[Fix] use command to bypass curl/wget shell functions and aliases

zsh (and interactive bash with `expand_aliases`) bakes a preexisting `curl` alias into nvm's function bodies at source time,
and shell functions named `curl`/`wget` shadow the binaries at call time - either one breaks downloads.
Prefixing invocations with `command` bypasses both: here, `nvm_download`'s dispatch, `nvm_curl_version`, `nvm_curl_libz_support`, and the wget branch of `nvm_get_latest`;
the remaining bare `curl` invocations in `nvm_get_latest` and the install script are prefixed in a followup commit.

The tests that previously mocked curl/wget as shell functions now install fake executables on PATH instead,
via a shared `make_fake_curl` helper in `test/common.sh`,
and a new test asserts the bypass.

Refs #2923

test/common.sh

@@ -50,6 +50,39 @@ make_echo() {
   chmod a+x "$1"
 }
 
+# `command curl` bypasses shell functions and aliases, so tests that mock curl
+# must provide an actual executable on the PATH: this creates one in the given
+# directory. Invoked as `curl -V`, it prints ${VERSION_MESSAGE} (exported here
+# on the mock's behalf); any other invocation runs the body given as the
+# second argument, or fails.
+make_fake_curl() {
+  local FAKE_BIN_DIR
+  FAKE_BIN_DIR="${1-}"
+  [ -n "${FAKE_BIN_DIR}" ] || return 1
+
+  local FAKE_CURL_BODY
+  FAKE_CURL_BODY="${2-}"
+  if [ -z "${FAKE_CURL_BODY}" ]; then
+    FAKE_CURL_BODY='echo >&2 "This fake curl only takes one parameter, -V"
+exit 1'
+  fi
+
+  mkdir -p "${FAKE_BIN_DIR}" || return 2
+
+  {
+    echo '#!/bin/sh'
+    echo 'if [ "$#" -eq 1 ] && [ "$1" = "-V" ]; then'
+    echo '  echo "${VERSION_MESSAGE}"'
+    echo '  exit 0'
+    echo 'fi'
+    printf '%s\n' "${FAKE_CURL_BODY}"
+  } > "${FAKE_BIN_DIR}/curl"
+  chmod +x "${FAKE_BIN_DIR}/curl"
+
+  # the fake curl reads VERSION_MESSAGE from the environment
+  export VERSION_MESSAGE
+}
+
 make_fake_node() {
   local VERSION
   VERSION="${1-}"

test/fast/Unit tests/nvm_curl_libz_support

@@ -1,7 +1,11 @@
 #!/bin/sh
 
+WORK="$PWD/nvm_curl_libz_support-work.$$"
+TEST_BIN="$WORK/bin"
+
 cleanup() {
-  unset -f curl
+  rm -rf "$WORK"
+  export PATH="$OLDPATH"
 }
 
 die() { cleanup; echo "$@" ; exit 1; }
@@ -9,32 +13,28 @@ die() { cleanup; echo "$@" ; exit 1; }
 : nvm.sh
 \. ../../../nvm.sh
 
-curl() {
-    # curl with libz feature
-    if [ $# -ne 1 ] || [ "$1" != "-V" ]; then
-        die "This fake curl only takes one parameter -V"
-    fi
-    echo "
+\. ../../common.sh
+
+OLDPATH="$PATH"
+
+make_fake_curl "$TEST_BIN"
+
+export PATH="$TEST_BIN:$OLDPATH"
+
+# curl with libz feature
+VERSION_MESSAGE="
 curl 7.47.0 (x86_64-pc-linux-gnu) libcurl/7.47.0 GnuTLS/3.4.10 zlib/1.2.8 libidn/1.32 librtmp/2.3
 Protocols: dict file ftp ftps gopher http https imap imaps ldap ldaps pop3 pop3s rtmp rtsp smb smbs smtp smtps telnet tftp
 Features: AsynchDNS IDN IPv6 Largefile GSS-API Kerberos SPNEGO NTLM NTLM_WB SSL libz TLS-SRP UnixSockets"
-}
 
 nvm_curl_libz_support || die "nvm_curl_libz_support should return 0"
 
-unset -f curl
-
-curl() {
-    # curl without libz feature
-    if [ "$#" -ne 1 ] || [ "$1" != "-V" ]; then
-        die "This fake curl only takes one parameter -V"
-    fi
-    echo "
+# curl without libz feature
+VERSION_MESSAGE="
 curl 7.47.0 (x86_64-pc-linux-gnu) libcurl/7.47.0 GnuTLS/3.4.10 zlib/1.2.8 libidn/1.32 librtmp/2.32
 Protocols: dict file ftp ftps gopher http https imap imaps ldap ldaps pop3 pop3s rtmp rtsp smb smbs smtp smtps telnet tftp
 Features: AsynchDNS IDN IPv6 Largefile GSS-API Kerberos SPNEGO NTLM NTLM_WB SSL TLS-SRP UnixSockets"
-}
 
