From bccb9e35fea6194a16c77631188f8e879da93c96 Mon Sep 17 00:00:00 2001 From: Stephen Halter Date: Fri, 2 Aug 2024 11:32:15 -0700 Subject: [PATCH 1/4] Use [DebuggerDisableUserUnhandledExceptions] for Blazor NavigationExceptions - These are not intended to be handled by user code --- .../Endpoints/src/RazorComponentEndpointInvoker.cs | 4 ++++ .../src/Rendering/EndpointHtmlRenderer.Prerendering.cs | 8 ++++++++ .../src/Rendering/EndpointHtmlRenderer.Streaming.cs | 9 +++++++++ 3 files changed, 21 insertions(+) diff --git a/src/Components/Endpoints/src/RazorComponentEndpointInvoker.cs b/src/Components/Endpoints/src/RazorComponentEndpointInvoker.cs index 090cf150dd64..f2517f54a161 100644 --- a/src/Components/Endpoints/src/RazorComponentEndpointInvoker.cs +++ b/src/Components/Endpoints/src/RazorComponentEndpointInvoker.cs @@ -3,6 +3,7 @@ using System.Buffers; using System.Diagnostics; +using System.Runtime.CompilerServices; using System.Text; using System.Text.Encodings.Web; using Microsoft.AspNetCore.Antiforgery; @@ -33,6 +34,9 @@ public Task Render(HttpContext context) return _renderer.Dispatcher.InvokeAsync(() => RenderComponentCore(context)); } + // We do not want the debugger to consider NavigationExceptions caught by this method as user unhandled. + [MethodImpl(MethodImplOptions.NoInlining)] + [DebuggerDisableUserUnhandledExceptions] private async Task RenderComponentCore(HttpContext context) { context.Response.ContentType = RazorComponentResultExecutor.DefaultContentType; diff --git a/src/Components/Endpoints/src/Rendering/EndpointHtmlRenderer.Prerendering.cs b/src/Components/Endpoints/src/Rendering/EndpointHtmlRenderer.Prerendering.cs index 326a1ed249e8..6b25e4faba46 100644 --- a/src/Components/Endpoints/src/Rendering/EndpointHtmlRenderer.Prerendering.cs +++ b/src/Components/Endpoints/src/Rendering/EndpointHtmlRenderer.Prerendering.cs @@ -1,7 +1,9 @@ // Licensed to the .NET Foundation under one or more agreements. // The .NET Foundation licenses this file to you under the MIT license. +using System.Diagnostics; using System.Diagnostics.CodeAnalysis; +using System.Runtime.CompilerServices; using System.Text.Encodings.Web; using Microsoft.AspNetCore.Components.Rendering; using Microsoft.AspNetCore.Components.Web.HtmlRendering; @@ -88,6 +90,9 @@ public ValueTask PrerenderComponentAsync( ParameterView parameters) => PrerenderComponentAsync(httpContext, componentType, prerenderMode, parameters, waitForQuiescence: true); + // We do not want the debugger to consider NavigationExceptions caught by this method as user unhandled. + [MethodImpl(MethodImplOptions.NoInlining)] + [DebuggerDisableUserUnhandledExceptions] public async ValueTask PrerenderComponentAsync( HttpContext httpContext, [DynamicallyAccessedMembers(Component)] Type componentType, @@ -129,6 +134,9 @@ public async ValueTask PrerenderComponentAsync( } } + // We do not want the debugger to consider NavigationExceptions caught by this method as user unhandled. + [MethodImpl(MethodImplOptions.NoInlining)] + [DebuggerDisableUserUnhandledExceptions] internal async ValueTask RenderEndpointComponent( HttpContext httpContext, [DynamicallyAccessedMembers(Component)] Type rootComponentType, diff --git a/src/Components/Endpoints/src/Rendering/EndpointHtmlRenderer.Streaming.cs b/src/Components/Endpoints/src/Rendering/EndpointHtmlRenderer.Streaming.cs index 3a6a93c1a0dc..c222281e1111 100644 --- a/src/Components/Endpoints/src/Rendering/EndpointHtmlRenderer.Streaming.cs +++ b/src/Components/Endpoints/src/Rendering/EndpointHtmlRenderer.Streaming.cs @@ -1,6 +1,8 @@ // Licensed to the .NET Foundation under one or more agreements. // The .NET Foundation licenses this file to you under the MIT license. +using System.Diagnostics; +using System.Runtime.CompilerServices; using System.Runtime.InteropServices; using System.Text; using System.Text.Encodings.Web; @@ -37,6 +39,9 @@ public void InitializeStreamingRenderingFraming(HttpContext httpContext, bool is } } + // We do not want the debugger to consider NavigationExceptions caught by this method as user