Aspnetcore: [Blazor] DOMException: Entry already exists

[mrpmorris]

Describe the bug

When running a simple Blazor WASM app I am seeing errors in the console saying "DOMException: Entry already exists".

For me, this only happens in Chrome.

To Reproduce

Run this app. https://drive.google.com/open?id=1MnWAzjHcMT60wbBlUhh_haIkTLM88vbo

Error details

Uncaught (in promise) DOMException: Entry already exists.

u | @ | blazor.webassembly.js:1
-- | -- | --
  | Promise.then (async) |   |  
  | s | @ | blazor.webassembly.js:1
  | a | @ | blazor.webassembly.js:1
  | Promise.then (async) |   |  
  | s | @ | blazor.webassembly.js:1
  | (anonymous) | @ | blazor.webassembly.js:1
  | r | @ | blazor.webassembly.js:1
  | e.addToCacheAsync | @ | blazor.webassembly.js:1
  | (anonymous) | @ | blazor.webassembly.js:1
  | (anonymous) | @ | blazor.webassembly.js:1
  | (anonymous) | @ | blazor.webassembly.js:1
  | a | @ | blazor.webassembly.js:1
  | Promise.then (async) |   |  
  | s | @ | blazor.webassembly.js:1
  | a | @ | blazor.webassembly.js:1
  | Promise.then (async) |   |  
  | s | @ | blazor.webassembly.js:1
  | (anonymous) | @ | blazor.webassembly.js:1
  | r | @ | blazor.webassembly.js:1
  | e.loadResourceWithCaching | @ | blazor.webassembly.js:1
  | e.loadResource | @ | blazor.webassembly.js:1
  | (anonymous) | @ | blazor.webassembly.js:1
  | e.loadResources | @ | blazor.webassembly.js:1
  | (anonymous) | @ | blazor.webassembly.js:1
  | callRuntimeCallbacks | @ | dotnet.3.2.0-preview3.20168.1.js:1
  | preRun | @ | dotnet.3.2.0-preview3.20168.1.js:1
  | run | @ | dotnet.3.2.0-preview3.20168.1.js:1
  | runCaller | @ | dotnet.3.2.0-preview3.20168.1.js:1
  | removeRunDependency | @ | dotnet.3.2.0-preview3.20168.1.js:1
  | receiveInstance | @ | dotnet.3.2.0-preview3.20168.1.js:1
  | (anonymous) | @ | blazor.webassembly.js:1
  | (anonymous) | @ | blazor.webassembly.js:1
  | (anonymous) | @ | blazor.webassembly.js:1
  | a | @ | blazor.webassembly.js:1
  | Promise.then (async) |   |  
  | s | @ | blazor.webassembly.js:1
  | a | @ | blazor.webassembly.js:1
  | Promise.then (async) |   |  
  | s | @ | blazor.webassembly.js:1
  | (anonymous) | @ | blazor.webassembly.js:1
  | r | @ | blazor.webassembly.js:1
  | p.instantiateWasm | @ | blazor.webassembly.js:1
  | createWasm | @ | dotnet.3.2.0-preview3.20168.1.js:1
  | (anonymous) | @ | dotnet.3.2.0-preview3.20168.1.js:1

Further technical details

• ASP.NET Core version 3.1.2

• The IDE (VS / VS Code/ VS4Mac) you're running on, and it's version
  Version 16.6.0 Preview 2.0

• Include the output of dotnet --info

.NET Core SDK (reflecting any global.json):
 Version:   3.1.300-preview-015048
 Commit:    13f19b4682

Runtime Environment:
 OS Name:     Windows
 OS Version:  10.0.17763
 OS Platform: Windows
 RID:         win10-x64
 Base Path:   C:\Program Files\dotnet\sdk\3.1.300-preview-015048\

Host (useful for support):
  Version: 3.1.2
  Commit:  916b5cba26

.NET Core SDKs installed:
  2.1.505 [C:\Program Files\dotnet\sdk]
  3.1.101 [C:\Program Files\dotnet\sdk]
  3.1.200 [C:\Program Files\dotnet\sdk]
  3.1.300-preview-015048 [C:\Program Files\dotnet\sdk]

