[Fix] ls: list versions whose directory is a symlink

nvm_ls collects installed versions with `find <dirs>/* -name . -o -type d -prune -o -path ...`,
and `-type d` is false for a symlink,
so a version dir that links to another volume was skipped from the listing entirely
- while `nvm version`, `nvm which` and `nvm use` all kept working on it.

Have that find follow symlinks,
which makes linked-in versions visible and still ignores a broken link.

Fixes #617.

nvm.sh

@@ -2516,7 +2516,7 @@ nvm_ls() {
       NVM_DIR_SED="$(nvm_echo "${NVM_DIR}" | command sed 's/[][\.*^$#]/\\&/g')"
       local NVM_VERSION_DIR_IOJS_SED
       NVM_VERSION_DIR_IOJS_SED="$(nvm_echo "${NVM_VERSION_DIR_IOJS}" | command sed 's/[][\.*^$#]/\\&/g')"
-      VERSIONS="$(command find "${NVM_DIRS_TO_SEARCH1}"/* "${NVM_DIRS_TO_SEARCH2}"/* "${NVM_DIRS_TO_SEARCH3}"/* -name . -o -type d -prune -o -path "${PATTERN}*" \
+      VERSIONS="$(command find -L "${NVM_DIRS_TO_SEARCH1}"/* "${NVM_DIRS_TO_SEARCH2}"/* "${NVM_DIRS_TO_SEARCH3}"/* -name . -o -type d -prune -o -path "${PATTERN}*" \
         | command sed -e "
             s#${NVM_VERSION_DIR_IOJS_SED}/#versions/${NVM_IOJS_PREFIX}/#;
             s#^${NVM_DIR_SED}/##;

test/fast/Listing versions/Running 'nvm ls' should list symlinked versions

@@ -0,0 +1,27 @@
+#!/bin/sh
+
+: nvm.sh
+\. ../../../nvm.sh
+\. ../../common.sh
+
+die () { echo "$@" ; exit 1; }
+
+make_fake_node v0.0.1 || die 'unable to make a fake node'
+
+# a version that lives outside of NVM_DIR and is linked in, which is how some
+# users keep their versions on a separate volume
+REAL_DIR="$(cd ../../.. && pwd)/symlink-target"
+rm -rf "${REAL_DIR}"
+mkdir -p "${REAL_DIR}/v0.0.2/bin" || die 'unable to make the link target dir'
+make_echo "${REAL_DIR}/v0.0.2/bin/node" v0.0.2 || die 'unable to make fake node bin'
+rm -f "$(nvm_version_path v0.0.2)"
+ln -s "${REAL_DIR}/v0.0.2" "$(nvm_version_path v0.0.2)" || die 'unable to symlink the version dir'
+
+nvm ls | grep v0.0.1 >/dev/null || die "v0.0.1 not found in: $(nvm ls)"
+nvm ls | grep v0.0.2 >/dev/null || die "the symlinked v0.0.2 not found in: $(nvm ls)"
+nvm ls 0.0 | grep v0.0.2 >/dev/null || die "the symlinked v0.0.2 not found with a pattern in: $(nvm ls 0.0)"
+nvm ls 0.0.2 | grep v0.0.2 >/dev/null || die "the symlinked v0.0.2 not found with an exact version in: $(nvm ls 0.0.2)"
+
+# leave no trace, so the tests that compare `nvm ls` output verbatim are unaffected
+rm -f "$(nvm_version_path v0.0.2)"
+rm -rf "${REAL_DIR}"

test/fast/Listing versions/teardown

@@ -14,3 +14,4 @@ rm -rf ../../../v0.20.3
 rm -rf ../../../versions
 rm -f ../../../alias/stable
 rm -f ../../../alias/unstable
+rm -rf ../../../symlink-target