Fixed race condition for default page title (#36099)

Co-authored-by: Mackinnon Buck <[email protected]>

Author: github-actions[bot]

src/Components/Components/src/Sections/SectionContent.cs

@@ -12,11 +12,17 @@ internal class SectionContent : ISectionContentProvider, IComponent, IDisposable
         private SectionRegistry _registry = default!;
 
         /// <summary>
-        /// Gets or sets the name that determines which <see cref="SectionOutlet"/> instances will render
+        /// Gets or sets the name that determines which <see cref="SectionOutlet"/> instance will render
         /// the content of this instance.
         /// </summary>
         [Parameter] public string Name { get; set; } = default!;
 
+        /// <summary>
+        /// Gets or sets whether this component should provide the default content for the target
+        /// <see cref="SectionOutlet"/>.
+        /// </summary>
+        [Parameter] public bool IsDefaultContent { get; set; }
+
         /// <summary>
         /// Gets or sets the content to be rendered in corresponding <see cref="SectionOutlet"/> instances.
         /// </summary>
@@ -45,7 +51,7 @@ Task IComponent.SetParametersAsync(ParameterView parameters)
                     _registry.RemoveProvider(_registeredName, this);
                 }
 
-                _registry.AddProvider(Name, this);
+                _registry.AddProvider(Name, this, IsDefaultContent);
                 _registeredName = Name;
             }
 

src/Components/Components/src/Sections/SectionRegistry.cs

@@ -8,15 +8,22 @@ internal sealed class SectionRegistry
         private readonly Dictionary<string, ISectionContentSubscriber> _subscribersByName = new();
         private readonly Dictionary<string, List<ISectionContentProvider>> _providersByName = new();
 
-        public void AddProvider(string name, ISectionContentProvider provider)
+        public void AddProvider(string name, ISectionContentProvider provider, bool isDefaultProvider)
         {
             if (!_providersByName.TryGetValue(name, out var providers))
             {
                 providers = new();
                 _providersByName.Add(name, providers);
             }
 
-            providers.Add(provider);
+            if (isDefaultProvider)
+            {
+                providers.Insert(0, provider);
+            }
+            else
+            {
+                providers.Add(provider);
+            }
         }
 
         public void RemoveProvider(string name, ISectionContentProvider provider)

src/Components/Web/src/Head/HeadOutlet.cs

@@ -45,13 +45,14 @@ protected override void BuildRenderTree(RenderTreeBuilder builder)
             {
                 builder.OpenComponent<SectionContent>(2);
                 builder.AddAttribute(3, nameof(SectionContent.Name), TitleSectionOutletName);
-                builder.AddAttribute(4, nameof(SectionContent.ChildContent), (RenderFragment)BuildDefaultTitleRenderTree);
+                builder.AddAttribute(4, nameof(SectionContent.IsDefaultContent), true);
+                builder.AddAttribute(5, nameof(SectionContent.ChildContent), (RenderFragment)BuildDefaultTitleRenderTree);
                 builder.CloseComponent();
             }
 
             // Render the rest of the head metadata
-            builder.OpenComponent<SectionOutlet>(5);
-            builder.AddAttribute(6, nameof(SectionOutlet.Name), HeadSectionOutletName);
+            builder.OpenComponent<SectionOutlet>(6);
+            builder.AddAttribute(7, nameof(SectionOutlet.Name), HeadSectionOutletName);
             builder.CloseComponent();
         }