C# Automatic indentation formatting appears to be broken

[NWGAlex]

Type: Bug

Issue Description

The formatter is now removing indentation automatically in many cases. This started happening today after updating to the latest version of the extension. Indentation works properly if I disable the extension.

Left side is the old behavior.
Right side is the new behavior.
In the video I'm creating a new line, then hitting Ctrl + Z to reverse it. You can clearly see that in the new behavior, the indentation comes back after hitting Ctrl + Z, indicating that it was there from the start, but then it was removed automatically.

20251009-0806-50.1815800.mp4

Steps to Reproduce

Create a new line inside of a class instance, or when defining enums. It happens elsewhere as well, but those are two easy ways to reproduce.

Expected Behavior

Indentation should be respected.

Actual Behavior

Indentation is completely removed.

Extension version: 2.93.22
VS Code version: Code 1.104.3 (385651c938df8a906869babee516bffd0ddb9829, 2025-10-02T12:30:51.747Z)
OS version: Windows_NT x64 10.0.26100
Modes:

Logs

C# log

2025-10-09 10:10:26.409 [info] Locating .NET runtime version 9.0.1
2025-10-09 10:10:27.309 [info] Dotnet path: C:\Program Files\dotnet\dotnet.exe
2025-10-09 10:10:27.309 [info] Activating C# + C# Dev Kit...
2025-10-09 10:10:27.774 [info] [stdout] info: Program[0]
      Server started with process ID 26564

2025-10-09 10:10:28.461 [info] [stdout] fail: Microsoft.CodeAnalysis.Remote.ExportProviderBuilder[0]
      Encountered errors in the MEF composition:
      ----- CompositionError level 1 ------
      Microsoft.VisualStudio.Copilot.Roslyn.Completion.CSharpReferencedSymbolDefinitionSnippetProvider.ctor(joinableTaskContext): expected exactly 1 export matching constraints:
          Contract name: Microsoft.VisualStudio.Threading.JoinableTaskContext
          TypeIdentityName: Microsoft.VisualStudio.Threading.JoinableTaskContext
      but found 0.
         part definition Microsoft.VisualStudio.Copilot.Roslyn.Completion.CSharpReferencedSymbolDefinitionSnippetProvider
      
      Microsoft.VisualStudio.Copilot.Roslyn.Completion.CSharpMemberAccessSymbolBlueprintProvider.ctor(joinableTaskContext): expected exactly 1 export matching constraints:
          Contract name: Microsoft.VisualStudio.Threading.JoinableTaskContext
          TypeIdentityName: Microsoft.VisualStudio.Threading.JoinableTaskContext
      but found 0.
         part definition Microsoft.VisualStudio.Copilot.Roslyn.Completion.CSharpMemberAccessSymbolBlueprintProvider
      
      Microsoft.VisualStudio.Copilot.Roslyn.Completion.CSharpMethodCallerBlueprintProvider.ctor(joinableTaskContext): expected exactly 1 export matching constraints:
          Contract name: Microsoft.VisualStudio.Threading.JoinableTaskContext
          TypeIdentityName: Microsoft.VisualStudio.Threading.JoinableTaskContext
      but found 0.
         part definition Microsoft.VisualStudio.Copilot.Roslyn.Completion.CSharpMethodCallerBlueprintProvider
      
      Microsoft.CodeAnalysis.ExternalAccess.Copilot.Internal.SemanticSearch.CopilotSemanticSearchQueryExecutor.ctor(workspaceProvider): expected exactly 1 export matching constraints:
          Contract name: Microsoft.CodeAnalysis.Host.IHostWorkspaceProvider
          TypeIdentityName: Microsoft.CodeAnalysis.Host.IHostWorkspaceProvider
      but found 0.
         part definition Microsoft.CodeAnalysis.ExternalAccess.Copilot.Internal.SemanticSearch.CopilotSemanticSearchQueryExecutor
      
      Microsoft.CodeAnalysis.ExternalAccess.Copilot.Internal.CodeMapper.CSharpMapCodeService.ctor(service): expected exactly 1 export matching constraints:
          Contract name: Microsoft.CodeAnalysis.ExternalAccess.Copilot.CodeMapper.ICSharpCopilotMapCodeService
          TypeIdentityName: Microsoft.CodeAnalysis.ExternalAccess.Copilot.CodeMapper.ICSharpCopilotMapCodeService
      but found 0.
         part definition Microsoft.CodeAnalysis.ExternalAccess.Copilot.Internal.CodeMapper.CSharpMapCodeService
      
