[release/10.0.2xx] Source code updates from dotnet/razor

[dotnet-maestro]

Note

This is a codeflow update. It may contain both source code changes from
the source repo
as well as dependency updates. Learn more here.

This pull request brings the following source code changes

From https://github.com/dotnet/razor

• Subscription: 57dbe1f4-3fba-4c64-9d1b-006d04467be7
• Build: 20260106.1 (296200)
• Date Produced: January 6, 2026 10:27:34 PM UTC
• Commit: a8b3ccb884e497811fa31ef385f9486211bf88c5
• Commit Diff: 191feab...a8b3ccb
• Branch: release/dev18.3

Diff the source with this PR branch

darc vmr diff --name-only https://github.com/dotnet/razor:a8b3ccb884e497811fa31ef385f9486211bf88c5..https://github.com/dotnet/dotnet:darc-release/10.0.2xx-ca97e402-82f6-41cb-a6c6-4fecaf98a68b

[dotnet-maestro]

Note

PRs from original repository included in this codeflow update:

• Bring back Go to Def, FAR and hover for components via Roslyn razor#12501
• Don't add newlines at the start of implicit expressions in on type formatting razor#12489
• Fix view component metadata serialization razor#12494
• Revert "Update VsSDK from 17.3.2094 to 17.14.1043-preview2" razor#12498
• Update ubuntu image to 22.04 razor#12495
• Update VsSDK from 17.3.2094 to 17.14.1043-preview2 razor#12493
• Disable AzDO dependabot razor#12490
• [main] Revert "Map component start tags to C#, for better GTD, FAR, Hover, etc. (#12287) razor#12486
• More rename  razor#12480
• [Test only change] Only track steps when needed razor#12479
• Better handle parameter attribute directive completion razor#12473
• Small cleanup to completion tests razor#12474
• Move Tooling Tests out of the Tooling folder razor#12472
• Support Roslyn's custom nested code actions in VS Code razor#12467
• Clean up MemoryCache and fix thread-safety issues razor#12440
• Actually use discards in places where intended razor#12464
• Port dataTipRange support to cohosting razor#12461
• Greatly improve Checksum performance razor#12444
• Format type parameter values as types razor#12448
• Avoid broken NetCore1ES-Svc-Internal in more places razor#12449
• [main] [release/dev18.3] Default the cohosting option in the generator to on. razor#12446
• Localized file check-in by OneLocBuild Task: Build definition ID 262: Build ID 2831227 razor#12442
• Avoid broken NetCore1ESPool-Svc-Internal pool razor#12441
• Add UnboundDirectiveAttributeAddUsingCodeActionProvider for directive attributes razor#12404
• Various follow ups from Roslyn features razor#12435
• Fix edit in one project not being reflected in consuming project razor#12439
• Revert "Remove procdump for now" razor#12431
• Restore internal tools via arcade sdk razor#12437
• [main] Update dependencies from dotnet/arcade razor#12241
• Update VsixVersionPrefix to 18.3.2 razor#12426

💡 You may consult the FAQ for more information or tag @dotnet/prodconsvcs for assistance.

[dotnet-maestro]

Note

PRs from original repository included in this codeflow update:

• Remove unused related document parameter handling razor#12513

💡 You may consult the FAQ for more information or tag @dotnet/prodconsvcs for assistance.

[dotnet-maestro]

Note

PRs from original repository included in this codeflow update:

• Explicitly handle switch expressions in parser razor#12500
• Don't replace the slashes in hint names razor#12477

💡 You may consult the FAQ for more information or tag @dotnet/prodconsvcs for assistance.

[dotnet-maestro]

Note

PRs from original repository included in this codeflow update:

• Update Main PublicApi files (#12516) razor#12517
• TagHelperCollection Prelude: Support types and helpers razor#12503

💡 You may consult the FAQ for more information or tag @dotnet/prodconsvcs for assistance.

[dotnet-maestro]

Note

PRs from original repository included in this codeflow update:

• [main] Source code updates from dotnet/dotnet razor#12521

💡 You may consult the FAQ for more information or tag @dotnet/prodconsvcs for assistance.

[DustinCampbell]

@davidwengier: It looks like dotnet/razor@ded0f0e is the cause of this build break.

[DustinCampbell]

‼️ Once the latest changes flow from dotnet/razor, this PR will need the changes in these commits:

• Update RazorSdk to account for changes to ITagHelperFeature (9a7e708)
• Update RazorSdk after DefaultTagHelperDescriptorProvider removal (dc17a09)

[dotnet-maestro]

Note

PRs from original repository included in this codeflow update:

• TagHelperCollection Part 5: Add weak cache for TagHelperDocumentContext razor#12509
• Remove non-cohost bits from C# extension razor#12518
• Resurrect our integration tests razor#12523
• TagHelperCollection Part 4: Rewrite Tag Helper Discovery(!) razor#12507
• TagHelperCollection Part 3: Optimize tag helper change detection logic in source generator razor#12506
• TagHelperCollection Part 2: Mechanical Updates razor#12505
• TagHelperCollection Part 1: The new bits razor#12504

💡 You may consult the FAQ for more information or tag @dotnet/prodconsvcs for assistance.

