bin/storm launcher script can be broken if CDPATH is exported from environment

In the bin/storm script there is logic that attempts to determine the fullpath of the bin directory, and it relies on using cd and pwd like so:

STORM_BIN_DIR=`dirname ${PRG}`
export STORM_BASE_DIR=`cd ${STORM_BIN_DIR}/..;pwd`

This is problematic if your environment has an exported CDPATH variable which contains a matching entry, because bash's built-in cd command prints out the directory upon successfully matching a CDPATH entry. And then the pwd command prints the same directory again. So the behavior results in the STORM_BASE_DIR variable containing duplicate paths with a newline in between. This results in a broken classpath in the Storm processes, which looks something like this:

...:/base/apache-storm-2.0.0-SNAPSHOT/lib/storm-rename-hack-2.0.0-SNAPSHOT.jar:/base/apache-storm-2.0.0-SNAPSHOT^J/base/apache-storm-2.0.0-SNAPSHOT/conf:/base/apache-storm-2.0.0-SNAPSHOT/storm-local/supervisor/stormdist/foo-1-1480491213/stormjar.jar

Or with the : chars replaced with newlines for ease of readability:

...
/base/apache-storm-2.0.0-SNAPSHOT/lib/storm-rename-hack-2.0.0-SNAPSHOT.jar
/base/apache-storm-2.0.0-SNAPSHOT^J/base/apache-storm-2.0.0-SNAPSHOT/conf
/base/apache-storm-2.0.0-SNAPSHOT/storm-local/supervisor/stormdist/foo-1-1480491213/stormjar.jar

Note that the classpath entry with /conf as a suffix is munged, with a ^J character in between duplicate copies of the base path.

The solution is easy: at the beginning of the bin/storm script we should unset CDPATH.

FYI, this "CDPATH + bash script" problem is covered in this blog entry:

• https://bosker.wordpress.com/2012/02/12/bash-scripters-beware-of-the-cdpath/