Move lots of shared code to Microsoft.Build.Framework by DustinCampbell · Pull Request #13364 · dotnet/msbuild

DustinCampbell · 2026-03-10T23:20:04Z

This is a big change, but it was created methodically and is highly mechanical. I highly recommend reviewing commit-by-commit.

The pull request is a follow up to #13232 that cleans up shared code and moves some core shared files to Microsoft.Build.Framework. Pruning all shared files in MSBuild is a long-term effort, so this change targets some of the more problematic types that contain state that is intended to be shared.

Here is a summary of the changes:

Remove #if'd code paths that are dead following msbuild#13232.
Move all IFileSystem types to Framework. Note that this means that it is now impossible for FileSystems.Default to diverge across binaries.
Move EscapingUtilities to Framework. This ensures that the static dictionary cache is shared across binaries.
Move FileUtilitiesRegex to Framework.
Split ExceptionHandling up into members into two categories:
- Members that validate Exception objects move to Framework.
- Members for dumping exceptions have moved to DebugUtils, which is still shared.
Move the rest of FileUtilities to Framework. This contains a lot of shared state that is now properly shared instead of being created per-binary.
Move files that are compiled into Microsoft.Build.Framework from the shared folder into Framework.
Rationalize FileUtilities.GetIsFileSystemCaseSensitive() to limit writing a file to the file system.

Now that all .NET 3.5 code has been consolidated in MSBuildTaskHost, the CLR2COMPATIBILITY conditional compiler constant can be removed entirely from the code base.

Now that all .NET 3.5 code has been consolidated in MSBuildTaskHost, the TASKHOST conditional compiler constant can be removed entirely from the code base.

Now that all .NET 3.5 code has been consolidated in MSBuildTaskHost, the NET35 conditionally compiled code can be removed entirely -- except for StringTools, which compiles for .NET 3.5.

Move FileUtilities.IsPathTooLong to FrameworkFileUtilities.IsPathTooLong.

- Move code from src/Shared/FileSystem to Microsoft.Build.Framework/FileSystem - Move "Shared.PathTooLong" resource string from Strings.Shared.resx to Microsoft.Build.Framework/Resources/SR.resx. (and move translated strings.) - Remove Shared/FileSystemSources.proj from Microsoft.Build.Engine.OM.UnitTests, Microsoft.Build, Microsoft.Build.Tasks, Microsoft.Build.Utilities, and MSBuild - Delete Shared/FileSystemSources.proj

- Move src/Shared/EscapingUtilities.cs to src/Framework/EscapingUtilities.cs - Add project reference from Microsoft.Build.Framework to StringTools.csproj. This dependency is needed by EscapingUtilities. - Remove all project reference to StringTools.csproj from projects that reference it transitively through Microsoft.Build.Framework.

- Move src/Shared/FileUtilitiesRegex.cs to src/Framework/FileUtilitiesRegex.cs

This change moves all of the implementations of exception dumping members from ExceptionHandling to DebugUtils. Member stubs have been left in ExceptionHandling that delegate to the implementations in DebugUtils. This will be cleaned up in a later commit. Note that references to the BUILDINGAPPXTASKS conditional compilation symbol have been removed from ExceptionHandling. BUILDINGAPPXTASKS isn't set anywhere within the msbuild repo.

- Add src/Framework/ExceptionHandling.cs containing FrameworkExceptionHandling static class. - Move implementations of members from src/Shared/ExceptionHandling.cs to src/Framework/ExceptionHandling.cs and leave stubs behind. The stubs will be cleaned up in a later commit. - Remove used ExceptionHandling.GetXmlLineAndColumn(Exception) method.

- Add src/Framework/FileUtilities_TemFiles.cs containing a new partial part of the FrameworkFileUtilities static class. - Move implementations of members from src/Shared/TempFileUtilities.cs to src/Framework/FileUtilities_TemFiles.cs and leave stubs behind. The stubs will be cleaned up in a later commit. - Remove TempWorkingDirectory nested type from src/Shared/TempFileUtilities.cs and update callers to use the type nested in FrameworkFileUtilities. - Add "FailedCreatingTempFile" string resource, taking care to copy the translated strings from "Shared.FailedCreatingTempFile"

- Move StreamExtensions from src/Shared/FileUtilities.cs to src/Framework/Polyfills/StreamExtensions.cs

- Add 'NewPath' type alias for Microsoft.IO.Path when compiling for net472. This will facilitate the process of copying members from `src/Shared/FileUtilities.cs` that all use System.IO.Path.

- Move implementations of all members (except ExecutingAssemblyPath) from src/Shared/FileUtilities.cs to src/Framework/FileUtilities.cs and leave stubs behind. The stubs will be cleaned up in a later commit. - Add "DebugPathTooLong" and "InvalidGetPathOfFileAboveParameter" string resources, taking care to copy the translated strings. - Add 'Path' and 'NewPath' aliases to avoid conflicts between System.IO.Path and Microsoft.IO.Path when compiling for net472 and netstandard2.0. This ensures that members copied from src/Shared/FileUtilities.cs continues to call into System.IO.Path, which is necessary to throw expected path exceptions when running on .NET Framework.

