FileSystemGlobbing: Allow rootDir paths ending with separator to match files correctly

[jozkee]

InMemoryDirectoryInfo.IsRootDirectory method was failing to evaluate correctly when the rootDir argument was ending with a separator e.g: C:\ or /. This PR changes the condition to correctly support the aforementioned cases.

Fixes #36415, #44767

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Issue Details

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InMemoryDirectoryInfo.IsRootDirectory method was failing to evaluate correctly when the rootDir argument was ending with a separator e.g: C:\ or /. This PR changes the condition to correctly support the aforementioned cases.

Fixes #36415 #44767

Author:	Jozkee
Assignees:	Jozkee
Labels:	area-Extensions-FileSystem
Milestone:	6.0.0

[jozkee]

Existing condition on line 126 was meant to avoid false positives when the path started with rootDir but it wasn't the complete name of the directory e.g:

var matcher = new Matcher();
matcher.AddInclude(@"**\*");

Console.WriteLine(matcher.Match(rootDir: @"C:\foo", file: @"C:\foo2\bar.cs").HasMatches); 
// prints false, which is correct.

However that same condition was interfering when rootDir = @"C:\foo\" since filePath.IndexOf(Path.DirectorySeparatorChar, rootDirLength) was always going to return the index of the separator of the next directory.

Therefore I added condition on line 125 in order to skip the length check when rootDir ends with a separator.

[iSazonov]

It seems line 126 checks one char in position rootDirLength - why do we use whole IndexOf() method instead of simple index - filePath[rootDirLength] == Path.DirectorySeparatorChar - like in line 125?

[carlossanlop]

LGTM. Left some minor comments.

[carlossanlop]

Actually, I noticed all the unit test failures are happening in Microsoft.Extensions.FileSystemGlobbing.Tests. Can you please take a look?

[jozkee]

@carlossanlop I excluded scenarios using Windows-like absolute paths from running on non-Windows OSes since FileSystemGlobbing is OS-dependent when dealing with paths. That should fix the issues on CI.