C#: Recognize .proj files in autobuilder

When determining the target of `msbuild` or `dotnet build`, first look for `.proj`
files, then `.sln` files, and finally `.csproj`/`.vcxproj` files. In all three cases,
choose the project/solution file closest to the root.

csharp/autobuilder/Semmle.Autobuild.Tests/BuildScripts.cs

@@ -4,6 +4,7 @@ using System.Collections.Generic;
 using System;
 using System.Linq;
 using Microsoft.Build.Construction;
+using System.Xml;
 
 namespace Semmle.Extraction.Tests
 {
@@ -129,12 +130,24 @@ namespace Semmle.Extraction.Tests
 
         string IBuildActions.PathCombine(params string[] parts)
         {
-            return string.Join('\\', parts);
+            return string.Join('\\', parts.Where(p => !string.IsNullOrWhiteSpace(p)));
         }
 
+        string IBuildActions.GetFullPath(string path) => path;
+
+        string IBuildActions.GetDirectoryName(string path) => System.IO.Path.GetDirectoryName(path);
+
         void IBuildActions.WriteAllText(string filename, string contents)
         {
         }
+
+        public IDictionary<string, XmlDocument> LoadXml = new Dictionary<string, XmlDocument>();
+        XmlDocument IBuildActions.LoadXml(string filename)
+        {
+            if (LoadXml.TryGetValue(filename, out var xml))
+                return xml;
+            throw new ArgumentException("Missing LoadXml " + filename);
+        }
     }
 
     /// <summary>
@@ -142,23 +155,21 @@ namespace Semmle.Extraction.Tests
     /// </summary>
     class TestSolution : ISolution
     {
-        public IEnumerable<Project> Projects => throw new NotImplementedException();
-
         public IEnumerable<SolutionConfigurationInSolution> Configurations => throw new NotImplementedException();
 
         public string DefaultConfigurationName => "Release";
 
         public string DefaultPlatformName => "x86";
 
-        public string Path { get; set; }
-
-        public int ProjectCount => throw new NotImplementedException();
+        public string FullPath { get; set; }
 
         public Version ToolsVersion => new Version("14.0");
 
+        public IEnumerable<IProjectOrSolution> IncludedProjects => throw new NotImplementedException();
+
         public TestSolution(string path)
         {
-            Path = path;
+            FullPath = path;
         }
     }
 
@@ -318,11 +329,11 @@ namespace Semmle.Extraction.Tests
         }
 
         Autobuilder CreateAutoBuilder(string lgtmLanguage, bool isWindows,
-            string buildless=null, string solution=null, string buildCommand=null, string ignoreErrors=null,
-            string msBuildArguments=null, string msBuildPlatform=null, string msBuildConfiguration=null, string msBuildTarget=null,
-            string dotnetArguments=null, string dotnetVersion=null, string vsToolsVersion=null,
-            string nugetRestore=null, string allSolutions=null,
-            string cwd=@"C:\Project")
+            string buildless = null, string solution = null, string buildCommand = null, string ignoreErrors = null,
+            string msBuildArguments = null, string msBuildPlatform = null, string msBuildConfiguration = null, string msBuildTarget = null,
+            string dotnetArguments = null, string dotnetVersion = null, string vsToolsVersion = null,
+            string nugetRestore = null, string allSolutions = null,
+            string cwd = @"C:\Project")
         {
             Actions.GetEnvironmentVariable["SEMMLE_DIST"] = @"C:\odasa";
             Actions.GetEnvironmentVariable["SEMMLE_JAVA_HOME"] = @"C:\odasa\tools\java";
@@ -354,16 +365,26 @@ namespace Semmle.Extraction.Tests
         public void TestDefaultCSharpAutoBuilder()
         {
             Actions.RunProcess["cmd.exe /C dotnet --info"] = 0;
-            Actions.RunProcess["cmd.exe /C dotnet clean"] = 0;
-            Actions.RunProcess["cmd.exe /C dotnet restore"] = 0;
-            Actions.RunProcess[@"cmd.exe /C C:\odasa\tools\odasa index --auto dotnet build --no-incremental /p:UseSharedCompilation=false"] = 0;
+            Actions.RunProcess["cmd.exe /C dotnet clean test.csproj"] = 0;
+            Actions.RunProcess["cmd.exe /C dotnet restore test.csproj"] = 0;
+            Actions.RunProcess[@"cmd.exe /C C:\odasa\tools\odasa index --auto dotnet build --no-incremental /p:UseSharedCompilation=false test.csproj"] = 0;
             Actions.RunProcess[@"cmd.exe /C C:\odasa\tools\java\bin\java -jar C:\odasa\tools\extractor-asp.jar ."] = 0;
             Actions.RunProcess[@"cmd.exe /C C:\odasa\tools\odasa index --xml --extensions config csproj props xml"] = 0;
             Actions.FileExists["csharp.log"] = true;
+            Actions.FileExists["test.csproj"] = true;
             Actions.GetEnvironmentVariable["TRAP_FOLDER"] = null;
             Actions.GetEnvironmentVariable["SOURCE_ARCHIVE"] = null;
-            Actions.EnumerateFiles[@"C:\Project"] = "foo.cs\nbar.cs";
+            Actions.EnumerateFiles[@"C:\Project"] = "foo.cs\nbar.cs\ntest.csproj";
             Actions.EnumerateDirectories[@"C:\Project"] = "";
+            var xml = new XmlDocument();
+            xml.LoadXml(@"<Project Sdk=""Microsoft.NET.Sdk"">
+  <PropertyGroup>
+    <OutputType>Exe</OutputType>
+    <TargetFramework>netcoreapp2.1</TargetFramework>
+  </PropertyGroup>
+
+</Project>");
+            Actions.LoadXml["test.csproj"] = xml;
 
             var autobuilder = CreateAutoBuilder("csharp", true);
             TestAutobuilderScript(autobuilder, 0, 6);
@@ -373,16 +394,26 @@ namespace Semmle.Extraction.Tests
         public void TestLinuxCSharpAutoBuilder()
         {
             Actions.RunProcess["dotnet --info"] = 0;
-            Actions.RunProcess["dotnet clean"] = 0;
-            Actions.RunProcess["dotnet restore"] = 0;
-            Actions.RunProcess[@"C:\odasa\tools\odasa index --auto dotnet build --no-incremental /p:UseSharedCompilation=false"] = 0;
+            Actions.RunProcess["dotnet clean test.csproj"] = 0;
+            Actions.RunProcess["dotnet restore test.csproj"] = 0;
+            Actions.RunProcess[@"C:\odasa\tools\odasa index --auto dotnet build --no-incremental /p:UseSharedCompilation=false test.csproj"] = 0;
             Actions.RunProcess[@"C:\odasa\tools\java\bin\java -jar C:\odasa\tools\extractor-asp.jar ."] = 0;
             Actions.RunProcess[@"C:\odasa\tools\odasa index --xml --extensions config csproj props xml"] = 0;
             Actions.FileExists["csharp.log"] = true;
+            Actions.FileExists["test.csproj"] = true;
             Actions.GetEnvironmentVariable["TRAP_FOLDER"] = null;
             Actions.GetEnvironmentVariable["SOURCE_ARCHIVE"] = null;
-            Actions.EnumerateFiles[@"C:\Project"] = "foo.cs\ntest.cs";
+            Actions.EnumerateFiles[@"C:\Project"] = "foo.cs\ntest.cs\ntest.csproj";
             Actions.EnumerateDirectories[@"C:\Project"] = "";
+            var xml = new XmlDocument();
+            xml.LoadXml(@"<Project Sdk=""Microsoft.NET.Sdk"">
+  <PropertyGroup>
+    <OutputType>Exe</OutputType>
+    <TargetFramework>netcoreapp2.1</TargetFramework>
+  </PropertyGroup>
+
+</Project>");
+            Actions.LoadXml["test.csproj"] = xml;
 
             var autobuilder = CreateAutoBuilder("csharp", false);
             TestAutobuilderScript(autobuilder, 0, 6);
@@ -391,10 +422,6 @@ namespace Semmle.Extraction.Tests
         [Fact]
         public void TestLinuxCSharpAutoBuilderExtractorFailed()
         {
-            Actions.RunProcess["dotnet --info"] = 0;
-            Actions.RunProcess["dotnet clean"] = 0;
-            Actions.RunProcess["dotnet restore"] = 0;
-            Actions.RunProcess[@"C:\odasa\tools\odasa index --auto dotnet build --no-incremental /p:UseSharedCompilation=false"] = 0;
             Actions.FileExists["csharp.log"] = false;
             Actions.GetEnvironmentVariable["TRAP_FOLDER"] = null;
             Actions.GetEnvironmentVariable["SOURCE_ARCHIVE"] = null;
@@ -402,7 +429,7 @@ namespace Semmle.Extraction.Tests
             Actions.EnumerateDirectories[@"C:\Project"] = "";
 
             var autobuilder = CreateAutoBuilder("csharp", false);
-            TestAutobuilderScript(autobuilder, 1, 4);
+            TestAutobuilderScript(autobuilder, 1, 0);
         }
 
