Get-ChildItem -Name and Get-ChildItem -Include / -Exclude unexpectedly follow symlinks with -Recurse

PowerShell Core (unlike Windows PowerShell) by default is supposed to not follow symlinks (symbolic links) to directories during recursive traversal with Get-ChildItem -Recurse (you can opt in with -FollowSymlink).

While this generally works, using the -Name or -Include / -Exclude switches unexpectedly causes symlinks to be followed even without the -FollowSymlink switch.

Note: On Windows, the tests currently fail categorically, due to an unrelated bug: #9127

Steps to reproduce (on Unix)

Run the following Pester tests:

Describe "Get-ChildItem: symlink-following tests" {
  BeforeAll {
    Push-Location TestDrive:/
    # Create a directory with 2 files in it. 
    $null = New-Item -Type Directory someDir
    1..2 | % { $_ > "someDir/$_.txt" }
    # Create a symlink to that directory, as a sibling.
    New-Item -Type SymbolicLink someDirLink -Target someDir
  }
  AfterAll {
    Pop-Location
  }
  
  It "Get-ChildItem -Recurse doesn't follow dir. symlinks." {
    (Get-ChildItem -File -Recurse).Count | Should -Be 2
  }

  It "Get-ChildItem -Recurse -Path with a wildcard doesn't follow dir. symlinks." {
    (Get-ChildItem -File -Recurse -Path *).Count | Should -Be 2
  }

  It "Get-ChildItem -Recurse -Name doesn't follow dir. symlinks." {
    (Get-ChildItem -File -Recurse -Name).Count | Should -Be 2
  }

  It "Get-ChildItem -Recurse -Include doesn't follow dir. symlinks." {
    (Get-ChildItem -File -Recurse -Include *).Count | Should -Be 2
  }

  It "Get-ChildItem -Recurse -Exclude doesn't follow dir. symlinks." {
    (Get-ChildItem -File -Recurse -Exclude nosuch).Count | Should -Be 2
  }
  
}

Expected behavior

All tests should pass.

Actual behavior

The last 3 tests fail.

Environment data

PowerShell Core 6.2.0-rc.1

on Windows all tests fails,
Describing Get-ChildItem: symlink-following tests
[-] Get-ChildItem -Recurse doesn't follow dir. symlinks. 6ms Expected 2, but got 3.
15: (Get-ChildItem -File -Recurse).Count | Should -Be 2
at <ScriptBlock>, C:\Users\ic-sc\test.ps1: line 15
[-] Get-ChildItem -Recurse -Path with a wildcard doesn't follow dir. symlinks. 5ms Expected 2, but got 3.
19: (Get-ChildItem -File -Recurse -Path *).Count | Should -Be 2 at <ScriptBlock>, C:\Users\ic-sc\test.ps1: line 19
[-] Get-ChildItem -Recurse -Name doesn't follow dir. symlinks. 7ms Expected 2, but got 3.
23: (Get-ChildItem -File -Recurse -Name).Count | Should -Be 2 at <ScriptBlock>, C:\Users\ic-sc\test.ps1: line 23
[-] Get-ChildItem -Recurse -Include doesn't follow dir. symlinks. 7ms Expected 2, but got 3.
27: (Get-ChildItem -File -Recurse -Include *).Count | Should -Be 2 at <ScriptBlock>, C:\Users\ic-sc\test.ps1: line 27
[-] Get-ChildItem -Recurse -Exclude doesn't follow dir. symlinks. 8ms Expected 2, but got 3.
31: (Get-ChildItem -File -Recurse -Exclude nosuch).Count | Should -Be 2 at <ScriptBlock>, C:\Users\ic-sc\test.ps1: line 31
Tests completed in 146ms
Tests Passed: 0, Failed: 5, Skipped: 0, Pending: 0, Inconclusive: 0

Christoph Schultz (@ChrSchultz)

Christoph Schultz (@ChrSchultz): That is due to an unrelated bug, reported in #9127 - I've added this info to the OP.

By changing #L4 New-Item -Type SymbolicLink someDirLink -Target someDir into New-Item -Type SymbolicLink someDirLink -Target .\someDir the tests can ignore the unrelated bug.
That bug is specifically caused by #15161, which was closed as duplicate of the more comprehensive issue #15235. (#9127 is closed as fixed, but was only partially fixed)

Result:

Describing Get-ChildItem: symlink-following tests
  [+] Get-ChildItem -Recurse doesn't follow dir. symlinks. 5ms (4ms|2ms)
  [+] Get-ChildItem -Recurse -Path with a wildcard doesn't follow dir. symlinks. 5ms (4ms|1ms)
  [-] Get-ChildItem -Recurse -Name doesn't follow dir. symlinks. 7ms (7ms|1ms)
   Expected 2, but got 4.
   at (Get-ChildItem -File -Recurse -Name).Count | Should -Be 2, C:\pester\symFollow.Tests.ps1:23
   at <ScriptBlock>, C:\pester\symFollow.Tests.ps1:23
  [-] Get-ChildItem -Recurse -Include doesn't follow dir. symlinks. 8ms (8ms|1ms)
   Expected 2, but got 4.
   at (Get-ChildItem -File -Recurse -Include *).Count | Should -Be 2, C:\pester\symFollow.Tests.ps1:27
   at <ScriptBlock>, C:\pester\symFollow.Tests.ps1:27
  [-] Get-ChildItem -Recurse -Exclude doesn't follow dir. symlinks. 10ms (10ms|1ms)
   Expected 2, but got 4.
   at (Get-ChildItem -File -Recurse -Exclude nosuch).Count | Should -Be 2, C:\pester\symFollow.Tests.ps1:31
   at <ScriptBlock>, C:\pester\symFollow.Tests.ps1:31
Tests completed in 116ms
Tests Passed: 2, Failed: 3, Skipped: 0 NotRun: 0

This issue has not had any activity in 6 months, if this is a bug please try to reproduce on the latest version of PowerShell and reopen a new issue and reference this issue if this is still a blocker for you.

This issue has been marked as "No Activity" as there has been no activity for 6 months. It has been closed for housekeeping purposes.

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Get-ChildItem -Name and Get-ChildItem -Include / -Exclude unexpectedly follow symlinks with -Recurse #9126

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Get-ChildItem -Name and Get-ChildItem -Include / -Exclude unexpectedly follow symlinks with -Recurse #9126

Description

Steps to reproduce (on Unix)

Expected behavior

Actual behavior

Environment data

Activity

ChrSchultz commented on Mar 13, 2019

mklement0 commented on Mar 13, 2019

Bertaz commented on Oct 9, 2022

microsoft-github-policy-service commented on Nov 16, 2023

microsoft-github-policy-service commented on Nov 16, 2023

microsoft-github-policy-service commented on Nov 16, 2023

microsoft-github-policy-service commented on Nov 23, 2023

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