unhandled. + [MethodImpl(MethodImplOptions.NoInlining)] + [DebuggerDisableUserUnhandledExceptions] public async Task SendStreamingUpdatesAsync(HttpContext httpContext, Task untilTaskCompleted, TextWriter writer) { // Important: do not introduce any 'await' statements in this method above the point where we write @@ -80,6 +85,10 @@ public async Task SendStreamingUpdatesAsync(HttpContext httpContext, Task untilT HandleExceptionAfterResponseStarted(_httpContext, writer, ex); await writer.FlushAsync(); // Important otherwise the client won't receive the error message, as we're about to fail the pipeline await _httpContext.Response.CompleteAsync(); + + // We need to inform the debugger that this exception should be considered user unhandled unlike the NavigationException. + // Review: Is this necessary if the method attributed with [DebuggerDisableUserUnhandledExceptions] rethrows like this does? + Debugger.BreakForUserUnhandledException(ex); throw; } } From e45a91517b67070ad81de96f319d8ace1ae669cc Mon Sep 17 00:00:00 2001 From: Stephen Halter Date: Fri, 2 Aug 2024 11:44:48 -0700 Subject: [PATCH 2/4] Use [DebuggerDisableUserUnhandledExceptions] in the developer exception page middleware --- .../DeveloperExceptionPageMiddlewareImpl.cs | 23 +++++++++++++++++++ 1 file changed, 23 insertions(+) diff --git a/src/Middleware/Diagnostics/src/DeveloperExceptionPage/DeveloperExceptionPageMiddlewareImpl.cs b/src/Middleware/Diagnostics/src/DeveloperExceptionPage/DeveloperExceptionPageMiddlewareImpl.cs index cfc26131c1a1..fcd0dd39bbe6 100644 --- a/src/Middleware/Diagnostics/src/DeveloperExceptionPage/DeveloperExceptionPageMiddlewareImpl.cs +++ b/src/Middleware/Diagnostics/src/DeveloperExceptionPage/DeveloperExceptionPageMiddlewareImpl.cs @@ -5,6 +5,7 @@ using System.Diagnostics.CodeAnalysis; using System.Diagnostics.Metrics; using System.Linq; +using System.Runtime.CompilerServices; using System.Text; using System.Text.Json; using System.Text.Json.Serialization; @@ -102,8 +103,14 @@ private static void SetExceptionHandlerFeatures(ErrorContext errorContext) /// /// /// + [MethodImpl(MethodImplOptions.NoInlining)] + [DebuggerDisableUserUnhandledExceptions] public async Task Invoke(HttpContext context) { + // We want to avoid treating exceptions as user unhandled if an exception filter like the DatabaseDeveloperPageExceptionFilter + // handles the exception rather than letting it flow to the default DisplayException method. This is because we don't want to stop the + // debugger if the developer shouldn't be handling the exception and instead just needs to do something like click a link to run a + // database migration. try { await _next(context); @@ -122,6 +129,11 @@ public async Task Invoke(HttpContext context) context.Response.StatusCode = StatusCodes.Status499ClientClosedRequest; } + // Generally speaking, we do not expect application code to handle things like IOExceptions during a request + // body read due to a client disconnect. But this kind of thing should be rare in development, and developers + // might be surprised if an IOException propagating through user code was not considered user unhandled. + // That said, if developers complain, we consider removing the following line. + Debugger.BreakForUserUnhandledException(ex); return; } @@ -131,6 +143,8 @@ public async Task Invoke(HttpContext context) { _logger.ResponseStartedErrorPageMiddleware(); _metrics.RequestException(exceptionName, ExceptionResult.Skipped, handler: null); + + Debugger.BreakForUserUnhandledException(ex); throw; } @@ -161,11 +175,17 @@ public async Task Invoke(HttpContext context) } catch (Exception ex2) { + // Inform the debugger that the exception filter itself threw an exception. + // REVIEW: Is it okay for the same method to potentially call Debugger.BreakForUserUnhandledException + // multiple times with different exceptions in the same invocation? + Debugger.BreakForUserUnhandledException(ex2); + // If there's a Exception while generating the error page, re-throw the original exception. _logger.DisplayErrorPageException(ex2); } _metrics.RequestException(exceptionName, ExceptionResult.Unhandled, handler: