dotnet/Documentation/compatibility/path-colon-checks-are-stricter.md

Path colon checks are stricter

Scope

Edge

Version Introduced

4.6.2

Source Analyzer Status

NotPlanned

Change Description

In .NET Framework 4.6.2, a number of changes were made to support previously unsupported paths (both in length and format). Checks for proper drive separator (colon) syntax were made more correct, which had the side effect of blocking some URI paths in a few select Path APIs where they used to be tolerated.

• Quirked
• Build-time break

Recommended Action

If passing a URI to affected APIs, modify the string to be a legal path first.

• Remove the scheme from URLs manually (e.g. remove file:// from URLs)
• Pass the URI to the xref:System.Uri class and use xref:System.Uri.LocalPath

Alternatively, you can opt out of the new path normalization by setting the Switch.System.IO.UseLegacyPathHandling AppContext switch to true.

Affected APIs

• M:System.IO.Path.GetDirectoryName(System.String)
• M:System.IO.Path.GetPathRoot(System.String)

Category

Core