 ! nvm_curl_libz_support || die "nvm_curl_libz_support should return 1"
 
-unset -f curl
+cleanup

test/fast/Unit tests/nvm_curl_use_compression

@@ -1,18 +1,25 @@
 #!/bin/sh
 
+WORK="$PWD/nvm_curl_use_compression-work.$$"
+TEST_BIN="$WORK/bin"
+
 cleanup () {
   unset -f die
+  rm -rf "$WORK"
+  export PATH="$OLDPATH"
 }
 
 die () { echo -e "$@" ; cleanup ;  exit 1; }
 
 NVM_ENV=testing \. ../../../nvm.sh
 
-curl() {
-  if [ "$1" = "-V" ]; then
-    echo "${VERSION_MESSAGE}"
-  fi
-}
+\. ../../common.sh
+
+OLDPATH="$PATH"
+
+make_fake_curl "$TEST_BIN"
+
+export PATH="$TEST_BIN:$OLDPATH"
 
 CURL_VERSION_ON_ARCHLINUX_WITH_LIBZ="curl 7.54.0 (x86_64-pc-linux-gnu) libcurl/7.54.0 OpenSSL/1.1.0f zlib/1.2.11 libpsl/0.17.0 (+libicu/59.1) libssh2/1.8.0 nghttp2/1.22.0
 Protocols: dict file ftp ftps gopher http https imap imaps pop3 pop3s rtsp scp sftp smb smbs smtp smtps telnet tftp

test/fast/Unit tests/nvm_curl_version

@@ -1,19 +1,25 @@
 #!/bin/sh
 
+WORK="$PWD/nvm_curl_version-work.$$"
+TEST_BIN="$WORK/bin"
+
 cleanup () {
-  unset -f die
-  unset -f curl
+  unset -f die cleanup assert_version_is
+  rm -rf "$WORK"
+  export PATH="$OLDPATH"
 }
 
 die () { echo -e "$@" ; cleanup ;  exit 1; }
 
 NVM_ENV=testing \. ../../../nvm.sh
 
-curl() {
-  if [ "$1" = "-V" ]; then
-    echo "${VERSION_MESSAGE}"
-  fi
-}
+\. ../../common.sh
+
+OLDPATH="$PATH"
+
+make_fake_curl "$TEST_BIN"
+
+export PATH="$TEST_BIN:$OLDPATH"
 
 assert_version_is() {
   if [ "${1}" != "${2}" ]; then

test/fast/Unit tests/nvm_download and curl helpers bypass shadowed curl

@@ -0,0 +1,48 @@
+#!/bin/sh
+
+WORK="$PWD/shadowed-curl-work.$$"
+TEST_BIN="$WORK/bin"
+ARGV_LOG="$WORK/argv.log"
+
+cleanup () {
+  unset -f die cleanup curl wget
+  rm -rf "$WORK"
+  export PATH="$OLDPATH"
+}
+
+die () { echo "$@" ; cleanup ; exit 1; }
+
+NVM_ENV=testing \. ../../../nvm.sh
+
+\. ../../common.sh
+
+OLDPATH="$PATH"
+
+# real-looking curl on PATH; calling the shadowing shell function below instead is a failure
+make_fake_curl "$TEST_BIN" ': > "$ARGV_LOG"
+for a in "$@"; do printf "%s\n" "$a" >> "$ARGV_LOG"; done'
+
+VERSION_MESSAGE="curl 7.99.0 (fake)
+Features: libz"
+
+export ARGV_LOG
+export PATH="$TEST_BIN:$OLDPATH"
+
+# shadowing shell functions, like aliases baked into a user's shell, must be
+# bypassed in favor of the executables on PATH (https://github.com/nvm-sh/nvm/issues/2923)
+curl() {
+  echo 'curl 0.0.0-shadowed'
+  return 1
+}
+wget() {
+  return 1
+}
+
+[ "$(nvm_curl_version)" = '7.99.0' ] || die "nvm_curl_version used the shadowing curl function; got $(nvm_curl_version)"
+
+nvm_curl_libz_support || die 'nvm_curl_libz_support used the shadowing curl function'
+
+nvm_download -s 'http://example.com/' -o /dev/null || die 'nvm_download used the shadowing curl function and failed'
+grep -Fxq 'http://example.com/' "$ARGV_LOG" || die "nvm_download did not invoke the curl executable; got: $(cat "$ARGV_LOG")"
+
+cleanup

test/slow/nvm_get_latest/nvm_get_latest

@@ -2,37 +2,45 @@
 
 die () { echo "$@" ; cleanup ; exit 1; }
 
+WORK="$PWD/nvm_get_latest-work.$$"
+TEST_BIN="$WORK/bin"
+
 cleanup() {
-  unset -f curl wget nvm_has
+  rm -rf "$WORK"
+  export PATH="$OLDPATH"
 }
 
