Fix Solution Explorer repo grouping, filtering, and theming for merged VMR sites

src/SourceBrowser/TestCode/RepoB/RepoB2.slnx

@@ -0,0 +1,3 @@
+<Solution>
+  <Project Path="RepoBLib2/RepoBLib2.csproj" />
+</Solution>

src/SourceBrowser/TestCode/RepoB/RepoBLib2/RepoBLib2.csproj

@@ -0,0 +1,8 @@
+<Project Sdk="Microsoft.NET.Sdk">
+
+  <PropertyGroup>
+    <TargetFramework>net10.0</TargetFramework>
+    <Nullable>disable</Nullable>
+  </PropertyGroup>
+
+</Project>

src/SourceBrowser/TestCode/RepoB/RepoBLib2/Widget.cs

@@ -0,0 +1,21 @@
+namespace RepoBLib2
+{
+    /// <summary>
+    /// Lives in a second solution (RepoB2.slnx) under the same RepoB /repoPath, so the merged
+    /// site groups both RepoB solutions under a Solution Explorer solutionTitle node -- the only
+    /// place the multi-solution grouping (and its theming) is exercised.
+    /// </summary>
+    public class Widget
+    {
+        public string Describe() => WidgetInfo.Label;
+    }
+
+    /// <summary>
+    /// Referenced by <see cref="Widget"/> so RepoBLib2 has an indexed cross-symbol reference; without
+    /// one, Pass2's DiscoverProjects skips the assembly (no R folder) and it never reaches the site.
+    /// </summary>
+    public static class WidgetInfo
+    {
+        public static string Label => "RepoBLib2.Widget";
+    }
+}

src/SourceBrowser/TestCode/Vmr/Vmr.slnx

@@ -0,0 +1,5 @@
+<Solution>
+  <Project Path="VmrCore/VmrCore.csproj" />
+  <Project Path="src/SubRepoX/SubRepoX.csproj" />
+  <Project Path="src/SubRepoY/SubRepoY.csproj" />
+</Solution>

src/SourceBrowser/TestCode/Vmr/VmrCore/Core.cs

@@ -0,0 +1,16 @@
+namespace VmrCore
+{
+    /// <summary>
+    /// Sits directly under the Vmr root (not under any src/SubRepo* /repoPath), so per-project repo
+    /// resolution falls back to the whole input's tag (dotnet/vmr) -- the fallback arm of the fix.
+    /// </summary>
+    public class Core
+    {
+        public string Describe() => CoreInfo.Label;
+    }
+
+    public static class CoreInfo
+    {
+        public static string Label => "VmrCore.Core";
+    }
+}

src/SourceBrowser/TestCode/Vmr/VmrCore/VmrCore.csproj

@@ -0,0 +1,8 @@
+<Project Sdk="Microsoft.NET.Sdk">
+
+  <PropertyGroup>
+    <TargetFramework>net10.0</TargetFramework>
+    <Nullable>disable</Nullable>
+  </PropertyGroup>
+
+</Project>

src/SourceBrowser/TestCode/Vmr/src/SubRepoX/Alpha.cs

@@ -0,0 +1,16 @@
+namespace SubRepoX
+{
+    /// <summary>
+    /// Lives under Vmr/src/SubRepoX, tagged via a nested /repoPath to dotnet/subx even though it's part
+    /// of the single Vmr.slnx input -- the sub-repo case that used to inherit the parent's tag.
+    /// </summary>
+    public class Alpha
+    {
+        public string Describe() => AlphaInfo.Label;
+    }
+
+    public static class AlphaInfo
+    {
+        public static string Label => "SubRepoX.Alpha";
+    }
+}

src/SourceBrowser/TestCode/Vmr/src/SubRepoX/SubRepoX.csproj

@@ -0,0 +1,8 @@
+<Project Sdk="Microsoft.NET.Sdk">
+
+  <PropertyGroup>
+    <TargetFramework>net10.0</TargetFramework>
+    <Nullable>disable</Nullable>
+  </PropertyGroup>
+
+</Project>

src/SourceBrowser/TestCode/Vmr/src/SubRepoY/Beta.cs

@@ -0,0 +1,16 @@
+namespace SubRepoY
+{
+    /// <summary>
+    /// Lives under Vmr/src/SubRepoY, tagged via a nested /repoPath to dotnet/suby -- a second sub-repo
+    /// under the same input, so the merged site distinguishes subx/suby/vmr rather than one repo.
+    /// </summary>
+    public class Beta
+    {
+        public string Describe() => BetaInfo.Label;
+    }
+
+    public static class BetaInfo
+    {
+        public static string Label => "SubRepoY.Beta";
+    }
+}

