Merge manifest nodes on case insensitive OSes

Author: javiercn

src/Hosting/Hosting/test/StaticWebAssets/ManifestStaticWebAssetsFileProviderTests.cs

@@ -57,6 +57,74 @@ public void GetFileInfoPrefixRespectsOsCaseSensitivity()
             Assert.Equal(expectedResult, file.Exists);
         }
 
+        [Theory]
+        [InlineData("/img/icon.png", true)]
+        [InlineData("/Img/hero.gif", true)]
+        // Note that we've changed the casing of the first segment
+        [InlineData("/Img/icon.png", false)]
+        [InlineData("/img/hero.gif", false)]
+        public void ParseWorksWithNodesThatOnlyDifferOnCasing(string path, bool exists)
+        {
+            exists = exists | OperatingSystem.IsWindows();
+            // Arrange
+            using var memoryStream = new MemoryStream();
+            using var writer = new StreamWriter(memoryStream);
+            writer.Write(@"{
+  ""ContentRoots"": [
+    ""D:\\path\\"",
+    ""D:\\other\\""
+  ],
+  ""Root"": {
+    ""Children"": {
+      ""img"": {
+        ""Children"": {
+          ""icon.png"": {
+            ""Asset"": {
+              ""ContentRootIndex"": 0,
+              ""SubPath"": ""icon.png""
+            }
+          }
+        }
+      },
+      ""Img"": {
+        ""Children"": {
+          ""hero.gif"": {
+            ""Asset"": {
+              ""ContentRootIndex"": 1,
+              ""SubPath"": ""hero.gif""
+            }
+          }
+        }
+      }
+    }
+  }
+}");
+            var first = new Mock<IFileProvider>();
+            first.Setup(s => s.GetFileInfo("icon.png")).Returns(new TestFileInfo() { Name = "icon.png", Exists = true });
+            var second = new Mock<IFileProvider>();
+            second.Setup(s => s.GetFileInfo("hero.gif")).Returns(new TestFileInfo() { Name = "hero.gif", Exists = true });
+
+            writer.Flush();
+            memoryStream.Seek(0, SeekOrigin.Begin);
+            var manifest = ManifestStaticWebAssetFileProvider.StaticWebAssetManifest.Parse(memoryStream);
+            var comparer = ManifestStaticWebAssetFileProvider.StaticWebAssetManifest.PathComparer;
+
+            var provider = new ManifestStaticWebAssetFileProvider(
+                manifest,
+                contentRoot => contentRoot switch
+                {
+                    "D:\\path\\" => first.Object,
+                    "D:\\other\\" => second.Object,
+                    _ => throw new InvalidOperationException("Unknown provider")
+                });
+
+            // Act
+            var file = provider.GetFileInfo(path);
+
+            // Assert
+            Assert.Equal(exists, file.Exists);
+        }
+
         [Fact]
         public void CanFindFileListedOnTheManifest()
         {

src/Shared/StaticWebAssets/ManifestStaticWebAssetFileProvider.cs

@@ -3,7 +3,6 @@
 
 using System.Collections;
 using System.Diagnostics.CodeAnalysis;
-using System.Linq;
 using System.Text.Json;
 using System.Text.Json.Serialization;
 using Microsoft.Extensions.FileProviders;
@@ -367,9 +366,58 @@ private sealed class OSBasedCaseConverter : JsonConverter<Dictionary<string, Sta
         {
             public override Dictionary<string, StaticWebAssetNode> Read(ref Utf8JsonReader reader, Type typeToConvert, JsonSerializerOptions options)
             {
-                return new Dictionary<string, StaticWebAssetNode>(
-                    JsonSerializer.Deserialize<IDictionary<string, StaticWebAssetNode>>(ref reader, options)!,
-                    StaticWebAssetManifest.PathComparer);
+                var parsed = JsonSerializer.Deserialize<IDictionary<string, StaticWebAssetNode>>(ref reader, options)!;
+                var result = new Dictionary<string, StaticWebAssetNode>(StaticWebAssetManifest.PathComparer);
+                MergeChildren(parsed, result);
+                return result;
+
+                static void MergeChildren(
+                    IDictionary<string, StaticWebAssetNode> newChildren,
+                    IDictionary<string, StaticWebAssetNode> existing)
+                {
+                    foreach (var (key, value) in newChildren)
+                    {
+                        if (!existing.TryGetValue(key, out var existingNode))
+                        {
+                            existing.Add(key, value);
+                        }
+                        else
+                        {
+                            if (value.Patterns != null)
+                            {
+                                if (existingNode.Patterns == null)
+                                {
+                                    existingNode.Patterns = value.Patterns;
+                                }
+                                else
+                                {
+                                    if (value.Patterns.Length > 0)
+                                    {
+                                        var newList = new StaticWebAssetPattern[existingNode.Patterns.Length + value.Patterns.Length];
+                                        existingNode.Patterns.CopyTo(newList, 0);
+                                        value.Patterns.CopyTo(newList, existingNode.Patterns.Length);
+                                        existingNode.Patterns = newList;
+                                    }
+                                }
+                            }
+
+                            if (value.Children != null)
+                            {
+                                if (existingNode.Children == null)
+                                {
+                                    existingNode.Children = value.Children;
+                                }
+                                else
+                                {
+                                    if (value.Children.Count > 0)
+                                    {
+                                        MergeChildren(value.Children, existingNode.Children);
+                                    }
+                                }
+                            }
+                        }
+                    }
+                }
             }
 
             public override void Write(Utf8JsonWriter writer, Dictionary<string, StaticWebAssetNode> value, JsonSerializerOptions options)