Enable LSP go-to-definition, find-all-references, and go-to-implementation with command handler precedence #80951

Copilot · 2025-10-29T20:06:57Z

Changes: Enable LSP Go-to-Definition, Find-All-References, and Go-to-Implementation Capabilities

Allows other extensions to call into our LSP handlers, but ensures that the MEF APIs are still used for normal user invoked commands by ensuring our MEF handlers are ordered before LSP MEF handlers.

Completed:

Enable DefinitionProvider, ReferencesProvider, and ImplementationProvider capabilities in AlwaysActivateInProcLanguageClient.GetCapabilities() regardless of the LSP feature flag
Add Order(Before = ...) attribute to GoToDefinitionCommandHandler to ensure it runs before any LSP command handlers
Add Order(Before = ...) attribute to FindReferencesCommandHandler to ensure it runs before any LSP command handlers
Add Order(Before = ...) attribute to GoToImplementationCommandHandler to ensure it runs before any LSP command handlers
Add new constants LspGoToDefinition, LspFindReferences, and LspGoToImplementation to PredefinedCommandHandlerNames
Update command handler name values to exact requested strings
Document that LSP command handler names are externally agreed upon and cannot be changed
Build verified successfully

Files Modified:

src/EditorFeatures/Core/LanguageServer/AlwaysActivateInProcLanguageClient.cs - Enabled DefinitionProvider, ReferencesProvider, and ImplementationProvider capabilities unconditionally
src/EditorFeatures/Core/GoToDefinition/GoToDefinitionCommandHandler.cs - Added Order(Before) attribute for LSP handler
src/EditorFeatures/Core/GoOrFind/FindReferences/FindReferencesCommandHandler.cs - Added Order(Before) attribute for LSP handler
src/EditorFeatures/Core/GoOrFind/GoToImplementation/GoToImplementationCommandHandler.cs - Added Order(Before) attribute for LSP handler
src/EditorFeatures/Core/Extensibility/Commands/PredefinedCommandHandlerNames.cs - Added LSP command handler name constants with exact values and documented they are externally agreed upon

Summary:

These changes enable clients to call the LSP go-to-definition, find-all-references, and go-to-implementation handlers by advertising the capabilities in the AlwaysActiveInProcLanguageServer. The traditional command handlers are ordered to run before any LSP-based command handlers, ensuring they remain active for normal scenarios while allowing experimentation with LSP handlers.

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… command handler ordering Co-authored-by: dibarbet <5749229+dibarbet@users.noreply.github.com>

hjihong · 2025-10-29T20:28:43Z

src/EditorFeatures/Core/Extensibility/Commands/PredefinedCommandHandlerNames.cs

+    /// <summary>
+    /// Command handler name for LSP Go To Definition.
+    /// </summary>
+    public const string LspGoToDefinition = "LSP Go To Definition Command Handler";


this one is "LSP GoToDefinitionCommandHandler" btw

dibarbet · 2025-10-29T20:28:11Z

src/EditorFeatures/Core/Extensibility/Commands/PredefinedCommandHandlerNames.cs

+    /// <summary>
+    /// Command handler name for LSP Find References.
+    /// </summary>
+    public const string LspFindReferences = "LSP Find References Command Handler";


@copilot use exactly LSP FindReferenceCommandHandler as the value.

Updated to "LSP FindReferenceCommandHandler" in e37817f

can you doc that these names are agreed upon externally and cannot change?

@copilot can you update the summary documentation that these names are agreed upon externally and cannot change?

Updated documentation for all three LSP command handler names to indicate they are agreed upon externally and cannot be changed in c63bb03

dibarbet · 2025-10-29T20:28:46Z

src/EditorFeatures/Core/Extensibility/Commands/PredefinedCommandHandlerNames.cs

+    /// <summary>
+    /// Command handler name for LSP Go To Definition.
+    /// </summary>
+    public const string LspGoToDefinition = "LSP Go To Definition Command Handler";


@copilot use exactly LSP GoToDefinitionCommandHandler as the value

Updated to "LSP GoToDefinitionCommandHandler" in e37817f

Co-authored-by: dibarbet <5749229+dibarbet@users.noreply.github.com>

hjihong · 2025-10-30T21:06:40Z

@copilot implement the same things for the Go To Implementation capability

dibarbet · 2025-10-30T21:21:32Z

@copilot implement the same things for the Go To Implementation capability

Co-authored-by: dibarbet <5749229+dibarbet@users.noreply.github.com>

Copilot · 2025-10-30T21:27:15Z

@copilot implement the same things for the Go To Implementation capability

Added Go To Implementation capability and command handler ordering in 93fcd0e. The changes include:

Enabled ImplementationProvider = true in AlwaysActivateInProcLanguageClient
Added LspGoToImplementation constant to PredefinedCommandHandlerNames
Added Order(Before = PredefinedCommandHandlerNames.LspGoToImplementation) to GoToImplementationCommandHandler

dibarbet · 2025-10-31T20:56:16Z

Tested with an additional fix on the LSP client side to ensure they are ordered after our handlers. This allows us to use VS MEF handlers for standard editor requests, but gives other extensions the ability to call our LSP handlers to retrieve definition /impl and reference information.