src/SourceBrowser/TestCode/Vmr/src/SubRepoY/SubRepoY.csproj

@@ -0,0 +1,8 @@
+<Project Sdk="Microsoft.NET.Sdk">
+
+  <PropertyGroup>
+    <TargetFramework>net10.0</TargetFramework>
+    <Nullable>disable</Nullable>
+  </PropertyGroup>
+
+</Project>

src/SourceBrowser/src/HtmlGenerator.Tests/CommandLineOptionsTests.cs

@@ -112,6 +112,21 @@ public void Repo_meta_option_sets_both_repo_path_and_server_path_mappings()
             serverMapping.Value.ShouldBe("https://example.com/");
         }
 
+        [TestMethod]
+        public void Duplicate_repo_folder_with_different_urls_keeps_the_last_one()
+        {
+            // The VMR is listed as both dotnet/dotnet and dotnet-dotnet-windows, which resolve to one
+            // local checkout -- so the same folder gets two /repo: URLs. Last writer wins (a warning is
+            // logged naming the kept vs. ignored URL); the folder still maps to exactly one URL.
+            var options = CommandLineOptions.Parse(
+                "/repo:\"a\"=\"dotnet/dotnet\"=\"https://example.com/first/\"",
+                "/repo:\"a\"=\"dotnet/dotnet\"=\"https://example.com/second/\"");
+
+            var serverMapping = options.ServerPathMappings.ShouldHaveSingleItem();
+            serverMapping.Key.ShouldBe(Path.GetFullPath("a"));
+            serverMapping.Value.ShouldBe("https://example.com/second/");
+        }
+
         [TestMethod]
         public void Repo_meta_option_requires_all_three_segments()
         {

src/SourceBrowser/src/HtmlGenerator.Tests/ConfigAwareProjectFinalizerTests.cs

@@ -335,9 +335,9 @@ public void Finalize_GroupsSolutionExplorer_UnderRepoFolders_WhenTheMergedSiteSp
 
             var solutionExplorerHtml = File.ReadAllText(Path.Combine(websiteDestinationFolder, Constants.SolutionExplorer + ".html"));
 
-            solutionExplorerHtml.Contains("<div class=\"folderTitle repoTitle\" data-repo=\"ClangSharp\">ClangSharp</div>").ShouldBeTrue(
+            solutionExplorerHtml.Contains("<div class=\"folderTitle repoTitle\" data-repo=\"ClangSharp\" data-repo-path=\"ClangSharp\">ClangSharp</div>").ShouldBeTrue(
                 "Utils must be nested under a ClangSharp repo folder now that the merged site spans two repos. Actual: " + solutionExplorerHtml);
-            solutionExplorerHtml.Contains("<div class=\"folderTitle repoTitle\" data-repo=\"LLVMSharp\">LLVMSharp</div>").ShouldBeTrue(
+            solutionExplorerHtml.Contains("<div class=\"folderTitle repoTitle\" data-repo=\"LLVMSharp\" data-repo-path=\"LLVMSharp\">LLVMSharp</div>").ShouldBeTrue(
                 "App must be nested under an LLVMSharp repo folder now that the merged site spans two repos. Actual: " + solutionExplorerHtml);
         }
 

src/SourceBrowser/src/HtmlGenerator.Tests/SerializationUnitTests.cs

@@ -68,8 +68,8 @@ public void WriteProjectMap_adds_repo_and_solution_fields_when_any_assembly_is_t
                 var lineA = lines.Single(l => l.StartsWith("A;", StringComparison.Ordinal));
                 var lineB = lines.Single(l => l.StartsWith("B;", StringComparison.Ordinal));
 