.NET Core runtimes installed:
  Microsoft.AspNetCore.All 2.1.9 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.All]
  Microsoft.AspNetCore.All 2.1.16 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.All]
  Microsoft.AspNetCore.App 2.1.9 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.App]
  Microsoft.AspNetCore.App 2.1.16 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.App]
  Microsoft.AspNetCore.App 3.0.0-preview8.19405.7 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.App]
  Microsoft.AspNetCore.App 3.1.1 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.App]
  Microsoft.AspNetCore.App 3.1.2 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.App]
  Microsoft.NETCore.App 2.1.9 [C:\Program Files\dotnet\shared\Microsoft.NETCore.App]
  Microsoft.NETCore.App 2.1.16 [C:\Program Files\dotnet\shared\Microsoft.NETCore.App]
  Microsoft.NETCore.App 3.0.0-preview8-28405-07 [C:\Program Files\dotnet\shared\Microsoft.NETCore.App]
  Microsoft.NETCore.App 3.1.1 [C:\Program Files\dotnet\shared\Microsoft.NETCore.App]
  Microsoft.NETCore.App 3.1.2 [C:\Program Files\dotnet\shared\Microsoft.NETCore.App]
  Microsoft.WindowsDesktop.App 3.0.0-preview8-28405-07 [C:\Program Files\dotnet\shared\Microsoft.WindowsDesktop.App]
  Microsoft.WindowsDesktop.App 3.1.1 [C:\Program Files\dotnet\shared\Microsoft.WindowsDesktop.App]
  Microsoft.WindowsDesktop.App 3.1.2 [C:\Program Files\dotnet\shared\Microsoft.WindowsDesktop.App]

[ThijsBoudrez]

I got those errors also in Edge (Chromium).

[jvallejoa]

Hello, this is a tremendous bug and I think is high priority. It ALWAYS happens when after creating a WebAssembly Client project with individual authentication the user scaffolds "Accounts" defaults razor pages for editing pages, like Register, Login, etc. Please, we developers do need this error be resolved asap. Thanks!!

[jg11jg]

I have this too on Edge (haven't tried Chrome). But I haven't noticed any actual functionality issues. Anyone know what are these error messages actually telling us - can we safely ignore?

[eric-king]

This happens to me also with a Blazor WebAssembly app I'm building. As with @jg11jg , I don't notice any problems with the application itself or with its rendering.

[Sm1le291]

Yeah, the same error in application with Authentication. And I don't show this error in Firefox. Only in Chrome based Edge

[pranavkm]

@mrpmorris I don't see any errors running the app in Chrome 81 and Edge 81. I tried scaffolding Identity, and that appeared to work just fine. If you're still seeing an issue, could one of you please share a minimal app that reproduces this error?

[mrpmorris]

I don't recall seeing this for a while now. I'll close it for now and reopen it off I start to see it again.

[netprok]

I am still getting this error.

blazor.webassembly.js:1 Uncaught (in promise) DOMException: Entry already exists.
u @ blazor.webassembly.js:1
Promise.then (async)
s @ blazor.webassembly.js:1
i @ blazor.webassembly.js:1
Promise.then (async)
s @ blazor.webassembly.js:1
(anonymous) @ blazor.webassembly.js:1
r @ blazor.webassembly.js:1
e.addToCacheAsync @ blazor.webassembly.js:1
(anonymous) @ blazor.webassembly.js:1
(anonymous) @ blazor.webassembly.js:1
(anonymous) @ blazor.webassembly.js:1
i @ blazor.webassembly.js:1
Promise.then (async)
s @ blazor.webassembly.js:1
i @ blazor.webassembly.js:1
Promise.then (async)
s @ blazor.webassembly.js:1
(anonymous) @ blazor.webassembly.js:1
r @ blazor.webassembly.js:1
e.loadResourceWithCaching @ blazor.webassembly.js:1
e.loadResource @ blazor.webassembly.js:1
(anonymous) @ blazor.webassembly.js:1
e.loadResources @ blazor.webassembly.js:1
(anonymous) @ blazor.webassembly.js:1
c @ blazor.webassembly.js:1
(anonymous) @ VM26:1
(anonymous) @ blazor.webassembly.js:1
start @ blazor.webassembly.js:1
(anonymous) @ blazor.webassembly.js:1
(anonymous) @ blazor.webassembly.js:1
(anonymous) @ blazor.webassembly.js:1
i @ blazor.webassembly.js:1
Promise.then (async)
s @ blazor.webassembly.js:1
i @ blazor.webassembly.js:1
Promise.then (async)
s @ blazor.webassembly.js:1
(anonymous) @ blazor.webassembly.js:1
r @ blazor.webassembly.js:1
v @ blazor.webassembly.js:1
(anonymous) @ blazor.webassembly.js:1
n @ blazor.webassembly.js:1
(anonymous) @ blazor.webassembly.js:1
(anonymous) @ blazor.webassembly.js:1

[mrpmorris]

I am seeing it again now too. This is in the official WebAssembly release.

