullPath)')"
+            Overwrite="true"
+            Encoding="Unicode" />
+
+        <WriteLinesToFile
+            File="$(_WslcTlogDir)wslc.$(_WslcName).write.1.tlog"
+            Lines="^$(_WslcDockerfileFullPath);$(_WslcMarkerFullPath)"
+            Overwrite="true"
+            Encoding="Unicode" />
+    </Target>
+
+    <!-- Clean tlog files -->
+    <Target Name="_WslcCleanTlogs"
+            AfterTargets="WslcClean"
+            Condition="'@(WslcImage)' != '' AND '$(TLogLocation)' != ''">
+        <Delete Files="$(TLogLocation)wslc.%(WslcImage.Identity).read.1.tlog" />
+        <Delete Files="$(TLogLocation)wslc.%(WslcImage.Identity).write.1.tlog" />
+    </Target>
+
 </Project>
\ No newline at end of file
diff --git a/nuget/Microsoft.WSL.Containers/build/net/Microsoft.WSL.Containers.targets b/nuget/Microsoft.WSL.Containers/build/net/Microsoft.WSL.Containers.targets
index 245e57a2c..27aece358 100644
--- a/nuget/Microsoft.WSL.Containers/build/net/Microsoft.WSL.Containers.targets
+++ b/nuget/Microsoft.WSL.Containers/build/net/Microsoft.WSL.Containers.targets
@@ -11,4 +11,13 @@
 
     <Import Project="$(MSBuildThisFileDirectory)..\Microsoft.WSL.Containers.common.targets" />
 
+    <!-- ================================================================== -->
+    <!-- C# specific: CPS Up-to-Date Check for container source files       -->
+    <!-- ================================================================== -->
+
+    <ItemGroup Condition="'$(UsingMicrosoftNETSdk)' == 'true'">
+        <UpToDateCheckInput Include="%(WslcImage.Sources)" />
+        <UpToDateCheckBuilt Include="$(IntDir)wslc_%(WslcImage.Identity).marker" />
+    </ItemGroup>
+
 </Project>
\ No newline at end of file

From 208e9ec3d3d05144373fe756342786eb69c47a5c Mon Sep 17 00:00:00 2001
From: Shawn Yuan <shuaiyuan@microsoft.com>
Date: Fri, 27 Mar 2026 11:23:56 +0800
Subject: [PATCH 2/8] update

Signed-off-by: Shawn Yuan <shuaiyuan@microsoft.com>
---
 .../Microsoft.WSL.Containers.common.targets   | 36 +++++++++----------
 .../build/cmake/wslcConfig.cmake              | 11 ++++--
 .../native/Microsoft.WSL.Containers.targets   |  4 +--
 3 files changed, 29 insertions(+), 22 deletions(-)

diff --git a/nuget/Microsoft.WSL.Containers/build/Microsoft.WSL.Containers.common.targets b/nuget/Microsoft.WSL.Containers/build/Microsoft.WSL.Containers.common.targets
index 3b38dfd05..b2830b11c 100644
--- a/nuget/Microsoft.WSL.Containers/build/Microsoft.WSL.Containers.common.targets
+++ b/nuget/Microsoft.WSL.Containers/build/Microsoft.WSL.Containers.common.targets
@@ -15,6 +15,7 @@
     <!-- Default properties -->
     <PropertyGroup>
         <WslcImageOutputDir Condition="'$(WslcImageOutputDir)' == ''">$(OutDir)</WslcImageOutputDir>
+        <WslcCliPath Condition="'$(WslcCliPath)' == '' AND Exists('$(ProgramW6432)\WSL\wslc.exe')">$(ProgramW6432)\WSL\wslc.exe</WslcCliPath>
         <WslcCliPath Condition="'$(WslcCliPath)' == ''">wslc</WslcCliPath>
     </PropertyGroup>
 
@@ -22,7 +23,7 @@
     <ItemDefinitionGroup>
         <WslcImage>
             <Tag>latest</Tag>
-            <Output>$(WslcImageOutputDir)</Output>
+            <OutputDir>$(WslcImageOutputDir)</OutputDir>
         </WslcImage>
     </ItemDefinitionGroup>
 
@@ -31,7 +32,7 @@
             BeforeTargets="WslcBuildAllImages"
             Condition="'@(WslcImage)' != ''">
 
-        <Exec Command="$(WslcCliPath) --version"
+        <Exec Command="&quot;$(WslcCliPath)&quot; --version"
               IgnoreExitCode="true"
               ConsoleToMSBuild="true"
               StandardOutputImportance="low"
@@ -52,13 +53,17 @@
 
         <MSBuild Projects="$(MSBuildProjectFullPath)"
                  Targets="_WslcBuildSingleImage"
-                 Properties="Configuration=$(Configuration);Platform=$(Platform);_WslcName=%(WslcImage.Identity);_WslcTag=%(WslcImage.Tag);_WslcDockerfile=%(WslcImage.Dockerfile);_WslcContext=%(WslcImage.Context);_WslcSources=%(WslcImage.Sources);_WslcOutput=%(WslcImage.Output)" />
+                 Properties="Configuration=$(Configuration);Platform=$(Platform);_WslcName=%(WslcImage.Identity);_WslcTag=%(WslcImage.Tag);_WslcDockerfile=%(WslcImage.Dockerfile);_WslcContext=%(WslcImage.Context);_WslcSourceDir=%(WslcImage.Sources);_WslcOutput=%(WslcImage.OutputDir)" />
     </Target>
 
-    <!-- Collect source files for incremental check (wildcards only expand in ItemGroup Include) -->
+    <!--
+        Collect source files for incremental check.
+        Wildcards are expanded here in ItemGroup Include (not in Inputs attribute or MSBuild task Properties,
+        where they get escaped). The Sources metadata is treated as a directory path; **\* is appended here.
+    -->
     <Target Name="_WslcCollectSources" BeforeTargets="_WslcBuildSingleImage">
         <ItemGroup>
-            <_WslcSourceFiles Include="$(_WslcDockerfile);$(_WslcSources)" />
+            <_WslcSourceFiles Include="$(_WslcDockerfile);$(_WslcSourceDir)\**\*" />
         </ItemGroup>
     </Target>
 
@@ -73,23 +78,18 @@
         <Message Importance="high"
                  Text="WSLC: Building image '$(_WslcName):$(_WslcTag)'..." />
 
-        <Exec Command="$(WslcCliPath) image build -t &quot;$(_WslcName):$(_WslcTag)&quot; -f &quot;$(_WslcDockerfile)&quot; &quot;$(_WslcContext)&quot;"
+        <Exec Command="&quot;$(WslcCliPath)&quot; image build -t &quot;$(_WslcName):$(_WslcTag)&quot; -f &quot;$(_WslcDockerfile)&quot; &quot;$(_WslcContext)&quot;"
               ConsoleToMSBuild="true" />
 