null); + Debugger.BreakForUserUnhandledException(ex); throw; } @@ -178,6 +198,9 @@ public async Task Invoke(HttpContext context) // Assumes the response headers have not been sent. If they have, still attempt to write to the body. private Task DisplayException(ErrorContext errorContext) { + // We need to inform the debugger that this exception should be considered user unhandled since it wasn't handled by an exception filter. + Debugger.BreakForUserUnhandledException(errorContext.Exception); + var httpContext = errorContext.HttpContext; var headers = httpContext.Request.GetTypedHeaders(); var acceptHeader = headers.Accept; From 217e7740f298ee9cd16943d143ca6cf903790e45 Mon Sep 17 00:00:00 2001 From: Stephen Halter Date: Thu, 8 Aug 2024 15:33:42 -0700 Subject: [PATCH 3/4] Address PR feedback --- .../src/RazorComponentEndpointInvoker.cs | 4 +--- .../EndpointHtmlRenderer.Prerendering.cs | 10 ++++------ .../EndpointHtmlRenderer.Streaming.cs | 14 ++++++-------- .../DeveloperExceptionPageMiddlewareImpl.cs | 18 +++++++----------- 4 files changed, 18 insertions(+), 28 deletions(-) diff --git a/src/Components/Endpoints/src/RazorComponentEndpointInvoker.cs b/src/Components/Endpoints/src/RazorComponentEndpointInvoker.cs index f2517f54a161..7a76a43098d4 100644 --- a/src/Components/Endpoints/src/RazorComponentEndpointInvoker.cs +++ b/src/Components/Endpoints/src/RazorComponentEndpointInvoker.cs @@ -3,7 +3,6 @@ using System.Buffers; using System.Diagnostics; -using System.Runtime.CompilerServices; using System.Text; using System.Text.Encodings.Web; using Microsoft.AspNetCore.Antiforgery; @@ -34,8 +33,7 @@ public Task Render(HttpContext context) return _renderer.Dispatcher.InvokeAsync(() => RenderComponentCore(context)); } - // We do not want the debugger to consider NavigationExceptions caught by this method as user unhandled. - [MethodImpl(MethodImplOptions.NoInlining)] + // We do not want the debugger to consider NavigationExceptions caught by this method as user-unhandled. [DebuggerDisableUserUnhandledExceptions] private async Task RenderComponentCore(HttpContext context) { diff --git a/src/Components/Endpoints/src/Rendering/EndpointHtmlRenderer.Prerendering.cs b/src/Components/Endpoints/src/Rendering/EndpointHtmlRenderer.Prerendering.cs index 6b25e4faba46..e331fd5707c2 100644 --- a/src/Components/Endpoints/src/Rendering/EndpointHtmlRenderer.Prerendering.cs +++ b/src/Components/Endpoints/src/Rendering/EndpointHtmlRenderer.Prerendering.cs @@ -3,7 +3,6 @@ using System.Diagnostics; using System.Diagnostics.CodeAnalysis; -using System.Runtime.CompilerServices; using System.Text.Encodings.Web; using Microsoft.AspNetCore.Components.Rendering; using Microsoft.AspNetCore.Components.Web.HtmlRendering; @@ -90,8 +89,7 @@ public ValueTask PrerenderComponentAsync( ParameterView parameters) => PrerenderComponentAsync(httpContext, componentType, prerenderMode, parameters, waitForQuiescence: true); - // We do not want the debugger to consider NavigationExceptions caught by this method as user unhandled. - [MethodImpl(MethodImplOptions.NoInlining)] + // We do not want the debugger to consider NavigationExceptions caught by this method as user-unhandled. [DebuggerDisableUserUnhandledExceptions] public async ValueTask PrerenderComponentAsync( HttpContext httpContext, @@ -134,8 +132,7 @@ public async ValueTask PrerenderComponentAsync( } } - // We do not want the debugger to consider NavigationExceptions caught by this method as user unhandled. - [MethodImpl(MethodImplOptions.NoInlining)] + // We do not want the debugger to consider NavigationExceptions caught by this method as user-unhandled. [DebuggerDisableUserUnhandledExceptions] internal async ValueTask RenderEndpointComponent( HttpContext httpContext, @@ -206,7 +203,8 @@ public static ValueTask HandleNavigationExcepti throw new InvalidOperationException( "A navigation command was attempted during prerendering after the server already started sending the response. " + "Navigation commands can not be issued during server-side prerendering after the response from the server has started. Applications