[PR] fix(wrapper): guard against null Target property in only-mvnw.cmd [maven-wrapper]

["armorbreak001 (via GitHub)" <gi...@apache.org>]

armorbreak001 opened a new pull request, #416:
URL: https://github.com/apache/maven-wrapper/pull/416

   ## Problem
   
   `only-mvnw.cmd` crashes with **"Cannot index into a null array"** when running under the Local System account in a 32-bit process (typical for Jenkins Agents running as a Windows Service).
   
   The root cause is on the symlink-resolution line:
   
   ```powershell
   if ((Get-Item -Path $MAVEN_M2_PATH -Force).Target[0] -eq $null)
   ```
   
   On the System Profile `.m2` path (`C:\WINDOWS\system32\config\systemprofile\.m2`) accessed from a 32-bit process, `Get-Item.Target` returns strictly `$null` (not an empty collection). Indexing `[0]` on `$null` throws `RuntimeException`.
   
   ## Fix
   
   Cache the `Get-Item` result and check that the `Target` property exists **and** is non-null before attempting to index it. When `Target` is unavailable, fall through to the standard (non-symlink) path — which is the correct behavior for non-symlinked directories.
   
   **Before:**
   ```powershell
   if ((Get-Item -Path $MAVEN_M2_PATH -Force).Target[0] -eq $null) {
     ...
   }
   ```
   
   **After:**
   ```powershell
   $m2Item = Get-Item -Path $MAVEN_M2_PATH -Force
   if ($m2Item.PSObject.Properties["Target"] -ne $null -and $m2Item.Target -ne $null) {
     $MAVEN_WRAPPER_DISTS = $m2Item.Target[0] + "/wrapper/dists"
   } else {
     $MAVEN_WRAPPER_DISTS = "$MAVEN_M2_PATH/wrapper/dists"
   }
   ```
   
   Also swapped the branch order so the common case (non-symlink) is the `else` branch, avoiding unnecessary property inspection for the majority of users.
   
   Fixes #395


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Re: [PR] fix(wrapper): guard against null Target property in only-mvnw.cmd [maven-wrapper]

["slachiewicz (via GitHub)" <gi...@apache.org>]

slachiewicz commented on PR #416:
URL: https://github.com/apache/maven-wrapper/pull/416#issuecomment-4296700152

   same as #405


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Re: [PR] fix(wrapper): guard against null Target property in only-mvnw.cmd [maven-wrapper]

["Copilot (via GitHub)" <gi...@apache.org>]

Copilot commented on code in PR #416:
URL: https://github.com/apache/maven-wrapper/pull/416#discussion_r3124403832


##########
maven-wrapper-distribution/src/resources/only-mvnw.cmd:
##########
@@ -89,10 +89,11 @@ if (-not (Test-Path -Path $MAVEN_M2_PATH)) {
 }
 
 $MAVEN_WRAPPER_DISTS = $null
-if ((Get-Item -Path $MAVEN_M2_PATH -Force).Target[0] -eq $null) {
-  $MAVEN_WRAPPER_DISTS = "$MAVEN_M2_PATH/wrapper/dists"
+$m2Item = Get-Item -Path $MAVEN_M2_PATH -Force
+if ($m2Item.PSObject.Properties['Target'] -ne $null -and $m2Item.Target -ne $null) {

Review Comment:
   The new symlink detection condition will mis-handle the common non-symlink case where `Get-Item ... .Target` is an empty collection (not `$null`). In that scenario `$m2Item.Target -ne $null` is true, but `$m2Item.Target[0]` is `$null`, causing `$MAVEN_WRAPPER_DISTS` to become just `"/wrapper/dists"` (relative path) instead of using `$MAVEN_M2_PATH`. Update the condition to also require a non-null first target (or a non-empty Target collection) before using `Target[0]`; otherwise fall back to `$MAVEN_M2_PATH/wrapper/dists`.
   ```suggestion
   if ($m2Item.PSObject.Properties['Target'] -ne $null -and $m2Item.Target -ne $null -and $m2Item.Target[0] -ne $null) {
   ```



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