Hot Reload unavailable #47836

wf-soft · 2023-04-22T13:07:50Z

Is there an existing issue for this?

I have searched the existing issues

Describe the bug

I am using the latest VS2022 17.6.0 Preview 4.0

The preview version created the BlazorServer project, and all hot reloads were invalidated without any prompt. I am unable to determine the reason

dotnet watch ⌚ File changed: C:\Users\wf-so\Downloads\HotReloadIssue45519Demo-main\HotReloadIssue45519Demo-main\TradeCars\Client\Pages\Index.razor.
dotnet watch ⌚ No hot reload changes to apply.

dotnet watch 🔥 Hot reload capabilities: Baseline AddMethodToExistingType AddStaticFieldToExistingType NewTypeDefinition ChangeCustomAttributes.
dotnet watch ⌚ File changed: C:\Users\wf-so\Downloads\HotReloadIssue45519Demo-main\HotReloadIssue45519Demo-main\TradeCars\Client\Pages\Index.razor.
info: Microsoft.AspNetCore.Hosting.Diagnostics[1]
      Request starting HTTP/2 POST https://localhost:5008/_framework/blazor-hotreload application/json 2835
dotnet watch ⌚ Received 0 from browser in [Count: 1, MessageType: Binary, EndOfMessage: True].
dotnet watch ⌚ Received failed apply from delta applier.
  ❔ Do you want to restart your app - Yes (y) / No (n) / Always (a) / Never (v)?

Expected Behavior

No response

Steps To Reproduce

No response

Exceptions (if any)

No response

.NET Version

dotnet-sdk-7.0.203

Anything else?

No response

The text was updated successfully, but these errors were encountered:

szalapski · 2023-06-05T16:04:45Z

This is a direct successor to #45519, which was closed with "Likely fixed by dotnet/sdk#31015.", but it was not fixed. I wish someone would have tested it with the provided example before deeming it "likely fixed". The test is very easy.

Here's the minimal example, the same one that was provided in #45519, now upgraded to use SDK 7.0.302

szalapski/HotReloadIssue45519Demo

Clone this and run

dotnet watch --verbose --project ./TradeCars/Server

The site should start up. You'll see Hot reload capabilities: . which portends the failure. Edit anything in Index.razor to watch hot reload fail.

Please get Hot Reload to work reliably and consistently with Blazor WebAssembly (and Blazor Server, likely the same problem), especially with changes to .razor files. This feature seems so buggy when it should "just work". It seems to work much better with non-Blazor server-side changes, e.g. to a Web API, but that's not where much productivity benefit would result.

When using dotnet watch on my Server project, with verbose logging , I get watch : Hot reload capabilities: . (not even Baseline) and, on a change, No hot reload changes to apply. (when there are). This is with .NET 7.0.5 and SDK 7.0.302 on a solution that was created with .NET 6 and recently upgraded to 7.

Starting...
dotnet watch 🔥 Hot reload capabilities: .
dotnet watch ⌚ File changed: .\MySoln\Client\Shared\MainLayout.razor.
dotnet watch ⌚ No deltas modified. Applying changes to clear diagnostics.
dotnet watch ⌚ Received 1 from browser in [Count: 1, MessageType: Binary, EndOfMessage: True].
dotnet watch ⌚ No hot reload changes to apply.
dotnet watch 🔥 Hot reload change handled in 4092.6926ms.

When running from VS (with or without debugging), I get similar output:
, or sometimes instead "Your debugged process might be corrupted and restarting it is recommended nearly always."

Expected Behavior

dotnet watch hot reload should just work. I don't want to see "No hot reload changes to apply."
If it isn't working and thus I get "watch : Hot reload capabilities: .", I'd like to see output that tells me why in the verbose output (indeed, perhaps even in warnings).

szalapski · 2023-06-05T16:14:31Z

@wf-soft Can I recommend you edit the title of this issue to read:

Hot Reload nearly always fails, with Blazor and "dotnet watch"

That will get it more attention and more closely link it to #45519.

danroth27 · 2023-06-05T17:38:14Z

Adding @phil-allen-msft @maddymontaquila and @mcumming for visibility.

tmat · 2023-06-21T18:03:15Z

I see this error in the browser with the latest .NET 8:

