[Fix] nvm_cd: bypass a user-defined cd function

`\cd` only bypasses aliases, so a user-defined `cd` function (eg, cdhist's) still ran,
and broke `NVM_DIR` auto-detection when it rejected zsh's `-q`.

Use `command cd`, which skips functions in POSIX shells.
zsh's `command` runs `/usr/bin/cd` instead of the builtin,
so use `builtin cd` there, as `nvm_echo` does for `printf`.
`nvm_die_on_prefix` also now uses `nvm_cd` instead of a bare `cd`.

Fixes #3835. See #3836.

Co-authored-by: Elan Ruusamäe <glen@delfi.ee>

nvm.sh

@@ -41,7 +41,13 @@ nvm_echo_with_colors() {
 }
 
 nvm_cd() {
-  \cd "$@"
+  # `\cd` still runs a user-defined `cd` function; in zsh, `command cd` runs `/usr/bin/cd` instead of the builtin
+  if [ -n "${ZSH_VERSION-}" ]; then
+    # shellcheck disable=SC3044
+    builtin cd "$@"
+  else
+    command cd "$@"
+  fi
 }
 
 # a caller that closed stderr, rather than redirecting it to /dev/null, makes
@@ -3516,7 +3522,7 @@ nvm_die_on_prefix() {
     local NVM_CONFIG_VALUE
     eval "NVM_CONFIG_VALUE=\"\$${NVM_NPM_CONFIG_x_PREFIX_ENV}\""
     if [ -n "${NVM_CONFIG_VALUE-}" ] && [ "_${NVM_OS}" = "_win" ]; then
-      NVM_CONFIG_VALUE="$(cd "$NVM_CONFIG_VALUE" 2>/dev/null && pwd)"
+      NVM_CONFIG_VALUE="$(nvm_cd "$NVM_CONFIG_VALUE" 2>/dev/null && pwd)"
     fi
     if [ -n "${NVM_CONFIG_VALUE-}" ] && ! nvm_tree_contains_path "${NVM_DIR}" "${NVM_CONFIG_VALUE}"; then
       nvm deactivate >/dev/null 2>&1

test/fast/Unit tests/nvm_cd

@@ -0,0 +1,23 @@
+#!/bin/sh
+
+die () { echo "$@" ; exit 1; }
+
+: nvm.sh
+\. ../../../nvm.sh
+
+EXPECTED="$(\cd .. && pwd)"
+
+# a user-defined `cd` function that rejects nvm's arguments, like cdhist's (#3835)
+cd() {
+  echo 'user-defined cd function was called' >&2
+  return 1
+}
+
+OUTPUT="$(nvm_cd .. 2>&1 && pwd)"
+[ "${OUTPUT}" = "${EXPECTED}" ] || die "expected '${EXPECTED}', got '${OUTPUT}'"
+
+# shellcheck disable=SC2086
+OUTPUT="$(nvm_cd ${NVM_CD_FLAGS} .. 2>&1 && pwd)"
+[ "${OUTPUT}" = "${EXPECTED}" ] || die "with NVM_CD_FLAGS '${NVM_CD_FLAGS}', expected '${EXPECTED}', got '${OUTPUT}'"
+
+unset -f cd