Error out early if the --copy-packages-from version is invalid.

nvm.sh

@@ -486,6 +486,14 @@ nvm() {
         shift
       done
 
+      if [ "~$(nvm_format_version "$PROVIDED_COPY_PACKAGES_FROM")" = "~$VERSION" ]; then
+        echo "You can't copy global packages from the same version of node you're installing." >&2
+        return 4
+      elif [ ! -z "$PROVIDED_COPY_PACKAGES_FROM" ] && [ "~$COPY_PACKAGES_FROM" = "~N/A" ]; then
+        echo "If --copy-packages-from is provided, it must point to an installed version of node." >&2
+        return 5
+      fi
+
       if [ -d "$(nvm_version_path "$VERSION")" ]; then
         echo "$VERSION is already installed." >&2
         nvm use "$VERSION"

test/fast/Running "nvm install" with "--copy-packages-from" requires a valid version

@@ -0,0 +1,31 @@
+#!/bin/sh
+
+die () { echo $@ ; cleanup ; exit 1; }
+cleanup () {
+  rm -rf ../../v0.10.4
+}
+
+mkdir ../../v0.10.4
+
+. ../../nvm.sh
+
+nvm deactivate >/dev/null 2>&1
+
+INSTALL_ERROR_MSG="$(nvm install v0.10.5 --copy-packages-from=0.11 2>&1)"
+EXPECTED_ERROR_MSG="If --copy-packages-from is provided, it must point to an installed version of node."
+[ "~$INSTALL_ERROR_MSG" = "~$EXPECTED_ERROR_MSG" ] \
+  || die ""nvm install --copy-packages" should fail when given an uninstalled version: expected '$EXPECTED_ERROR_MSG', got '$INSTALL_ERROR_MSG'"
+
+INSTALL_EXIT_CODE="$(nvm install v0.10.5 --copy-packages-from=0.11 >/dev/null 2>&1; echo $?)"
+[ "~$INSTALL_EXIT_CODE" = "~5" ] \
+  || die ""nvm install --copy-packages" should exit with code 5 when given an uninstalled version, got $INSTALL_EXIT_CODE"
+
+INSTALL_ERROR_MSG="$(nvm install v0.10.5 --copy-packages-from=0.10.5 2>&1)"
+EXPECTED_ERROR_MSG="You can't copy global packages from the same version of node you're installing."
+[ "~$INSTALL_ERROR_MSG" = "~$EXPECTED_ERROR_MSG" ] \
+  || die ""nvm install --copy-packages" should fail when given the same version: expected '$EXPECTED_ERROR_MSG', got '$INSTALL_ERROR_MSG'"
+
+INSTALL_EXIT_CODE="$(nvm install v0.10.5 --copy-packages-from=0.10.5 >/dev/null 2>&1; echo $?)"
+[ "~$INSTALL_EXIT_CODE" = "~4" ] \
+  || die ""nvm install --copy-packages" should exit with code 4 when given the same version, got $INSTALL_EXIT_CODE"
+