-        <Message Importance="high"
-                 Text="WSLC: Saving image '$(_WslcName):$(_WslcTag)' to $(_WslcOutput)\$(_WslcName).tar..." />
-
-        <Exec Command="$(WslcCliPath) image save &quot;$(_WslcName):$(_WslcTag)&quot; -o &quot;$(_WslcOutput)\$(_WslcName).tar&quot;"
-              ConsoleToMSBuild="true" />
-
-        <!-- Save image ID for efficient check-then-load at runtime -->
-        <Exec Command="$(WslcCliPath) image inspect &quot;$(_WslcName):$(_WslcTag)&quot; --format {{.Id}} &gt; &quot;$(_WslcOutput)\$(_WslcName).id&quot;"
-              IgnoreStandardErrorWarningFormat="true" />
+        <!--
+            TODO: Export image to tar when wslc image save is available.
+            TODO: Save image ID for check then load when wslc image inspect supports format flag.
+        -->
 
         <Touch Files="$(IntDir)wslc_$(_WslcName).marker" AlwaysCreate="true" />
 
         <Message Importance="high"
-                 Text="WSLC: [$(_WslcName)] Image built and saved successfully." />
+                 Text="WSLC: [$(_WslcName)] Image '$(_WslcName):$(_WslcTag)' built successfully." />
     </Target>
 
     <!-- Clean container artifacts -->
@@ -97,8 +97,8 @@
             AfterTargets="Clean"
             Condition="'@(WslcImage)' != ''">
 
-        <Delete Files="%(WslcImage.Output)\%(WslcImage.Identity).tar" />
-        <Delete Files="%(WslcImage.Output)\%(WslcImage.Identity).id" />
+        <Delete Files="%(WslcImage.OutputDir)\%(WslcImage.Identity).tar" />
+        <Delete Files="%(WslcImage.OutputDir)\%(WslcImage.Identity).id" />
         <Delete Files="$(IntDir)wslc_%(WslcImage.Identity).marker" />
     </Target>
 
diff --git a/nuget/Microsoft.WSL.Containers/build/cmake/wslcConfig.cmake b/nuget/Microsoft.WSL.Containers/build/cmake/wslcConfig.cmake
index f64db3609..c139fb6dc 100644
--- a/nuget/Microsoft.WSL.Containers/build/cmake/wslcConfig.cmake
+++ b/nuget/Microsoft.WSL.Containers/build/cmake/wslcConfig.cmake
@@ -43,6 +43,14 @@ function(wslc_add_image)
         set(ARG_OUTPUT "${CMAKE_CURRENT_BINARY_DIR}")
     endif()
 
+    # Find wslc CLI
+    if(NOT WSLC_CLI_PATH)
+        find_program(WSLC_CLI_PATH wslc PATHS "$ENV{ProgramW6432}/WSL" "$ENV{ProgramFiles}/WSL")
+        if(NOT WSLC_CLI_PATH)
+            message(FATAL_ERROR "wslc CLI not found. Install WSL by running: wsl --install --no-distribution")
+        endif()
+    endif()
+
     set(_image_ref "${ARG_NAME}:${ARG_TAG}")
     set(_tar_output "${ARG_OUTPUT}/${ARG_NAME}.tar")
     set(_id_output "${ARG_OUTPUT}/${ARG_NAME}.id")
@@ -53,8 +61,7 @@ function(wslc_add_image)
 
     add_custom_command(
         OUTPUT "${_marker}"
-        COMMAND wslc image build -t "${_image_ref}" -f "${ARG_DOCKERFILE}" "${ARG_CONTEXT}"
-        COMMAND wslc image save "${_image_ref}" -o "${_tar_output}"
+        COMMAND "${WSLC_CLI_PATH}" image build -t "${_image_ref}" -f "${ARG_DOCKERFILE}" "${ARG_CONTEXT}"
         COMMAND ${CMAKE_COMMAND} -E touch "${_marker}"
         DEPENDS ${_resolved_sources} "${ARG_DOCKERFILE}"
         COMMENT "WSLC: Building image '${_image_ref}'..."
diff --git a/nuget/Microsoft.WSL.Containers/build/native/Microsoft.WSL.Containers.targets b/nuget/Microsoft.WSL.Containers/build/native/Microsoft.WSL.Containers.targets
index abf5db776..5256f3a60 100644
--- a/nuget/Microsoft.WSL.Containers/build/native/Microsoft.WSL.Containers.targets
+++ b/nuget/Microsoft.WSL.Containers/build/native/Microsoft.WSL.Containers.targets
@@ -34,12 +34,12 @@
 
         <MSBuild Projects="$(MSBuildProjectFullPath)"
                  Targets="_WslcWriteSingleTlog"
-                 Properties="Configuration=$(Configuration);Platform=$(Platform);_WslcName=%(WslcImage.Identity);_WslcDockerfile=%(WslcImage.Dockerfile);_WslcSources=%(WslcImage.Sources);_WslcOutput=%(WslcImage.Output);_WslcTlogDir=$(TLogLocation)" />
+                 Properties="Configuration=$(Configuration);Platform=$(Platform);_WslcName=%(WslcImage.Identity);_WslcDockerfile=%(WslcImage.Dockerfile);_WslcSourceDir=%(WslcImage.Sources);_WslcOutput=%(WslcImage.OutputDir);_WslcTlogDir=$(TLogLocation)" />
     </Target>
 
     <Target Name="_WslcWriteSingleTlog">
         <ItemGroup>
-            <_WslcTlogInputs Include="$(_WslcDockerfile);$(_WslcSources)" />
+            <_WslcTlogInputs Include="$(_WslcDockerfile);$(_WslcSourceDir)\**\*" />
         </ItemGroup>
 
         <PropertyGroup>

From af041e469fef056e494e0f01b72f4aef935aa45f Mon Sep 17 00:00:00 2001
From: Shawn Yuan <shuaiyuan@microsoft.com>
Date: Fri, 27 Mar 2026 12:49:49 +0800
Subject: [PATCH 3/8] update

Signed-off-by: Shawn Yuan <shuaiyuan@microsoft.com>
---
 .../Microsoft.WSL.Containers.common.targets   | 29 +++++++++++++++----
 .../build/cmake/wslcConfig.cmake              |  3 +-
 .../native/Microsoft.WSL.Containers.targets   |  6 ++--
 .../net/Microsoft.WSL.Containers.targets      | 12 +++++++-
 .../Microsoft.WSL.Containers.targets          |  4 +++
 .../native/Microsoft.WSL.Containers.targets   |  4 +++
 6 files changed, 48 insertions(+), 10 deletions(-)
 create mode 100644 nuget/Microsoft.WSL.Containers/buildTransitive/Microsoft.WSL.Containers.targets
 create mode 100644 nuget/Microsoft.WSL.Containers/buildTransitive/native/Microsoft.WSL.Containers.targets

diff --git a/nuget/Microsoft.WSL.Containers/build/Microsoft.WSL.Containers.common.targets b/nuget/Microsoft.WSL.Containers/build/Microsoft.WSL.Containers.common.targets
index b2830b11c..4176d843b 100644
--- a/nuget/Microsoft.WSL.Containers/build/Microsoft.WSL.Containers.common.targets
+++ b/nuget/Microsoft.WSL.Containers/build/Microsoft.WSL.Containers.common.targets
@@ -27,6 +27,21 @@
         </WslcImage>
     </ItemDefinitionGroup>
 