-                Assert.AreEqual("A;0;1;clangsharp;ClangSharp", lineA);
-                Assert.AreEqual("B;1;0;;", lineB);
+                Assert.AreEqual("A;0;1;clangsharp;ClangSharp;clangsharp", lineA);
+                Assert.AreEqual("B;1;0;;;", lineB);
             }
             finally
             {

src/SourceBrowser/src/HtmlGenerator.Tests/SolutionExplorerGroupingTests.cs

@@ -78,5 +78,90 @@ public void Repeated_calls_for_the_same_repo_reuse_the_same_folder_node()
             first.ShouldBeSameAs(second);
             root.Folders.Count.ShouldBe(1);
         }
+
+        [TestMethod]
+        public void ResolveRepoName_prefers_the_most_specific_nested_mapping()
+        {
+            // A single VMR-style input rooted at the parent folder, with nested sub-repo mappings: each
+            // project must tag to the deepest mapping containing its own folder, not the parent's.
+            var mappings = new Dictionary<string, string>
+            {
+                [@"C:\vmr"] = "dotnet/vmr",
+                [@"C:\vmr\src\arcade"] = "dotnet/arcade",
+                [@"C:\vmr\src\roslyn"] = "dotnet/roslyn",
+            };
+
+            Program.ResolveRepoName(@"C:\vmr\src\arcade\src\Foo\Foo.csproj", mappings, "dotnet/vmr").ShouldBe("dotnet/arcade");
+            Program.ResolveRepoName(@"C:\vmr\src\roslyn\Bar\Bar.csproj", mappings, "dotnet/vmr").ShouldBe("dotnet/roslyn");
+        }
+
+        [TestMethod]
+        public void ResolveRepoName_falls_back_to_the_input_tag_outside_any_nested_mapping()
+        {
+            var mappings = new Dictionary<string, string>
+            {
+                [@"C:\vmr"] = "dotnet/vmr",
+                [@"C:\vmr\src\arcade"] = "dotnet/arcade",
+            };
+
+            // Directly under the VMR root but not under any sub-repo -> the whole input's tag.
+            Program.ResolveRepoName(@"C:\vmr\eng\Build\Build.csproj", mappings, "dotnet/vmr").ShouldBe("dotnet/vmr");
+            // No mapping contains it and no fallback -> untagged.
+            Program.ResolveRepoName(@"C:\other\Baz\Baz.csproj", mappings, "").ShouldBe("");
+        }
+
+        [TestMethod]
+        public void ResolveRepoChain_returns_the_full_ancestry_outermost_first()
+        {
+            var mappings = new Dictionary<string, string>
+            {
+                [@"C:\vmr"] = "dotnet/vmr",
+                [@"C:\vmr\src\arcade"] = "dotnet/arcade",
+            };
+
+            // A sub-repo project carries both its parent (vmr) and its own repo (arcade), parent first.
+            Program.ResolveRepoChain(@"C:\vmr\src\arcade\src\Foo\Foo.csproj", mappings, "dotnet/vmr")
+                .ShouldBe(new[] { "dotnet/vmr", "dotnet/arcade" });
+
+            // A project only under the VMR root is a single-element chain of just the parent.
+            Program.ResolveRepoChain(@"C:\vmr\eng\Build\Build.csproj", mappings, "dotnet/vmr")
+                .ShouldBe(new[] { "dotnet/vmr" });
+        }
+
+        [TestMethod]
+        public void ResolveRepoChain_falls_back_to_the_input_tag_or_empty()
+        {
+            var mappings = new Dictionary<string, string>
+            {
+                [@"C:\vmr\src\arcade"] = "dotnet/arcade",
+            };
+
+            // No mapping contains it -> single-element fallback chain.
+            Program.ResolveRepoChain(@"C:\other\Baz\Baz.csproj", mappings, "dotnet/vmr")
+                .ShouldBe(new[] { "dotnet/vmr" });
+            // No mapping and no fallback -> untagged (empty chain).
+            Program.ResolveRepoChain(@"C:\other\Baz\Baz.csproj", mappings, "").ShouldBeEmpty();
+        }
+
+        [TestMethod]
+        public void Nested_repo_chain_groups_a_sub_repo_under_its_parent_repo_folder()
+        {
+            var root = new Folder<ProjectSkeleton>();
+            var solutionCounts = new Dictionary<string, int> { ["dotnet/subx"] = 1 };
+
+            var folder = Program.GetSolutionExplorerGroupingFolder(
+                root, new[] { "dotnet/vmr", "dotnet/subx" }, "SubX", distinctRepoCount: 3, solutionCounts);
+
+            // The sub-repo folder is nested under its parent repo folder, each carrying its own ancestry.
+            var vmrFolder = root.Folders["dotnet/vmr"];
+            vmrFolder.Kind.ShouldBe(FolderKind.Repo);
+            vmrFolder.RepoChain.ShouldBe(new[] { "dotnet/vmr" });
+
+            var subxFolder = vmrFolder.Folders["dotnet/subx"];
+            subxFolder.ShouldBeSameAs(folder);
+            subxFolder.Kind.ShouldBe(FolderKind.Repo);
+            subxFolder.RepoName.ShouldBe("dotnet/subx");
+            subxFolder.RepoChain.ShouldBe(new[] { "dotnet/vmr", "dotnet/subx" });
+        }
     }
 }

