Updates from review feedback.

* Don't bail if GOENV_ROOT not set
* Set GOENV_ROOT to ~/.goenv if not set and installed there
* Only munge path if goenv not on path and exists in GOENV_ROOT/bin
* More comments

plugins/available/goenv.plugin.bash

@@ -1,21 +1,29 @@
 cite about-plugin
 about-plugin 'Init goenv, if installed. Plays nicely with package managers'
 
-# Try to set GOENV_ROOT if not already set
-if [ -z "${GOENV_ROOT}" ]; then
-	# Bail if cannot be set
-	if [ ! -d "$HOME/.goenv" ]; then
-		return
-	fi
-	export GOENV_ROOT="$HOME/.goenv"
+# GOENV_ROOT does not need to be configured.
+# If it is configured, it should not be overridden.
+# However, let's try to handle the case where:
+# - goenv is not already on the path
+# - GOENV_ROOT is not configured
+# - User has installed goenv in ~/.goenv
+# In this case, we'll do the user a solid and configure
+# the goenv they've taken the time to install.
+if ! _command_exists goenv && [ -z "${GOENV_ROOT}" ] && [ -x "${HOME}/.goenv/bin/goenv" ]; then
+	export GOENV_ROOT="${HOME}/.goenv"
 fi
 
-# Add GOENV_ROOT/bin to path if goenv not already on path
-if ! _command_exists goenv && [ -x "${GOENV_ROOT}/bin/goenv" ]; then
-	pathmunge "$GOENV_ROOT/bin"
+# Add GOENV_ROOT/bin to path if:
+# - goenv not already on path
+# - GOENV_ROOT is configured
+# - User has installed goenv in GOENV_ROOT
+if ! _command_exists goenv && [ -n "${GOENV_ROOT}" ] && [ -x "${GOENV_ROOT}/bin/goenv" ]; then
+	pathmunge "${GOENV_ROOT}/bin"
 fi
 
-# Initialize goenv - Play nicely if goenv not on path
+# Initialize goenv - Play nicely if goenv never made it to the path
+# NOTE: In the off-chance that goenv has already been initialized,
+#       it should be safe to re-initialize
 if _command_exists goenv ; then
 	eval "$(goenv init - bash)"
 fi