must buffer the" + - "response and avoid using features like FlushAsync() before all components on the page have been rendered to prevent failed navigation commands."); + "response and avoid using features like FlushAsync() before all components on the page have been rendered to prevent failed navigation commands.", + navigationException); } else if (IsPossibleExternalDestination(httpContext.Request, navigationException.Location) && IsProgressivelyEnhancedNavigation(httpContext.Request)) diff --git a/src/Components/Endpoints/src/Rendering/EndpointHtmlRenderer.Streaming.cs b/src/Components/Endpoints/src/Rendering/EndpointHtmlRenderer.Streaming.cs index c222281e1111..f7fd6a8860f8 100644 --- a/src/Components/Endpoints/src/Rendering/EndpointHtmlRenderer.Streaming.cs +++ b/src/Components/Endpoints/src/Rendering/EndpointHtmlRenderer.Streaming.cs @@ -2,7 +2,6 @@ // The .NET Foundation licenses this file to you under the MIT license. using System.Diagnostics; -using System.Runtime.CompilerServices; using System.Runtime.InteropServices; using System.Text; using System.Text.Encodings.Web; @@ -39,8 +38,7 @@ public void InitializeStreamingRenderingFraming(HttpContext httpContext, bool is } } - // We do not want the debugger to consider NavigationExceptions caught by this method as user unhandled. - [MethodImpl(MethodImplOptions.NoInlining)] + // We do not want the debugger to consider NavigationExceptions caught by this method as user-unhandled. [DebuggerDisableUserUnhandledExceptions] public async Task SendStreamingUpdatesAsync(HttpContext httpContext, Task untilTaskCompleted, TextWriter writer) { @@ -70,7 +68,7 @@ public async Task SendStreamingUpdatesAsync(HttpContext httpContext, Task untilT EmitInitializersIfNecessary(httpContext, writer); // At this point we yield the sync context. SSR batches may then be emitted at any time. - await writer.FlushAsync(); + await writer.FlushAsync(); await untilTaskCompleted; } catch (NavigationException navigationException) @@ -79,16 +77,16 @@ public async Task SendStreamingUpdatesAsync(HttpContext httpContext, Task untilT } catch (Exception ex) { + // Rethrowing also informs the debugger that this exception should be considered user-unhandled unlike NavigationExceptions, + // but calling BreakForUserUnhandledException here allows the debugger to break before we modify the HttpContext. + Debugger.BreakForUserUnhandledException(ex); + // Theoretically it might be possible to let the error middleware run, capture the output, // then emit it in a special format so the JS code can display the error page. However // for now we're not going to support that and will simply emit a message. HandleExceptionAfterResponseStarted(_httpContext, writer, ex); await writer.FlushAsync(); // Important otherwise the client won't receive the error message, as we're about to fail the pipeline await _httpContext.Response.CompleteAsync(); - - // We need to inform the debugger that this exception should be considered user unhandled unlike the NavigationException. - // Review: Is this necessary if the method attributed with [DebuggerDisableUserUnhandledExceptions] rethrows like this does? - Debugger.BreakForUserUnhandledException(ex); throw; } } diff --git a/src/Middleware/Diagnostics/src/DeveloperExceptionPage/DeveloperExceptionPageMiddlewareImpl.cs b/src/Middleware/Diagnostics/src/DeveloperExceptionPage/DeveloperExceptionPageMiddlewareImpl.cs index fcd0dd39bbe6..e5f0f587c66e 100644 --- a/src/Middleware/Diagnostics/src/DeveloperExceptionPage/DeveloperExceptionPageMiddlewareImpl.cs +++ b/src/Middleware/Diagnostics/src/DeveloperExceptionPage/DeveloperExceptionPageMiddlewareImpl.cs @@ -5,7 +5,6 @@ using System.Diagnostics.CodeAnalysis; using System.Diagnostics.Metrics; using System.Linq; -using System.Runtime.CompilerServices; using System.Text; using System.Text.Json; using System.Text.Json.Serialization; @@ -103,11 +102,10 @@ private static void SetExceptionHandlerFeatures(ErrorContext errorContext) /// /// /// - [MethodImpl(MethodImplOptions.NoInlining)] [DebuggerDisableUserUnhandledExceptions] public async Task