Updated repro project:
Net8.zip

 at System.Reflection.Metadata.MetadataUpdater.ApplyUpdate(Assembly assembly, ReadOnlySpan`1 metadataDelta, ReadOnlySpan`1 ilDelta, ReadOnlySpan`1 pdbDelta)
   at Microsoft.Extensions.HotReload.HotReloadAgent.ApplyDeltas(IReadOnlyList`1 deltas)
   at Microsoft.AspNetCore.Components.WebAssembly.HotReload.WebAssemblyHotReload.ApplyHotReloadDelta(String moduleIdString, Byte[] metadataDelta, Byte[] ilDelta, Byte[] pdbBytes)
   at System.Reflection.MethodInvoker.InterpretedInvoke(Object obj, IntPtr* args)
   at System.Reflection.MethodInvoker.Invoke(Object obj, IntPtr* args, BindingFlags invokeAttr)
--- End of stack trace from previous location ---
   at Microsoft.JSInterop.Infrastructure.DotNetDispatcher.InvokeSynchronously(JSRuntime jsRuntime, DotNetInvocationInfo& callInfo, IDotNetObjectReference objectReference, String argsJson)
   at Microsoft.JSInterop.Infrastructure.DotNetDispatcher.Invoke(JSRuntime jsRuntime, DotNetInvocationInfo& invocationInfo, String argsJson)
   at Microsoft.AspNetCore.Components.WebAssembly.Services.DefaultWebAssemblyJSRuntime.InvokeDotNet(String assemblyName, String methodIdentifier, Int64 dotNetObjectId, String argsJson)
   at Microsoft.AspNetCore.Components.WebAssembly.Services.DefaultWebAssemblyJSRuntime.__Wrapper_InvokeDotNet_1772498872(JSMarshalerArgument* __arguments_buffer)
Error: The assembly can not be edited or changed.
    at yr (https://localhost:5008/_framework/dotnet.runtime.8.0.0-preview.6.23316.2.dk1nh2rbrm.js:3:35896)
    at Uo (https://localhost:5008/_framework/dotnet.runtime.8.0.0-preview.6.23316.2.dk1nh2rbrm.js:3:53691)
    at Object.<anonymous> (https://localhost:5008/_framework/dotnet.runtime.8.0.0-preview.6.23316.2.dk1nh2rbrm.js:3:52482)
    at Object.invokeDotNetFromJS (https://localhost:5008/_framework/blazor.webassembly.js:1:43350)
    at b.invokeDotNetMethod (https://localhost:5008/_framework/blazor.webassembly.js:1:3485)
    at b.invokeDotNetStaticMethod (https://localhost:5008/_framework/blazor.webassembly.js:1:3241)
    at Wt.Ye._internal.applyHotReload (https://localhost:5008/_framework/blazor.webassembly.js:1:52017)
    at https://localhost:5008/_framework/aspnetcore-browser-refresh.js:140:35
    at Array.forEach (<anonymous>)
    at applyBlazorDeltas (https://localhost:5008/_framework/aspnetcore-browser-refresh.js:138:14)
(anonymous) @ aspnetcore-browser-refresh.js:142
applyBlazorDeltas @ aspnetcore-browser-refresh.js:138
BlazorHotReloadDeltav1 @ aspnetcore-browser-refresh.js:46
connection.onmessage @ aspnetcore-browser-refresh.js:53

tmat · 2023-06-21T18:04:02Z

@lambdageek

lambdageek · 2023-06-21T18:48:56Z

@tmat I can repro that failure if I have VS Code editing the project (I have the C# Dev Kit installed). I get different results if I edit with Emacs or vim. In general The assembly can not be edited or changed. can happen if:

the DOTNET_MODIFIABLE_ASSEMBLIES=debug environment variable is not set in the client-side runtime
or the baseline assembly does not have the "optimizer disabled" attribute (essentially the assembly was compiled in Release mode, not Debug)

There's definitely something here. I'll try to get some more info

lambdageek · 2023-06-21T18:52:44Z

@tmat yea, I don't see that The assembly can not be edited or changed. error if I disabled the C# Dev Kit extension in VS Code

Update
If I just have ms-dotnettools.csharp (v2.0.238) enabled, I dont' have the apply update exception when I try to make changes to Client/Pages/Index.razor
If I also enable ms-dotnettools.csdevkit (v0.1.103) then I get "the assembly can not be edited or changed" if I run dotnet watch --verbose --project ./TradeCars/Server and then edit the client Index.razor page.

tmat · 2023-06-21T19:11:37Z

This change will communicate the error message to dotnet-watch and print it out, for easier diagnostics in future: dotnet/sdk#33471

lambdageek · 2023-06-21T19:45:43Z

This should improve the "assembly cannot be edited or changed" error message dotnet/runtime#87880

tmat · 2023-06-21T22:02:51Z

@szalapski
We found that the issue is with launchSettings.json configuration. The value of ASPNETCORE_ENVIRONMENT should be Development, not Developer. Then builder.Environment.IsEnvironment("Developer") in Program.cs also needs to be updated.

After these changes Hot Reload works.

We certainly need to improve the error reporting.

szalapski · 2023-06-21T22:16:42Z

We use "Developer" for local machines and "Development" for a deployed dev environment. Is there any way to get it to work? The docs say that we can use any value we want for Environment so i'd hope there's a way.

tmat · 2023-06-21T22:41:21Z

@szalapski Not currently, but fixing that: #48953

Meanwhile you may consider changing developer -> development and development -> deployed, or something like that.

szalapski · 2023-06-22T04:00:07Z

Thanks @tmat. I got rid of the notion of "Developer" in my demo app, instead using "Development", and I modified Program.cs accordingly, and I still see no change. I still get dotnet watch ⌚ No hot reload changes to apply. Would you be willing to pull the latest and run the demo app (see README.md) and see if you can get HotReload to work?

https://github.com/szalapski/HotReloadIssue45519Demo

tmat · 2023-06-22T17:22:49Z

@szalapski I did. It works for me :-/

I had to remove <PackageReference Include="GeneralMills.VaultSharp.Client" Version="1.19.0" /> though since it did not restore.

szalapski · 2023-06-22T17:45:29Z

I had to remove <PackageReference Include="GeneralMills.VaultSharp.Client" Version="1.19.0" /> though since it did not

Thanks, I just removed that package reference as well and pushed.