+    <!-- Auto-detection fallback: if no WslcImage declared, detect container/Dockerfile -->
+    <ItemGroup Condition="'@(WslcImage)' == '' AND Exists('$(ProjectDir)container\Dockerfile')">
+        <WslcImage Include="$(MSBuildProjectName)"
+                   Dockerfile="$(ProjectDir)container\Dockerfile"
+                   Context="$(ProjectDir)container"
+                   Sources="$(ProjectDir)container" />
+    </ItemGroup>
+
+    <ItemGroup Condition="'@(WslcImage)' == '' AND Exists('$(ProjectDir)docker\Dockerfile')">
+        <WslcImage Include="$(MSBuildProjectName)"
+                   Dockerfile="$(ProjectDir)docker\Dockerfile"
+                   Context="$(ProjectDir)docker"
+                   Sources="$(ProjectDir)docker" />
+    </ItemGroup>
+
     <!-- Check that wslc CLI is installed -->
     <Target Name="WslcCheckDependencies"
             BeforeTargets="WslcBuildAllImages"
@@ -59,11 +74,14 @@
     <!--
         Collect source files for incremental check.
         Wildcards are expanded here in ItemGroup Include (not in Inputs attribute or MSBuild task Properties,
-        where they get escaped). The Sources metadata is treated as a directory path; **\* is appended here.
+        where they get escaped). Sources can be semicolon separated directory paths;
+        each is expanded with **\* to collect all files recursively.
     -->
     <Target Name="_WslcCollectSources" BeforeTargets="_WslcBuildSingleImage">
         <ItemGroup>
-            <_WslcSourceFiles Include="$(_WslcDockerfile);$(_WslcSourceDir)\**\*" />
+            <_WslcSourceDirs Include="$(_WslcSourceDir.Split(';'))" />
+            <_WslcSourceFiles Include="$(_WslcDockerfile)" />
+            <_WslcSourceFiles Include="%(_WslcSourceDirs.Identity)\**\*" />
         </ItemGroup>
     </Target>
 
@@ -73,7 +91,7 @@
             Inputs="@(_WslcSourceFiles)"
             Outputs="$(IntDir)wslc_$(_WslcName).marker">
 
-        <MakeDir Directories="$(IntDir);$(_WslcOutput)" />
+        <MakeDir Directories="$(IntDir)" />
 
         <Message Importance="high"
                  Text="WSLC: Building image '$(_WslcName):$(_WslcTag)'..." />
@@ -97,9 +115,10 @@
             AfterTargets="Clean"
             Condition="'@(WslcImage)' != ''">
 
-        <Delete Files="%(WslcImage.OutputDir)\%(WslcImage.Identity).tar" />
-        <Delete Files="%(WslcImage.OutputDir)\%(WslcImage.Identity).id" />
         <Delete Files="$(IntDir)wslc_%(WslcImage.Identity).marker" />
+        <!--
+            TODO: Also clean tar and id files when wslc image save is available.
+        -->
     </Target>
 
 </Project>
\ No newline at end of file
diff --git a/nuget/Microsoft.WSL.Containers/build/cmake/wslcConfig.cmake b/nuget/Microsoft.WSL.Containers/build/cmake/wslcConfig.cmake
index c139fb6dc..70240e761 100644
--- a/nuget/Microsoft.WSL.Containers/build/cmake/wslcConfig.cmake
+++ b/nuget/Microsoft.WSL.Containers/build/cmake/wslcConfig.cmake
@@ -52,9 +52,8 @@ function(wslc_add_image)
     endif()
 
     set(_image_ref "${ARG_NAME}:${ARG_TAG}")
-    set(_tar_output "${ARG_OUTPUT}/${ARG_NAME}.tar")
-    set(_id_output "${ARG_OUTPUT}/${ARG_NAME}.id")
     set(_marker "${CMAKE_CURRENT_BINARY_DIR}/wslc_${ARG_NAME}.marker")
+    # TODO: set(_tar_output "${ARG_OUTPUT}/${ARG_NAME}.tar") when wslc image save is available
 
     # Resolve source globs to file lists
     file(GLOB_RECURSE _resolved_sources ${ARG_SOURCES})
diff --git a/nuget/Microsoft.WSL.Containers/build/native/Microsoft.WSL.Containers.targets b/nuget/Microsoft.WSL.Containers/build/native/Microsoft.WSL.Containers.targets
index 5256f3a60..c55353dc6 100644
--- a/nuget/Microsoft.WSL.Containers/build/native/Microsoft.WSL.Containers.targets
+++ b/nuget/Microsoft.WSL.Containers/build/native/Microsoft.WSL.Containers.targets
@@ -34,12 +34,14 @@
 
         <MSBuild Projects="$(MSBuildProjectFullPath)"
                  Targets="_WslcWriteSingleTlog"
-                 Properties="Configuration=$(Configuration);Platform=$(Platform);_WslcName=%(WslcImage.Identity);_WslcDockerfile=%(WslcImage.Dockerfile);_WslcSourceDir=%(WslcImage.Sources);_WslcOutput=%(WslcImage.OutputDir);_WslcTlogDir=$(TLogLocation)" />
+                 Properties="Configuration=$(Configuration);Platform=$(Platform);_WslcName=%(WslcImage.Identity);_WslcDockerfile=%(WslcImage.Dockerfile);_WslcSourceDir=%(WslcImage.Sources);_WslcTlogDir=$(TLogLocation)" />
     </Target>
 
     <Target Name="_WslcWriteSingleTlog">
         <ItemGroup>
-            <_WslcTlogInputs Include="$(_WslcDockerfile);$(_WslcSourceDir)\**\*" />
+            <_WslcTlogSourceDirs Include="$(_WslcSourceDir.Split(';'))" />
+            <_WslcTlogInputs Include="$(_WslcDockerfile)" />
+            <_WslcTlogInputs Include="%(_WslcTlogSourceDirs.Identity)\**\*" />
         </ItemGroup>
 