src/SourceBrowser/src/HtmlGenerator/CommandLineOptions.cs

@@ -157,6 +157,22 @@ public static CommandLineOptions Parse(params string[] args)
             var configAxes = new Dictionary<string, string>(StringComparer.OrdinalIgnoreCase);
             var mergeConfigsOnly = false;
 
+            // Both /serverPath: and /repo: map a local repo folder to a source-link base URL, keyed by
+            // that folder. Mapping the same folder twice with different URLs (e.g. the VMR listed as both
+            // dotnet/dotnet and dotnet-dotnet-windows, resolving to one checkout) is last-writer-wins, so
+            // warn which URL is kept and which is dropped rather than silently losing one.
+            void MapServerPath(string folder, string url)
+            {
+                if (serverPathMappings.TryGetValue(folder, out var existing) && existing != url)
+                {
+                    Log.Write(
+                        $"Duplicate server URL for repo folder '{folder}': keeping '{url}' (last wins), ignoring '{existing}'.",
+                        ConsoleColor.Yellow);
+                }
+
+                serverPathMappings[folder] = url;
+            }
+
             foreach (var arg in args)
             {
                 if (arg.StartsWith("/out:", StringComparison.Ordinal))
@@ -190,7 +206,7 @@ public static CommandLineOptions Parse(params string[] args)
                         continue;
                     }
 
-                    serverPathMappings[Path.GetFullPath(match.Groups["from"].Value)] = match.Groups["to"].Value;
+                    MapServerPath(Path.GetFullPath(match.Groups["from"].Value), match.Groups["to"].Value);
                     continue;
                 }
 
@@ -240,7 +256,7 @@ public static CommandLineOptions Parse(params string[] args)
 
                     var repoFolder = Path.GetFullPath(match.Groups["from"].Value);
                     repoPathMappings[repoFolder] = match.Groups["name"].Value;
-                    serverPathMappings[repoFolder] = match.Groups["to"].Value;
+                    MapServerPath(repoFolder, match.Groups["to"].Value);
                     continue;
                 }
 

src/SourceBrowser/src/HtmlGenerator/Pass1-Generation/GenerateFromBuildLog.cs

@@ -23,7 +23,10 @@ public static async Task GenerateInvocationAsync(CompilerInvocation invocation,
             Dictionary<(string, string), string> typeForwards = null,
             bool includeSourceGeneratedDocuments = true,
             string repoName = "",
-            string solutionName = "")
+            string solutionName = "",
+            IReadOnlyDictionary<string, string> repoPathMappings = null,
+            int distinctRepoCount = 0,
+            IReadOnlyDictionary<string, int> solutionCountsByRepo = null)
         {
             try
             {
@@ -48,6 +51,9 @@ public static async Task GenerateInvocationAsync(CompilerInvocation invocation,
                     solutionGenerator.GlobalAssemblyList = assemblyNames;
                     solutionGenerator.RepoName = repoName ?? string.Empty;
                     solutionGenerator.SolutionName = solutionName ?? string.Empty;
+                    solutionGenerator.RepoPathMappings = repoPathMappings;
+                    solutionGenerator.DistinctRepoCount = distinctRepoCount;
+                    solutionGenerator.SolutionCountsByRepo = solutionCountsByRepo;
                     await solutionGenerator.GenerateAsync(cancellationToken, processedAssemblyList, solutionExplorerRoot);
                 }
                 else
@@ -60,6 +66,9 @@ public static async Task GenerateInvocationAsync(CompilerInvocation invocation,
                         typeForwards: typeForwards);
                     solutionGenerator.RepoName = repoName ?? string.Empty;
                     solutionGenerator.SolutionName = solutionName ?? string.Empty;
+                    solutionGenerator.RepoPathMappings = repoPathMappings;
+                    solutionGenerator.DistinctRepoCount = distinctRepoCount;
+                    solutionGenerator.SolutionCountsByRepo = solutionCountsByRepo;
                     await solutionGenerator.GenerateAsync(cancellationToken);
                 }
             }

src/SourceBrowser/src/HtmlGenerator/Pass1-Generation/ProjectGenerator.ProjectInfo.cs