[DustinCampbell]

‼️ Once the latest changes flow from dotnet/razor, this PR will need the changes in these commits:

• Update RazorSdk to account for changes to ITagHelperFeature (9a7e708)
• Update RazorSdk after DefaultTagHelperDescriptorProvider removal (dc17a09)

This is done.

[dotnet-maestro]

Note

PRs from original repository included in this codeflow update:

• Update invalid langver error message razor#12611
• Don't colour background of whitespace before component attributes razor#12610

💡 You may consult the FAQ for more information or tag @dotnet/prodconsvcs for assistance.

[davidwengier]

Build is green. I have no idea why.

Stopping the Razor analyzer from building made the build start to fail with null annotation compiler errors, and VSTHRD002 errors in tests, which didn't affect us before, and don't affect us in main. Not sure if anyone from VMR can explain, but it's nothing I know how to deal with, that's for sure. Hopefully none of the million random changes I made cause any other issues 🤷‍♂️

[mmitche]

This looks questionable...why do the analyzers not need to be built in the VMR?

[mmitche]

This also looks questionable. Why is the tests property being used for the analyzers project?

[mmitche]

The analyzer can only reference a version of MS.CA.CSharp as high as the build compiler, either from the SDK or IDE. The VMR build here is using 10.0.101 and so cannot using anything higher than a 5.0.0 version of Roslyn. So I don't think we can use the version from Version.Details.props.

Why would you not be able to reference a version of M.CA higher than the build compiler? I definitely can see that restriction at runtime, but at build time it doesn't make much sense to me.

[davidwengier]

The analyzer in question is one for developers working in our repo, not one we deploy to the general public of Razor users, so "runtime" in this case is "a build of Razor.slnx", hence, this build. What I can't explain is why stopping that analyzer building caused the introduction of other analyzer and compiler warnings that weren't present two days ago. I only took the analyzer out of the build because it seemed like having the pre-built was less desirable, based on comments above.

[dotnet-maestro]

Note

PRs from original repository included in this codeflow update:

• Delete azure-pipelines-conditional-integration.yml razor#12615
• Remove ConditionalSkipIdeFact razor#12617
• Update TextMate from C# extension razor#12618

💡 You may consult the FAQ for more information or tag @dotnet/prodconsvcs for assistance.

[dkurepa]

the build is green, can this be merged?

[dotnet-maestro]

Note

PRs from original repository included in this codeflow update:

• [main] Update dependencies from dotnet/arcade razor#12586

💡 You may consult the FAQ for more information or tag @dotnet/prodconsvcs for assistance.

[dotnet-maestro]

Note

PRs from original repository included in this codeflow update:

• Fix rename integration test razor#12634
• Fix cross project span and edit mapping razor#12614
• Create cohosting tests for existing LSP server endpoint test coverage razor#12630
• Always specify the same project information as Roslyn in VS diagnostics razor#12629

💡 You may consult the FAQ for more information or tag @dotnet/prodconsvcs for assistance.

[dotnet-maestro]

Note

PRs from original repository included in this codeflow update:

• Change vsBranch from 'main' to 'rel/d18.3' razor#12643
• Snap for 18.3 razor#12638
• Revert "Map component start tags to C#, for better GTD, FAR, Hover, etc. (#12287) razor#12485
• Fix branch name in PublishData.json razor#12456
• [release/dev18.3] Disable source build since it hardcodes Svc pool razor#12453
• [release/dev18.3] Restore internal tools via arcade sdk razor#12451
• [release/dev18.3] Avoid broken NetCore1ES-Svc-Internal in more places razor#12450
• [release/dev18.3] Avoid broken NetCore1ESPool-Svc-Internal pool razor#12447
• [release/dev18.3] Default the cohosting option in the generator to on. razor#12443

💡 You may consult the FAQ for more information or tag @dotnet/prodconsvcs for assistance.

[premun]

@mmitche @DustinCampbell this is green again but I don't understand if we want to merge

[DustinCampbell]

@mmitche @DustinCampbell this is green again but I don't understand if we want to merge

@davidwengier?

[davidwengier]

No issues from me, I would love to merge this as I think (hope!) it unblocks some other things we have going on. @mmitche had concerns though, and definitely understands how things should work in the VMR better than me. I just threw spaghetti at the wall until the build went green :)