Non-Terminating Exception in Folder Deletion Script - powershell

Question

I've written a Powershell script that would periodically delete folders on my machine.
The algorithm is as follows:
Drill down into each directory structure to the lowest subfolders
Check the creation date of the subfolder
If it's 14 days old, or older, delete it
LOG EVERYTHING (not part of the algorithm, just good practise)
When running, it operates exactly as expected...
... Except it throws the following, non-terminating exception:
Get-ChildItem : Could not find a part of the path 'C:\foo\baz'.
At C:\src\CoreDev\Trunk\Tools\BuildClean script\buildclean.ps1:55 char:15
+ Get-ChildItem <<<< -recurse -force |
+ CategoryInfo : ReadError: (C:\foo\baz:String) [Get-ChildItem],
DirectoryNotFoundException
+ FullyQualifiedErrorId : DirIOError,Microsoft.PowerShell.Commands.GetChil
dItemCommand
Why is this happening? More importantly, how can I remove it, and will it cause an issue?
The script is as follows:
# folderclean.ps1
# This script will remove each leaf node of a directory, provided that leaf is over
# 14 days old.
# CONSTANT DECLARATIONS
# testing (run on my local machine)
$proj_loc = "C:\foo", "C:\bar"
$logpath = "C:\Logs\BuildClean\$(Get-Date -format yyyyMMdd).log"
function Write-ToLogFile {
param ([string]$stringToWrite)
Add-Content $logpath -value $stringToWrite
}
# Function to check if a folder is a leaf folder.
# First, retrieve the directory $item is pointing to
# Then, create a list of children of $item that are folders
# If this list is either empty or null, return $true
# Otherwise, return $false
function Folder-IsLeaf($item) {
$ary = Get-ChildItem $item -force | ?{ $_.PSIsContainer }
if (($ary.length) -eq 0 -or $ary -eq $null) {
return $true
}
return $false
}
# Deletes leaf folders that are older than a certain threshhold.
# Get a list of children of the folder, where each child is a folder itself and
# was created over 14 days ago and the folder is a leaf
# For each of these children, delete them and increment $folderCount
# Get a list of children of the folder, where each child is a folder itself and
# was last modified over 14 days ago and the folder is a leaf
# For each of these children, delete them and increment $folderCount
function Remove-LeafFolders($path) {
$createdCount = 0
$modifiedCount = 0
Write-ToLogFile "Operation started at $(Get-Date -format "dd/MM/yyyy hh:mm:ss.fff")"
Write-ToLogFile "Looking in $proj_loc"
Write-ToLogFile ""
$start = $(Get-Date)
$proj_loc |
Get-ChildItem -recurse -force |
?{
$_.PSIsContainer -and ($_.CreationTime).AddDays(15) -lt $(Get-Date) -and $(Folder-IsLeaf $_.FullName) -eq $true
} | %{
$formattedDate = $($_.CreationTime).ToString("dd/MM/yyyy hh:mm:ss");
Write-ToLogFile "Folder $($_.FullName) is being removed; created: $formattedDate"
Remove-Item $_.FullName -recurse;
$createdCount += 1
}
$end = $(Get-Date)
$elapsed = $end - $start
Write-ToLogFile "Operation completed at $(Get-Date -format "dd/MM/yyyy hh:mm:ss.fff")."
Write-ToLogFile "Folders removed: $createdCount"
Write-ToLogFile "Time elapsed: $(($elapsed).TotalMilliseconds) ms"
Write-ToLogFile "-------------------------------"
}
Remove-LeafFolders($proj_loc)

Answer 1

I found this other StackOverflow question, and, after looking through the answer, I realised that the problem was the pipeline. So, I changed my code as follows:
...
$leafList = $proj_loc |
Get-ChildItem -recurse -force |
?{
$_.PSIsContainer -and ($_.CreationTime).AddDays(15) -lt $(Get-Date) -and $(Folder-IsLeaf $_.FullName) -eq $true
}
Foreach ($folder in $leafList)
{
$formattedDate = $($folder.CreationTime).ToString("dd/MM/yyyy hh:mm:ss");
Write-ToLogFile "Folder $($folder.FullName) is being removed; created: $formattedDate"
Remove-Item $folder.FullName -recurse;
$createdCount += 1
}
...
I created a few local folders and screwed around with them. No exceptions cropped up, so this appears to have worked:
Operation started at 10/12/2012 05:16:18.631
Looking in C:\foo C:\bar
Folder C:\foo\baz is being removed; created: 09/01/2010 02:00:00
Folder C:\bar\baz3\recursion is being removed; created: 01/01/2008 01:00:00
Operation completed at 10/12/2012 05:16:18.748.
Folders removed: 2
Time elapsed: 33.0033 ms
-------------------------------
Operation started at 10/12/2012 05:41:59.246
Looking in C:\foo C:\bar
Folder C:\foo\baz2\NewFolder is being removed; created: 10/10/2010 10:10:10
Folder C:\bar\baz3\barbar is being removed; created: 20/11/2012 05:37:38
Operation completed at 10/12/2012 05:41:59.279.
Folders removed: 2
Time elapsed: 21.0021 ms
-------------------------------

Answer 2

I think it would be easier to accomplish this sort of recursive deletion using a bottom-up approach rather than a top-down which is what Get-ChildItem gives you by default. Try this instead:
$proj_loc |
Get-ChildItem -recurse -force -Name | sort -desc | Get-Item |
? { ....
}