Extract raw string literal auto-insert logic into reusable service by Copilot · Pull Request #80871 · dotnet/roslyn

Copilot · 2025-10-23T18:48:23Z

Resolves #68537 by extracting the custom Visual Studio behavior for raw string literal auto-insertion into a workspace service that can be shared between the VS command handler and LSP OnAutoInsert handler.

Problem

Previously, the logic for automatically expanding raw string literals when typing quote characters was hardcoded in the VS-specific command handler (RawStringLiteralCommandHandler_TypeChar.cs). This made it impossible to provide the same functionality through LSP for other editors.

Solution

This PR extracts the raw string literal expansion logic into a new workspace service:

Created IRawStringLiteralOnAutoInsertService interface in the Features layer
- Takes a document and caret position as input
- Returns a TextChange if raw string expansion should occur
- Returns null if no special handling is needed
Implemented CSharpRawStringLiteralOnAutoInsertService in the C# Features layer
- Extracted the three expansion scenarios from the command handler:
  - Generate initial empty raw string: "" + " → """"""
  - Grow initial empty raw string: """$$""" + " → """"$$""""
  - Grow raw string delimiters: """$$ content """ + " → """" content """"
Updated RawStringLiteralCommandHandler_TypeChar.cs to use the service
- Maintains all existing VS behavior and user experience
- Code is now cleaner and more maintainable
- Removed ~170 lines of inline logic in favor of service call
Integrated with OnAutoInsertHandler.cs
- Added support for quote character auto-insertion
- Foundation in place for LSP-based editors to provide raw string expansion

Impact

VS users: No behavior change, existing functionality preserved
LSP users: Infrastructure now available for raw string literal support
Codebase: Better separation of concerns, reusable service interface

The service follows Roslyn's standard patterns with [ExportLanguageService] and proper MEF construction.

Warning

Firewall rules blocked me from connecting to one or more addresses (expand for details)

I tried to connect to the following addresses, but was blocked by firewall rules:

https://api.github.com/repos/dotnet/roslyn/issues/68537
- Triggering command: curl -s REDACTED (http block)

If you need me to access, download, or install something from one of these locations, you can either:

Configure Actions setup steps to set up my environment, which run before the firewall is enabled
Add the appropriate URLs or hosts to the custom allowlist in this repository's Copilot coding agent settings (admins only)

Original prompt

I'd like you to resolve this issue #68537 using the implementation notes below.

This should essentially just be extracting out the existing, custom VS behavior from here -

roslyn/src/EditorFeatures/CSharp/RawStringLiteral/RawStringLiteralCommandHandler_TypeChar.cs

Line 52 in 9cdd3c9

var textChangeOpt =

into its own workspace service and calling that service in on auto insert - https://github.com/dotnet/roslyn/blob/main/src/LanguageServer/Protocol/Handler/OnAutoInsert/OnAutoInsertHandler.cs

Generally, the service can take in the document and caret position and return a text edit (if any). This service interface should be defined in features, with the implementation in c# features layer. The autoinsert implementation should call the service to get the text edit and return it. The existing VS command handler should be updated to use the service

✨ Let Copilot coding agent set things up for you — coding agent works faster and does higher quality work when set up for your repo.

Co-authored-by: dibarbet <[email protected]>

CyrusNajmabadi · 2025-10-24T02:43:39Z

I can review tomorrow

dibarbet · 2025-10-24T03:28:13Z

src/LanguageServer/ProtocolUnitTests/OnAutoInsert/AbstractOnAutoInsertTests.cs

+namespace Microsoft.CodeAnalysis.LanguageServer.UnitTests.OnAutoInsert;
+
+[Trait(Traits.Feature, Traits.Features.AutomaticCompletion)]
+public abstract class AbstractOnAutoInsertTests(ITestOutputHelper testOutputHelper) : AbstractLanguageServerProtocolTests(testOutputHelper)


all this is moved

CyrusNajmabadi · 2025-10-24T12:47:12Z

src/EditorFeatures/CSharp/RawStringLiteral/RawStringLiteralCommandHandler_TypeChar.cs

-            TryGenerateInitialEmptyRawString(caret.Value, cancellationToken) ??
-            TryGrowInitialEmptyRawString(caret.Value, cancellationToken) ??
-            TryGrowRawStringDelimiters(caret.Value, cancellationToken);
+        var root = document.GetRequiredSyntaxRootSynchronously(cancellationToken);


This is a problem for me. A core idea in the original code was that it did nothing related to syntax unless it first had verified textually that it was in a reasonable position to do so (like checking if it was around quotes). This prevented parsing the syntax tree for most edits.