      Microsoft.CodeAnalysis.ExternalAccess.Pythia.PythiaSignatureHelpProvider.ctor(implementation): expected exactly 1 export matching constraints:
          Contract name: Microsoft.CodeAnalysis.ExternalAccess.Pythia.Api.IPythiaSignatureHelpProviderImplementation
          TypeIdentityName: Microsoft.CodeAnalysis.ExternalAccess.Pythia.Api.IPythiaSignatureHelpProviderImplementation
      but found 0.
         part definition Microsoft.CodeAnalysis.ExternalAccess.Pythia.PythiaSignatureHelpProvider
      
      
      Microsoft.VisualStudio.Composition.CompositionFailedException: Errors exist in the composition.
         at Microsoft.VisualStudio.Composition.CompositionConfiguration.ThrowOnErrors()
         at Microsoft.CodeAnalysis.Remote.ExportProviderBuilder.CheckForAndReportCompositionErrors(CompositionConfiguration configuration, ComposableCatalog catalog) in /_/src/Workspaces/Remote/Core/ExportProviderBuilder.cs:line 208

2025-10-09 10:10:29.473 [info] [stdout] {"pipeName":"\\\\.\\pipe\\82d88b9b"}

2025-10-09 10:10:29.473 [info] received named pipe information from server
2025-10-09 10:10:29.501 [info] client has connected to server
2025-10-09 10:10:29.538 [info] [Program] Language server initialized
2025-10-09 10:10:30.239 [info] [textDocument/_vs_getProjectContexts] [Microsoft.CodeAnalysis.LanguageServer.DotnetCliHelper] Using dotnet executable configured on the PATH
2025-10-09 10:10:30.636 [info] [textDocument/_vs_getProjectContexts] [Microsoft.CodeAnalysis.LanguageServer.FileBasedPrograms.FileBasedProgramsProjectSystem] Failed to obtain virtual project for 'c:\Private\Projects\EPiBackend\NWG.Commerce\Data\Export\ApiExport.cs' using dotnet run-api. Falling back to directly creating the virtual project.
2025-10-09 10:10:31.292 [info] [textDocument/_vs_getProjectContexts] [Microsoft.CodeAnalysis.MSBuild.BuildHostProcessManager] .NET BuildHost started from c:\Users\stnalwu1\.vscode\extensions\ms-dotnettools.csharp-2.93.22-win32-x64\.roslyn\Microsoft.CodeAnalysis.LanguageServer.exe reloading to start from C:\Program Files\dotnet\dotnet.exe to match necessary SDK location.
2025-10-09 10:10:33.009 [warning] [textDocument/_vs_getProjectContexts] [LanguageServerProjectLoader] Project c:\Private\Projects\EPiBackend\NWG.Commerce\Data\Export\ApiExport.csproj has unresolved dependencies
2025-10-09 10:10:33.082 [info] [textDocument/_vs_getProjectContexts] [LanguageServerProjectLoader] Successfully completed load of c:\Private\Projects\EPiBackend\NWG.Commerce\Data\Export\ApiExport.cs
2025-10-09 10:10:33.364 [info] [serviceBroker/connect] [WorkspaceProjectFactoryService] Project C:\Private\Projects\EPiBackend\NWG.Commerce.WebJob\NWG.Commerce.WebJob.csproj loaded by C# Dev Kit
2025-10-09 10:10:33.373 [info] [serviceBroker/connect] [WorkspaceProjectFactoryService] Project C:\Private\Projects\EPiBackend\NWG.Commerce\NWG.Commerce.csproj loaded by C# Dev Kit
2025-10-09 10:10:33.489 [info] [serviceBroker/connect] [WorkspaceProjectFactoryService] Project C:\Private\Projects\EPiBackend\NWG.Azure\NWG.Azure.csproj loaded by C# Dev Kit
2025-10-09 10:10:33.538 [info] [serviceBroker/connect] [WorkspaceProjectFactoryService] Project C:\Private\Projects\EPiBackend\NWG.Commerce.WebJob.Shared\NWG.Commerce.WebJob.Shared.csproj loaded by C# Dev Kit
2025-10-09 10:10:33.810 [error] [workspace/_roslyn_restore] [Microsoft.CodeAnalysis.LanguageServer.Handler.RestoreHandler] Restore completed with errors.
2025-10-09 10:10:33.812 [info] [serviceBroker/connect] [WorkspaceProjectFactoryService] Project C:\Private\Projects\EPiBackend\NWG.Commerce.Identity\NWG.Commerce.Identity.csproj loaded by C# Dev Kit
2025-10-09 10:10:33.815 [info] [textDocument/_vs_getProjectContexts] [LanguageServerProjectLoader] Completed (re)load of all projects in 00:00:03.6016525
2025-10-09 10:10:34.076 [info] [serviceBroker/connect] [WorkspaceProjectFactoryService] Project C:\Private\Projects\EPiBackend\NWG.Commerce.Microshop\NWG.Commerce.Microshop.csproj loaded by C# Dev Kit
2025-10-09 10:10:34.204 [info] [serviceBroker/connect] [WorkspaceProjectFactoryService] Project C:\Private\Projects\EPiBackend\NWG.Commerce.Test\NWG.Commerce.Test.csproj loaded by C# Dev Kit
2025-10-09 10:10:34.436 [info] [serviceBroker/connect] [WorkspaceProjectFactoryService] Project C:\Private\Projects\EPiBackend\NWG.Commerce.Api\NWG.Commerce.Api.csproj loaded by C# Dev Kit
2025-10-09 10:10:34.447 [info] [serviceBroker/connect] [WorkspaceProjectFactoryService] Project C:\Private\Projects\EPiBackend\NWG.Commerce.ReturnCenter\NWG.Commerce.ReturnCenter.csproj loaded by C# Dev Kit
2025-10-09 10:10:34.699 [info] [serviceBroker/connect] [WorkspaceProjectFactoryService] Project C:\Private\Projects\EPiBackend\NWG.CommerceFunction\NWG.CommerceFunction.csproj loaded by C# Dev Kit

