Bug 60138 - [Unix] System.IO.Path.GetPathRoot hardcodes result to '/'
Summary: [Unix] System.IO.Path.GetPathRoot hardcodes result to '/'
Status: RESOLVED FEATURE
Alias: None
Product: Class Libraries
Classification: Mono
Component: mscorlib ()
Version: master
Hardware: PC Linux
: --- normal
Target Milestone: Future Release
Assignee: Egorbo
URL:
Depends on:
Blocks:
 
Reported: 2017-10-11 18:11 UTC by Ethan Lee
Modified: 2018-04-16 18:27 UTC (History)
4 users (show)

Tags: bugpool-archived
Is this bug a regression?: ---
Last known good build:

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Status:
RESOLVED FEATURE

Description Ethan Lee 2017-10-11 18:11:34 UTC
In the current version of Mono, Path.GetPathRoot will hardcode the root path to '/' instead of actually checking the logical drive list to find the appropriate root directory:

https://github.com/mono/mono/blob/master/mcs/class/corlib/System.IO/Path.cs#L443

So, for example, if Environment.GetLogicalDrives() looks like this...

/host
/home
/run
/tmp
/var

... and we try to call new DriveInfo(Path.GetPathRoot("/home/dude/.local/share")), we get an Exception because "/" is not in the list of drive names:

https://github.com/mono/mono/blob/master/mcs/class/corlib/System.IO/DriveInfo.cs#L57

For now I have a workaround in FNA that deals with this specific case; it's not ideal but it does fix the problem for us:

https://github.com/FNA-XNA/FNA/blob/6a7a362963eb9de892f0c3bf6444bc231d1bbecc/src/Storage/StorageDevice.cs#L377
Comment 1 Egorbo 2017-11-17 13:21:49 UTC
Fix: https://github.com/mono/mono/pull/6040
Comment 2 Egorbo 2017-11-22 02:20:40 UTC
@Ethan Lee
Thanks for the bug report, I noticed you use

if (storageRoot.StartsWith(drives[i]) &&

if your storageRoot is (for example) /tmp/foooo
and one of the drives is /tmp/foo - it will use it as root directory.
Comment 3 Marek Safar 2018-04-10 08:47:26 UTC
Closing as won't fix and it'd break existing code and makes us incompatible with netcore.