I don't want to roll that logic back. Can the service just take the document and defer creating the root until needed?

CyrusNajmabadi · 2025-10-24T12:47:34Z

src/EditorFeatures/CSharp/RawStringLiteral/RawStringLiteralCommandHandler_TypeChar.cs

+        var textChange = service.GetTextChangeForQuote(root, text, caret.Value.Position);

-        if (textChangeOpt is not TextChange textChange)
+        if (textChange is null)


seems like you could keep this code :)

reverted - but originally changed this because thjere was an info diagnostic on it

src/Features/CSharp/Portable/RawStringLiteral/CSharpRawStringLiteralOnAutoInsertService.cs

CyrusNajmabadi

tentatively approving, since hte overall change is good. just please change to defer syntaxroot acquisition until needed.

Three things I've been tracking from Roslyn: 1. Auto insert support for raw string literals: dotnet/roslyn#80871 2. Line Folding Only support in VS Code: dotnet/roslyn#80955 (fixes #12414) * We already did this in our folding range response anyway 3. Allow FormattingLogTest can use real types, and remove our temporary equivalent

Initial plan

54de0af

Copilot AI assigned Copilot and dibarbet Oct 23, 2025

Copilot started work on behalf of dibarbet October 23, 2025 18:48 View session

Add raw string literal service and integrate with VS handler

f284b14

Co-authored-by: dibarbet <[email protected]>

dotnet-policy-service bot added the VSCode label Oct 23, 2025

Copilot AI and others added 2 commits October 23, 2025 19:22

Add LSP tests and fix OnAutoInsert integration (WIP)

bec6ee9

Co-authored-by: dibarbet <[email protected]>

Complete raw string literal service integration with basic support

4f3f6d8

Co-authored-by: dibarbet <[email protected]>

Copilot AI changed the title ~~[WIP] Extract custom VS behavior into workspace service~~ Extract raw string literal auto-insert logic into reusable service Oct 23, 2025

Copilot AI requested a review from dibarbet October 23, 2025 19:31

Copilot finished work on behalf of dibarbet October 23, 2025 19:31

Adjust and fix handler plus tests

ad3edeb

build-analysis bot mentioned this pull request Oct 24, 2025

The Operation will be canceled. The next steps may not contain expected logs. dotnet/dnceng#3008

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dibarbet marked this pull request as ready for review October 24, 2025 03:27

dibarbet requested a review from a team as a code owner October 24, 2025 03:27

dibarbet reviewed Oct 24, 2025

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CyrusNajmabadi reviewed Oct 24, 2025

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src/Features/CSharp/Portable/RawStringLiteral/CSharpRawStringLiteralOnAutoInsertService.cs Show resolved Hide resolved

CyrusNajmabadi approved these changes Oct 24, 2025

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review feedback

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dibarbet merged commit 326ae03 into main Oct 24, 2025
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dotnet-policy-service bot added this to the Next milestone Oct 24, 2025

dotnet-maestro bot mentioned this pull request Oct 29, 2025

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

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This was referenced Oct 30, 2025

[Automated] PRs inserted in VS build main-11129.33 #80956

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[Automated] PRs inserted in VS build feature.debugger.main-11131.247 #80976

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davidwengier mentioned this pull request Nov 3, 2025

Various follow ups from Roslyn features dotnet/razor#12435

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jcouv deleted the copilot/extract-vs-behavior-service branch November 13, 2025 17:35

dotnet-maestro bot mentioned this pull request Dec 18, 2025

[main] Source code updates from dotnet/roslyn dotnet/dotnet#3957

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davidwengier modified the milestones: Next, 18.3 Jan 6, 2026

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Extract raw string literal auto-insert logic into reusable service#80871

Extract raw string literal auto-insert logic into reusable service#80871
dibarbet merged 6 commits intomainfrom
copilot/extract-vs-behavior-service

Copilot AI commented Oct 23, 2025 •

edited by dibarbet

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Copilot AI commented Oct 23, 2025 •

edited by dibarbet

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