 
@@ -438,7 +465,7 @@ namespace Semmle.Extraction.Tests
 
             var autobuilder = CreateAutoBuilder("cpp", true);
             var solution = new TestSolution(@"C:\Project\test.sln");
-            autobuilder.SolutionsToBuild.Add(solution);
+            autobuilder.ProjectsOrSolutionsToBuild.Add(solution);
             TestAutobuilderScript(autobuilder, 0, 2);
         }
 
@@ -495,7 +522,7 @@ namespace Semmle.Extraction.Tests
             Actions.EnumerateFiles[@"C:\Project"] = "foo.cs\ntest.sln";
             Actions.EnumerateDirectories[@"C:\Project"] = "";
 
-            var autobuilder = CreateAutoBuilder("csharp", false, buildless:"true");
+            var autobuilder = CreateAutoBuilder("csharp", false, buildless: "true");
             TestAutobuilderScript(autobuilder, 0, 3);
         }
 
@@ -550,7 +577,7 @@ namespace Semmle.Extraction.Tests
             Assert.Equal(commandsRun, EndCallbackReturn.Count);
 
             var action = Actions.RunProcess.GetEnumerator();
-            for(int cmd=0; cmd<commandsRun; ++cmd)
+            for (int cmd = 0; cmd < commandsRun; ++cmd)
             {
                 Assert.True(action.MoveNext());
 
@@ -573,7 +600,7 @@ namespace Semmle.Extraction.Tests
 
             SkipVsWhere();
 
-            var autobuilder = CreateAutoBuilder("csharp", false, buildCommand:"./build.sh --skip-tests");
+            var autobuilder = CreateAutoBuilder("csharp", false, buildCommand: "./build.sh --skip-tests");
             TestAutobuilderScript(autobuilder, 0, 3);
         }
 
@@ -584,7 +611,6 @@ namespace Semmle.Extraction.Tests
             Actions.EnumerateDirectories[@"C:\Project"] = "";
             Actions.GetEnvironmentVariable["TRAP_FOLDER"] = null;
             Actions.GetEnvironmentVariable["SOURCE_ARCHIVE"] = null;
-            Actions.RunProcess["dotnet --info"] = 1;
             Actions.RunProcess["/bin/chmod u+x build/build.sh"] = 0;
             Actions.RunProcess[@"C:\odasa\tools\odasa index --auto build/build.sh"] = 0;
             Actions.RunProcessWorkingDirectory[@"C:\odasa\tools\odasa index --auto build/build.sh"] = "build";
@@ -593,7 +619,7 @@ namespace Semmle.Extraction.Tests
             Actions.FileExists["csharp.log"] = true;
 
             var autobuilder = CreateAutoBuilder("csharp", false);
-            TestAutobuilderScript(autobuilder, 0, 5);
+            TestAutobuilderScript(autobuilder, 0, 4);
         }
 
         [Fact]
@@ -604,14 +630,13 @@ namespace Semmle.Extraction.Tests
             Actions.GetEnvironmentVariable["TRAP_FOLDER"] = null;
             Actions.GetEnvironmentVariable["SOURCE_ARCHIVE"] = null;
 
-            Actions.RunProcess["dotnet --info"] = 1;
             Actions.RunProcess["/bin/chmod u+x build.sh"] = 0;
             Actions.RunProcess[@"C:\odasa\tools\odasa index --auto build.sh"] = 0;
             Actions.RunProcessWorkingDirectory[@"C:\odasa\tools\odasa index --auto build.sh"] = "";
             Actions.FileExists["csharp.log"] = false;
 
             var autobuilder = CreateAutoBuilder("csharp", false);
-            TestAutobuilderScript(autobuilder, 1, 3);
+            TestAutobuilderScript(autobuilder, 1, 2);
         }
 
         [Fact]
@@ -622,14 +647,13 @@ namespace Semmle.Extraction.Tests
             Actions.GetEnvironmentVariable["TRAP_FOLDER"] = null;
             Actions.GetEnvironmentVariable["SOURCE_ARCHIVE"] = null;
 
-            Actions.RunProcess["dotnet --info"] = 1;
             Actions.RunProcess["/bin/chmod u+x build.sh"] = 0;
             Actions.RunProcess[@"C:\odasa\tools\odasa index --auto build.sh"] = 5;
             Actions.RunProcessWorkingDirectory[@"C:\odasa\tools\odasa index --auto build.sh"] = "";
             Actions.FileExists["csharp.log"] = true;
 
             var autobuilder = CreateAutoBuilder("csharp", false);
-            TestAutobuilderScript(autobuilder, 1, 3);
+            TestAutobuilderScript(autobuilder, 1, 2);
         }
 
         [Fact]
@@ -639,7 +663,6 @@ namespace Semmle.Extraction.Tests
             Actions.EnumerateDirectories[@"C:\Project"] = "";
             Actions.GetEnvironmentVariable["TRAP_FOLDER"] = null;
             Actions.GetEnvironmentVariable["SOURCE_ARCHIVE"] = null;
-            Actions.RunProcess["cmd.exe /C dotnet --info"] = 1;
             Actions.RunProcess[@"cmd.exe /C C:\odasa\tools\odasa index --auto build.bat"] = 0;
             Actions.RunProcessWorkingDirectory[@"cmd.exe /C C:\odasa\tools\odasa index --auto build.bat"] = "";
             Actions.RunProcess[@"cmd.exe /C C:\odasa\tools\java\bin\java -jar C:\odasa\tools\extractor-asp.jar ."] = 0;
@@ -647,7 +670,7 @@ namespace Semmle.Extraction.Tests
             Actions.FileExists["csharp.log"] = true;
 
             var autobuilder = CreateAutoBuilder("csharp", true);
-            TestAutobuilderScript(autobuilder, 0, 4);
+            TestAutobuilderScript(autobuilder, 0, 3);
         }
 
         [Fact]
@@ -657,15 +680,14 @@ namespace Semmle.Extraction.Tests
             Actions.EnumerateDirectories[@"C:\Project"] = "";
             Actions.GetEnvironmentVariable["TRAP_FOLDER"] = null;
             Actions.GetEnvironmentVariable["SOURCE_ARCHIVE"] = null;
-            Actions.RunProcess["cmd.exe /C dotnet --info"] = 1;
             Actions.RunProcess[@"cmd.exe /C C:\odasa\tools\odasa index --auto build.bat"] = 1;
             Actions.RunProcessWorkingDirectory[@"cmd.exe /C C:\odasa\tools\odasa index --auto build.bat"] = "";
             Actions.RunProcess[@"cmd.exe /C C:\odasa\tools\java\bin\java -jar C:\odasa\tools\extractor-asp.jar ."] = 0;
             Actions.RunProcess[@"cmd.exe /C C:\odasa\tools\odasa index --xml --extensions config"] = 0;
             Actions.FileExists["csharp.log"] = true;
 
-            var autobuilder = CreateAutoBuilder("csharp", true, ignoreErrors:"true");
-            TestAutobuilderScript(autobuilder, 1, 2);
+            var autobuilder = CreateAutoBuilder("csharp", true, ignoreErrors: "true");
+            TestAutobuilderScript(autobuilder, 1, 1);
         }
 
         [Fact]
@@ -707,12 +729,12 @@ namespace Semmle.Extraction.Tests
             Actions.EnumerateFiles[@"C:\Project"] = "foo.cs\ntest1.cs\ntest2.cs";
             Actions.EnumerateDirectories[@"C:\Project"] = "";
 
