Bug in GetFullPath(basePath, Path) (dotnet/coreclr#16598)

Anipik · ahsonkhan · commit 4d06437287bf · 2018-02-28T17:02:22.000-08:00
* GetFullPath and GetRootLength Corrected

* Removed getpathroot

* using span

* "\\" changed to @"\"

Signed-off-by: dotnet-bot-corefx-mirror &lt;dotnet-bot@microsoft.com&gt;
diff --git a/src/Common/src/CoreLib/System/IO/Path.Windows.cs b/src/Common/src/CoreLib/System/IO/Path.Windows.cs
@@ -98,8 +98,8 @@ public static string GetFullPath(string path, string basePath)
                 {
                     // No matching root, root to specified drive
                     // "D:Foo" and "C:\Bar" => "D:Foo"
-                    // "D:\Foo" and "\\?\C:\Bar" => "\\?\D:\Foo"
-                    combinedPath = path.Insert(2, "\\");
+                    // "D:Foo" and "\\?\C:\Bar" => "\\?\D:\Foo"
+                    combinedPath = PathInternal.IsDevice(basePath) ? CombineNoChecksInternal(basePath.AsSpan().Slice(0, 4), path.AsSpan().Slice(0, 2), @"\", path.AsSpan().Slice(2)) : path.Insert(2, "\\");
                 }
             }
             else

Original file line number	Diff line number	Diff line change
`@@ -98,8 +98,8 @@ public static string GetFullPath(string path, string basePath)`
`98`	`98`	`{`
`99`	`99`	`// No matching root, root to specified drive`
`100`	`100`	`// "D:Foo" and "C:\Bar" => "D:Foo"`
`101`		`- // "D:\Foo" and "\\?\C:\Bar" => "\\?\D:\Foo"`
`102`		`- combinedPath = path.Insert(2, "\\");`
	`101`	`+ // "D:Foo" and "\\?\C:\Bar" => "\\?\D:\Foo"`
	`102`	`+ combinedPath = PathInternal.IsDevice(basePath) ? CombineNoChecksInternal(basePath.AsSpan().Slice(0, 4), path.AsSpan().Slice(0, 2), @"\", path.AsSpan().Slice(2)) : path.Insert(2, "\\");`
`103`	`103`	`}`
`104`	`104`	`}`
`105`	`105`	`else`