C# LSP Trace Logs log

Environment Information

VSCode version: 1.104.3
C# Extension: 2.93.22
Using OmniSharp: false

Dotnet Information

.NET SDK: Version: 9.0.305 Commit: 3fc74f3529 Workload version: 9.0.300-manifests.6fcb754b MSBuild version: 17.14.21+8929ca9e3

Runtime Environment:
OS Name: Windows
OS Version: 10.0.26100
OS Platform: Windows
RID: win-x64
Base Path: C:\Program Files\dotnet\sdk\9.0.305\

.NET workloads installed:
[aspire]
Installation Source: VS 17.14.36518.9
Manifest Version: 8.2.2/8.0.100
Manifest Path: C:\Program Files\dotnet\sdk-manifests\8.0.100\microsoft.net.sdk.aspire\8.2.2\WorkloadManifest.json
Install Type: Msi

Configured to use loose manifests when installing new manifests.

Host:
Version: 9.0.9
Architecture: x64
Commit: 893c2ebbd4

.NET SDKs installed:
6.0.428 [C:\Program Files\dotnet\sdk]
9.0.305 [C:\Program Files\dotnet\sdk]

.NET runtimes installed:
Microsoft.AspNetCore.App 5.0.17 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.App]
Microsoft.AspNetCore.App 6.0.36 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.App]
Microsoft.AspNetCore.App 7.0.20 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.App]
Microsoft.AspNetCore.App 8.0.20 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.App]
Microsoft.AspNetCore.App 9.0.9 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.App]
Microsoft.NETCore.App 5.0.17 [C:\Program Files\dotnet\shared\Microsoft.NETCore.App]
Microsoft.NETCore.App 6.0.27 [C:\Program Files\dotnet\shared\Microsoft.NETCore.App]
Microsoft.NETCore.App 6.0.36 [C:\Program Files\dotnet\shared\Microsoft.NETCore.App]
Microsoft.NETCore.App 7.0.20 [C:\Program Files\dotnet\shared\Microsoft.NETCore.App]
Microsoft.NETCore.App 8.0.20 [C:\Program Files\dotnet\shared\Microsoft.NETCore.App]
Microsoft.NETCore.App 9.0.9 [C:\Program Files\dotnet\shared\Microsoft.NETCore.App]
Microsoft.WindowsDesktop.App 5.0.17 [C:\Program Files\dotnet\shared\Microsoft.WindowsDesktop.App]
Microsoft.WindowsDesktop.App 6.0.27 [C:\Program Files\dotnet\shared\Microsoft.WindowsDesktop.App]
Microsoft.WindowsDesktop.App 6.0.36 [C:\Program Files\dotnet\shared\Microsoft.WindowsDesktop.App]
Microsoft.WindowsDesktop.App 7.0.20 [C:\Program Files\dotnet\shared\Microsoft.WindowsDesktop.App]
Microsoft.WindowsDesktop.App 8.0.20 [C:\Program Files\dotnet\shared\Microsoft.WindowsDesktop.App]
Microsoft.WindowsDesktop.App 9.0.9 [C:\Program Files\dotnet\shared\Microsoft.WindowsDesktop.App]