-            var autobuilder = CreateAutoBuilder("csharp", true, msBuildArguments:"/P:Fu=Bar", msBuildTarget:"Windows", msBuildPlatform:"x86", msBuildConfiguration:"Debug",
-                vsToolsVersion:"12", allSolutions:"true");
+            var autobuilder = CreateAutoBuilder("csharp", true, msBuildArguments: "/P:Fu=Bar", msBuildTarget: "Windows", msBuildPlatform: "x86", msBuildConfiguration: "Debug",
+                vsToolsVersion: "12", allSolutions: "true");
             var testSolution1 = new TestSolution(@"C:\Project\test1.sln");
             var testSolution2 = new TestSolution(@"C:\Project\test2.sln");
-            autobuilder.SolutionsToBuild.Add(testSolution1);
-            autobuilder.SolutionsToBuild.Add(testSolution2);
+            autobuilder.ProjectsOrSolutionsToBuild.Add(testSolution1);
+            autobuilder.ProjectsOrSolutionsToBuild.Add(testSolution2);
 
             TestAutobuilderScript(autobuilder, 0, 6);
         }
@@ -737,8 +759,8 @@ namespace Semmle.Extraction.Tests
                 vsToolsVersion: "12", allSolutions: "true");
             var testSolution1 = new TestSolution(@"C:\Project\test1.sln");
             var testSolution2 = new TestSolution(@"C:\Project\test2.sln");
-            autobuilder.SolutionsToBuild.Add(testSolution1);
-            autobuilder.SolutionsToBuild.Add(testSolution2);
+            autobuilder.ProjectsOrSolutionsToBuild.Add(testSolution1);
+            autobuilder.ProjectsOrSolutionsToBuild.Add(testSolution2);
 
             TestAutobuilderScript(autobuilder, 1, 2);
         }
@@ -764,11 +786,11 @@ namespace Semmle.Extraction.Tests
 
             var autobuilder = CreateAutoBuilder("csharp", true, msBuildArguments: "/P:Fu=Bar", msBuildTarget: "Windows",
                 msBuildPlatform: "x86", msBuildConfiguration: "Debug", vsToolsVersion: "12",
-                allSolutions: "true", nugetRestore:"false");
+                allSolutions: "true", nugetRestore: "false");
             var testSolution1 = new TestSolution(@"C:\Project\test1.sln");
             var testSolution2 = new TestSolution(@"C:\Project\test2.sln");
-            autobuilder.SolutionsToBuild.Add(testSolution1);
-            autobuilder.SolutionsToBuild.Add(testSolution2);
+            autobuilder.ProjectsOrSolutionsToBuild.Add(testSolution1);
+            autobuilder.ProjectsOrSolutionsToBuild.Add(testSolution2);
 
             TestAutobuilderScript(autobuilder, 0, 4);
         }
@@ -785,7 +807,7 @@ namespace Semmle.Extraction.Tests
             Actions.EnumerateFiles[@"C:\Project"] = "foo.cs\ntest.sln";
             Actions.EnumerateDirectories[@"C:\Project"] = "";
 
-            var autobuilder = CreateAutoBuilder("csharp", false, buildless: "true", solution: "foo.sln", nugetRestore:"false");
+            var autobuilder = CreateAutoBuilder("csharp", false, buildless: "true", solution: "foo.sln", nugetRestore: "false");
             TestAutobuilderScript(autobuilder, 0, 3);
         }
 
@@ -794,18 +816,28 @@ namespace Semmle.Extraction.Tests
         public void TestSkipNugetDotnet()
         {
             Actions.RunProcess["dotnet --info"] = 0;
-            Actions.RunProcess["dotnet clean"] = 0;
-            Actions.RunProcess["dotnet restore"] = 0;
-            Actions.RunProcess[@"C:\odasa\tools\odasa index --auto dotnet build --no-incremental /p:UseSharedCompilation=false --no-restore"] = 0;
+            Actions.RunProcess["dotnet clean test.csproj"] = 0;
+            Actions.RunProcess["dotnet restore test.csproj"] = 0;
+            Actions.RunProcess[@"C:\odasa\tools\odasa index --auto dotnet build --no-incremental /p:UseSharedCompilation=false --no-restore test.csproj"] = 0;
             Actions.RunProcess[@"C:\odasa\tools\java\bin\java -jar C:\odasa\tools\extractor-asp.jar ."] = 0;
             Actions.RunProcess[@"C:\odasa\tools\odasa index --xml --extensions config csproj props xml"] = 0;
             Actions.FileExists["csharp.log"] = true;
+            Actions.FileExists["test.csproj"] = true;
             Actions.GetEnvironmentVariable["TRAP_FOLDER"] = null;
             Actions.GetEnvironmentVariable["SOURCE_ARCHIVE"] = null;
-            Actions.EnumerateFiles[@"C:\Project"] = "foo.cs\ntest.cs";
+            Actions.EnumerateFiles[@"C:\Project"] = "foo.cs\ntest.cs\ntest.csproj";
             Actions.EnumerateDirectories[@"C:\Project"] = "";
+            var xml = new XmlDocument();
+            xml.LoadXml(@"<Project Sdk=""Microsoft.NET.Sdk"">
+  <PropertyGroup>
+    <OutputType>Exe</OutputType>
+    <TargetFramework>netcoreapp2.1</TargetFramework>
+  </PropertyGroup>
 
-            var autobuilder = CreateAutoBuilder("csharp", false, dotnetArguments:"--no-restore");  // nugetRestore=false does not work for now.
+</Project>");
+            Actions.LoadXml["test.csproj"] = xml;
+
+            var autobuilder = CreateAutoBuilder("csharp", false, dotnetArguments: "--no-restore");  // nugetRestore=false does not work for now.
             TestAutobuilderScript(autobuilder, 0, 6);
         }
 
@@ -818,19 +850,29 @@ namespace Semmle.Extraction.Tests
             Actions.RunProcess[@"chmod u+x dotnet-install.sh"] = 0;
             Actions.RunProcess[@"./dotnet-install.sh --channel release --version 2.1.3 --install-dir C:\Project\.dotnet"] = 0;
             Actions.RunProcess[@"C:\Project\.dotnet\dotnet --info"] = 0;
-            Actions.RunProcess[@"C:\Project\.dotnet\dotnet clean"] = 0;
-            Actions.RunProcess[@"C:\Project\.dotnet\dotnet restore"] = 0;
-            Actions.RunProcess[@"C:\odasa\tools\odasa index --auto C:\Project\.dotnet\dotnet build --no-incremental /p:UseSharedCompilation=false"] = 0;
+            Actions.RunProcess[@"C:\Project\.dotnet\dotnet clean test.csproj"] = 0;
+            Actions.RunProcess[@"C:\Project\.dotnet\dotnet restore test.csproj"] = 0;
+            Actions.RunProcess[@"C:\odasa\tools\odasa index --auto C:\Project\.dotnet\dotnet build --no-incremental /p:UseSharedCompilation=false test.csproj"] = 0;
             Actions.RunProcess[@"C:\odasa\tools\java\bin\java -jar C:\odasa\tools\extractor-asp.jar ."] = 0;
             Actions.RunProcess[@"C:\odasa\tools\odasa index --xml --extensions config csproj props xml"] = 0;
             Actions.FileExists["csharp.log"] = true;
+            Actions.FileExists["test.csproj"] = true;
             Actions.GetEnvironmentVariable["TRAP_FOLDER"] = null;
             Actions.GetEnvironmentVariable["SOURCE_ARCHIVE"] = null;
             Actions.GetEnvironmentVariable["PATH"] = "/bin:/usr/bin";
-            Actions.EnumerateFiles[@"C:\Project"] = "foo.cs\ntest.cs";
+            Actions.EnumerateFiles[@"C:\Project"] = "foo.cs\ntest.cs\ntest.csproj";
             Actions.EnumerateDirectories[@"C:\Project"] = "";
+            var xml = new XmlDocument();
+            xml.LoadXml(@"<Project Sdk=""Microsoft.NET.Sdk"">
+  <PropertyGroup>
+    <OutputType>Exe</OutputType>
+    <TargetFramework>netcoreapp2.1</TargetFramework>
+  </PropertyGroup>
 
