commit 3243f7a08272a5f973a92fec781589e98f9f47b7
author Brandon L. Reiss <brandon@frame.ai> Wed Jan 27 13:12:17 2021 -0500
committer Jordan Harband <ljharb@gmail.com> Wed Jan 27 13:12:17 2021 -0500
tree 73d7245393f9f2a337f927a4d4f414ce087a23b3
parent 015623ee6d1827f83d3e1ff8d37fcf9da735fa73

[Fix] Fix potential unbound var error on nvm install

Fixes #2420. When using `nvm install` with an already installed
version, Bash (and potentially other shells) may emit an unbound
variable error when `set -u` is set. The presence of the error depends
on specific shell versions, but appears to happen in MacOS 11.1 (Big
Sur) using a recent Bash version installed via Homebrew (as of this
writing).

The fix accesses `ALIAS` correctly for the case where it is not set by
an `alias` option to `nvm install`.

nvm.sh

diff --git a/nvm.sh b/nvm.sh
index 8d57cae..e0eccfe 100644
--- a/nvm.sh
+++ b/nvm.sh
@@ -3078,7 +3078,7 @@
           nvm_ensure_default_set "${provided_version}"
         fi
 
-        if [ -n "${ALIAS}" ]; then
+        if [ -n "${ALIAS-}" ]; then
           nvm alias "${ALIAS}" "${provided_version}"
         fi