Other architectures found:
x86 [C:\Program Files (x86)\dotnet]
registered at [HKLM\SOFTWARE\dotnet\Setup\InstalledVersions\x86\InstallLocation]

Environment variables:
Not set

global.json file:
Not found

Learn more:
https://aka.ms/dotnet/info

Download .NET:
https://aka.ms/dotnet/download

Visual Studio Code Extensions

Extension	Author	Version	Folder Name
command-server	pokey	0.12.0	pokey.command-server-0.12.0
copilot	GitHub	1.372.0	github.copilot-1.372.0
copilot-chat	GitHub	0.31.5	github.copilot-chat-0.31.5
csdevkit	ms-dotnettools	1.60.2	ms-dotnettools.csdevkit-1.60.2-win32-x64
csharp	ms-dotnettools	2.93.22	ms-dotnettools.csharp-2.93.22-win32-x64
errorlens	usernamehw	3.26.0	usernamehw.errorlens-3.26.0
es7-react-js-snippets	dsznajder	4.4.3	dsznajder.es7-react-js-snippets-4.4.3
gitlens	eamodio	17.6.1	eamodio.gitlens-17.6.1
indent-rainbow	oderwat	8.3.1	oderwat.indent-rainbow-8.3.1
parse-tree	pokey	0.43.0	pokey.parse-tree-0.43.0
prettier-vscode	esbenp	11.0.0	esbenp.prettier-vscode-11.0.0
pretty-ts-errors	YoavBls	0.6.1	yoavbls.pretty-ts-errors-0.6.1
rest-client	humao	0.25.1	humao.rest-client-0.25.1
talon	pokey	0.2.0	pokey.talon-0.2.0
vscode-dotnet-runtime	ms-dotnettools	2.3.7	ms-dotnettools.vscode-dotnet-runtime-2.3.7
vscode-fileutils	sleistner	3.10.3	sleistner.vscode-fileutils-3.10.3
vscode-styled-components	styled-components	1.7.8	styled-components.vscode-styled-components-1.7.8
vscode-talonscript	mrob95	0.3.24	mrob95.vscode-talonscript-0.3.24
vsliveshare	ms-vsliveshare	1.0.5959	ms-vsliveshare.vsliveshare-1.0.5959

C# Settings

Setting	Value
preferCSharpExtension	false
compilerDiagnosticScope	openFiles
analyzerDiagnosticScope	openFiles
enableXamlTools	true
useServerGC	true

System Info

Item	Value
CPUs	13th Gen Intel(R) Core(TM) i7-13800H (20 x 2918)
GPU Status	2d_canvas: enabled direct_rendering_display_compositor: disabled_off_ok gpu_compositing: enabled multiple_raster_threads: enabled_on opengl: enabled_on rasterization: enabled raw_draw: disabled_off_ok skia_graphite: disabled_off trees_in_viz: disabled_off video_decode: enabled video_encode: enabled vulkan: disabled_off webgl: enabled webgl2: enabled webgpu: enabled webnn: disabled_off
Load (avg)	undefined
Memory (System)	31.69GB (13.21GB free)
Process Argv	C:\Private\Projects\EPiBackend
Screen Reader	no
VM	0%

[JoeRobich]

@NWGAlex What are your settings for editor.formatOn* and files.autoSave*?

[NWGAlex]

"editor.formatOnSave": true,

I can't see any files.autoSave* settings in my settings.json, so I assume that they're the default value.
As far as I can see, that's false/off.

Setting "editor.formatOnSave" to false does not solve the issue.