-            var autobuilder = CreateAutoBuilder("csharp", false, dotnetVersion:"2.1.3");
+</Project>");
+            Actions.LoadXml["test.csproj"] = xml;
+
+            var autobuilder = CreateAutoBuilder("csharp", false, dotnetVersion: "2.1.3");
             TestAutobuilderScript(autobuilder, 0, 10);
         }
 
@@ -843,17 +885,27 @@ namespace Semmle.Extraction.Tests
             Actions.RunProcess[@"chmod u+x dotnet-install.sh"] = 0;
             Actions.RunProcess[@"./dotnet-install.sh --channel release --version 2.1.3 --install-dir C:\Project\.dotnet"] = 0;
             Actions.RunProcess[@"C:\Project\.dotnet\dotnet --info"] = 0;
-            Actions.RunProcess[@"C:\Project\.dotnet\dotnet clean"] = 0;
-            Actions.RunProcess[@"C:\Project\.dotnet\dotnet restore"] = 0;
-            Actions.RunProcess[@"C:\odasa\tools\odasa index --auto C:\Project\.dotnet\dotnet build --no-incremental /p:UseSharedCompilation=false"] = 0;
+            Actions.RunProcess[@"C:\Project\.dotnet\dotnet clean test.csproj"] = 0;
+            Actions.RunProcess[@"C:\Project\.dotnet\dotnet restore test.csproj"] = 0;
+            Actions.RunProcess[@"C:\odasa\tools\odasa index --auto C:\Project\.dotnet\dotnet build --no-incremental /p:UseSharedCompilation=false test.csproj"] = 0;
             Actions.RunProcess[@"C:\odasa\tools\java\bin\java -jar C:\odasa\tools\extractor-asp.jar ."] = 0;
             Actions.RunProcess[@"C:\odasa\tools\odasa index --xml --extensions config csproj props xml"] = 0;
             Actions.FileExists["csharp.log"] = true;
+            Actions.FileExists["test.csproj"] = true;
             Actions.GetEnvironmentVariable["TRAP_FOLDER"] = null;
             Actions.GetEnvironmentVariable["SOURCE_ARCHIVE"] = null;
             Actions.GetEnvironmentVariable["PATH"] = "/bin:/usr/bin";
-            Actions.EnumerateFiles[@"C:\Project"] = "foo.cs\nbar.cs";
+            Actions.EnumerateFiles[@"C:\Project"] = "foo.cs\nbar.cs\ntest.csproj";
             Actions.EnumerateDirectories[@"C:\Project"] = "";
+            var xml = new XmlDocument();
+            xml.LoadXml(@"<Project Sdk=""Microsoft.NET.Sdk"">
+  <PropertyGroup>
+    <OutputType>Exe</OutputType>
+    <TargetFramework>netcoreapp2.1</TargetFramework>
+  </PropertyGroup>
+
+</Project>");
+            Actions.LoadXml["test.csproj"] = xml;
 
             var autobuilder = CreateAutoBuilder("csharp", false, dotnetVersion: "2.1.3");
             TestAutobuilderScript(autobuilder, 0, 10);
@@ -866,20 +918,109 @@ namespace Semmle.Extraction.Tests
             Actions.RunProcessOut["cmd.exe /C dotnet --list-sdks"] = "2.1.3 [C:\\Program Files\\dotnet\\sdks]\n2.1.4 [C:\\Program Files\\dotnet\\sdks]";
             Actions.RunProcess[@"cmd.exe /C powershell -NoProfile -ExecutionPolicy unrestricted -file C:\Project\install-dotnet.ps1 -Version 2.1.3 -InstallDir C:\Project\.dotnet"] = 0;
             Actions.RunProcess[@"cmd.exe /C C:\Project\.dotnet\dotnet --info"] = 0;
-            Actions.RunProcess[@"cmd.exe /C C:\Project\.dotnet\dotnet clean"] = 0;
-            Actions.RunProcess[@"cmd.exe /C C:\Project\.dotnet\dotnet restore"] = 0;
-            Actions.RunProcess[@"cmd.exe /C C:\odasa\tools\odasa index --auto C:\Project\.dotnet\dotnet build --no-incremental /p:UseSharedCompilation=false"] = 0;
+            Actions.RunProcess[@"cmd.exe /C C:\Project\.dotnet\dotnet clean test.csproj"] = 0;
+            Actions.RunProcess[@"cmd.exe /C C:\Project\.dotnet\dotnet restore test.csproj"] = 0;
+            Actions.RunProcess[@"cmd.exe /C C:\odasa\tools\odasa index --auto C:\Project\.dotnet\dotnet build --no-incremental /p:UseSharedCompilation=false test.csproj"] = 0;
             Actions.RunProcess[@"cmd.exe /C C:\odasa\tools\java\bin\java -jar C:\odasa\tools\extractor-asp.jar ."] = 0;
             Actions.RunProcess[@"cmd.exe /C C:\odasa\tools\odasa index --xml --extensions config csproj props xml"] = 0;
             Actions.FileExists["csharp.log"] = true;
+            Actions.FileExists["test.csproj"] = true;
             Actions.GetEnvironmentVariable["TRAP_FOLDER"] = null;
             Actions.GetEnvironmentVariable["SOURCE_ARCHIVE"] = null;
             Actions.GetEnvironmentVariable["PATH"] = "/bin:/usr/bin";
-            Actions.EnumerateFiles[@"C:\Project"] = "foo.cs\ntest.cs";
+            Actions.EnumerateFiles[@"C:\Project"] = "foo.cs\ntest.cs\ntest.csproj";
             Actions.EnumerateDirectories[@"C:\Project"] = "";
+            var xml = new XmlDocument();
+            xml.LoadXml(@"<Project Sdk=""Microsoft.NET.Sdk"">
+  <PropertyGroup>
+    <OutputType>Exe</OutputType>
+    <TargetFramework>netcoreapp2.1</TargetFramework>
+  </PropertyGroup>
+
+</Project>");
+            Actions.LoadXml["test.csproj"] = xml;
 
