From 898124fd60b80b432d7600276ec80dd499b74666 Mon Sep 17 00:00:00 2001
From: Jordan Harband <ljharb@gmail.com>
Date: Sun, 25 Oct 2026 11:42:45 -0700
Subject: [PATCH] [Fix] `nvm debug`: don't let the shell read stdin when asked
 for its version

busybox's shells have no `--version`, and start an interactive shell instead,
so with `$SHELL` set to busybox `sh` on a terminal, `nvm debug` waited for input forever,
which hung the alpine `sh` CI lanes in the "mirror URL credentials are masked in output" test.
Like the other busybox tools, its version now comes from `--help`,
and every shell is given no stdin to read.
---
 nvm.sh                                        |  9 ++-
 ...s not read stdin to find the shell version | 58 +++++++++++++++++++
 2 files changed, 66 insertions(+), 1 deletion(-)
 create mode 100755 test/fast/Unit tests/nvm debug does not read stdin to find the shell version

diff --git a/nvm.sh b/nvm.sh
index 83431490..2719409d 100755
--- a/nvm.sh
+++ b/nvm.sh
@@ -4268,7 +4268,14 @@ nvm() {
       nvm_err "\${NPM_CONFIG_PREFIX}: '$(nvm_sanitize_path "${NPM_CONFIG_PREFIX-}")'"
       nvm_err "\$NVM_NODEJS_ORG_MIRROR: '$(nvm_sanitize_url "${NVM_NODEJS_ORG_MIRROR-}")'"
       nvm_err "\$NVM_IOJS_ORG_MIRROR: '$(nvm_sanitize_url "${NVM_IOJS_ORG_MIRROR-}")'"
-      nvm_err "shell version: '$(${SHELL} --version | command head -n 1)'"
+      local NVM_SHELL_VERSION
+      # busybox's shells have no `--version`, and start an interactive shell instead
+      if command ls -l "$(command -v "${SHELL}" 2>/dev/null)" 2>/dev/null | nvm_grep -q busybox; then
+        NVM_SHELL_VERSION="$(${SHELL} --help 2>&1 </dev/null | command head -n 1)"
+      else
+        NVM_SHELL_VERSION="$(${SHELL} --version </dev/null | command head -n 1)"
+      fi
+      nvm_err "shell version: '${NVM_SHELL_VERSION}'"
       nvm_err "uname -a: '$(command uname -a | command awk '{$2=""; print}' | command xargs)'"
       nvm_err "checksum binary: '$(nvm_get_checksum_binary 2>/dev/null)'"
       if [ "$(nvm_get_os)" = "darwin" ] && nvm_has sw_vers; then
diff --git a/test/fast/Unit tests/nvm debug does not read stdin to find the shell version b/test/fast/Unit tests/nvm debug does not read stdin to find the shell version
new file mode 100755
index 00000000..559a7987
--- /dev/null
+++ b/test/fast/Unit tests/nvm debug does not read stdin to find the shell version	
@@ -0,0 +1,58 @@
+#!/bin/sh
+
+TMP_DIR=''
+
+cleanup () {
+  case "${TMP_DIR}" in
+    /*) rm -rf "${TMP_DIR}" ;;
+  esac
+}
+
+die () { echo "$@" ; cleanup ; exit 1; }
+
+: nvm.sh
+\. ../../../nvm.sh
+
+TMP_DIR="$(mktemp -d)"
+
+# like busybox's `sh`, which starts an interactive shell for `--version`
+cat > "${TMP_DIR}/busybox" <<'FAKE'
+#!/bin/sh
+if [ "$1" = '--help' ]; then
+  echo 'BusyBox v9.9.9 (fake) multi-call binary.'
+elif read -r LINE; then
+  echo 'interactive shell read stdin'
+fi
+FAKE
+chmod +x "${TMP_DIR}/busybox" || die 'could not make the fake busybox'
+ln -s "${TMP_DIR}/busybox" "${TMP_DIR}/sh" || die 'could not link the fake busybox sh'
+
+cat > "${TMP_DIR}/fakesh" <<'FAKE'
+#!/bin/sh
+if read -r LINE; then
+  echo 'fake shell read stdin'
+else
+  echo 'fake shell 1.0'
+fi
+FAKE
+chmod +x "${TMP_DIR}/fakesh" || die 'could not make the fake shell'
+
+OUTPUT="$(SHELL="${TMP_DIR}/sh" nvm debug 2>&1 <<STDIN
+a line a shell must not read
+STDIN
+)"
+case "${OUTPUT}" in
+  *"shell version: 'BusyBox v9.9.9 (fake) multi-call binary.'"*) ;;
+  *) die "nvm debug should get a busybox shell's version from --help; got >${OUTPUT}<" ;;
+esac
+
+OUTPUT="$(SHELL="${TMP_DIR}/fakesh" nvm debug 2>&1 <<STDIN
+a line a shell must not read
+STDIN
+)"
+case "${OUTPUT}" in
+  *"shell version: 'fake shell 1.0'"*) ;;
+  *) die "nvm debug should not let the shell read stdin for its version; got >${OUTPUT}<" ;;
+esac
+
+cleanup