[JoeRobich]

LSP Trace Logs

2025-10-10 06:28:59.226 [trace] Sending notification 'textDocument/didChange'.
Params: {
    "textDocument": {
        "uri": "file:///Users/joeyrobichaud/Source/roslyn-tools/src/dotnet-roslyn-tools/Commands/NuGetPrepareCommand.cs",
        "version": 21
    },
    "contentChanges": [
        {
            "range": {
                "start": {
                    "line": 20,
                    "character": 28
                },
                "end": {
                    "line": 20,
                    "character": 28
                }
            },
            "rangeLength": 0,
            "text": "\n            "
        }
    ]
}
2025-10-10 06:28:59.226 [trace] Sending request 'textDocument/_vs_onAutoInsert - (963)'.
Params: {
    "_vs_textDocument": {
        "uri": "file:///Users/joeyrobichaud/Source/roslyn-tools/src/dotnet-roslyn-tools/Commands/NuGetPrepareCommand.cs",
        "version": 21
    },
    "_vs_position": {
        "line": 20,
        "character": 41
    },
    "_vs_ch": "\n",
    "_vs_options": {
        "tabSize": 4,
        "insertSpaces": true
    }
}
2025-10-10 06:28:59.227 [trace] Sending request 'textDocument/onTypeFormatting - (964)'.
Params: {
    "textDocument": {
        "uri": "file:///Users/joeyrobichaud/Source/roslyn-tools/src/dotnet-roslyn-tools/Commands/NuGetPrepareCommand.cs"
    },
    "position": {
        "line": 21,
        "character": 12
    },
    "ch": "\n",
    "options": {
        "tabSize": 4,
        "insertSpaces": true,
        "trimTrailingWhitespace": true
    }
}
2025-10-10 06:28:59.227 [trace] Received notification 'window/logMessage'.
Params: {
    "type": 5,
    "message": "[textDocument/didChange] [LSP] Starting request handler"
}
2025-10-10 06:28:59.227 [trace] Received notification 'window/logMessage'.
Params: {
    "type": 5,
    "message": "[textDocument/didChange] [LSP] Request handler completed successfully."
}
2025-10-10 06:28:59.232 [trace] Received notification 'window/logMessage'.
Params: {
    "type": 5,
    "message": "[textDocument/_vs_onAutoInsert] [LSP] /Users/joeyrobichaud/Source/roslyn-tools/src/dotnet-roslyn-tools/Commands/NuGetPrepareCommand.cs found in workspace Host; project Microsoft.RoslynTools"
}
2025-10-10 06:28:59.233 [trace] Received notification 'window/logMessage'.
Params: {
    "type": 5,
    "message": "[textDocument/_vs_onAutoInsert] [LSP] Starting request handler"
}
2025-10-10 06:28:59.240 [trace] Received notification 'window/logMessage'.
Params: {
    "type": 5,
    "message": "[textDocument/onTypeFormatting] [LSP] /Users/joeyrobichaud/Source/roslyn-tools/src/dotnet-roslyn-tools/Commands/NuGetPrepareCommand.cs found in workspace Host; project Microsoft.RoslynTools"
}
2025-10-10 06:28:59.240 [trace] Received notification 'window/logMessage'.
Params: {
    "type": 5,
    "message": "[textDocument/onTypeFormatting] [LSP] Starting request handler"
}
2025-10-10 06:28:59.240 [trace] Received response 'textDocument/_vs_onAutoInsert - (963)' in 14ms.
No result returned.
2025-10-10 06:28:59.240 [trace] Received notification 'window/logMessage'.
Params: {
    "type": 5,
    "message": "[textDocument/_vs_onAutoInsert] [LSP] Request handler completed successfully."
}
2025-10-10 06:28:59.241 [trace] Received response 'textDocument/onTypeFormatting - (964)' in 14ms.
Result: [
    {
        "range": {
            "start": {
                "line": 21,
                "character": 0
            },
            "end": {
                "line": 22,
                "character": 8
            }
        },
        "newText": "\n        "
    }
]
2025-10-10 06:28:59.247 [trace] Sending notification 'textDocument/didChange'.
Params: {
    "textDocument": {
        "uri": "file:///Users/joeyrobichaud/Source/roslyn-tools/src/dotnet-roslyn-tools/Commands/NuGetPrepareCommand.cs",
        "version": 22
    },
    "contentChanges": [
        {
            "range": {
                "start": {
                    "line": 21,
                    "character": 0
                },
                "end": {
                    "line": 21,
                    "character": 12
                }
            },
            "rangeLength": 12,
            "text": ""
        }
    ]
}

It is a problem in OnTypeFormatting which we now enable for C# files. The initial edit comes in which adds a newline to line 20 (the last ,) and the expected indentation on line 21 (the new line). OnTypeFormatting then returns a newline for line 21 (the new line) and indentation for line 22 (the }).

[BuyMyBeard]

Encountering the same issue. Reverting to v2.90.60 fixed the issue for me. v2.94.41 prerelease also has this issue it seems.