Deprecate stand-alone error message and fieldset tag helpers

Author: gunndabad

CHANGELOG.md

@@ -7,6 +7,9 @@
 #### `asp-for` attributes
 The `asp-for` attribute is now obsolete; the `for` attribute should be used in its place.
 
+#### `<govuk-error-message>` and `<govuk-fieldset>` tag helpers
+The `<govuk-error-message>` and `<govuk-fieldset>` tag helpers are deprecated and will be removed in a future release.
+
 ## 2.8.0
 
 Targets GOV.UK Frontend v5.8.0.

src/GovUk.Frontend.AspNetCore.DocSamples/GovUk.Frontend.AspNetCore.DocSamples.csproj

@@ -2,6 +2,7 @@
 
   <PropertyGroup>
     <TargetFramework>net8.0</TargetFramework>
+    <NoWarn>CS0618</NoWarn>
   </PropertyGroup>
 
   <ItemGroup>

src/GovUk.Frontend.AspNetCore/TagHelpers/ErrorMessageTagHelper.cs

@@ -17,6 +17,7 @@ namespace GovUk.Frontend.AspNetCore.TagHelpers;
 /// </summary>
 [HtmlTargetElement(TagName)]
 [OutputElementHint(ComponentGenerator.ErrorMessageElement)]
+[Obsolete("This tag helper will be removed in a future release.")]
 public class ErrorMessageTagHelper : TagHelper
 {
     internal const string TagName = "govuk-error-message";

src/GovUk.Frontend.AspNetCore/TagHelpers/FieldsetContext.cs

@@ -16,9 +16,11 @@ public void SetLegend(
 
         if (Legend != null)
         {
+#pragma warning disable CS0618 // Type or member is obsolete
             throw ExceptionHelper.OnlyOneElementIsPermittedIn(
                 FieldsetLegendTagHelper.TagName,
                 FieldsetTagHelper.TagName);
+#pragma warning restore CS0618 // Type or member is obsolete
         }
 
         Legend = (isPageHeading, attributes, content);
@@ -28,7 +30,9 @@ public void ThrowIfNotComplete()
     {
         if (Legend == null)
         {
+#pragma warning disable CS0618 // Type or member is obsolete
             throw ExceptionHelper.AChildElementMustBeProvided(FieldsetLegendTagHelper.TagName);
+#pragma warning restore CS0618 // Type or member is obsolete
         }
     }
 }

src/GovUk.Frontend.AspNetCore/TagHelpers/FieldsetLegendTagHelper.cs

@@ -1,3 +1,4 @@
+using System;
 using System.Threading.Tasks;
 using GovUk.Frontend.AspNetCore.HtmlGeneration;
 using Microsoft.AspNetCore.Razor.TagHelpers;
@@ -9,6 +10,7 @@ namespace GovUk.Frontend.AspNetCore.TagHelpers;
 /// </summary>
 [HtmlTargetElement(TagName, ParentTag = FieldsetTagHelper.TagName)]
 [OutputElementHint(ComponentGenerator.FieldsetLegendElement)]
+[Obsolete("This tag helper will be removed in a future release.")]
 public class FieldsetLegendTagHelper : TagHelper
 {
     internal const string TagName = "govuk-fieldset-legend";

src/GovUk.Frontend.AspNetCore/TagHelpers/FieldsetTagHelper.cs

@@ -1,3 +1,4 @@
+using System;
 using System.Threading.Tasks;
 using GovUk.Frontend.AspNetCore.HtmlGeneration;
 using Microsoft.AspNetCore.Html;
@@ -11,6 +12,7 @@ namespace GovUk.Frontend.AspNetCore.TagHelpers;
 /// </summary>
 [HtmlTargetElement(TagName)]
 [OutputElementHint(ComponentGenerator.FieldsetElement)]
+[Obsolete("This tag helper will be removed in a future release.")]
 public class FieldsetTagHelper : TagHelper
 {
     internal const string TagName = "govuk-fieldset";

tests/GovUk.Frontend.AspNetCore.Tests/TagHelpers/ErrorMessageTagHelperTests.cs

@@ -10,6 +10,7 @@
 using Microsoft.AspNetCore.Razor.TagHelpers;
 using Moq;
 using Xunit;
+#pragma warning disable CS0618 // Type or member is obsolete
 
 namespace GovUk.Frontend.AspNetCore.Tests.TagHelpers;
 

tests/GovUk.Frontend.AspNetCore.Tests/TagHelpers/FieldsetLegendTagHelperTests.cs

@@ -5,6 +5,7 @@
 using Microsoft.AspNetCore.Html;
 using Microsoft.AspNetCore.Razor.TagHelpers;
 using Xunit;
+#pragma warning disable CS0618 // Type or member is obsolete
 
 namespace GovUk.Frontend.AspNetCore.Tests.TagHelpers;
 

tests/GovUk.Frontend.AspNetCore.Tests/TagHelpers/FieldsetTagHelperTests.cs

@@ -6,6 +6,7 @@
 using Microsoft.AspNetCore.Html;
 using Microsoft.AspNetCore.Razor.TagHelpers;
 using Xunit;
+#pragma warning disable CS0618 // Type or member is obsolete
 
 namespace GovUk.Frontend.AspNetCore.Tests.TagHelpers;