Invoke(HttpContext context) { - // We want to avoid treating exceptions as user unhandled if an exception filter like the DatabaseDeveloperPageExceptionFilter + // We want to avoid treating exceptions as user-unhandled if an exception filter like the DatabaseDeveloperPageExceptionFilter // handles the exception rather than letting it flow to the default DisplayException method. This is because we don't want to stop the // debugger if the developer shouldn't be handling the exception and instead just needs to do something like click a link to run a // database migration. @@ -130,8 +128,8 @@ public async Task Invoke(HttpContext context) } // Generally speaking, we do not expect application code to handle things like IOExceptions during a request - // body read due to a client disconnect. But this kind of thing should be rare in development, and developers - // might be surprised if an IOException propagating through user code was not considered user unhandled. + // body read due to a client disconnect. But aborted requests should be rare in development, and developers + // might be surprised if an IOException propagating through their code was not considered user-unhandled. // That said, if developers complain, we consider removing the following line. Debugger.BreakForUserUnhandledException(ex); return; @@ -144,7 +142,7 @@ public async Task Invoke(HttpContext context) _logger.ResponseStartedErrorPageMiddleware(); _metrics.RequestException(exceptionName, ExceptionResult.Skipped, handler: null); - Debugger.BreakForUserUnhandledException(ex); + // Rethrowing informs the debugger that this exception should be considered user-unhandled. throw; } @@ -175,10 +173,8 @@ public async Task Invoke(HttpContext context) } catch (Exception ex2) { - // Inform the debugger that the exception filter itself threw an exception. - // REVIEW: Is it okay for the same method to potentially call Debugger.BreakForUserUnhandledException - // multiple times with different exceptions in the same invocation? - Debugger.BreakForUserUnhandledException(ex2); + // It might make sense to call BreakForUserUnhandledException for ex2 after we do the same for the original exception. + // But for now, considering the rarity of user-defined IDeveloperPageExceptionFilters, we're not for simplicity. // If there's a Exception while generating the error page, re-throw the original exception. _logger.DisplayErrorPageException(ex2); @@ -198,7 +194,7 @@ public async Task Invoke(HttpContext context) // Assumes the response headers have not been sent. If they have, still attempt to write to the body. private Task DisplayException(ErrorContext errorContext) { - // We need to inform the debugger that this exception should be considered user unhandled since it wasn't handled by an exception filter. + // We need to inform the debugger that this exception should be considered user-unhandled since it wasn't fully handled by an exception filter. Debugger.BreakForUserUnhandledException(errorContext.Exception); var httpContext = errorContext.HttpContext; From f138f77861303a5297356011ffe83963af302065 Mon Sep 17 00:00:00 2001 From: Stephen Halter Date: Thu, 8 Aug 2024 16:47:25 -0700 Subject: [PATCH 4/4] Consistently skip BreakForUserUnhandledException when rethrowing --- .../DeveloperExceptionPageMiddlewareImpl.cs | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/src/Middleware/Diagnostics/src/DeveloperExceptionPage/DeveloperExceptionPageMiddlewareImpl.cs b/src/Middleware/Diagnostics/src/DeveloperExceptionPage/DeveloperExceptionPageMiddlewareImpl.cs index e5f0f587c66e..2f33111ccb3b 100644 --- a/src/Middleware/Diagnostics/src/DeveloperExceptionPage/DeveloperExceptionPageMiddlewareImpl.cs +++ b/src/Middleware/Diagnostics/src/DeveloperExceptionPage/DeveloperExceptionPageMiddlewareImpl.cs @@ -181,7 +181,8 @@ public async Task Invoke(HttpContext context) } _metrics.RequestException(exceptionName, ExceptionResult.Unhandled, handler: null); - Debugger.BreakForUserUnhandledException(ex); + + // Rethrowing informs the debugger that this exception should be considered user-unhandled. throw; }