Razor regression in ASP .NET Core 9.0

[AlexBAV]

Is there an existing issue for this?

• [x] I have searched the existing issues

Describe the bug

The following razor snippet renders to nothing (is completely ignored??) in ASP.NET Core 9.0. Used to work correctly in previous version:

<script type="importmap">
     {
         "imports": {
         }
    }
</script>

Looks like a bug in server-side script tag helper.

Expected Behavior

Should render "as is", without modifications

Steps To Reproduce

No response

Exceptions (if any)

No response

.NET Version

9.0.100

Anything else?

No response

[ahazelwood]

I would like to upgrade to 9.0, however this is hitting me on a asp.net core mvc project upgrading from net8.0. Any suggestions for how to get it to render correctly would be greatly appreciated. I concur that it should not override anything but render it as written.

[AlexBAV]

I currently use the following workaround for tag helpers that definitely should not be processed on a server side:

<!script type="importmap">...</!script>

<!tag> syntax is an official way to turn off tag helper processing.

However, I'm still sure that tag helper should not remove a tag if it cannot process it on a server side.

[ahazelwood]

Thanks Alexanderm, that’s a nice addition to know. I hadn’t come across that before. However, this should be fixed as it is an unexpected condition. At the very least, the documentation for importmap should indicate this as a temporary workaround until they are able to fix it.

Thanks for the pointer.

From: Alexander Bessonov @.> Sent: Thursday, November 21, 2024 4:20 AM To: dotnet/aspnetcore @.> Cc: Andre Hazelwood @.>; Comment @.> Subject: Re: [dotnet/aspnetcore] Razor regression in ASP .NET Core 9.0 (Issue #58973)

I currently use the following workaround for tag helpers that definitely should not be processed on a server side:

<!script type="importmap">...</!script>

<!tag> syntax is an official way to turn off tag helper processing.

However, I'm still sure that tag helper should not remove a tag if it cannot process it on a server side.

— Reply to this email directly, view it on GitHubhttps://github.com/dotnet/aspnetcore/issues/58973#issuecomment-2490478089, or unsubscribehttps://github.com/notifications/unsubscribe-auth/AACS73GFMU2IM5ND3H5IIV32BWQTLAVCNFSM6AAAAABR2WEKWGVHI2DSMVQWIX3LMV43OSLTON2WKQ3PNVWWK3TUHMZDIOJQGQ3TQMBYHE. You are receiving this because you commented.Message ID: @.**@.>>

[AlexBAV]

BTW, I suggest using this workaround for all "non-default" usages of script tag. It looks like they correctly recognize <script type="text/javascript">, <script type="module"> and <script>. All other usages should be guarded.

We, for example also had to implement a workaround for <script type="application/ld+json"> as it was also removed after upgrade to ASP.NET Core 9.0

[StevePy]

This one caught me as well, a bit sweaty when my importmap (part of _Layout.cshtml) wasn't rendered, considering the relatively good feeling I had combining razor views with ES6 modules. Fortunately the work-around with the <!script type="importmap"> works a treat, but I can't see how that should be an expected breaking change since it's kind of a necessity for module scripts which are recognized. Fortunately a small work-around and pretty much everything else with the switch to .Net 9 has been relatively painless.