             var autobuilder = CreateAutoBuilder("csharp", true, dotnetVersion: "2.1.3");
             TestAutobuilderScript(autobuilder, 0, 8);
         }
+
+        [Fact]
+        public void TestDirsProjWindows()
+        {
+            Actions.RunProcess[@"cmd.exe /C C:\odasa\tools\csharp\nuget\nuget.exe restore dirs.proj"] = 1;
+            Actions.RunProcess["cmd.exe /C CALL ^\"C:\\Program Files ^(x86^)\\Microsoft Visual Studio 12.0\\VC\\vcvarsall.bat^\" && C:\\odasa\\tools\\odasa index --auto msbuild dirs.proj /p:UseSharedCompilation=false /t:Windows /p:Platform=\"x86\" /p:Configuration=\"Debug\" /p:MvcBuildViews=true /P:Fu=Bar"] = 0;
+            Actions.RunProcess[@"cmd.exe /C C:\odasa\tools\java\bin\java -jar C:\odasa\tools\extractor-asp.jar ."] = 0;
+            Actions.RunProcess[@"cmd.exe /C C:\odasa\tools\odasa index --xml --extensions config csproj props xml"] = 0;
+            Actions.FileExists["csharp.log"] = true;
+            Actions.FileExists[@"a\test.csproj"] = true;
+            Actions.FileExists["dirs.proj"] = true;
+            Actions.FileExists[@"C:\Program Files (x86)\Microsoft Visual Studio\Installer\vswhere.exe"] = false;
+            Actions.FileExists[@"C:\Program Files (x86)\Microsoft Visual Studio 14.0\VC\vcvarsall.bat"] = false;
+            Actions.FileExists[@"C:\Program Files (x86)\Microsoft Visual Studio 12.0\VC\vcvarsall.bat"] = true;
+            Actions.FileExists[@"C:\Program Files (x86)\Microsoft Visual Studio 11.0\VC\vcvarsall.bat"] = false;
+            Actions.FileExists[@"C:\Program Files (x86)\Microsoft Visual Studio 10.0\VC\vcvarsall.bat"] = true;
+
+            Actions.GetEnvironmentVariable["TRAP_FOLDER"] = null;
+            Actions.GetEnvironmentVariable["SOURCE_ARCHIVE"] = null;
+            Actions.EnumerateFiles[@"C:\Project"] = "a\\test.cs\na\\test.csproj\ndirs.proj";
+            Actions.EnumerateDirectories[@"C:\Project"] = "";
+
+            var csproj = new XmlDocument();
+            csproj.LoadXml(@"<?xml version=""1.0"" encoding=""utf - 8""?>
+  <Project ToolsVersion=""15.0"" xmlns=""http://schemas.microsoft.com/developer/msbuild/2003"">
+    <ItemGroup>
+      <Compile Include=""test.cs"" />
+    </ItemGroup>
+  </Project>");
+            Actions.LoadXml["a\\test.csproj"] = csproj;
+
+            var dirsproj = new XmlDocument();
+            dirsproj.LoadXml(@"<Project DefaultTargets=""Build"" xmlns=""http://schemas.microsoft.com/developer/msbuild/2003"" ToolsVersion=""3.5"">
+  <ItemGroup>
+    <ProjectFiles Include=""a\test.csproj"" />
+  </ItemGroup>
+</Project>");
+            Actions.LoadXml["dirs.proj"] = dirsproj;
+
+            var autobuilder = CreateAutoBuilder("csharp", true, msBuildArguments: "/P:Fu=Bar", msBuildTarget: "Windows", msBuildPlatform: "x86", msBuildConfiguration: "Debug",
+                vsToolsVersion: "12", allSolutions: "true");
+            TestAutobuilderScript(autobuilder, 0, 4);
+        }
+
+        [Fact]
+        public void TestDirsProjLinux()
+        {
+            Actions.RunProcess[@"mono C:\odasa\tools\csharp\nuget\nuget.exe restore dirs.proj"] = 1;
+            Actions.RunProcess[@"C:\odasa\tools\odasa index --auto msbuild dirs.proj /p:UseSharedCompilation=false /t:rebuild /p:MvcBuildViews=true"] = 0;
+            Actions.RunProcess[@"C:\odasa\tools\java\bin\java -jar C:\odasa\tools\extractor-asp.jar ."] = 0;
+            Actions.RunProcess[@"C:\odasa\tools\odasa index --xml --extensions config csproj props xml"] = 0;
+            Actions.FileExists["csharp.log"] = true;
+            Actions.FileExists["a/test.csproj"] = true;
+            Actions.FileExists["dirs.proj"] = true;
+            Actions.GetEnvironmentVariable["TRAP_FOLDER"] = null;
+            Actions.GetEnvironmentVariable["SOURCE_ARCHIVE"] = null;
+            Actions.EnumerateFiles[@"C:\Project"] = "a/test.cs\na/test.csproj\ndirs.proj";
+            Actions.EnumerateDirectories[@"C:\Project"] = "";
+
+            var csproj = new XmlDocument();
+            csproj.LoadXml(@"<?xml version=""1.0"" encoding=""utf - 8""?>
+  <Project ToolsVersion=""15.0"" xmlns=""http://schemas.microsoft.com/developer/msbuild/2003"">
+    <ItemGroup>
+      <Compile Include=""test.cs"" />
+    </ItemGroup>
+  </Project>");
+            Actions.LoadXml["a/test.csproj"] = csproj;
+
+            var dirsproj = new XmlDocument();
+            dirsproj.LoadXml(@"<Project DefaultTargets=""Build"" xmlns=""http://schemas.microsoft.com/developer/msbuild/2003"" ToolsVersion=""3.5"">
+  <ItemGroup>
+    <ProjectFiles Include=""a\test.csproj"" />
+  </ItemGroup>
+</Project>");
+            Actions.LoadXml["dirs.proj"] = dirsproj;
+
+            var autobuilder = CreateAutoBuilder("csharp", false);
+            TestAutobuilderScript(autobuilder, 0, 4);
+        }
     }
 }

csharp/autobuilder/Semmle.Autobuild/Autobuilder.cs

@@ -29,26 +29,32 @@ namespace Semmle.Autobuild
     public class Autobuilder
     {
         /// <summary>
-        /// Full file paths of files found in the project directory.
+        /// Full file paths of files found in the project directory, as well
+        /// their distance from the project root folder. The list is sorted
+        /// by distance in ascending order.
         /// </summary>
-        public IEnumerable<string> Paths => pathsLazy.Value;
-        readonly Lazy<IEnumerable<string>> pathsLazy;
+        public IEnumerable<(string, int)> Paths => pathsLazy.Value;
+        readonly Lazy<IEnumerable<(string, int)>> pathsLazy;
 
         /// <summary>
         /// Gets a list of paths matching a set of extensions
-        /// (including the ".").
+        /// (including the "."), as well their distance from the project root folder.
+        /// The list is sorted by distance in ascending order.
         /// </summary>
         /// <param name="extensions">The extensions to find.</param>
         /// <returns>The files matching the extension.</returns>
-        public IEnumerable<string> GetExtensions(params string[] extensions) =>
-            Paths.Where(p => extensions.Contains(Path.GetExtension(p)));
+        public IEnumerable<(string, int)> GetExtensions(params string[] extensions) =>
+            Paths.Where(p => extensions.Contains(Path.GetExtension(p.Item1)));
 
         /// <summary>
-        /// Gets all paths matching a particular filename.
+        /// Gets all paths matching a particular filename, as well
+        /// their distance from the project root folder.  The list is sorted
+        /// by distance in ascending order.
         /// </summary>
         /// <param name="name">The filename to find.</param>
         /// <returns>Possibly empty sequence of paths with the given filename.</returns>
-        public IEnumerable<string> GetFilename(string name) => Paths.Where(p => Path.GetFileName(p) == name);
+        public IEnumerable<(string, int)> GetFilename(string name) =>
+            Paths.Where(p => Path.GetFileName(p.Item1) == name);
 
         /// <summary>
         /// Holds if a given path, relative to the root of the source directory
@@ -59,30 +65,30 @@ namespace Semmle.Autobuild
         public bool HasRelativePath(string path) => HasPath(Actions.PathCombine(RootDirectory, path));
 
         /// <summary>
-        /// List of solution files to build.
+        /// List of project/solution files to build.
         /// </summary>
-        public IList<ISolution> SolutionsToBuild => solutionsToBuildLazy.Value;
-        readonly Lazy<IList<ISolution>> solutionsToBuildLazy;
+        public IList<IProjectOrSolution> ProjectsOrSolutionsToBuild => projectsOrSolutionsToBuildLazy.Value;
+        readonly Lazy<IList<IProjectOrSolution>> projectsOrSolutionsToBuildLazy;
 
         /// <summary>
         /// Holds if a given path was found.
         /// </summary>
         /// <param name="path">The path of the file.</param>
         /// <returns>True iff the path was found.</returns>
-        public bool HasPath(string path) => Paths.Any(p => path == p);
+        public bool HasPath(string path) => Paths.Any(p => path == p.Item1);
 
-        void FindFiles(string dir, int depth, IList<string> results)
+        void FindFiles(string dir, int depth, int maxDepth, IList<(string, int)> results)
         {
             foreach (var f in Actions.EnumerateFiles(dir))
             {
-                results.Add(f);
+                results.Add((f, depth));
             }
 
-            if (depth > 1)
+            if (depth < maxDepth)
             {
                 foreach (var d in Actions.EnumerateDirectories(dir))
                 {
-                    FindFiles(d, depth - 1, results);
+                    FindFiles(d, depth + 1, maxDepth, results);
                 }
             }
         }
@@ -113,46 +119,75 @@ namespace Semmle.Autobuild
             Actions = actions;
             Options = options;
 
-            pathsLazy = new Lazy<IEnumerable<string>>(() =>
+            pathsLazy = new Lazy<IEnumerable<(string, int)>>(() =>
             {
-                var files = new List<string>();
-                FindFiles(options.RootDirectory, options.SearchDepth, files);
-                return files.
-                    OrderBy(s => s.Count(c => c == Path.DirectorySeparatorChar)).
-                    ThenBy(s => Path.GetFileName(s).Length).
-                    ToArray();
+                var files = new List<(string, int)>();
+                FindFiles(options.RootDirectory, 0, options.SearchDepth, files);
+                return files.OrderBy(f => f.Item2).ToArray();
             });
 
