Make skipping of unsupported projects off by default

src/Traversal.UnitTests/SolutionTests.cs

@@ -32,12 +32,12 @@ public void SolutionsCanSkipProjects()
             ProjectCreator.Templates.SolutionMetaproj(
                 TestRootPath,
                 new[] { projectA, projectB })
+                .Property("TraversalSkipUnsupportedProjects", bool.TrueString)
                 .TryBuild("Build", out bool result, out BuildOutput buildOutput, out IDictionary<string, TargetResult> targetOutputs);
 
             result.ShouldBeTrue();
 
-            buildOutput.Messages.High.ShouldHaveSingleItem()
-                .ShouldContain("Project B is skipped!");
+            buildOutput.Messages.High.ShouldContain(i => i.Contains("Project B is skipped!"));
 
             targetOutputs.TryGetValue("Build", out TargetResult buildTargetResult).ShouldBeTrue();
 

src/Traversal.UnitTests/TraversalTests.cs

@@ -432,12 +432,12 @@ public void TraversalsCanSkipProjects()
 
             ProjectCreator.Templates
                 .TraversalProject(new string[] { projectA, projectB }, path: GetTempFile("dirs.proj"))
+                .Property("TraversalSkipUnsupportedProjects", bool.TrueString)
                 .TryBuild("Build", out bool result, out BuildOutput buildOutput, out IDictionary<string, TargetResult> targetOutputs);
 
             result.ShouldBeTrue();
 
-            buildOutput.Messages.High.ShouldHaveSingleItem()
-                .ShouldContain("Project B is skipped!");
+            buildOutput.Messages.High.ShouldContain(i => i.Contains("Project B is skipped!"), buildOutput.GetConsoleLog());
 
             targetOutputs.TryGetValue("Build", out TargetResult buildTargetResult).ShouldBeTrue();
 
@@ -472,14 +472,7 @@ public void TraversalTargetsRun(string target)
 
             result.ShouldBeTrue(buildOutput.GetConsoleLog());
 
-            buildOutput.Messages.High.ShouldBe(
-                    new[]
-                    {
-                        "BF0C6E1044514FE3AE4B78EC308D6F45",
-                        "40869F4000B44D75A52AB305F24E0FDB",
-                    },
-                    ignoreOrder: true,
-                    buildOutput.GetConsoleLog());
+            buildOutput.Messages.High.ShouldContain(i => string.Equals(i, "BF0C6E1044514FE3AE4B78EC308D6F45") || string.Equals(i, "40869F4000B44D75A52AB305F24E0FDB"), buildOutput.GetConsoleLog());
         }
 
         [Theory]

src/Traversal/README.md

@@ -59,8 +59,15 @@ This allows you to pass MSBuild global properties to skip a particular project:
 msbuild /Property:DoNotBuildWebApp=true
 ```
 
-Another method is to add a `ShouldSkipProject` target to your `Directory.Build.targets`.  Use the target below as a template:
+Another method is to enable skipping of unsupported projects by setting the `TraversalSkipUnsupportedProjects` MSBuild property in `Directory.Build.props`:
 
+```xml
+<PropertyGroup>
+  <TraversalSkipUnsupportedProjects>true</TraversalSkipUnsupportedProjects>
+</PropertyGroup>
+```
+
+Then you define a `ShouldSkipProject` target to your `Directory.Build.targets` that skips projects if they are unsupported.  Use the target below as a template:
 ```xml
 <Target Name="ShouldSkipProject" Returns="@(ProjectToSkip)">
   <ItemGroup>
@@ -89,6 +96,9 @@ in the same folder of any solution with the following contents:
 Directory.Solution.props:
 ```xml
 <Project>
+  <PropertyGroup>
+    <TraversalSkipUnsupportedProjects>true</TraversalSkipUnsupportedProjects>
+  </PropertyGroup>
   <Import Project="Microsoft.Build.Traversal" Project="Sdk.props" />
 </Project>
 ```

src/Traversal/Sdk/Sdk.targets

@@ -13,7 +13,7 @@
 
   <Target Name="SkipProjects"
           DependsOnTargets="GetProjectsToSkip"
-          Condition="'$(SkipProjects)' != 'false'">
+          Condition="'$(TraversalSkipUnsupportedProjects)' == 'true'">
     <ItemGroup>
       <_NonExistentProjectToSkip Include="@(ProjectToSkip)" Condition="!Exists('%(ProjectToSkip.Identity)')"/>
       <ProjectReference Remove="%(ProjectToSkip.OriginalItemSpec)" />

src/Traversal/version.json

@@ -1,4 +1,4 @@
 {
   "inherit": true,
-  "version": "4.0"
+  "version": "4.1"
 }