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@DustinCampbell DustinCampbell commented Nov 18, 2025

| Prelude | Part 1 | Part 2 | Part 3 | Part 4 | Part 5 |

This is a set of support utilities and helpers added as part of the TagHelperCollection changes:

  • Added InterlockedOperations.Initialize(...) overloads for lock free initialization with a factory method. (f3686aa)
  • Added two LazyValue structs that use the new InterlockedOperations.Initialize(...) overloads. These are useful for lazily initializing a value without extra allocations or locks. (81795f5)
  • Added OverloadResolutionPriorityAttribute polyfill type. (27ab174)
  • Refactored TagHelperCache to extract CleanableWeakCache<TKey, TValue>. This caches items as weak references. When the number of items added reaches a configurable threshold, the cache is cleaned up, and any dead weak references are removed. (673a9b5)

CI Build: https://dev.azure.com/dnceng/internal/_build/results?buildId=2842136&view=results
Toolset Run: https://dev.azure.com/dnceng/internal/_build/results?buildId=2842197&view=results

@davidwengier
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davidwengier commented Nov 18, 2025

Just when I'm starting to think about what to work on today, here comes Dustin with a PR series that has a freakin' table of contents 😛

But seriously, thank you for the effort in making these easier to review, I really really appreciate it.

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:shipit:

@DustinCampbell DustinCampbell merged commit 322e3bc into dotnet:main Nov 20, 2025
11 checks passed
@dotnet-policy-service dotnet-policy-service bot added this to the Next milestone Nov 20, 2025
DustinCampbell added a commit that referenced this pull request Nov 24, 2025
| [Prelude](#12503) | Part 1 | [Part
2](#12505) | [Part
3](#12506) | [Part
4](#12507) | [Part
5](#12509) |

This pull request represents all new code! It introduces a new immutable
collection type, `TagHelperCollection`, that is designed to contain
`TagHelperDescriptors`. It is built with the following principles:

1. Guarantee that collections never contain duplicate tag helpers.
2. Collections can be compared efficiently via checksums.
3. Multiple collections can be merged into a single collection
efficiently, with minimal array copying.
4. Determining whether a collection contains a tag helper is efficient.

> [!TIP]
> Since this is all new code, I recommend reviewing commit-by-commit.
Each commit represents a cohesive portion of new code.

----
CI Build:
https://dev.azure.com/dnceng/internal/_build/results?buildId=2842145&view=results
Toolset Run:
https://dev.azure.com/dnceng/internal/_build/results?buildId=2842216&view=results
DustinCampbell added a commit that referenced this pull request Nov 24, 2025
| [Prelude](#12503) | [Part
1](#12504) | Part 2 | [Part
3](#12506) | [Part
4](#12507) | [Part
5](#12509) |

> [!WARNING]
> This pull request contains breaking changes for the RazorSdk. Once
this is merged and flows to the VMR,
dotnet/dotnet@9a7e708
will need to be cherry-picked to resolve build breaks in
`src/sdk/src/RazorSdk`.

These commits represent the (mostly) mechanical changes needed to
integrate `TagHelperCollection` across the Razor code base. Most
references to `ImmutableArrary<TagHelperDescriptor>`,
`IReadOnlyList<TagHelperDescriptor>`,
`IEnumerable<TagHelperDescriptor>`, and `TagHelperDescriptor[]` have
been replaced with `TagHelperCollection`. This is **by far** the largest
of the `TagHelperCollection` pull requests.

While most of the commits contain mechanical changes across the code
base, there are few that include more substantial work that require a
bit more scrutiny:

- **Update `RenameService` to remove
`ImmutableArray<TagHelperDescriptor>`**
(fa3ad2b)
This includes a fair amount of refactoring in `RenameService` to fix
bugs found when moving to `TagHelperCollection`.

- **Update `TagHelperFacts` to use `TagHelperCollection`**
Extra work was done in `DirectiveAttributeComplationItemProvider` to
clean up a bit following #12473.

----
CI Build:
https://dev.azure.com/dnceng/internal/_build/results?buildId=2842165&view=results
Toolset Run:
https://dev.azure.com/dnceng/internal/_build/results?buildId=2842237&view=results
@DustinCampbell DustinCampbell deleted the taghelpercollection-part0-prelude branch November 24, 2025 19:00
DustinCampbell added a commit that referenced this pull request Nov 24, 2025
…c in source generator (#12506)

| [Prelude](#12503) | [Part
1](#12504) | [Part
2](#12505) | Part 3 | [Part
4](#12507) | [Part
5](#12509) |

This is a relatively small change to remove LINQ from the Razor source
generator and use `TagHelperCollection` when checking for added/removed
tag helpers.

----
CI Build:
https://dev.azure.com/dnceng/internal/_build/results?buildId=2842169&view=results
Toolset Run:
https://dev.azure.com/dnceng/internal/_build/results?buildId=2842240&view=results
DustinCampbell added a commit that referenced this pull request Nov 24, 2025
| [Prelude](#12503) | [Part
1](#12504) | [Part
2](#12505) | [Part
3](#12506) | Part 4 | [Part
5](#12509) |

> [!WARNING]
> This pull request contains breaking changes for the RazorSdk. Once
this is merged and flows to the VMR,
dotnet/dotnet@dc17a09
will need to be cherry-picked to resolve build breaks in
`src/sdk/src/RazorSdk`.

Previously, tag helpers were discovered by
`ITagHelperDescriptorProvider`. Each provider was responsible for
walking a compilation's assemblies and producing `TagHelperDescriptors`
from the types within. This change inverts the tag helper discovery
process by introducing `ITagHelperDiscoveryService` and moving the tag
helper construction logic into a set of `TagHelperProducers`. The
`ITagHelperDiscoveryService` performs a single walk of the compilation
or assembly and calls the producers as needed.

Importantly, the new process allows a more expansive cache to be
maintained. There is now a per-assembly cache that holds onto
`TagHelperCollection` instances. The old cache that was owned by
providers via `TagHelperCollector` has been removed.

To complete this change, `ITagHelperDescriptorProvider` and related
types have been _deleted_.

----
CI Build:
https://dev.azure.com/dnceng/internal/_build/results?buildId=2842196&view=results
Toolset Run:
https://dev.azure.com/dnceng/internal/_build/results?buildId=2842249&view=results
DustinCampbell added a commit that referenced this pull request Nov 24, 2025
…xt (#12509)

| [Prelude](#12503) | [Part
1](#12504) | [Part
2](#12505) | [Part
3](#12506) | [Part
4](#12507) | Part 5 |

This change introduces a weak cache for `TagHelperDocumentContext` keyed
by the tag helper prefix string and `TagHelperCollection` checksum. This
helps avoid creating new `TagHelperBinders` for the same set of tag
helpers, since `TagHelperBinder` is expensive to create.

----
CI Build:
https://dev.azure.com/dnceng/internal/_build/results?buildId=2842228&view=results
Toolset Run:
https://dev.azure.com/dnceng/internal/_build/results?buildId=2842250&view=results
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4 participants