[MaxMommersteeg]

I'm experiencing the same issue using the 3.2.0 WebAssembly NuGet packages.

[hsinyu-chen]

same issue here ,got 113 Uncaught (in promise) DOMException: Entry already exists. when I upgrade package to 3.2 and launch blazor template project

[lgulliver]

I'm getting this too since updating Visual Studio to 16.6. I was previously working in VSCode with no issues, but needed to switch to run multiple function apps alongside it more easily, but now I'm hitting the same issues as above.

[achmstein]

I'm experiencing the same issue!

[SteveSandersonMS]

People experiencing this issue, is anybody able to post a minimal repro? We'll need this in order to investigate.

[HAL-NINE-THOUSAND]

For me it happens on the default blazor app template. WASM, ASP core hosted. On 16.6.0 and 16.6.1.

Copying the same project to another machine running 16.5.5 doesn't have the errors

-edit- added project but it's just the unmodified template
BlazorApp1.zip

[mrpmorris]

I can give you remote access to my laptop if you wish?

[lgulliver]

For me it happens on the default blazor app template. WASM, ASP core hosted. On 16.6.0 and 16.6.1.

Copying the same project to another machine running 16.5.5 doesn't have the errors

-edit- added project but it's just the unmodified template
BlazorApp1.zip

I have the same here, but without the hosted option.

https://github.com/lgulliver/blazor-webassembly-serverless-chat-demo or https://github.com/lgulliver/squaddle have the issue.

Both we're originally created in VSCode but opening them in Visual Studio 16.6.x and running with debug gives the exception.

[SteveSandersonMS]

Just to check whether this is a caching issue in your browser, could you please try the following and let us know if it works?

1. Try running the app in a different browser (eg Firefox or Chrome if you normally use Edge, or vice-versa)
2. Try clearing all data for the affected site in your normal browser then run the app again (https://www.howtogeek.com/664912/how-to-clear-storage-and-site-data-for-a-single-site-on-google-chrome/)

[mrpmorris]

@SteveSandersonMS
1: File->New Blazor Wasm ASP.NET Hosted
2: Run app in Chrome, errors occur
3: Run app in Edge / Firefox, no errors
4: Clear all Chrome browsing history and re-run app = errors occur
5: Clear cache for that site only and re-run = errors occur
6: Change the port and re-run = errors occur

Chrome Version 83.0.4103.61 (Official Build) (64-bit)

[lgulliver]

Okay, so for me, I normally use Edge (current version I have is 83.0.478.44) and I encounter the issue there. I still encounter it even after clearing all data.

In Chrome (83.0.4103.61) however, I don't encounter the errors in question.

[jssmotta]

Hello, in my case, I were getting this error after I added:

https://www.nuget.org/packages/TG.Blazor.IndexedDB

and

https://github.com/Reshiru/Blazor.IndexedDB.Framework/

I removed them from the project and the problem was solved.

I bet that the problem is the dependencies from https://www.nuget.org/packages/TG.Blazor.IndexedDB, but I could no test it.

I hope this information could help someone.

Best,

Jeff

[Sm1le291]

Regularly facing with similar issue

Everything works fine, despite this messages. Sometimes page stops to load and I must open console and press continue because I see message Debugger in pause, it happens randomly. I don't know is it connect with this messages in console output or not.

Visual Studio 2019 16.6.1
Blazor 3.1.4
Edge 83.0.478.37

in Firefox 77 and on published site everything looks good

[pranavkm]

@SteveSandersonMS could you have a look? I tried a few of the apps here on a few machines and I a don't see the issue.

For folks reporting here, does opening the browser in a different profile work? For instance, Edge and Chrome have an option to browse using the guest profile.

[mrpmorris]

@pranavkm I've tested a few scenarios. It only seems to be a problem (for me) when VS is responsible for launching the browser.

When VS launches Chrome I see the problem.
If I open a new tab in the same browser and go to the URL I see the problem.
If I open an incognito window and go to the URL, no errors.
If I open a new instance of Chrome (not incognito) no errors (whether signed in or as Guest).

I hope that helps.

[Sm1le291]

You can download archive with project here
https://1drv.ms/u/s!AkIXAhGlJ7OukMVzE2JZ6y-gjexNKg?e=T17ReD
If you will run it, please create empty sql server db with name AuctionSpaDBTest
and execute migrations from project *.DataAccess

[pthomson]

I experience this issue as well but @mrpmorris is correct, only in the browser window that VS2019 16.6 opens. If I open the URL in another browser instance then no error.

[mkArtakMSFT]

@pranavkm should this be resolved now?