C#: Guard against cyclic inclusions in project files

Author: hvitved

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

@@ -1020,5 +1020,27 @@ public void TestDirsProjLinux()
             var autobuilder = CreateAutoBuilder("csharp", false);
             TestAutobuilderScript(autobuilder, 0, 4);
         }
+
+        [Fact]
+        public void TestCyclicDirsProj()
+        {
+            Actions.FileExists["dirs.proj"] = true;
+            Actions.GetEnvironmentVariable["TRAP_FOLDER"] = null;
+            Actions.GetEnvironmentVariable["SOURCE_ARCHIVE"] = null;
+            Actions.FileExists["csharp.log"] = false;
+            Actions.EnumerateFiles[@"C:\Project"] = "dirs.proj";
+            Actions.EnumerateDirectories[@"C:\Project"] = "";
+
+            var dirsproj1 = new XmlDocument();
+            dirsproj1.LoadXml(@"<Project DefaultTargets=""Build"" xmlns=""http://schemas.microsoft.com/developer/msbuild/2003"" ToolsVersion=""3.5"">
+  <ItemGroup>
+    <ProjectFiles Include=""dirs.proj"" />
+  </ItemGroup>
+</Project>");
+            Actions.LoadXml["dirs.proj"] = dirsproj1;
+
+            var autobuilder = CreateAutoBuilder("csharp", false);
+            TestAutobuilderScript(autobuilder, 1, 0);
+        }
     }
 }

csharp/autobuilder/Semmle.Autobuild/Project.cs

@@ -23,13 +23,13 @@ public class Project : ProjectOrSolution
 
         public Version ToolsVersion { get; private set; }
 
-        readonly List<Project> includedProjects = new List<Project>();
-        public override IEnumerable<IProjectOrSolution> IncludedProjects =>
-            includedProjects.Concat(includedProjects.SelectMany(s => s.IncludedProjects));
+        readonly Lazy<List<Project>> includedProjectsLazy;
+        public override IEnumerable<IProjectOrSolution> IncludedProjects => includedProjectsLazy.Value;
 
         public Project(Autobuilder builder, string path) : base(builder, path)
         {
             ToolsVersion = new Version();
+            includedProjectsLazy = new Lazy<List<Project>>(() => new List<Project>());
 
             if (!builder.Actions.FileExists(FullPath))
                 return;
@@ -69,17 +69,22 @@ public Project(Autobuilder builder, string path) : base(builder, path)
                     }
                 }
 
-                // 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))
+                includedProjectsLazy = new Lazy<List<Project>>(() =>
                 {
-                    var includePath = builder.Actions.IsWindows() ? include.Value : include.Value.Replace("\\", "/");
-                    includedProjects.Add(new Project(builder, builder.Actions.PathCombine(Path.GetDirectoryName(this.FullPath), includePath)));
-                }
+                    var ret = new List<Project>();
+                    // 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("\\", "/");
+                        ret.Add(new Project(builder, builder.Actions.PathCombine(Path.GetDirectoryName(this.FullPath), includePath)));
+                    }
+                    return ret;
+                });
             }
         }
     }

csharp/autobuilder/Semmle.Autobuild/ProjectOrSolution.cs

@@ -15,7 +15,7 @@ public interface IProjectOrSolution
         string FullPath { get; }
 
         /// <summary>
-        /// Gets a list of other projects included by this file.
+        /// Gets a list of other projects directly included by this file.
         /// </summary>
         IEnumerable<IProjectOrSolution> IncludedProjects { get; }
     }
@@ -39,8 +39,16 @@ 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));
+        public static bool HasLanguage(this IProjectOrSolution p, Language l)
+        {
+            bool HasLanguage(IProjectOrSolution p0, HashSet<string> seen)
+            {
+                if (seen.Contains(p0.FullPath))
+                    return false;
+                seen.Add(p0.FullPath); // guard against cyclic includes
+                return l.ProjectFileHasThisLanguage(p0.FullPath) || p0.IncludedProjects.Any(p1 => HasLanguage(p1, seen));
+            }
+            return HasLanguage(p, new HashSet<string>());
+        }
     }
 }