-            solutionsToBuildLazy = new Lazy<IList<ISolution>>(() =>
+            projectsOrSolutionsToBuildLazy = new Lazy<IList<IProjectOrSolution>>(() =>
             {
                 if (options.Solution.Any())
                 {
-                    var ret = new List<ISolution>();
+                    var ret = new List<IProjectOrSolution>();
                     foreach (var solution in options.Solution)
                     {
                         if (actions.FileExists(solution))
                             ret.Add(new Solution(this, solution));
                         else
-                            Log(Severity.Error, "The specified solution file {0} was not found", solution);
+                            Log(Severity.Error, $"The specified solution file {solution} was not found");
                     }
                     return ret;
                 }
 
-                var solutions = GetExtensions(".sln").
-                        Select(s => new Solution(this, s)).
-                        Where(s => s.ProjectCount > 0).
-                        OrderByDescending(s => s.ProjectCount).
-                        ThenBy(s => s.Path.Length).
+                bool FindFiles(string extension, Func<string, ProjectOrSolution> create, out IEnumerable<IProjectOrSolution> files)
+                {
+                    var allFiles = GetExtensions(extension).
+                        Select(p => (ProjectOrSolution: create(p.Item1), DistanceFromRoot: p.Item2)).
+                        Where(p => p.ProjectOrSolution.HasLanguage(this.Options.Language)).
                         ToArray();
 
-                foreach (var sln in solutions)
-                {
-                    Log(Severity.Info, $"Found {sln.Path} with {sln.ProjectCount} {this.Options.Language} projects, version {sln.ToolsVersion}, config {string.Join(" ", sln.Configurations.Select(c => c.FullName))}");
+                    if (allFiles.Length == 0)
+                    {
+                        files = null;
+                        return false;
+                    }
+
+                    if (options.AllSolutions)
+                    {
+                        files = allFiles.Select(p => p.ProjectOrSolution);
+                        return true;
+                    }
+
+                    var firstIsClosest = allFiles.Length > 1 && allFiles[0].DistanceFromRoot < allFiles[1].DistanceFromRoot;
+                    if (allFiles.Length == 1 || firstIsClosest)
+                    {
+                        files = allFiles.Select(p => p.ProjectOrSolution).Take(1);
+                        return true;
+                    }
+
+                    var candidates = allFiles.
+                        Where(f => f.DistanceFromRoot == allFiles[0].DistanceFromRoot).
+                        Select(f => f.ProjectOrSolution);
+                    Log(Severity.Info, $"Found multiple '{extension}' files, giving up: {string.Join(", ", candidates)}.");
+                    files = new IProjectOrSolution[0];
+                    return true;
                 }
 
-                return new List<ISolution>(options.AllSolutions ?
-                    solutions :
-                    solutions.Take(1));
+                // First look for `.proj` files
+                if (FindFiles(".proj", f => new Project(this, f), out var ret1))
+                    return ret1.ToList();
+
+                // Then look for `.sln` files
+                if (FindFiles(".sln", f => new Solution(this, f), out var ret2))
+                    return ret2.ToList();
+
+                // Finally look for language specific project files, e.g. `.csproj` files
+                if (FindFiles(this.Options.Language.ProjectExtension, f => new Project(this, f), out var ret3))
+                    return ret3.ToList();
+
+                return new List<IProjectOrSolution>();
             });
 
             SemmleDist = Actions.GetEnvironmentVariable("SEMMLE_DIST");

csharp/autobuilder/Semmle.Autobuild/BuildActions.cs

@@ -3,6 +3,7 @@ using System;
 using System.Collections.Generic;
 using System.Diagnostics;
 using System.IO;
+using System.Xml;
 
 namespace Semmle.Autobuild
 {
@@ -96,12 +97,27 @@ namespace Semmle.Autobuild
         /// <returns>The combined path.</returns>
         string PathCombine(params string[] parts);
 
+        /// <summary>
+        /// Gets the full path for <paramref name="path"/>, Path.GetFullPath().
+        /// </summary>
+        string GetFullPath(string path);
+
+        /// <summary>
+        /// Gets the directory of <paramref name="path"/>, Path.GetDirectoryName().
+        /// </summary>
+        string GetDirectoryName(string path);
+
         /// <summary>
         /// Writes contents to file, File.WriteAllText().
         /// </summary>
         /// <param name="filename">The filename.</param>
         /// <param name="contents">The text.</param>
         void WriteAllText(string filename, string contents);
+
+        /// <summary>
+        /// Loads the XML document from <paramref name="filename"/>.
+        /// </summary>
+        XmlDocument LoadXml(string filename);
     }
 
     /// <summary>
@@ -167,10 +183,17 @@ namespace Semmle.Autobuild
 
         void IBuildActions.WriteAllText(string filename, string contents) => File.WriteAllText(filename, contents);
 
-        private SystemBuildActions()
+        XmlDocument IBuildActions.LoadXml(string filename)
         {
+            var ret = new XmlDocument();
+            ret.Load(filename);
+            return ret;
         }
 
+        string IBuildActions.GetFullPath(string path) => Path.GetFullPath(path);
+
+        string IBuildActions.GetDirectoryName(string path) => Path.GetDirectoryName(path);
+
         public static readonly IBuildActions Instance = new SystemBuildActions();
     }
 }

csharp/autobuilder/Semmle.Autobuild/BuildCommandAutoRule.cs

@@ -1,7 +1,6 @@
 using System.Collections.Generic;
 using System.IO;
 using System.Linq;
-using Semmle.Util;
 using Semmle.Util.Logging;
 
 namespace Semmle.Autobuild
@@ -32,7 +31,7 @@ namespace Semmle.Autobuild
 
             var extensions = builder.Actions.IsWindows() ? winExtensions : linuxExtensions;
             var scripts = buildScripts.SelectMany(s => extensions.Select(e => s + e));
-            var scriptPath = builder.Paths.Where(p => scripts.Any(p.ToLower().EndsWith)).OrderBy(p => p.Length).FirstOrDefault();
+            var scriptPath = builder.Paths.Where(p => scripts.Any(p.Item1.ToLower().EndsWith)).OrderBy(p => p.Item2).Select(p => p.Item1).FirstOrDefault();
 
             if (scriptPath == null)
                 return BuildScript.Failure;
@@ -41,12 +40,12 @@ namespace Semmle.Autobuild
             chmod.RunCommand("/bin/chmod", $"u+x {scriptPath}");
             var chmodScript = builder.Actions.IsWindows() ? BuildScript.Success : BuildScript.Try(chmod.Script);
 
-            var path = Path.GetDirectoryName(scriptPath);
+            var dir = builder.Actions.GetDirectoryName(scriptPath);
 
             // A specific .NET Core version may be required
             return chmodScript & DotNetRule.WithDotNet(builder, dotNet =>
             {
-                var command = new CommandBuilder(builder.Actions, path, dotNet?.Environment);
+                var command = new CommandBuilder(builder.Actions, dir, dotNet?.Environment);
 
                 // A specific Visual Studio version may be required
                 var vsTools = MsBuildRule.GetVcVarsBatFile(builder);

csharp/autobuilder/Semmle.Autobuild/DotNetRule.cs

@@ -4,6 +4,7 @@ using System.Linq;
 using Newtonsoft.Json.Linq;
 using System.Collections.Generic;
 using System.IO;
+using Semmle.Util;
 
 namespace Semmle.Autobuild
 {
@@ -15,46 +16,36 @@ namespace Semmle.Autobuild
     {
         public BuildScript Analyse(Autobuilder builder)
         {
-            builder.Log(Severity.Info, "Attempting to build using .NET Core");
+            if (!builder.ProjectsOrSolutionsToBuild.Any())
+                return BuildScript.Failure;
 
-            var projects = builder.SolutionsToBuild.Any()
-                ? builder.SolutionsToBuild.SelectMany(s => s.Projects).ToArray()
-                : builder.GetExtensions(Language.CSharp.ProjectExtension).Select(p => new Project(builder, p)).ToArray();
-
-            var notDotNetProject = projects.FirstOrDefault(p => !p.DotNetProject);
+            var notDotNetProject = builder.ProjectsOrSolutionsToBuild.
+                SelectMany(p => Enumerators.Singleton(p).Concat(p.IncludedProjects)).
+                OfType<Project>().
+                FirstOrDefault(p => !p.DotNetProject);
             if (notDotNetProject != null)
             {
                 builder.Log(Severity.Info, "Not using .NET Core because of incompatible project {0}", notDotNetProject);
                 return BuildScript.Failure;
             }
 
