[release/9.1] Update Dcp out of date error message

src/Aspire.Hosting/Dcp/DcpDependencyCheck.cs

@@ -2,6 +2,7 @@
 // The .NET Foundation licenses this file to you under the MIT license.
 
 using System.Globalization;
+using System.Reflection;
 using System.Text;
 using System.Text.Json;
 using System.Text.RegularExpressions;
@@ -161,7 +162,8 @@ private static void EnsureDcpVersion(DcpInfo dcpInfo)
                 {
                     throw new DistributedApplicationException(string.Format(
                         CultureInfo.InvariantCulture,
-                        Resources.DcpVersionCheckTooLowMessage
+                        Resources.DcpVersionCheckTooLowMessage,
+                        GetCurrentPackageVersion(typeof(DcpDependencyCheck).Assembly)
                     ));
                 }
 
@@ -174,6 +176,35 @@ private static void EnsureDcpVersion(DcpInfo dcpInfo)
         }
     }
 
+    private static string GetCurrentPackageVersion(Assembly assembly)
+    {
+        // The package version is stamped into the assembly's AssemblyInformationalVersionAttribute at build time, followed by a '+' and
+        // the commit hash, e.g.:
+        // [assembly: AssemblyInformationalVersion("9.1.0-preview.1.25111.1+ad18db0213e9db8209bca0feb83fc801f34634f5)]
+
+        var version = assembly.GetCustomAttribute<AssemblyInformationalVersionAttribute>()?.InformationalVersion;
+
+        if (version is not null)
+        {
+            var plusIndex = version.IndexOf('+');
+
+            if (plusIndex > 0)
+            {
+                return version[..plusIndex];
+            }
+
+            return version;
+        }
+
+        // Fallback to the first 3 parts of the assembly version
+        if (Version.TryParse(assembly.GetCustomAttribute<AssemblyVersionAttribute>()?.Version, out var assemblyVersion))
+        {
+            return assemblyVersion.ToString(3);
+        }
+
+        return "<unknown>";
+    }
+
     internal static void CheckDcpInfoAndLogErrors(ILogger logger, DcpOptions options, DcpInfo dcpInfo, bool throwIfUnhealthy = false)
     {
         var containerRuntime = options.ContainerRuntime;

src/Aspire.Hosting/Properties/Resources.resx

@@ -140,7 +140,7 @@ See https://aka.ms/dotnet/aspire/containers for more details on supported contai
     <value>Application orchestrator dependency check returned an error: {0}</value>
   </data>
   <data name="DcpVersionCheckTooLowMessage" xml:space="preserve">
-    <value>Newer version of .NET Aspire workload is required to run the application. Run 'dotnet workload update' to get it.</value>
+    <value>Newer version of the Aspire.Hosting.AppHost package is required to run the application. Ensure you are referencing at least version '{0}'.</value>
   </data>
   <data name="LaunchSettingsFileDoesNotContainProfileExceptionMessage" xml:space="preserve">
     <value>Launch settings file does not contain '{0}' profile.</value>
@@ -151,4 +151,4 @@ See https://aka.ms/dotnet/aspire/containers for more details on supported contai
   <data name="ProjectFileNotFoundExceptionMessage" xml:space="preserve">
     <value>Project file '{0}' was not found.</value>
   </data>
-</root>
+</root>