         <PropertyGroup>
diff --git a/nuget/Microsoft.WSL.Containers/build/net/Microsoft.WSL.Containers.targets b/nuget/Microsoft.WSL.Containers/build/net/Microsoft.WSL.Containers.targets
index 27aece358..66501e601 100644
--- a/nuget/Microsoft.WSL.Containers/build/net/Microsoft.WSL.Containers.targets
+++ b/nuget/Microsoft.WSL.Containers/build/net/Microsoft.WSL.Containers.targets
@@ -15,9 +15,19 @@
     <!-- C# specific: CPS Up-to-Date Check for container source files       -->
     <!-- ================================================================== -->
 
+    <!-- Register marker files as build outputs for CPS up-to-date check -->
     <ItemGroup Condition="'$(UsingMicrosoftNETSdk)' == 'true'">
-        <UpToDateCheckInput Include="%(WslcImage.Sources)" />
         <UpToDateCheckBuilt Include="$(IntDir)wslc_%(WslcImage.Identity).marker" />
     </ItemGroup>
 
+    <!-- Expand multi-directory Sources into UpToDateCheckInput at target time -->
+    <Target Name="_WslcRegisterUpToDateCheckInputs"
+            BeforeTargets="CollectUpToDateCheckBuiltDesignTime"
+            Condition="'$(UsingMicrosoftNETSdk)' == 'true' AND '@(WslcImage)' != ''">
+        <ItemGroup>
+            <_WslcUpToDateDirs Include="%(WslcImage.Sources)" Separator=";" />
+            <UpToDateCheckInput Include="%(_WslcUpToDateDirs.Identity)\**\*" />
+        </ItemGroup>
+    </Target>
+
 </Project>
\ No newline at end of file
diff --git a/nuget/Microsoft.WSL.Containers/buildTransitive/Microsoft.WSL.Containers.targets b/nuget/Microsoft.WSL.Containers/buildTransitive/Microsoft.WSL.Containers.targets
new file mode 100644
index 000000000..b5ada5ff6
--- /dev/null
+++ b/nuget/Microsoft.WSL.Containers/buildTransitive/Microsoft.WSL.Containers.targets
@@ -0,0 +1,4 @@
+<?xml version="1.0" encoding="utf-8"?>
+<Project xmlns="http://schemas.microsoft.com/developer/msbuild/2003">
+    <Import Project="$(MSBuildThisFileDirectory)..\build\Microsoft.WSL.Containers.common.targets" />
+</Project>
diff --git a/nuget/Microsoft.WSL.Containers/buildTransitive/native/Microsoft.WSL.Containers.targets b/nuget/Microsoft.WSL.Containers/buildTransitive/native/Microsoft.WSL.Containers.targets
new file mode 100644
index 000000000..0f50deabc
--- /dev/null
+++ b/nuget/Microsoft.WSL.Containers/buildTransitive/native/Microsoft.WSL.Containers.targets
@@ -0,0 +1,4 @@
+<?xml version="1.0" encoding="utf-8"?>
+<Project xmlns="http://schemas.microsoft.com/developer/msbuild/2003">
+    <Import Project="$(MSBuildThisFileDirectory)..\..\build\native\Microsoft.WSL.Containers.targets" />
+</Project>

From e5f990d4f32d1a6a0a14499be29d1594ed6f1f19 Mon Sep 17 00:00:00 2001
From: Shawn Yuan <shuaiyuan@microsoft.com>
Date: Fri, 27 Mar 2026 15:30:00 +0800
Subject: [PATCH 4/8] resolve comments

---
 .../Microsoft.WSL.Containers.common.targets    |  2 +-
 .../build/cmake/wslcConfig.cmake               | 18 +++++++++++++++---
 .../native/Microsoft.WSL.Containers.targets    |  2 +-
 .../build/net/Microsoft.WSL.Containers.targets |  2 +-
 4 files changed, 18 insertions(+), 6 deletions(-)

diff --git a/nuget/Microsoft.WSL.Containers/build/Microsoft.WSL.Containers.common.targets b/nuget/Microsoft.WSL.Containers/build/Microsoft.WSL.Containers.common.targets
index 4176d843b..f7e6708ea 100644
--- a/nuget/Microsoft.WSL.Containers/build/Microsoft.WSL.Containers.common.targets
+++ b/nuget/Microsoft.WSL.Containers/build/Microsoft.WSL.Containers.common.targets
@@ -81,7 +81,7 @@
         <ItemGroup>
             <_WslcSourceDirs Include="$(_WslcSourceDir.Split(';'))" />
             <_WslcSourceFiles Include="$(_WslcDockerfile)" />
-            <_WslcSourceFiles Include="%(_WslcSourceDirs.Identity)\**\*" />
+            <_WslcSourceFiles Include="%(_WslcSourceDirs.Identity)\**\*" Condition="'%(_WslcSourceDirs.Identity)' != ''" />
         </ItemGroup>
     </Target>
 
diff --git a/nuget/Microsoft.WSL.Containers/build/cmake/wslcConfig.cmake b/nuget/Microsoft.WSL.Containers/build/cmake/wslcConfig.cmake
index 70240e761..512e65ab2 100644
--- a/nuget/Microsoft.WSL.Containers/build/cmake/wslcConfig.cmake
+++ b/nuget/Microsoft.WSL.Containers/build/cmake/wslcConfig.cmake
@@ -15,12 +15,21 @@
 #       TAG         latest
 #       OUTPUT      ${CMAKE_BINARY_DIR}/images
 #   )
+#
+#   # With explicit image registry/name (IMAGE defaults to NAME if omitted):
+#   wslc_add_image(
+#       NAME        my-server
+#       IMAGE       ghcr.io/myorg/my-server
+#       TAG         v1.2.3
+#       DOCKERFILE  container/Dockerfile
+#       CONTEXT     container/
+#   )
 
 function(wslc_add_image)
     cmake_parse_arguments(
         PARSE_ARGV 0 ARG
         ""                                      # options (none)
-        "NAME;TAG;DOCKERFILE;CONTEXT;OUTPUT"     # one-value keywords
+        "NAME;IMAGE;TAG;DOCKERFILE;CONTEXT;OUTPUT" # one-value keywords
         "SOURCES"                                # multi-value keywords
     )
 
@@ -36,6 +45,9 @@ function(wslc_add_image)
     endif()
 
     # Defaults
+    if(NOT ARG_IMAGE)
+        set(ARG_IMAGE "${ARG_NAME}")
+    endif()
     if(NOT ARG_TAG)
         set(ARG_TAG "latest")
     endif()
@@ -51,12 +63,12 @@ function(wslc_add_image)
         endif()
     endif()
 
-    set(_image_ref "${ARG_NAME}:${ARG_TAG}")
+    set(_image_ref "${ARG_IMAGE}:${ARG_TAG}")
     set(_marker "${CMAKE_CURRENT_BINARY_DIR}/wslc_${ARG_NAME}.marker")
     # TODO: set(_tar_output "${ARG_OUTPUT}/${ARG_NAME}.tar") when wslc image save is available
 
