naotsugu opened a new issue, #395:
URL: https://github.com/apache/maven-wrapper/issues/395
### Affected version
3.3.3
### Bug description
## Description
In `mvnw.cmd`, the logic introduced by PR #143 to handle symlinks attempts
to access an array index on the `Target` property without checking if it is
null.
`mvnw.cmd` fails immediately upon execution with a "Cannot index into a null
array" error. This issue specifically occurs when the script runs under the
**Local System account** in a **32-bit process** (typical for Jenkins Agents
running as a Windows Service), where the default `.m2` home resolves to the
System Profile directory.
## Error Log
```Plaintext
icm : Cannot index into a null array
At line:1 char:81
+ ... 'mvnw.cmd'; icm -ScriptBlock ([Scriptblock]::Create((Get-Content -Raw
...
+ ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+ CategoryInfo : InvalidOperation: (:) [Invoke-Command],
RuntimeException
+ FullyQualifiedErrorId :
NullArray,Microsoft.PowerShell.Commands.InvokeCommandCommand
```
## Environment
- **OS:** Windows Server 2022
- **Process Architecture:** 32-bit (x86)
- **User:** `NT AUTHORITY\SYSTEM`
- **Target Path:** `C:\WINDOWS\system32\config\systemprofile\.m2`
- **PowerShell:** 5.1
## Root Cause Analysis
The script contains the following logic to handle symlinks:
```PowerShell
if ((Get-Item $MAVEN_M2_PATH).Target[0] -eq $null) { ... }
```
We verified the behavior of the `Target` property on this specific
environment:
1. **Standard Paths (e.g., Workspace drive):** The `Target` property returns
an **empty collection**. Accessing `[0]` returns `$null` safely (in PowerShell
5.1).
2. **System Profile Path (`.m2`):** When accessing the `.m2` directory in
the System Profile from a 32-bit process, the `Target` property returns
**strictly `$null`**.
Since `mvnw.cmd` defaults `MAVEN_M2_PATH` to the user home (System Profile),
the script attempts to access index `[0]` on `$null`, causing a fatal
`RuntimeException`.
## Verification Code & Result
We ran the following diagnostic inside the failing Jenkins environment,
specifically targeting the `.m2` directory:
```PowerShell
$basePath = $env:USERPROFILE
$m2Path = Join-Path $basePath ".m2"
# Ensure .m2 exists for testing
if (-not (Test-Path -Path $m2Path)) { New-Item -Path $m2Path -ItemType
Directory | Out-Null }
$prop = (Get-Item $m2Path).Target
Write-Host "Testing Path: $m2Path"
Write-Host "Is Null? : " ($prop -eq $null)
try { $null = $prop[0]; Write-Host "Safe" } catch { Write-Host "CRASH" }
```
**Output:**
```
Testing Path: C:\WINDOWS\system32\config\systemprofile\.m2
Is Null? : True
CRASH
```
## Proposed Fix
The script must check if the `Target` property is not null before attempting
to index it.
**Suggested Change:**
```PowerShell
$m2Item = Get-Item $MAVEN_M2_PATH
# Safe check: Ensure property exists and is not null before indexing
if ($m2Item.PSObject.Properties['Target'] -ne $null -and $m2Item.Target -ne
$null) {
$MAVEN_WRAPPER_DISTS = $m2Item.Target + "/wrapper/dists"
} else {
$MAVEN_WRAPPER_DISTS = "$MAVEN_M2_PATH/wrapper/dists"
}
```
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