Fix global resource registration in master pages

When the RequiredResource controls are
added at the end of the page, the
DefaultDotvvmViewBuilder would crash.
This specialcases the RequiredResource,
since it doesn't render anything, it's safe to include anywhere

src/Framework/Framework/Runtime/DefaultDotvvmViewBuilder.cs

@@ -2,6 +2,7 @@
 using System.Collections.Generic;
 using System.Collections.Immutable;
 using System.Linq;
+using System.Linq.Expressions;
 using System.Reflection;
 using System.Threading.Tasks;
 using DotVVM.Framework.Binding;
@@ -107,7 +108,7 @@ private void PerformMasterPageComposition(DotvvmView childPage, DotvvmView maste
             var placeHolders = GetMasterPageContentPlaceHolders(masterPage);
 
             // find contents
-            var contents = GetChildPageContents(childPage, placeHolders);
+            var (contents, auxControls) = GetChildPageContents(childPage, placeHolders);
 
             // perform the composition
             foreach (var content in contents)
@@ -133,7 +134,10 @@ private void PerformMasterPageComposition(DotvvmView childPage, DotvvmView maste
                 content.SetValue(Internal.MarkupFileNameProperty, childPage.GetValue(Internal.MarkupFileNameProperty));
                 content.SetValue(Internal.ReferencedViewModuleInfoProperty, childPage.GetValue(Internal.ReferencedViewModuleInfoProperty));
             }
-
+
+            foreach (var control in auxControls)
+                masterPage.Children.Add(control);
+
             // copy the directives from content page to the master page (except the @masterpage)
             masterPage.ViewModelType = childPage.ViewModelType;
         }
@@ -160,11 +164,30 @@ private List<ContentPlaceHolder> GetMasterPageContentPlaceHolders(DotvvmControl
         /// <summary>
         /// Checks that the content page does not contain invalid content.
         /// </summary>
-        private List<Content> GetChildPageContents(DotvvmView childPage, List<ContentPlaceHolder> parentPlaceHolders)
+        private (List<Content> contents, List<DotvvmControl> auxiliaryControls) GetChildPageContents(DotvvmView childPage, List<ContentPlaceHolder> parentPlaceHolders)
         {
-            // make sure that the body contains only whitespace and Content controls
-            var nonContentElements =
-                childPage.Children.Where(c => !((c is RawLiteral && ((RawLiteral)c).IsWhitespace) || (c is Content)));
+            // make sure that the body contains only Content controls (and whitespace and auxiliary controls)
+            var nonContentElements = new List<DotvvmControl>();
+            // controls which don't render anything and may be placed anywhere (RequireResource)
+            var auxiliaryControls = new List<DotvvmControl>();
+            foreach (var child in childPage.Children)
+            {
+                if (child is RawLiteral { IsWhitespace: true })
+                {
+                    // ignored
+                }
+                else if (child is RequiredResource)
+                {
+                    child.Parent = null; // childPage view is discarded
+                    auxiliaryControls.Add(child);
+                }
+                else if (child is Content)
+                {
+                    // handled bellow
+                }
+                else
+                    nonContentElements.Add(child);
+            }
             if (nonContentElements.Any())
             {
                 // show all error lines
@@ -182,10 +205,10 @@ private List<Content> GetChildPageContents(DotvvmView childPage, List<ContentPla
                 .ToList();
             if (contents.FirstOrDefault(c => c.Parent != childPage) is {} invalidContent)
             {
-                throw new DotvvmControlException(invalidContent, "The control <dot:Content /> cannot be placed inside any control!");
+                throw new DotvvmControlException(invalidContent, $"The control <dot:Content ContentPlaceHolderID='{invalidContent.ContentPlaceHolderID ?? "<null>"}' /> cannot be placed inside any control!");
             }
 
-            return contents;
+            return (contents, auxiliaryControls);
         }
     }
 }

src/Framework/Testing/ControlTestHelper.cs

@@ -134,15 +134,15 @@ public ControlTestHelper(bool debug = true, Action<DotvvmConfiguration>? config
             ClaimsPrincipal? user = null,
             CultureInfo? culture = null)
         {
-            if (!markup.Contains("<body"))
+            if (!markup.Contains("<body") && !markup.Contains("<dot:Content"))
             {
                 markup = $"<body Validation.Enabled=false >\n{markup}\n{(renderResources ? "" : "<tc:FakeBodyResourceLink />")}\n</body>";
             }
             else if (!renderResources)
             {
                 markup = "<tc:FakeBodyResourceLink />" + markup;
             }
-            if (!markup.Contains("<head"))
+            if (!markup.Contains("<head") && !markup.Contains("<dot:Content"))
             {
                 markup = $"<head></head>\n{markup}";
             }

src/Tests/ControlTests/ServerSideStyleTests.cs

@@ -443,6 +443,67 @@ @viewModel int
             check.CheckString(r.FormattedHtml, fileExtension: "html");
         }
 