-            if (!builder.SolutionsToBuild.Any())
-                // Attempt dotnet build in root folder
-                return WithDotNet(builder, dotNet =>
-                    {
-                        var info = GetInfoCommand(builder.Actions, dotNet);
-                        var clean = GetCleanCommand(builder.Actions, dotNet).Script;
-                        var restore = GetRestoreCommand(builder.Actions, dotNet).Script;
-                        var build = GetBuildCommand(builder, dotNet).Script;
-                        return info & clean & BuildScript.Try(restore) & build;
-                    });
+            builder.Log(Severity.Info, "Attempting to build using .NET Core");
 
-            // Attempt dotnet build on each solution
             return WithDotNet(builder, dotNet =>
                 {
                     var ret = GetInfoCommand(builder.Actions, dotNet);
-                    foreach (var solution in builder.SolutionsToBuild)
+                    foreach (var projectOrSolution in builder.ProjectsOrSolutionsToBuild)
                     {
                         var cleanCommand = GetCleanCommand(builder.Actions, dotNet);
-                        cleanCommand.QuoteArgument(solution.Path);
+                        cleanCommand.QuoteArgument(projectOrSolution.FullPath);
                         var clean = cleanCommand.Script;
 
                         var restoreCommand = GetRestoreCommand(builder.Actions, dotNet);
-                        restoreCommand.QuoteArgument(solution.Path);
+                        restoreCommand.QuoteArgument(projectOrSolution.FullPath);
                         var restore = restoreCommand.Script;
 
                         var buildCommand = GetBuildCommand(builder, dotNet);
-                        buildCommand.QuoteArgument(solution.Path);
+                        buildCommand.QuoteArgument(projectOrSolution.FullPath);
                         var build = buildCommand.Script;
 
                         ret &= clean & BuildScript.Try(restore) & build;
@@ -110,7 +101,7 @@ namespace Semmle.Autobuild
             // See https://docs.microsoft.com/en-us/dotnet/core/tools/global-json
             var installScript = BuildScript.Success;
             var validGlobalJson = false;
-            foreach (var path in builder.Paths.Where(p => p.EndsWith("global.json", StringComparison.Ordinal)))
+            foreach (var path in builder.Paths.Select(p => p.Item1).Where(p => p.EndsWith("global.json", StringComparison.Ordinal)))
             {
                 string version;
                 try

csharp/autobuilder/Semmle.Autobuild/Language.cs

@@ -8,9 +8,6 @@
         public bool ProjectFileHasThisLanguage(string path) =>
             System.IO.Path.GetExtension(path) == ProjectExtension;
 
-        public static bool IsProjectFileForAnySupportedLanguage(string path) =>
-            Cpp.ProjectFileHasThisLanguage(path) || CSharp.ProjectFileHasThisLanguage(path);
-
         public readonly string ProjectExtension;
 
         private Language(string extension)

csharp/autobuilder/Semmle.Autobuild/MsBuildRule.cs

@@ -16,19 +16,19 @@ namespace Semmle.Autobuild
 
         public BuildScript Analyse(Autobuilder builder)
         {
-            builder.Log(Severity.Info, "Attempting to build using MSBuild");
-
-            if (!builder.SolutionsToBuild.Any())
-            {
-                builder.Log(Severity.Info, "Could not find a suitable solution file to build");
+            if (!builder.ProjectsOrSolutionsToBuild.Any())
                 return BuildScript.Failure;
-            }
+
+            builder.Log(Severity.Info, "Attempting to build using MSBuild");
 
             var vsTools = GetVcVarsBatFile(builder);
 
-            if (vsTools == null && builder.SolutionsToBuild.Any())
+            if (vsTools == null && builder.ProjectsOrSolutionsToBuild.Any())
             {
-                vsTools = BuildTools.FindCompatibleVcVars(builder.Actions, builder.SolutionsToBuild.First());
+                var firstSolution = builder.ProjectsOrSolutionsToBuild.OfType<ISolution>().FirstOrDefault();
+                vsTools = firstSolution != null
+                                ? BuildTools.FindCompatibleVcVars(builder.Actions, firstSolution)
+                                : BuildTools.VcVarsAllBatFiles(builder.Actions).OrderByDescending(b => b.ToolsVersion).FirstOrDefault();
             }
 
             if (vsTools == null && builder.Actions.IsWindows())
@@ -40,36 +40,42 @@ namespace Semmle.Autobuild
 
             var ret = BuildScript.Success;
 
-            foreach (var solution in builder.SolutionsToBuild)
+            foreach (var projectOrSolution in builder.ProjectsOrSolutionsToBuild)
             {
                 if (builder.Options.NugetRestore)
                 {
                     var nugetCommand = new CommandBuilder(builder.Actions).
                         RunCommand(nuget).
                         Argument("restore").
-                        QuoteArgument(solution.Path);
+                        QuoteArgument(projectOrSolution.FullPath);
                     ret &= BuildScript.Try(nugetCommand.Script);
                 }
 
                 var command = new CommandBuilder(builder.Actions);
 
                 if (vsTools != null)
-                {
                     command.CallBatFile(vsTools.Path);
-                }
 
                 command.IndexCommand(builder.Odasa, MsBuild);
-                command.QuoteArgument(solution.Path);
+                command.QuoteArgument(projectOrSolution.FullPath);
 
                 command.Argument("/p:UseSharedCompilation=false");
 
-                string target = builder.Options.MsBuildTarget != null ? builder.Options.MsBuildTarget : "rebuild";
-                string platform = builder.Options.MsBuildPlatform != null ? builder.Options.MsBuildPlatform : solution.DefaultPlatformName;
-                string configuration = builder.Options.MsBuildConfiguration != null ? builder.Options.MsBuildConfiguration : solution.DefaultConfigurationName;
+                string target = builder.Options.MsBuildTarget != null
+                                       ? builder.Options.MsBuildTarget
+                                       : "rebuild";
+                string platform = builder.Options.MsBuildPlatform != null
+                                         ? builder.Options.MsBuildPlatform
+                                         : projectOrSolution is ISolution s1 ? s1.DefaultPlatformName : null;
+                string configuration = builder.Options.MsBuildConfiguration != null
+                                              ? builder.Options.MsBuildConfiguration
+                                              : projectOrSolution is ISolution s2 ? s2.DefaultConfigurationName : null;
 
                 command.Argument("/t:" + target);
-                command.Argument(string.Format("/p:Platform=\"{0}\"", platform));
-                command.Argument(string.Format("/p:Configuration=\"{0}\"", configuration));
+                if (platform != null)
+                    command.Argument(string.Format("/p:Platform=\"{0}\"", platform));
+                if (configuration != null)
+                    command.Argument(string.Format("/p:Configuration=\"{0}\"", configuration));
                 command.Argument("/p:MvcBuildViews=true");
 
                 command.Argument(builder.Options.MsBuildArguments);

csharp/autobuilder/Semmle.Autobuild/Project.cs

@@ -1,16 +1,18 @@
 using System;
+using System.Collections.Generic;
 using System.IO;
+using System.Linq;
 using System.Xml;
 using Semmle.Util.Logging;
 
 namespace Semmle.Autobuild
 {
     /// <summary>
-    /// Representation of a .csproj (C#) or .vcxproj (C++) file.
+    /// Representation of a .proj file, a .csproj file (C#), or a .vcxproj file (C++).
     /// C# project files come in 2 flavours, .Net core and msbuild, but they
     /// have the same file extension.
     /// </summary>
-    public class Project
+    public class Project : ProjectOrSolution
     {
         /// <summary>
         /// Holds if this project is for .Net core.
@@ -21,18 +23,28 @@ namespace Semmle.Autobuild
 
         public Version ToolsVersion { get; private set; }
 
-        readonly string filename;
+        readonly List<Project> includedProjects = new List<Project>();
+        public override IEnumerable<IProjectOrSolution> IncludedProjects =>
+            includedProjects.Concat(includedProjects.SelectMany(s => s.IncludedProjects));
 
-        public Project(Autobuilder builder, string filename)
+        public Project(Autobuilder builder, string path) : base(builder, path)
         {
-            this.filename = filename;
             ToolsVersion = new Version();
 
-            if (!File.Exists(filename))
+            if (!builder.Actions.FileExists(FullPath))
                 return;
 