@szalapski I did. It works for me :-/

Hmm, I was afraid of that. I'm going to retry. I deleted my local repo and run exactly as follows

git clone https://github.com/szalapski/HotReloadIssue45519Demo
cd .\HotReloadIssue45519Demo\
dotnet watch --project ./TradeCars/Server

I got a lot of irrelevant info output, but after I edit Index.razor and save it, I get:

dotnet watch ⌚ File changed: .\TradeCars\Client\Pages\Index.razor.
info: Microsoft.AspNetCore.Hosting.Diagnostics[1]
      Request starting HTTP/2 POST https://localhost:5008/_framework/blazor-hotreload application/json 2
dotnet watch ⌚ No hot reload changes to apply.
info: Microsoft.AspNetCore.Hosting.Diagnostics[2]
      Request finished HTTP/2 POST https://localhost:5008/_framework/blazor-hotreload application/json 2 - 2

I have .NET SDK 7.0.302 running on Windows 10. @tmat What could be different in your run? What output do you see?

dotnet-issue-labeler bot added the area-commandlinetools Includes: Command line tools, dotnet-dev-certs, dotnet-user-jwts, and OpenAPI label Apr 22, 2023

amcasey added the feature-dotnetwatch This issue is related to the dotnet-watch command-line tool (now external) label May 19, 2023

amcasey assigned tmat May 19, 2023

szalapski mentioned this issue Jun 5, 2023

For a "dotnet new web" project, if you try to make a change and hit save, you will not see the change even if you force refresh the browser #33696

Open

szalapski mentioned this issue Jun 5, 2023

Hot Reload nearly always fails, with Blazor WebAssembly and "dotnet watch" #45519

Closed

1 task

lambdageek mentioned this issue Jun 21, 2023

[hot_reload] Give more info about why the runtime can't apply updates dotnet/runtime#87880

Merged

tmat mentioned this issue Jun 21, 2023

Set Hot Reload controlling headers DOTNET-MODIFIABLE-ASSEMBLIES and A… #48953

Merged

tmat closed this as completed in #48953 Jun 30, 2023

ghost locked as resolved and limited conversation to collaborators Jul 30, 2023

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Hot Reload unavailable #47836

Hot Reload unavailable #47836

wf-soft commented Apr 22, 2023 •

edited

szalapski commented Jun 5, 2023 •

edited

szalapski commented Jun 5, 2023

danroth27 commented Jun 5, 2023

tmat commented Jun 21, 2023 •

edited

tmat commented Jun 21, 2023

lambdageek commented Jun 21, 2023

lambdageek commented Jun 21, 2023 •

edited

tmat commented Jun 21, 2023

lambdageek commented Jun 21, 2023

tmat commented Jun 21, 2023 •

edited

szalapski commented Jun 21, 2023 •

edited

tmat commented Jun 21, 2023 •

edited

szalapski commented Jun 22, 2023 •

edited

tmat commented Jun 22, 2023

szalapski commented Jun 22, 2023 •

edited

Hot Reload unavailable #47836

Hot Reload unavailable #47836

Comments

wf-soft commented Apr 22, 2023 • edited

Is there an existing issue for this?

Describe the bug

Expected Behavior

Steps To Reproduce

Exceptions (if any)

.NET Version

Anything else?

szalapski commented Jun 5, 2023 • edited

Expected Behavior

szalapski commented Jun 5, 2023

danroth27 commented Jun 5, 2023

tmat commented Jun 21, 2023 • edited

tmat commented Jun 21, 2023

lambdageek commented Jun 21, 2023

lambdageek commented Jun 21, 2023 • edited

tmat commented Jun 21, 2023

lambdageek commented Jun 21, 2023

tmat commented Jun 21, 2023 • edited

szalapski commented Jun 21, 2023 • edited

tmat commented Jun 21, 2023 • edited

szalapski commented Jun 22, 2023 • edited

tmat commented Jun 22, 2023

szalapski commented Jun 22, 2023 • edited

wf-soft commented Apr 22, 2023 •

edited

szalapski commented Jun 5, 2023 •

edited

tmat commented Jun 21, 2023 •

edited

lambdageek commented Jun 21, 2023 •

edited

tmat commented Jun 21, 2023 •

edited

szalapski commented Jun 21, 2023 •

edited

tmat commented Jun 21, 2023 •

edited

szalapski commented Jun 22, 2023 •

edited

szalapski commented Jun 22, 2023 •

edited