Add check to ensure vcpkg triplets match across projects

src/AppInstallerCLI.sln

@@ -1,7 +1,7 @@
 
 Microsoft Visual Studio Solution File, Format Version 12.00
-# Visual Studio Version 17
-VisualStudioVersion = 17.2.32630.192
+# Visual Studio Version 18
+VisualStudioVersion = 18.0.11205.157
 MinimumVisualStudioVersion = 10.0.40219.1
 Project("{C7167F0D-BC9F-4E6E-AFE1-012C56B48DB5}") = "AppInstallerCLIPackage", "AppInstallerCLIPackage\AppInstallerCLIPackage.wapproj", "{6AA3791A-0713-4548-A357-87A323E7AC3A}"
 	ProjectSection(ProjectDependencies) = postProject
@@ -37,7 +37,6 @@ Project("{2150E333-8FDC-42A3-9474-1A3956D46DE8}") = "Project", "Project", "{8D53
 		..\azure-pipelines.nuget.yml = ..\azure-pipelines.nuget.yml
 		..\azure-pipelines.yml = ..\azure-pipelines.yml
 		..\cgmanifest.json = ..\cgmanifest.json
-		Directory.Build.props = Directory.Build.props
 		Get-VcxprojNugetPackageVersions.ps1 = Get-VcxprojNugetPackageVersions.ps1
 		..\README.md = ..\README.md
 		..\doc\ReleaseNotes.md = ..\doc\ReleaseNotes.md
@@ -97,7 +96,9 @@ EndProject
 Project("{2150E333-8FDC-42A3-9474-1A3956D46DE8}") = "Solution Items", "Solution Items", "{1A5D7A7D-5CB2-47D5-B40D-4E61CAEDC798}"
 	ProjectSection(SolutionItems) = preProject
 		CodeAnalysis.ruleset = CodeAnalysis.ruleset
+		Directory.Build.props = Directory.Build.props
 		Directory.Packages.props = Directory.Packages.props
+		Directory.Solution.props = Directory.Solution.props
 		nuget.config = nuget.config
 		stylecop.json = stylecop.json
 		vcpkg.json = vcpkg.json
@@ -1043,11 +1044,8 @@ Global
 		{E5BCFF58-7D0C-4770-ABB9-AECE1027CD94}.Release|x86.ActiveCfg = Release|Win32
 		{E5BCFF58-7D0C-4770-ABB9-AECE1027CD94}.Release|x86.Build.0 = Release|Win32
 		{E5BCFF58-7D0C-4770-ABB9-AECE1027CD94}.ReleaseStatic|ARM64.ActiveCfg = Release|ARM64
-		{E5BCFF58-7D0C-4770-ABB9-AECE1027CD94}.ReleaseStatic|ARM64.Build.0 = Release|ARM64
 		{E5BCFF58-7D0C-4770-ABB9-AECE1027CD94}.ReleaseStatic|x64.ActiveCfg = Release|x64
-		{E5BCFF58-7D0C-4770-ABB9-AECE1027CD94}.ReleaseStatic|x64.Build.0 = Release|x64
 		{E5BCFF58-7D0C-4770-ABB9-AECE1027CD94}.ReleaseStatic|x86.ActiveCfg = Release|Win32
-		{E5BCFF58-7D0C-4770-ABB9-AECE1027CD94}.ReleaseStatic|x86.Build.0 = Release|Win32
 	EndGlobalSection
 	GlobalSection(SolutionProperties) = preSolution
 		HideSolutionNode = FALSE

src/Directory.Solution.props

@@ -0,0 +1,4 @@
+<!-- This file is automatically included in the (autogenerated) project file for the solution. -->
+<Project>
+    <Import Project="$(MSBuildProjectDirectory)\vcpkg.props" />
+</Project>

src/vcpkg.props

@@ -2,7 +2,7 @@
 <Project ToolsVersion="4.0" xmlns="http://schemas.microsoft.com/developer/msbuild/2003">
   <PropertyGroup Label="Vcpkg">
     <VcpkgEnableManifest>true</VcpkgEnableManifest>
-    <VcpkgInstalledDir>$(MSBuildThisFileDirectory)\vcpkg_installed</VcpkgInstalledDir>
+    <VcpkgInstalledDir>$(MSBuildThisFileDirectory)vcpkg_installed\</VcpkgInstalledDir>
   </PropertyGroup>
   <PropertyGroup Label="Vcpkg" Condition="'$(Configuration)|$(Platform)'=='Debug|x64'">
     <VcpkgTriplet>x64</VcpkgTriplet>
@@ -48,4 +48,47 @@
     <VcpkgTriplet>x86-fuzzing</VcpkgTriplet>
     <VcpkgConfiguration>Release</VcpkgConfiguration>
   </PropertyGroup>
+
+  <!-- vcpkg can only install ports for one triplet at a time, so we need to ensure that every project using vcpkg uses the same triplet.
+       If there is a triplet mismatch, the ports for one of the triplets will be deleted when installing a second one.
+       In parallel builds, this can lead to projects that use the first triplet not being able to find the headers or binaries, and cause an error. -->
+
+  <PropertyGroup>
+      <!-- The MSBuild process starts with the solution file, and each individual project is built recursively from there.
+           When building the .sln, we will write a file to indicate which triplet should be used in all projects.
+           Each project will later read this file to verify that it is using the same triplet. -->
+      <_IsBuildingSln>$(MSBuildProjectName.EndsWith('.sln'))</_IsBuildingSln>
+      <_TripletFile>$(VcpkgInstalledDir).solution-triplet</_TripletFile>
+  </PropertyGroup>
+
+  <Target Name="WriteSolutionTripletToFile"
+          BeforeTargets="Build"
+          Condition="'$(_IsBuildingSln)' == 'true'">
+    <WriteLinesToFile File="$(_TripletFile)" Lines="$(VcpkgTriplet)" Overwrite="true" />
+  </Target>
+
+  <!-- Note: Visual Studio does not build the .sln in the same way that MSBuild.exe does, so the above target is not executed.
+        In that case we try to write the file on the first project we build.
+        There is a race condition for parallel builds in doing this, but it won't happen on pipeline builds... -->
+  <Target Name="WriteProjectTripletToFile"
+          BeforeTargets="EnsureNoTripletMismatch"
+          Condition="!Exists('$(_TripletFile)')">
+    <WriteLinesToFile File="$(_TripletFile)" Lines="$(VcpkgTriplet)" Overwrite="true" />
+  </Target>
+
+  <Target Name="EnsureNoTripletMismatch"
+          BeforeTargets="PrepareForBuild"
+          Condition="'$(_IsBuildingSln)' != 'true'" >
+
+    <ReadLinesFromFile File="$(_TripletFile)">
+      <Output TaskParameter="Lines" ItemName="_TripletFileLines" />
+    </ReadLinesFromFile>
+
+    <PropertyGroup>
+      <_SolutionTriplet>@(_TripletFileLines)</_SolutionTriplet>
+    </PropertyGroup>
+
+    <Error Condition=" '$(_SolutionTriplet)' != '$(VcpkgTriplet)' "
+           Text="The vcpkg triplet '$(VcpkgTriplet)' selected for project '$(MSBuildProjectName)' does not match with the solution triplet '$(_SolutionTriplet)'. If you are building from Visual Studio, try deleting the file '$(_TripletFile)'." />
+  </Target>
 </Project>