[MNG-8315] Fix MAVEN_PROJECTBASEDIR in mvn.cmd when .mvn is at drive root (#1808)

fixes https://issues.apache.org/jira/browse/MNG-8315

Co-authored-by: Francois Marot <[email protected]>

Author: gnodet

apache-maven/src/assembly/maven/bin/mvn.cmd

@@ -171,6 +171,9 @@ for /F "usebackq delims=" %%a in ("%MAVEN_PROJECTBASEDIR%\.mvn\jvm.config") do s
 
 :endReadJvmConfig
 
+@REM do not let MAVEN_PROJECTBASEDIR end with a single backslash which would escape the double quote. This happens when .mvn at drive root.
+if "_%MAVEN_PROJECTBASEDIR:~-1%"=="_\" set "MAVEN_PROJECTBASEDIR=%MAVEN_PROJECTBASEDIR%\"
+
 for %%i in ("%MAVEN_HOME%"\boot\plexus-classworlds-*) do set LAUNCHER_JAR="%%i"
 set LAUNCHER_CLASS=org.codehaus.plexus.classworlds.launcher.Launcher
 if "%MAVEN_MAIN_CLASS%"=="" @set MAVEN_MAIN_CLASS=org.apache.maven.cling.MavenCling