Skip to content

Backslash mapping breaking change #33790

New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

Sign up for GitHub

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

Merged
merged 2 commits into from
Jan 31, 2023
Merged

Backslash mapping breaking change #33790

Show file tree
Hide file tree
Changes from all commits
Commits
Show all changes
2 commits
Select commit Hold shift + click to select a range
f893482
backslash mapping breaking change
gewarren Jan 31, 2023
24634d2
touch ups
gewarren Jan 31, 2023
File filter

Filter by extension

Filter by extension
Conversations
Failed to load comments.
Loading
Jump to
Jump to file
Failed to load files.
Loading
Diff view
Diff view
1 change: 1 addition & 0 deletions docs/core/compatibility/8.0.md
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -19,6 +19,7 @@ If you're migrating an app to .NET 8, the breaking changes listed here might aff
| Title | Type of change | Introduced |
| --------------------------------------------------------------------------------------- | ----------------- | ---------- |
| [Activity operation name when null](core-libraries/8.0/activity-operation-name.md) | Behavioral change | Preview 1 |
| [Backslash mapping in Unix file paths](core-libraries/8.0/file-path-backslash.md) | Behavioral change | Preview 1 |
| [FileStream writes when pipe is closed](core-libraries/8.0/filestream-disposed-pipe.md) | Behavioral change | Preview 1 |
| [GetFolderPath behavior on Unix](core-libraries/8.0/getfolderpath-unix.md) | Behavioral change | Preview 1 |
| [Legacy Console.ReadKey removed](core-libraries/8.0/console-readkey-legacy.md) | Behavioral change | Preview 1 |
Expand Down
47 changes: 47 additions & 0 deletions docs/core/compatibility/core-libraries/8.0/file-path-backslash.md
View file
Open in desktop
Original file line number Diff line number Diff line change
@@ -0,0 +1,47 @@
---
title: ".NET 8 breaking change: Backslash mapping in Unix file paths"
description: Learn about the .NET 8 breaking change in core .NET libraries where the CoreCLR native runtime no longer maps backslashes to forward slashes in file paths on Unix.
ms.date: 01/30/2023
---
# Backslash mapping in Unix file paths

Backslash (`\`) characters are valid in directory and file names on Unix. Starting in .NET 8, the native CoreCLR runtime no longer converts `\` characters to directory separators—forward slashes (`/`)—on Unix. This change enables .NET applications to be located on paths with names that contain backslash characters. It also allows the native runtime, `dotnet` host, and the `ilasm` and `ildasm` tools to access files on paths that contain backslash characters.

## Previous behavior

The native CoreCLR runtime automatically converted backslash (`\`) characters in file paths to forward slashes (`/`) on Unix.

## New behavior

The native CoreCLR runtime doesn't convert any file path characters on Unix.

## Version introduced

.NET 8 Preview 1

## Type of breaking change

This change is a [behavioral change](../../categories.md#behavioral-change).

## Reason for change

Without this change, .NET apps located in directories that contain backslash characters fail to start.

## Recommended action

- Use <xref:System.IO.Path.DirectorySeparatorChar?displayProperty=nameWithType> as a directory separator in your app instead of hardcoding it to `\` or `/`.
- Use `/` as a directory separator on Unix in file paths that you pass to the `dotnet` host, hosting APIs, and `ilasm` and `ildasm` tools.
- Use `/` as a directory separator on Unix in file paths in various `DOTNET_xxx` [environment variables](../../../tools/dotnet-environment-variables.md).

## Affected APIs

- Hosting APIs
- <xref:System.Runtime.InteropServices.DllImportAttribute.Value?displayProperty=fullName>
- <xref:System.Runtime.InteropServices.NativeLibrary.Load%2A?displayProperty=fullName>
- <xref:System.Runtime.InteropServices.NativeLibrary.TryLoad%2A?displayProperty=fullName>
- <xref:System.Reflection.Assembly.LoadFrom%2A?displayProperty=fullName>
- <xref:System.Reflection.Assembly.LoadFile%2A?displayProperty=fullName>
- <xref:System.Reflection.Assembly.UnsafeLoadFrom(System.String)?displayProperty=fullName>
- <xref:System.Runtime.Loader.AssemblyLoadContext.LoadFromAssemblyPath(System.String)?displayProperty=fullName>
- <xref:System.Runtime.Loader.AssemblyLoadContext.LoadFromNativeImagePath(System.String,System.String)?displayProperty=fullName>
- <xref:System.Runtime.Loader.AssemblyLoadContext.LoadUnmanagedDllFromPath(System.String)?displayProperty=fullName>
4 changes: 4 additions & 0 deletions docs/core/compatibility/toc.yml
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -12,6 +12,8 @@ items:
items:
- name: Activity operation name when null
href: core-libraries/8.0/activity-operation-name.md
- name: Backslash mapping in Unix file paths
href: core-libraries/8.0/file-path-backslash.md
- name: FileStream writes when pipe is closed
href: core-libraries/8.0/filestream-disposed-pipe.md
- name: GetFolderPath behavior on Unix
Expand Down Expand Up @@ -892,6 +894,8 @@ items:
items:
- name: Activity operation name when null
href: core-libraries/8.0/activity-operation-name.md
- name: Backslash mapping in Unix file paths
href: core-libraries/8.0/file-path-backslash.md
- name: FileStream writes when pipe is closed
href: core-libraries/8.0/filestream-disposed-pipe.md
- name: GetFolderPath behavior on Unix
Expand Down