@@ -31,6 +31,14 @@ private void GenerateProjectInfo()
                 sb.Append("RepoName=").AppendLine(RepoName);
             }
 
+            // Full repo ancestry (outermost first, own repo last), '|'-joined -- lets a parent repo
+            // include its nested sub-repos in filtering/grouping. '|' can't occur in an owner/repo name,
+            // so it stays a safe field separator here and in Assemblies.txt.
+            if (RepoChain is { Count: > 0 })
+            {
+                sb.Append("RepoChain=").AppendLine(string.Join("|", RepoChain));
+            }
+
             if (!string.IsNullOrEmpty(SolutionName))
             {
                 sb.Append("SolutionName=").AppendLine(SolutionName);

src/SourceBrowser/src/HtmlGenerator/Pass1-Generation/ProjectGenerator.cs

@@ -27,8 +27,14 @@ public partial class ProjectGenerator
         public string ProjectSourcePath { get; set; }
         public string ProjectFilePath { get; private set; }
 
-        /// <summary>Repo/solution tags inherited from the owning SolutionGenerator, if any.</summary>
-        public string RepoName => SolutionGenerator?.RepoName ?? string.Empty;
+        /// <summary>Repo tag resolved per project from the owning SolutionGenerator's /repoPath
+        /// mappings (falling back to its per-input tag); solution tag is inherited as-is.</summary>
+        public string RepoName => SolutionGenerator?.ResolveRepoName(ProjectFilePath) ?? string.Empty;
+
+        /// <summary>Repo ancestry resolved per project (outermost repo first, own repo last), so a
+        /// parent repo can include its nested sub-repos in filtering/grouping. See
+        /// <see cref="SolutionGenerator.ResolveRepoChain"/>.</summary>
+        public IReadOnlyList<string> RepoChain => SolutionGenerator?.ResolveRepoChain(ProjectFilePath) ?? (IReadOnlyList<string>)System.Array.Empty<string>();
         public string SolutionName => SolutionGenerator?.SolutionName ?? string.Empty;
         public List<string> OtherFiles { get; set; }
         public IEnumerable<MEF.ISymbolVisitor> PluginSymbolVisitors { get; private set; }

src/SourceBrowser/src/HtmlGenerator/Pass1-Generation/SolutionGenerator.SolutionExplorer.cs

@@ -51,6 +51,18 @@ private void AddProjectToFolder(Folder folder, Project project, IEnumerable<stri
         {
             var folderList = folders?.ToArray() ?? Array.Empty<string>();
 
+            // Repo/Solution grouping is per project: a single input can span several repos (e.g. a VMR
+            // whose sub-repos are tagged via nested /repoPath), so descend this project's full repo
+            // ancestry (parent repo -> sub-repo) before laying down the .sln folder chain underneath it.
+            var repoChain = ResolveRepoChain(project.FilePath);
+            var repoName = repoChain.Count > 0 ? repoChain[repoChain.Count - 1] : string.Empty;
+            folder = Program.GetSolutionExplorerGroupingFolder(folder, repoChain, SolutionName, DistinctRepoCount, SolutionCountsByRepo);
+
+            AddProjectToFolderCore(folder, project, folderList, repoName, repoChain);
+        }
+
+        private void AddProjectToFolderCore(Folder folder, Project project, string[] folderList, string repoName, IReadOnlyList<string> repoChain)
+        {
             // Additive persistence only -- see Constants.SolutionFolderFileName. Written regardless of
             // whether the project ends up nested or at the root (empty file = root), and is best-effort:
             // a project this Pass1 run didn't actually generate output for (e.g. it was filtered out
@@ -64,12 +76,12 @@ private void AddProjectToFolder(Folder folder, Project project, IEnumerable<stri
 
             if (folderList.Length == 0)
             {
-                folder.Add(new ProjectSkeleton(project.AssemblyName, project.Name, RepoName));
+                folder.Add(new ProjectSkeleton(project.AssemblyName, project.Name, repoName, repoChain));
             }
             else
             {
                 var subfolder = folder.GetOrCreateFolder(folderList[0]);
-                AddProjectToFolder(subfolder, project, folderList.Skip(1));
+                AddProjectToFolderCore(subfolder, project, folderList.Skip(1).ToArray(), repoName, repoChain);
             }
         }