File.Exists returns true for non existing file (Azure Windows Web App)

[lampersky]

Description

I created few files (and directories) inside azure web app file system, with quite long names.
Then I deleted directories and files.

File.Exists still returns True for non existing files, when I tried to delete them again I'm getting an exception.
Other than that, I can't create files again this time getting Could not find a part of the path.

Here is a repro repo.

117718507-7348bb80-b1dc-11eb-8696-d16b453b1e9e.mp4

This issue was first observed within Orchard Core.

Configuration

• Which version of .NET is the code running on?
  dotnetcore3.1
  net5.0
• What OS and version, and what distro if applicable?
  azure web app (windows)
• What is the architecture (x64, x86, ARM, ARM64)?
  I've only checked x64
• Do you know whether it is specific to that configuration?
  this can't be reproduced locally inside my Windows 10 environment

Regression?

I tried with both dotnetcore3.1 and net5.0, on both same issue.

Other information

App was deployed to azure using WebDeploy.
After restarting webapp, files are not locked anymore, File.Exists returns relevant result.

I couldn't figure out the best area label to add to this issue. If you have write-permissions please help me learn by adding exactly one area label.

Tagging subscribers to this area: @carlossanlop
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Issue Details

---

Description

I created few files (and directories) inside azure web app file system, with quite long names.
Then I deleted directories and files.

File.Exists still returns True for non existing files, when I tried to delete them again I'm getting an exception.
Other than that, I can't create files again this time getting Could not find a part of the path.

Here is a repro repo.

117718507-7348bb80-b1dc-11eb-8696-d16b453b1e9e.mp4

This issue was first observed within Orchard Core.

Configuration

• Which version of .NET is the code running on?
  dotnetcore3.1
  net5.0
• What OS and version, and what distro if applicable?
  azure web app (windows)
• What is the architecture (x64, x86, ARM, ARM64)?
  I've only checked x64
• Do you know whether it is specific to that configuration?
  this can't be reproduced locally inside my Windows 10 environment

Regression?

I tried with both dotnetcore3.1 and net5.0, on both same issue.

Other information

App was deployed to azure using WebDeploy.
After restarting webapp, files are not locked anymore, File.Exists returns relevant result.

Author:	lampersky
Assignees:	-
Labels:	area-System.IO, untriaged
Milestone:	-

[jhudsoncedaron]

Your PurgeAsync assumes that Root is ".".

[lampersky]

Your PurgeAsync assumes that Root is ".".

@jhudsoncedaron I'm not sure what do you mean.

MyFileProvider.PurgeAsync method simply iterates over all files and directories based on PhysicalFileProvider.GetDirectoryContents results.

MyFileProvider is configured as follows:

services.AddSingleton<IMyFileProvider>(serviceProvider =>
{
    var hostingEnvironment = serviceProvider.GetRequiredService<IWebHostEnvironment>();
    var root = $"{hostingEnvironment.WebRootPath}\\ms-cache\\Default";
    if (!Directory.Exists(root))
    {
        Directory.CreateDirectory(root);
    }
    return new MyFileProvider(root);
});

which means root (locally) is:

[lampersky]

This issue can't be reproduced on azure free plan nor locally.
So problem exists in paid plans.

[davidfowl]

cc @sebastienros

[sebastienros]

I provided a repro to the Antares team and they are investigating

[adamsitnik]

I provided a repro to the Antares team and they are investigating

@sebastienros any update on this?