     # Resolve source globs to file lists
-    file(GLOB_RECURSE _resolved_sources ${ARG_SOURCES})
+    file(GLOB_RECURSE _resolved_sources CONFIGURE_DEPENDS ${ARG_SOURCES})
 
     add_custom_command(
         OUTPUT "${_marker}"
diff --git a/nuget/Microsoft.WSL.Containers/build/native/Microsoft.WSL.Containers.targets b/nuget/Microsoft.WSL.Containers/build/native/Microsoft.WSL.Containers.targets
index c55353dc6..53bf0f6a6 100644
--- a/nuget/Microsoft.WSL.Containers/build/native/Microsoft.WSL.Containers.targets
+++ b/nuget/Microsoft.WSL.Containers/build/native/Microsoft.WSL.Containers.targets
@@ -34,7 +34,7 @@
 
         <MSBuild Projects="$(MSBuildProjectFullPath)"
                  Targets="_WslcWriteSingleTlog"
-                 Properties="Configuration=$(Configuration);Platform=$(Platform);_WslcName=%(WslcImage.Identity);_WslcDockerfile=%(WslcImage.Dockerfile);_WslcSourceDir=%(WslcImage.Sources);_WslcTlogDir=$(TLogLocation)" />
+                 Properties="Configuration=$(Configuration);Platform=$(Platform);_WslcName=%(WslcImage.Identity);_WslcDockerfile=%(WslcImage.Dockerfile);_WslcSourceDir=%(WslcImage.Sources);_WslcTlogDir=$([MSBuild]::EnsureTrailingSlash('$(TLogLocation)'))" />
     </Target>
 
     <Target Name="_WslcWriteSingleTlog">
diff --git a/nuget/Microsoft.WSL.Containers/build/net/Microsoft.WSL.Containers.targets b/nuget/Microsoft.WSL.Containers/build/net/Microsoft.WSL.Containers.targets
index 66501e601..cb1500527 100644
--- a/nuget/Microsoft.WSL.Containers/build/net/Microsoft.WSL.Containers.targets
+++ b/nuget/Microsoft.WSL.Containers/build/net/Microsoft.WSL.Containers.targets
@@ -26,7 +26,7 @@
             Condition="'$(UsingMicrosoftNETSdk)' == 'true' AND '@(WslcImage)' != ''">
         <ItemGroup>
             <_WslcUpToDateDirs Include="%(WslcImage.Sources)" Separator=";" />
-            <UpToDateCheckInput Include="%(_WslcUpToDateDirs.Identity)\**\*" />
+            <UpToDateCheckInput Include="%(_WslcUpToDateDirs.Identity)\**\*" Condition="'%(_WslcUpToDateDirs.Identity)' != ''" />
         </ItemGroup>
     </Target>
 

From e00d4eda0e61208077b91f614c834161f69db0da Mon Sep 17 00:00:00 2001
From: Shawn Yuan <shuaiyuan@microsoft.com>
Date: Mon, 30 Mar 2026 13:04:14 +0800
Subject: [PATCH 5/8] add placeholder for wslc save step.

---
 .../build/Microsoft.WSL.Containers.common.targets    |  9 ++++++---
 .../build/cmake/wslcConfig.cmake                     |  6 +++++-
 .../build/native/Microsoft.WSL.Containers.targets    | 12 ++++++++++++
 3 files changed, 23 insertions(+), 4 deletions(-)

diff --git a/nuget/Microsoft.WSL.Containers/build/Microsoft.WSL.Containers.common.targets b/nuget/Microsoft.WSL.Containers/build/Microsoft.WSL.Containers.common.targets
index f7e6708ea..9bb5a7d6d 100644
--- a/nuget/Microsoft.WSL.Containers/build/Microsoft.WSL.Containers.common.targets
+++ b/nuget/Microsoft.WSL.Containers/build/Microsoft.WSL.Containers.common.targets
@@ -100,8 +100,10 @@
               ConsoleToMSBuild="true" />
 
         <!--
-            TODO: Export image to tar when wslc image save is available.
-            TODO: Save image ID for check then load when wslc image inspect supports format flag.
+            Uncomment when wslc image save is available:
+        <MakeDir Directories="$(_WslcOutput)" />
+        <Exec Command="&quot;$(WslcCliPath)&quot; image save -o &quot;$(_WslcOutput)\$(_WslcName).tar&quot; &quot;$(_WslcName):$(_WslcTag)&quot;"
+              ConsoleToMSBuild="true" />
         -->
 
         <Touch Files="$(IntDir)wslc_$(_WslcName).marker" AlwaysCreate="true" />
@@ -117,7 +119,8 @@
 
         <Delete Files="$(IntDir)wslc_%(WslcImage.Identity).marker" />
         <!--
-            TODO: Also clean tar and id files when wslc image save is available.
+            Uncomment when wslc image save is available:
+        <Delete Files="%(WslcImage.OutputDir)\%(WslcImage.Identity).tar" />
         -->
     </Target>
 
diff --git a/nuget/Microsoft.WSL.Containers/build/cmake/wslcConfig.cmake b/nuget/Microsoft.WSL.Containers/build/cmake/wslcConfig.cmake
index 512e65ab2..eaf51cb3c 100644
--- a/nuget/Microsoft.WSL.Containers/build/cmake/wslcConfig.cmake
+++ b/nuget/Microsoft.WSL.Containers/build/cmake/wslcConfig.cmake
@@ -65,7 +65,8 @@ function(wslc_add_image)
 
     set(_image_ref "${ARG_IMAGE}:${ARG_TAG}")
     set(_marker "${CMAKE_CURRENT_BINARY_DIR}/wslc_${ARG_NAME}.marker")
-    # TODO: set(_tar_output "${ARG_OUTPUT}/${ARG_NAME}.tar") when wslc image save is available
+    # Uncomment when wslc image save is available:
+    # set(_tar_output "${ARG_OUTPUT}/${ARG_NAME}.tar")
 
