Add error message to AuthorizeState

If PAR fails, we now surface that failure in the same way that other response types do.

Author: josephdecock

src/OidcClient/AuthorizeClient.cs

@@ -46,6 +46,13 @@ public async Task<AuthorizeResult> AuthorizeAsync(AuthorizeRequest request,
                 State = await CreateAuthorizeStateAsync(request.ExtraParameters)
             };
 
+            if(result.State.IsError)
+            {
+                result.Error = result.State.Error;
+                result.ErrorDescription = result.State.ErrorDescription;
+                return result;
+            }
+
             var browserOptions = new BrowserOptions(result.State.StartUrl, _options.RedirectUri)
             {
                 Timeout = TimeSpan.FromSeconds(request.Timeout),
@@ -103,11 +110,11 @@ public async Task<AuthorizeState> CreateAuthorizeStateAsync(Parameters frontChan
                 var parResponse = await PushAuthorizationRequestAsync(state.State, pkce.CodeChallenge, frontChannelParameters);
                 if(parResponse.IsError)
                 {
-                    // TODO - Consider logging more information (but we would need to sanitize?)
                     _logger.LogError("Failed to push authorization parameters");
 
-                    // TODO - Consider how to signal errors to the caller/which exception type to throw
-                    throw new InvalidOperationException(parResponse.Error);
+                    state.Error = "Failed to push authorization parameters";
+                    state.ErrorDescription = parResponse.Error;
+                    return state;
                 }
                 state.StartUrl = CreateAuthorizeUrl(parResponse.RequestUri, _options.ClientId);
             }

src/OidcClient/AuthorizeState.cs

@@ -7,7 +7,7 @@ namespace IdentityModel.OidcClient
     /// <summary>
     /// Represents the state the needs to be hold between starting the authorize request and the response
     /// </summary>
-    public class AuthorizeState
+    public class AuthorizeState : Result
     {
         /// <summary>
         /// Gets or sets the start URL.