-            var projFile = new XmlDocument();
-            projFile.Load(filename);
+            XmlDocument projFile;
+            try
+            {
+                projFile = builder.Actions.LoadXml(FullPath);
+            }
+            catch (XmlException)
+            {
+                builder.Log(Severity.Info, $"Skipping project file {path} as it is not a valid XML document.");
+                return;
+            }
+
             var root = projFile.DocumentElement;
 
             if (root.Name == "Project")
@@ -40,30 +52,35 @@ namespace Semmle.Autobuild
                 if (root.HasAttribute("Sdk"))
                 {
                     DotNetProject = true;
+                    return;
                 }
-                else
+
+                var toolsVersion = root.GetAttribute("ToolsVersion");
+                if (!string.IsNullOrEmpty(toolsVersion))
                 {
-                    var toolsVersion = root.GetAttribute("ToolsVersion");
-                    if (string.IsNullOrEmpty(toolsVersion))
+                    try
                     {
-                        builder.Log(Severity.Warning, "Project {0} is missing a tools version", filename);
+                        ToolsVersion = new Version(toolsVersion);
+                        ValidToolsVersion = true;
                     }
-                    else
+                    catch   // Generic catch clause - Version constructor throws about 5 different exceptions.
                     {
-                        try
-                        {
-                            ToolsVersion = new Version(toolsVersion);
-                            ValidToolsVersion = true;
-                        }
-                        catch   // Generic catch clause - Version constructor throws about 5 different exceptions.
-                        {
-                            builder.Log(Severity.Warning, "Project {0} has invalid tools version {1}", filename, toolsVersion);
-                        }
+                        builder.Log(Severity.Warning, "Project {0} has invalid tools version {1}", path, toolsVersion);
                     }
                 }
+
+                // The documentation on `.proj` files is very limited, but it appears that both
+                // `<ProjectFile Include="X"/>` and `<ProjectFiles Include="X"/>` is valid
+                var mgr = new XmlNamespaceManager(projFile.NameTable);
+                mgr.AddNamespace("msbuild", "http://schemas.microsoft.com/developer/msbuild/2003");
+                var projectFileIncludes = root.SelectNodes("//msbuild:Project/msbuild:ItemGroup/msbuild:ProjectFile/@Include", mgr).OfType<XmlNode>();
+                var projectFilesIncludes = root.SelectNodes("//msbuild:Project/msbuild:ItemGroup/msbuild:ProjectFiles/@Include", mgr).OfType<XmlNode>();
+                foreach (var include in projectFileIncludes.Concat(projectFilesIncludes))
+                {
+                    var includePath = builder.Actions.IsWindows() ? include.Value : include.Value.Replace("\\", "/");
+                    includedProjects.Add(new Project(builder, builder.Actions.PathCombine(builder.Actions.GetDirectoryName(this.FullPath), includePath)));
+                }
             }
         }
-
-        public override string ToString() => filename;
     }
 }

csharp/autobuilder/Semmle.Autobuild/ProjectOrSolution.cs

@@ -0,0 +1,47 @@
+using System.Collections.Generic;
+using System.IO;
+using System.Linq;
+
+namespace Semmle.Autobuild
+{
+    /// <summary>
+    /// A file that can be the target in an invocation of `msbuild` or `dotnet build`.
+    /// Either a solution file or a project file (`.proj`, `.csproj`, or `.vcxproj`).
+    /// </summary>
+    public interface IProjectOrSolution
+    {
+        /// <summary>
+        /// Gets the full path of this file.
+        /// </summary>
+        string FullPath { get; }
+
+        /// <summary>
+        /// Gets a list of other projects included by this file.
+        /// </summary>
+        IEnumerable<IProjectOrSolution> IncludedProjects { get; }
+    }
+
+    public abstract class ProjectOrSolution : IProjectOrSolution
+    {
+        public string FullPath { get; private set; }
+
+        protected ProjectOrSolution(Autobuilder builder, string path)
+        {
+            FullPath = builder.Actions.GetFullPath(path);
+        }
+
+        public abstract IEnumerable<IProjectOrSolution> IncludedProjects { get; }
+
+        public override string ToString() => FullPath;
+    }
+
+    public static class IProjectOrSolutionExtensions
+    {
+        /// <summary>
+        /// Holds if this file includes a project with code from language <paramref name="l"/>.
+        /// </summary>
+        public static bool HasLanguage(this IProjectOrSolution p, Language l) =>
+            l.ProjectFileHasThisLanguage(p.FullPath) ||
+            p.IncludedProjects.Any(p0 => l.ProjectFileHasThisLanguage(p0.FullPath));
+    }
+}

csharp/autobuilder/Semmle.Autobuild/Solution.cs

@@ -10,15 +10,8 @@ namespace Semmle.Autobuild
     /// <summary>
     /// A solution file, extension .sln.
     /// </summary>
-    public interface ISolution
+    public interface ISolution : IProjectOrSolution
     {
-        /// <summary>
-        /// List of C# or C++ projects contained in the solution.
-        /// (There could be other project types as well - these are ignored.)
-        /// </summary>
-
-        IEnumerable<Project> Projects { get; }
-
         /// <summary>
         /// Solution configurations.
         /// </summary>
@@ -34,16 +27,6 @@ namespace Semmle.Autobuild
         /// </summary>
         string DefaultPlatformName { get; }
 
-        /// <summary>
-        /// The path of the solution file.
-        /// </summary>
-        string Path { get; }
-
-        /// <summary>
-        /// The number of C# or C++ projects.
-        /// </summary>
-        int ProjectCount { get; }
-
         /// <summary>
         /// Gets the "best" tools version for this solution.
         /// If there are several versions, because the project files
@@ -56,11 +39,12 @@ namespace Semmle.Autobuild
     /// <summary>
     /// A solution file on the filesystem, read using Microsoft.Build.
     /// </summary>
-    class Solution : ISolution
+    class Solution : ProjectOrSolution, ISolution
     {
         readonly SolutionFile solution;
 
-        public IEnumerable<Project>  Projects { get; private set; }
+        readonly IEnumerable<Project> includedProjects;
+        public override IEnumerable<IProjectOrSolution> IncludedProjects => includedProjects;
 
         public IEnumerable<SolutionConfigurationInSolution> Configurations =>
             solution == null ? Enumerable.Empty<SolutionConfigurationInSolution>() : solution.SolutionConfigurations;
@@ -71,18 +55,16 @@ namespace Semmle.Autobuild
         public string DefaultPlatformName =>
             solution == null ? "" : solution.GetDefaultPlatformName();
 
-        public Solution(Autobuilder builder, string path)
+        public Solution(Autobuilder builder, string path) : base(builder, path)
         {
-            Path = System.IO.Path.GetFullPath(path);
             try
             {
-                solution = SolutionFile.Parse(Path);
+                solution = SolutionFile.Parse(FullPath);
 
-                Projects =
+                includedProjects =
                     solution.ProjectsInOrder.
                     Where(p => p.ProjectType == SolutionProjectType.KnownToBeMSBuildFormat).
-                    Select(p => System.IO.Path.GetFullPath(FileUtils.ConvertToNative(p.AbsolutePath))).
-                    Where(p => builder.Options.Language.ProjectFileHasThisLanguage(p)).
+                    Select(p => builder.Actions.GetFullPath(FileUtils.ConvertToNative(p.AbsolutePath))).
                     Select(p => new Project(builder, p)).
                     ToArray();
             }
@@ -90,17 +72,11 @@ namespace Semmle.Autobuild
             {
                 // We allow specifying projects as solutions in lgtm.yml, so model
                 // that scenario as a solution with just that one project
-                Projects = Language.IsProjectFileForAnySupportedLanguage(Path)
-                    ? new[] { new Project(builder, Path) }
-                    : new Project[0];
+                includedProjects = new[] { new Project(builder, path) };
             }
         }
 
-        public string Path { get; private set; }
-
-        public int ProjectCount => Projects.Count();
-
-        IEnumerable<Version> ToolsVersions => Projects.Where(p => p.ValidToolsVersion).Select(p => p.ToolsVersion);
+        IEnumerable<Version> ToolsVersions => includedProjects.Where(p => p.ValidToolsVersion).Select(p => p.ToolsVersion);
 
         public Version ToolsVersion => ToolsVersions.Any() ? ToolsVersions.Max() : new Version();
     }