     # Resolve source globs to file lists
     file(GLOB_RECURSE _resolved_sources CONFIGURE_DEPENDS ${ARG_SOURCES})
@@ -73,6 +74,9 @@ function(wslc_add_image)
     add_custom_command(
         OUTPUT "${_marker}"
         COMMAND "${WSLC_CLI_PATH}" image build -t "${_image_ref}" -f "${ARG_DOCKERFILE}" "${ARG_CONTEXT}"
+        # Uncomment when wslc image save is available:
+        # COMMAND ${CMAKE_COMMAND} -E make_directory "${ARG_OUTPUT}"
+        # COMMAND "${WSLC_CLI_PATH}" image save -o "${_tar_output}" "${_image_ref}"
         COMMAND ${CMAKE_COMMAND} -E touch "${_marker}"
         DEPENDS ${_resolved_sources} "${ARG_DOCKERFILE}"
         COMMENT "WSLC: Building image '${_image_ref}'..."
diff --git a/nuget/Microsoft.WSL.Containers/build/native/Microsoft.WSL.Containers.targets b/nuget/Microsoft.WSL.Containers/build/native/Microsoft.WSL.Containers.targets
index 53bf0f6a6..f3d2a6868 100644
--- a/nuget/Microsoft.WSL.Containers/build/native/Microsoft.WSL.Containers.targets
+++ b/nuget/Microsoft.WSL.Containers/build/native/Microsoft.WSL.Containers.targets
@@ -47,6 +47,10 @@
         <PropertyGroup>
             <_WslcDockerfileFullPath>$([System.IO.Path]::GetFullPath('$(_WslcDockerfile)'))</_WslcDockerfileFullPath>
             <_WslcMarkerFullPath>$([System.IO.Path]::GetFullPath('$(IntDir)wslc_$(_WslcName).marker'))</_WslcMarkerFullPath>
+            <!--
+                Uncomment when wslc image save is available:
+            <_WslcTarFullPath>$([System.IO.Path]::GetFullPath('$(WslcImageOutputDir)$(_WslcName).tar'))</_WslcTarFullPath>
+            -->
         </PropertyGroup>
 
         <WriteLinesToFile
@@ -55,6 +59,14 @@
             Overwrite="true"
             Encoding="Unicode" />
 
+        <!--
+            Uncomment when wslc image save is available, to track tar output:
+        <WriteLinesToFile
+            File="$(_WslcTlogDir)wslc.$(_WslcName).write.1.tlog"
+            Lines="^$(_WslcDockerfileFullPath);$(_WslcMarkerFullPath);$(_WslcTarFullPath)"
+            Overwrite="true"
+            Encoding="Unicode" />
+        -->
         <WriteLinesToFile
             File="$(_WslcTlogDir)wslc.$(_WslcName).write.1.tlog"
             Lines="^$(_WslcDockerfileFullPath);$(_WslcMarkerFullPath)"

From 14e0dbf421eab42544fad601e0fc916504015fe0 Mon Sep 17 00:00:00 2001
From: Shawn Yuan <shuaiyuan@microsoft.com>
Date: Mon, 30 Mar 2026 16:36:09 +0800
Subject: [PATCH 6/8] merge cmake file

---
 .../build/cmake/wslcConfig.cmake              | 89 ------------------
 .../Microsoft.WSL.ContainersConfig.cmake      | 91 +++++++++++++++++++
 2 files changed, 91 insertions(+), 89 deletions(-)
 delete mode 100644 nuget/Microsoft.WSL.Containers/build/cmake/wslcConfig.cmake