- Add src/Framework/ItemSpecModifiers.cs containing a new ItemSpecModifiers static class. - Move implementations of members from src/Shared/Modifiers.cs to src/Framework/ItemSpecModifiers.cs and leave stubs behind. The stubs will be cleaned up in a later commit. - Add "InvalidFilespecForTransform" string resource, taking care to copy the translated strings from "Shared.InvalidFilespecForTransform"

- Move FileUtilities.ExecutingAssemblyPath property to BuildEnvironemtnHelper. This property depends on the code being compiled into the binary that calls it. So, moving this call to another file allows src/Shared/FileUtilities.cs to be deleted.

- Update all usages of Microsoft.Build.Shared.FileUtilities.ItemSpecModifiers to Microsoft.Build.Framework.ItemSpecModifiers. - Remove src/Shared/Modifiers.cs.

- Remove src/Shared/FileUtilities.cs and src/Shared/TempFileUtilities.cs from all project files. - Rename FrameworkFileUtilities to FileUtilities. - Delete src/Shared/FileUtilities.cs and src/Shared/TempFileUtilities.cs - Fix all remaining usages of Microsoft.Build.Shared.FileUtilities to point to Microsoft.Build.Framework.FileUtilities. - Clean up using directives

Update usages of ExceptionHandling members that were delegating to DebugUtills to just use DebugUtils directly.

- Remove src/Shared/ExceptionHandling.cs from all project files. - Rename FrameworkExceptionHandling to ExceptionHandling. - Delete src/Shared/ExceptionHandling.cs - Fix all remaining usages of Microsoft.Build.Shared.ExceptionHandling to point to Microsoft.Build.Framework.ExceptionHandling. - Clean up using directives

This type was compiled from src/Shared/Constants.cs but it wasn't included in any other projects. This change removes it completely from src/Shared and includes it directly in src/Framework.

This type was compiled from src/Shared/EnvironmentUtilities.cs but it wasn't included in any other projects. This change removes it completely from src/Shared and includes it directly in src/Framework. In addition, it has been moved to the Microsoft.Build.Framework namespace.

These types were compiled from src/Shared/BinaryReaderExtensions.cs and src/Shared/BinaryWriterExtensions.cs but they weren't included in any other projects. This change removes them completely from src/Shared and includes them directly in src/Framework. In addition, they have been moved to the Microsoft.Build.Framework namespace.

This type was compiled from src/Shared/IMSBuildElementLocation.cs but it wasn't included in any other projects. This change removes it completely from src/Shared and includes it directly in src/Framework. It has to remain in the Microsoft.Build.Shared namespace, since it's a public API.

This method creates a temp file to check whether the file system is case sensitive or not. Since the check relies on writing a file to disk, this change caches the result (like the .NET Runtime does) and converts the GetIsFileSystemCaseSensitive() method to a property called, IsFileSystemCaseSensitive.

Copilot

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DustinCampbell · 2026-03-10T23:23:18Z

Copilot wasn't able to review this pull request because it exceeds the maximum number of files (300). Try reducing the number of changed files and requesting a review from Copilot again.

This should be accompanied by an "Achievement Unlocked"

JanProvaznik

everything makes sense thanks, looking for second reviewer

src/MSBuild/OutOfProcTaskHostNode.cs

JanProvaznik · 2026-03-11T12:27:59Z

Note: this makes Framework depend on StringTools, I think that's fine, but flagging for @rainersigwald

rainersigwald · 2026-03-11T22:20:49Z

A Framework->StringTools dependency should be fine, but I'm paranoid so I kicked off an experimental insertion: https://dev.azure.com/devdiv/DevDiv/_git/VS/pullrequest/716860.

DustinCampbell · 2026-03-11T23:15:31Z

A Framework->StringTools dependency should be fine, but I'm paranoid so I kicked off an experimental insertion: https://dev.azure.com/devdiv/DevDiv/_git/VS/pullrequest/716860.

Yeah, StringTools gets pulled in by the first thing that calls into the EscapingUtilities, so I don't expect this to be a problem either. Stranger things have happened though! 😄

rainersigwald · 2026-03-12T14:31:40Z

We had a bad fire drill a while ago where an API NuGet called got a new assembly dependency (that the DLL already had, just not this specific method!) and broke a bunch of folks using the default AzDO configuration. This at least didn't break that thing, since we have a regression test

msbuild/src/Build.OM.UnitTests/Microsoft.Build.Engine.OM.UnitTests.csproj

Line 28 in 8cee1da

    
           <PackageDownload Include="NuGet.CommandLine" Version="[$(NuGetCommandLinePackageVersion)]" />

And the exp insertion looks fine. I'm good with this change as soon as we unblock insertions (VS repo self-build test is currently broken by a not-MSBuild change, but that is a required scenario test for us).