+
+
+        [TestMethod]
+        public async Task AddResourceWithMasterPage()
+        {
+            var cth = createHelper(c => {
+
+                c.Resources.Register("test-resource1", new InlineScriptResource("alert(1)"));
+                c.Resources.Register("test-resource2", new InlineScriptResource("alert(2)"));
+                c.Resources.Register("test-resource3", new InlineScriptResource("alert(3)"));
+                c.Resources.Register("test-resource4", new InlineScriptResource("alert(4)"));
+                c.Resources.Register("test-resource5", new InlineScriptResource("alert(5)"));
+
+                c.Styles.RegisterRoot()
+                    .AddRequiredResource(cx => {
+                        return cx.Control.TreeRoot.Directives.GetValueOrDefault("custom_resource_import", new()).Select(d => d.Value).ToArray();
+                    });
+            });
+
+            var r = await cth.RunPage(typeof(object), """
+
+                <dot:Content ContentPlaceHolderID="nested-body">
+                    real body
+                </dot:Content>
+
+                <dot:RequiredResource Name="test-resource5" />
+            """,
+            directives: """
+                @masterPage master1.dotmaster
+                @custom_resource_import test-resource1
+            """,
+            markupFiles: new Dictionary<string, string> {
+                ["master1.dotmaster"] = """
+                    @viewModel object
+                    @masterPage master2.dotmaster
+                    @custom_resource_import test-resource2
+
+                    <dot:Content ContentPlaceHolderID="head">
+                        <dot:RequiredResource Name=test-resource4 />
+                    </dot:Content>
+                    <dot:Content ContentPlaceHolderID="body">
+                        <div class="master1">
+                            <dot:ContentPlaceHolder ID="nested-body" />
+                        </div>
+                    </dot:Content>
+                """,
+                ["master2.dotmaster"] = """
+                    @custom_resource_import test-resource3
+                    @viewModel object
+
+                    <head>
+                        <dot:ContentPlaceHolder ID="head" />
+                    </head>
+                    <body>
+                        <dot:ContentPlaceHolder ID="body" />
+                    </body>
+                """
+            }, renderResources: true);
+            check.CheckString(r.OutputString, fileExtension: "html");
+        }
+
         public class BasicTestViewModel: DotvvmViewModelBase
         {
             [Bind(Name = "int")]

src/Tests/ControlTests/testoutputs/ServerSideStyleTests.AddResourceWithMasterPage.html

@@ -0,0 +1,53 @@
+
+    <head>
+
+
+
+
+    <!-- Resource knockout of type ScriptResource. Pointing to EmbeddedResourceLocation. -->
+    <script src=/dotvvmResource/knockout/knockout defer></script>
+    <!-- Resource dotvvm.internal of type ScriptModuleResource. Pointing to EmbeddedResourceLocation. -->
+    <script src=/dotvvmResource/dotvvm--internal/dotvvm--internal type=module defer></script>
+    <!-- Resource dotvvm of type InlineScriptResource. -->
+
+    <!-- Resource dotvvm.debug of type ScriptResource. Pointing to EmbeddedResourceLocation. -->
+    <script src=/dotvvmResource/dotvvm--debug/dotvvm--debug defer></script>
+</head>
+    <body>
+
+        <div class=master1>
+
+        real body
+
+        </div>
+
+
+    <!-- Resource test-resource4 of type InlineScriptResource. -->
+    <script>alert(4)</script>
+    <!-- Resource test-resource3 of type InlineScriptResource. -->
+    <script>alert(3)</script>
+    <!-- Resource test-resource2 of type InlineScriptResource. -->
+    <script>alert(2)</script>
+    <!-- Resource test-resource5 of type InlineScriptResource. -->
+    <script>alert(5)</script>
+    <!-- Resource test-resource1 of type InlineScriptResource. -->
+    <script>alert(1)</script>
+<input type=hidden id=__dot_viewmodel_root value='{
+  "viewModel": {
+    "$csrfToken": "Not a CSRF token."
+  },
+  "url": "/testpage",
+  "virtualDirectory": "",
+  "renderedResources": [
+    "knockout",
+    "dotvvm.internal",
+    "dotvvm",
+    "dotvvm.debug",
+    "test-resource4",
+    "test-resource3",
+    "test-resource2",
+    "test-resource5",
+    "test-resource1"
+  ],
+  "typeMetadata": {}
+}' /><script defer src="data:text/javascript;base64,ZG90dnZtLm9wdGlvbnMuY29tcHJlc3NQT1NUPWZhbHNlOwp3aW5kb3cuZG90dnZtLmluaXQoImVuLVVTIik7"></script></body>