diff --git a/nuget/Microsoft.WSL.Containers/build/cmake/wslcConfig.cmake b/nuget/Microsoft.WSL.Containers/build/cmake/wslcConfig.cmake
deleted file mode 100644
index eaf51cb3c..000000000
--- a/nuget/Microsoft.WSL.Containers/build/cmake/wslcConfig.cmake
+++ /dev/null
@@ -1,89 +0,0 @@
-# wslcConfig.cmake - Container image build support for CMake
-#
-# Provides the wslc_add_image() function for declaring container image
-# build targets with incremental rebuild support.
-#
-# Usage:
-#   list(APPEND CMAKE_MODULE_PATH "<nuget>/build/cmake")
-#   find_package(wslc REQUIRED)
-#
-#   wslc_add_image(
-#       NAME        my-server
-#       DOCKERFILE  container/Dockerfile
-#       CONTEXT     container/
-#       SOURCES     container/src/*.cpp container/src/*.h
-#       TAG         latest
-#       OUTPUT      ${CMAKE_BINARY_DIR}/images
-#   )
-#
-#   # With explicit image registry/name (IMAGE defaults to NAME if omitted):
-#   wslc_add_image(
-#       NAME        my-server
-#       IMAGE       ghcr.io/myorg/my-server
-#       TAG         v1.2.3
-#       DOCKERFILE  container/Dockerfile
-#       CONTEXT     container/
-#   )
-
-function(wslc_add_image)
-    cmake_parse_arguments(
-        PARSE_ARGV 0 ARG
-        ""                                      # options (none)
-        "NAME;IMAGE;TAG;DOCKERFILE;CONTEXT;OUTPUT" # one-value keywords
-        "SOURCES"                                # multi-value keywords
-    )
-
-    # Validate required arguments
-    if(NOT ARG_NAME)
-        message(FATAL_ERROR "wslc_add_image: NAME is required")
-    endif()
-    if(NOT ARG_DOCKERFILE)
-        message(FATAL_ERROR "wslc_add_image: DOCKERFILE is required")
-    endif()
-    if(NOT ARG_CONTEXT)
-        message(FATAL_ERROR "wslc_add_image: CONTEXT is required")
-    endif()
-
-    # Defaults
-    if(NOT ARG_IMAGE)
-        set(ARG_IMAGE "${ARG_NAME}")
-    endif()
-    if(NOT ARG_TAG)
-        set(ARG_TAG "latest")
-    endif()
-    if(NOT ARG_OUTPUT)
-        set(ARG_OUTPUT "${CMAKE_CURRENT_BINARY_DIR}")
-    endif()
-
-    # Find wslc CLI
-    if(NOT WSLC_CLI_PATH)
-        find_program(WSLC_CLI_PATH wslc PATHS "$ENV{ProgramW6432}/WSL" "$ENV{ProgramFiles}/WSL")
-        if(NOT WSLC_CLI_PATH)
-            message(FATAL_ERROR "wslc CLI not found. Install WSL by running: wsl --install --no-distribution")
-        endif()
-    endif()
-
-    set(_image_ref "${ARG_IMAGE}:${ARG_TAG}")
-    set(_marker "${CMAKE_CURRENT_BINARY_DIR}/wslc_${ARG_NAME}.marker")
-    # Uncomment when wslc image save is available:
-    # set(_tar_output "${ARG_OUTPUT}/${ARG_NAME}.tar")
-
-    # Resolve source globs to file lists
-    file(GLOB_RECURSE _resolved_sources CONFIGURE_DEPENDS ${ARG_SOURCES})
-
-    add_custom_command(
-        OUTPUT "${_marker}"
-        COMMAND "${WSLC_CLI_PATH}" image build -t "${_image_ref}" -f "${ARG_DOCKERFILE}" "${ARG_CONTEXT}"
-        # Uncomment when wslc image save is available:
-        # COMMAND ${CMAKE_COMMAND} -E make_directory "${ARG_OUTPUT}"
-        # COMMAND "${WSLC_CLI_PATH}" image save -o "${_tar_output}" "${_image_ref}"
-        COMMAND ${CMAKE_COMMAND} -E touch "${_marker}"
-        DEPENDS ${_resolved_sources} "${ARG_DOCKERFILE}"
-        COMMENT "WSLC: Building image '${_image_ref}'..."
-        VERBATIM
-    )
-
-    add_custom_target(wslc_image_${ARG_NAME} ALL
-        DEPENDS "${_marker}"
-    )
-endfunction()
diff --git a/nuget/Microsoft.WSL.Containers/cmake/Microsoft.WSL.ContainersConfig.cmake b/nuget/Microsoft.WSL.Containers/cmake/Microsoft.WSL.ContainersConfig.cmake
index 0ea5f0642..33dd180f7 100644
--- a/nuget/Microsoft.WSL.Containers/cmake/Microsoft.WSL.ContainersConfig.cmake
+++ b/nuget/Microsoft.WSL.Containers/cmake/Microsoft.WSL.ContainersConfig.cmake
@@ -55,3 +55,94 @@ unset(_wslcsdk_arch)
 unset(_wslcsdk_root)
 unset(_wslcsdk_include_dir)
 unset(_wslcsdk_lib_dir)
+
+# ============================================================================
+# Container Image Build Targets
+# ============================================================================
+#
+# Provides the wslc_add_image() function for declaring container image
+# build targets with incremental rebuild support.
+#
+# Usage:
+#   find_package(Microsoft.WSL.Containers REQUIRED)
+#
+#   wslc_add_image(
+#       NAME        my-server
+#       DOCKERFILE  container/Dockerfile
+#       CONTEXT     container/
+#       SOURCES     container/src/*.cpp container/src/*.h
+#       TAG         latest
+#       OUTPUT      ${CMAKE_BINARY_DIR}/images
+#   )
+#
+#   # With explicit image registry/name (IMAGE defaults to NAME if omitted):
+#   wslc_add_image(
+#       NAME        my-server
+#       IMAGE       ghcr.io/myorg/my-server
+#       TAG         v1.2.3
+#       DOCKERFILE  container/Dockerfile
+#       CONTEXT     container/
+#   )
+
+function(wslc_add_image)
+    cmake_parse_arguments(
+        PARSE_ARGV 0 ARG
+        ""                                      # options (none)
+        "NAME;IMAGE;TAG;DOCKERFILE;CONTEXT;OUTPUT" # one-value keywords
+        "SOURCES"                                # multi-value keywords
+    )
+
+    # Validate required arguments
+    if(NOT ARG_NAME)
+        message(FATAL_ERROR "wslc_add_image: NAME is required")
+    endif()
+    if(NOT ARG_DOCKERFILE)
+        message(FATAL_ERROR "wslc_add_image: DOCKERFILE is required")
+    endif()
+    if(NOT ARG_CONTEXT)
+        message(FATAL_ERROR "wslc_add_image: CONTEXT is required")
+    endif()
+
+    # Defaults
+    if(NOT ARG_IMAGE)
+        set(ARG_IMAGE "${ARG_NAME}")
+    endif()
+    if(NOT ARG_TAG)
+        set(ARG_TAG "latest")
+    endif()
+    if(NOT ARG_OUTPUT)
+        set(ARG_OUTPUT "${CMAKE_CURRENT_BINARY_DIR}")
+    endif()
+
+    # Find wslc CLI
+    if(NOT WSLC_CLI_PATH)
+        find_program(WSLC_CLI_PATH wslc PATHS "$ENV{ProgramW6432}/WSL" "$ENV{ProgramFiles}/WSL")
+        if(NOT WSLC_CLI_PATH)
+            message(FATAL_ERROR "wslc CLI not found. Install WSL by running: wsl --install --no-distribution")
+        endif()
+    endif()
+
+    set(_image_ref "${ARG_IMAGE}:${ARG_TAG}")
+    set(_marker "${CMAKE_CURRENT_BINARY_DIR}/wslc_${ARG_NAME}.marker")
+    # Uncomment when wslc image save is available:
+    # set(_tar_output "${ARG_OUTPUT}/${ARG_NAME}.tar")
+
+    # Resolve source globs to file lists
+    file(GLOB_RECURSE _resolved_sources CONFIGURE_DEPENDS ${ARG_SOURCES})
+
+    add_custom_command(
+        OUTPUT "${_marker}"
+        COMMAND "${WSLC_CLI_PATH}" image build -t "${_image_ref}" -f "${ARG_DOCKERFILE}" "${ARG_CONTEXT}"
+        # Uncomment when wslc image save is available:
+        # COMMAND ${CMAKE_COMMAND} -E make_directory "${ARG_OUTPUT}"
+        # COMMAND "${WSLC_CLI_PATH}" image save -o "${_tar_output}" "${_image_ref}"
+        COMMAND ${CMAKE_COMMAND} -E touch "${_marker}"
+        DEPENDS ${_resolved_sources} "${ARG_DOCKERFILE}"
+        COMMENT "WSLC: Building image '${_image_ref}'..."
+        VERBATIM
+    )
+
+    add_custom_target(wslc_image_${ARG_NAME} ALL
+        DEPENDS "${_marker}"
+    )
+endfunction()

From 955453955398822ac13fb3ae7656bf5738326c29 Mon Sep 17 00:00:00 2001
From: Shawn Yuan <128874481+shuaiyuanxx@users.noreply.github.com>
Date: Mon, 30 Mar 2026 17:06:39 +0800
Subject: [PATCH 7/8] Apply suggestion from @Copilot

Co-authored-by: Copilot <175728472+Copilot@users.noreply.github.com>
---
 .../build/native/Microsoft.WSL.Containers.targets               | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/nuget/Microsoft.WSL.Containers/build/native/Microsoft.WSL.Containers.targets b/nuget/Microsoft.WSL.Containers/build/native/Microsoft.WSL.Containers.targets
index f3d2a6868..daf072efe 100644
--- a/nuget/Microsoft.WSL.Containers/build/native/Microsoft.WSL.Containers.targets
+++ b/nuget/Microsoft.WSL.Containers/build/native/Microsoft.WSL.Containers.targets
@@ -41,7 +41,7 @@
         <ItemGroup>
             <_WslcTlogSourceDirs Include="$(_WslcSourceDir.Split(';'))" />
             <_WslcTlogInputs Include="$(_WslcDockerfile)" />
-            <_WslcTlogInputs Include="%(_WslcTlogSourceDirs.Identity)\**\*" />
+            <_WslcTlogInputs Condition="'%(_WslcTlogSourceDirs.Identity)' != ''" Include="%(_WslcTlogSourceDirs.Identity)\**\*" />
         </ItemGroup>
 
         <PropertyGroup>

From d3dc0e60c7a5d67611f97e0fd12995171c2edd42 Mon Sep 17 00:00:00 2001
From: Shawn Yuan <shuaiyuan@microsoft.com>
Date: Tue, 31 Mar 2026 09:43:45 +0800
Subject: [PATCH 8/8] remove comments for wslc save