DustinCampbell · 2026-03-12T14:35:53Z

We had a bad fire drill a while ago where an API NuGet called got a new assembly dependency (that the DLL already had, just not this specific method!) and broke a bunch of folks using the default AzDO configuration.

Yeah, that's exactly the sort of "stranger thing" I was thinking of. 😄

After FileUtilities moved from Shared to Framework (dotnet#13364), all assemblies share the same cacheDirectory static. ClearCacheDirectory() in XMake.cs now deletes the same directory that ProjectImportsCollector uses for its temporary archive, causing 'Could not find a part of the path' errors during binlog finalization. Fix: Store the temporary ProjectImports archive in TempFileDirectory (the parent) rather than GetCacheDirectory() (the child that gets wiped). Also make DeleteArchive resilient to the archive already being cleaned up. Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

DustinCampbell added 26 commits March 10, 2026 09:03

Remove all CLR2COMPATIBILITY code paths

3cf160b

Now that all .NET 3.5 code has been consolidated in MSBuildTaskHost, the CLR2COMPATIBILITY conditional compiler constant can be removed entirely from the code base.

Remove all TASKHOST code paths

83253e4

Now that all .NET 3.5 code has been consolidated in MSBuildTaskHost, the TASKHOST conditional compiler constant can be removed entirely from the code base.

Remove all NET35 code paths (except StringTools)

5e8c0ef

Now that all .NET 3.5 code has been consolidated in MSBuildTaskHost, the NET35 conditionally compiled code can be removed entirely -- except for StringTools, which compiles for .NET 3.5.

Move FileUtilities.IsPathTooLong to Framework

f8699df

Move FileUtilities.IsPathTooLong to FrameworkFileUtilities.IsPathTooLong.

Move FileUtilitiesRegex to Framework

bbfccd9

- Move src/Shared/FileUtilitiesRegex.cs to src/Framework/FileUtilitiesRegex.cs

Move StreamExtensions from FileUtilities.cs to Framework

abf128e

- Move StreamExtensions from src/Shared/FileUtilities.cs to src/Framework/Polyfills/StreamExtensions.cs

Prepare FrameworkFileUtiliites for FileUtilities merge

07d931d

- Add 'NewPath' type alias for Microsoft.IO.Path when compiling for net472. This will facilitate the process of copying members from `src/Shared/FileUtilities.cs` that all use System.IO.Path.

Update ItemSpecModifiers usages and remove Modifiers.cs

5e51cbb

- Update all usages of Microsoft.Build.Shared.FileUtilities.ItemSpecModifiers to Microsoft.Build.Framework.ItemSpecModifiers. - Remove src/Shared/Modifiers.cs.

Update ExceptionHandling usages to DebugUtils

2a69cd0

Update usages of ExceptionHandling members that were delegating to DebugUtills to just use DebugUtils directly.

Move FileUtilities_Tests to Framework.UnitTests

765c837

Move EscapingUtilities_Tests to Framework.UnitTests

79fb6df

Move MSBuildConstants to Framework

b280244

This type was compiled from src/Shared/Constants.cs but it wasn't included in any other projects. This change removes it completely from src/Shared and includes it directly in src/Framework.

Copilot AI review requested due to automatic review settings March 10, 2026 23:20

Copilot AI reviewed Mar 10, 2026

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JanProvaznik approved these changes Mar 11, 2026

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src/MSBuild/OutOfProcTaskHostNode.cs Outdated Show resolved Hide resolved

rainersigwald approved these changes Mar 11, 2026

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DustinCampbell mentioned this pull request Mar 11, 2026

Move more shared files to a single binary #13370

Open

DustinCampbell added 2 commits March 11, 2026 16:07

Merge branch 'main' into isolate-taskhost-followup

119a67e

Remove a couple of lingering CLRCOMPATIBILITY code paths

0d3953a

JanProvaznik merged commit df3c977 into main Mar 12, 2026
10 checks passed

JanProvaznik deleted the dev/dustinca/isolate-taskhost-followup branch March 12, 2026 15:41

This was referenced Mar 12, 2026

[release/10.0.3xx] Source code updates from dotnet/msbuild dotnet/dotnet#5419

Open

[main] Source code updates from dotnet/msbuild dotnet/dotnet#5433

Open

This was referenced Mar 13, 2026

Fix ProjectImports.zip regression from shared FileUtilities statics JanProvaznik/msbuild#18

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Fix ProjectImports.zip regression from shared FileUtilities statics #13382

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Move lots of shared code to Microsoft.Build.Framework#13364

Move lots of shared code to Microsoft.Build.Framework#13364
JanProvaznik merged 28 commits intomainfrom
dev/dustinca/isolate-taskhost-followup

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