Current thought is to take this in dev18 to make sure that this ordering works

…d cannot change Co-authored-by: dibarbet <5749229+dibarbet@users.noreply.github.com>

dotnet#80951 slightly broke Peek Definition by making editor pick VS LSP client implementation of IPeekableSourceProvider instead of this one. Similarly to command handlers this provider also needs to be ordered before LSP's one.

#80951 slightly broke Peek Definition by making editor pick VS LSP client implementation of IPeekableSourceProvider instead of this one. Similarly to command handlers this provider also needs to be ordered before LSP's one.

Initial plan

a6810ee

Copilot AI assigned Copilot and dibarbet Oct 29, 2025

Copilot started work on behalf of dibarbet October 29, 2025 20:07 View session

Enable LSP go-to-definition and find-all-references capabilities with…

84c9fbe

… command handler ordering Co-authored-by: dibarbet <5749229+dibarbet@users.noreply.github.com>

Copilot AI changed the title ~~[WIP] Experiment with enabling LSP go to definition and FAR handlers~~ Experiment: Enable LSP go-to-definition and find-all-references with command handler precedence Oct 29, 2025

Copilot AI requested a review from dibarbet October 29, 2025 20:26

Copilot finished work on behalf of dibarbet October 29, 2025 20:26

hjihong reviewed Oct 29, 2025

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dibarbet reviewed Oct 29, 2025

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Copilot started work on behalf of dibarbet October 29, 2025 20:29 View session

Update LSP command handler names to exact requested values

e37817f

Co-authored-by: dibarbet <5749229+dibarbet@users.noreply.github.com>

Copilot AI requested a review from dibarbet October 29, 2025 20:35

Copilot finished work on behalf of dibarbet October 29, 2025 20:35

Copilot started work on behalf of dibarbet October 30, 2025 21:21 View session

Add Go To Implementation capability and command handler ordering

93fcd0e

Co-authored-by: dibarbet <5749229+dibarbet@users.noreply.github.com>

Copilot AI changed the title ~~Experiment: Enable LSP go-to-definition and find-all-references with command handler precedence~~ Experiment: Enable LSP go-to-definition, find-all-references, and go-to-implementation with command handler precedence Oct 30, 2025

Copilot finished work on behalf of dibarbet October 30, 2025 21:28

dibarbet changed the title ~~Experiment: Enable LSP go-to-definition, find-all-references, and go-to-implementation with command handler precedence~~ Enable LSP go-to-definition, find-all-references, and go-to-implementation with command handler precedence Oct 31, 2025

dibarbet marked this pull request as ready for review October 31, 2025 20:56

dibarbet requested a review from a team as a code owner October 31, 2025 20:56

dibarbet requested a review from jasonmalinowski October 31, 2025 20:58

CyrusNajmabadi approved these changes Nov 2, 2025

View reviewed changes

Copilot started work on behalf of dibarbet November 3, 2025 21:59 View session

Document that LSP command handler names are externally agreed upon an…

c63bb03

…d cannot change Co-authored-by: dibarbet <5749229+dibarbet@users.noreply.github.com>

Copilot finished work on behalf of dibarbet November 3, 2025 22:04

dibarbet merged commit 85dda97 into main Nov 4, 2025
25 checks passed

dotnet-policy-service bot added this to the Next milestone Nov 4, 2025

This was referenced Nov 5, 2025

[main] Source code updates from dotnet/roslyn dotnet/dotnet#3147

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[release/10.0.2xx] Source code updates from dotnet/roslyn dotnet/dotnet#3244

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dotnet-bot mentioned this pull request Nov 7, 2025

[Automated] PRs inserted in VS build main-11206.22 #81091

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olegtk mentioned this pull request Nov 7, 2025

Add order attribute to PeekableItemSourceProvider #81095

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dotnet-bot mentioned this pull request Nov 7, 2025

[Automated] PRs inserted in VS build feature.debugger.main-11206.224 #81096

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Enable LSP go-to-definition, find-all-references, and go-to-implementation with command handler precedence #80951

Enable LSP go-to-definition, find-all-references, and go-to-implementation with command handler precedence #80951

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Changes: Enable LSP Go-to-Definition, Find-All-References, and Go-to-Implementation Capabilities

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Copilot AI commented Oct 29, 2025 •

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