---
 .../build/Microsoft.WSL.Containers.common.targets     |  9 ++-------
 .../build/native/Microsoft.WSL.Containers.targets     | 11 -----------
 .../cmake/Microsoft.WSL.ContainersConfig.cmake        | 10 ++++------
 3 files changed, 6 insertions(+), 24 deletions(-)

diff --git a/nuget/Microsoft.WSL.Containers/build/Microsoft.WSL.Containers.common.targets b/nuget/Microsoft.WSL.Containers/build/Microsoft.WSL.Containers.common.targets
index 9bb5a7d6d..810c31260 100644
--- a/nuget/Microsoft.WSL.Containers/build/Microsoft.WSL.Containers.common.targets
+++ b/nuget/Microsoft.WSL.Containers/build/Microsoft.WSL.Containers.common.targets
@@ -99,17 +99,15 @@
         <Exec Command="&quot;$(WslcCliPath)&quot; image build -t &quot;$(_WslcName):$(_WslcTag)&quot; -f &quot;$(_WslcDockerfile)&quot; &quot;$(_WslcContext)&quot;"
               ConsoleToMSBuild="true" />
 
-        <!--
-            Uncomment when wslc image save is available:
         <MakeDir Directories="$(_WslcOutput)" />
+
         <Exec Command="&quot;$(WslcCliPath)&quot; image save -o &quot;$(_WslcOutput)\$(_WslcName).tar&quot; &quot;$(_WslcName):$(_WslcTag)&quot;"
               ConsoleToMSBuild="true" />
-        -->
 
         <Touch Files="$(IntDir)wslc_$(_WslcName).marker" AlwaysCreate="true" />
 
         <Message Importance="high"
-                 Text="WSLC: [$(_WslcName)] Image '$(_WslcName):$(_WslcTag)' built successfully." />
+                 Text="WSLC: [$(_WslcName)] Image '$(_WslcName):$(_WslcTag)' saved to '$(_WslcOutput)\$(_WslcName).tar'." />
     </Target>
 
     <!-- Clean container artifacts -->
@@ -118,10 +116,7 @@
             Condition="'@(WslcImage)' != ''">
 
         <Delete Files="$(IntDir)wslc_%(WslcImage.Identity).marker" />
-        <!--
-            Uncomment when wslc image save is available:
         <Delete Files="%(WslcImage.OutputDir)\%(WslcImage.Identity).tar" />
-        -->
     </Target>
 
 </Project>
\ No newline at end of file
diff --git a/nuget/Microsoft.WSL.Containers/build/native/Microsoft.WSL.Containers.targets b/nuget/Microsoft.WSL.Containers/build/native/Microsoft.WSL.Containers.targets
index f3d2a6868..480d85e5e 100644
--- a/nuget/Microsoft.WSL.Containers/build/native/Microsoft.WSL.Containers.targets
+++ b/nuget/Microsoft.WSL.Containers/build/native/Microsoft.WSL.Containers.targets
@@ -47,10 +47,7 @@
         <PropertyGroup>
             <_WslcDockerfileFullPath>$([System.IO.Path]::GetFullPath('$(_WslcDockerfile)'))</_WslcDockerfileFullPath>
             <_WslcMarkerFullPath>$([System.IO.Path]::GetFullPath('$(IntDir)wslc_$(_WslcName).marker'))</_WslcMarkerFullPath>
-            <!--
-                Uncomment when wslc image save is available:
             <_WslcTarFullPath>$([System.IO.Path]::GetFullPath('$(WslcImageOutputDir)$(_WslcName).tar'))</_WslcTarFullPath>
-            -->
         </PropertyGroup>
 
         <WriteLinesToFile
@@ -59,19 +56,11 @@
             Overwrite="true"
             Encoding="Unicode" />
 
-        <!--
-            Uncomment when wslc image save is available, to track tar output:
         <WriteLinesToFile
             File="$(_WslcTlogDir)wslc.$(_WslcName).write.1.tlog"
             Lines="^$(_WslcDockerfileFullPath);$(_WslcMarkerFullPath);$(_WslcTarFullPath)"
             Overwrite="true"
             Encoding="Unicode" />
-        -->
-        <WriteLinesToFile
-            File="$(_WslcTlogDir)wslc.$(_WslcName).write.1.tlog"
-            Lines="^$(_WslcDockerfileFullPath);$(_WslcMarkerFullPath)"
-            Overwrite="true"
-            Encoding="Unicode" />
     </Target>
 
     <!-- Clean tlog files -->
diff --git a/nuget/Microsoft.WSL.Containers/cmake/Microsoft.WSL.ContainersConfig.cmake b/nuget/Microsoft.WSL.Containers/cmake/Microsoft.WSL.ContainersConfig.cmake
index 33dd180f7..07a38e4ae 100644
--- a/nuget/Microsoft.WSL.Containers/cmake/Microsoft.WSL.ContainersConfig.cmake
+++ b/nuget/Microsoft.WSL.Containers/cmake/Microsoft.WSL.ContainersConfig.cmake
@@ -124,8 +124,7 @@ function(wslc_add_image)
 
     set(_image_ref "${ARG_IMAGE}:${ARG_TAG}")
     set(_marker "${CMAKE_CURRENT_BINARY_DIR}/wslc_${ARG_NAME}.marker")
-    # Uncomment when wslc image save is available:
-    # set(_tar_output "${ARG_OUTPUT}/${ARG_NAME}.tar")
+    set(_tar_output "${ARG_OUTPUT}/${ARG_NAME}.tar")
 
     # Resolve source globs to file lists
     file(GLOB_RECURSE _resolved_sources CONFIGURE_DEPENDS ${ARG_SOURCES})
@@ -133,12 +132,11 @@ function(wslc_add_image)
     add_custom_command(
         OUTPUT "${_marker}"
         COMMAND "${WSLC_CLI_PATH}" image build -t "${_image_ref}" -f "${ARG_DOCKERFILE}" "${ARG_CONTEXT}"
-        # Uncomment when wslc image save is available:
-        # COMMAND ${CMAKE_COMMAND} -E make_directory "${ARG_OUTPUT}"
-        # COMMAND "${WSLC_CLI_PATH}" image save -o "${_tar_output}" "${_image_ref}"
+        COMMAND ${CMAKE_COMMAND} -E make_directory "${ARG_OUTPUT}"
+        COMMAND "${WSLC_CLI_PATH}" image save -o "${_tar_output}" "${_image_ref}"
         COMMAND ${CMAKE_COMMAND} -E touch "${_marker}"
         DEPENDS ${_resolved_sources} "${ARG_DOCKERFILE}"
-        COMMENT "WSLC: Building image '${_image_ref}'..."
+        COMMENT "WSLC: Building and saving image '${_image_ref}' to '${_tar_output}'..."
         VERBATIM
     )