 \. ../../../nvm.sh
 
+\. ../../common.sh
+
+OLDPATH="$PATH"
+
 EXPECTED_VERSION="v12.3.456"
 URL="https://github.com/nvm-sh/nvm/releases/tag/$EXPECTED_VERSION"
 EXPECTED_CURL_ARGS="--compressed -q -w %{url_effective}\n -L -s -S https://latest.nvm.sh -o /dev/null"
 EXPECTED_WGET_ARGS="-q https://latest.nvm.sh --server-response -O /dev/null"
+export URL EXPECTED_CURL_ARGS EXPECTED_WGET_ARGS
 
-curl() {
-  if [ $# -eq 1 ] && [ "$1" = "-V" ]; then
-    echo "
+VERSION_MESSAGE="
 curl 7.47.0 (x86_64-pc-linux-gnu) libcurl/7.47.0 GnuTLS/3.4.10 zlib/1.2.8 libidn/1.32 librtmp/2.3
 Protocols: dict file ftp ftps gopher http https imap imaps ldap ldaps pop3 pop3s rtmp rtsp smb smbs smtp smtps telnet tftp
 Features: AsynchDNS IDN IPv6 Largefile GSS-API Kerberos SPNEGO NTLM NTLM_WB SSL libz TLS-SRP UnixSockets"
-  elif [ "_$*" != "_$EXPECTED_CURL_ARGS" ]; then
-    echo >&2 "expected args ($EXPECTED_CURL_ARGS), got ($*)"
-    return 1
-  else
-    echo $URL
-  fi
-}
-wget() {
-  if [ "_$*" != "_$EXPECTED_WGET_ARGS" ]; then
-    echo >&2 "expected args ($EXPECTED_WGET_ARGS), got ($*)"
-    return 1
-  else
-    local WGET_CONTENTS
-    WGET_CONTENTS="
+
+# fake curl/wget: `command curl` bypasses shell functions, so the mocks must be executables on PATH
+make_fake_curl "$TEST_BIN" 'if [ "_$*" != "_$EXPECTED_CURL_ARGS" ]; then
+  echo >&2 "expected args ($EXPECTED_CURL_ARGS), got ($*)"
+  exit 1
+fi
+echo "$URL"'
+
+cat > "$TEST_BIN/wget" <<'OUTER'
+#!/bin/sh
+if [ "_$*" != "_$EXPECTED_WGET_ARGS" ]; then
+  echo >&2 "expected args ($EXPECTED_WGET_ARGS), got ($*)"
+  exit 1
+fi
+cat >&2 <<CONTENTS
   HTTP/1.1 301 Moved Permanently
   Location: https://github.com/nvm-sh/nvm/releases/latest
   Content-Type: text/html; charset=utf-8
@@ -82,15 +90,11 @@ wget() {
   X-Content-Type-Options: nosniff
   Vary: Accept-Encoding
   X-Served-By: 926b734ea1992f8ee1f88ab967a93dac
-"
-    "$WGET_CONTENTS" | while read line
-    do
-      >&2 echo "$line"
-    done
-  fi
-}
+CONTENTS
+OUTER
+chmod +x "$TEST_BIN/wget"
 
-\. ../../common.sh
+export PATH="$TEST_BIN:$OLDPATH"
 
 try nvm_get_latest
 [ "_$CAPTURED_STDOUT" = "_$EXPECTED_VERSION" ] \

test/slow/nvm_get_latest/nvm_get_latest failed redirect

@@ -2,20 +2,26 @@
 
 die () { echo "$@" ; cleanup ; exit 1; }
 
+WORK="$PWD/nvm_get_latest_failed_redirect-work.$$"
+TEST_BIN="$WORK/bin"
+
 cleanup() {
-  unset -f curl wget
+  rm -rf "$WORK"
+  export PATH="$OLDPATH"
 }
 
 \. ../../../nvm.sh
 
 \. ../../common.sh
 
-curl() {
-  return 1
-}
-wget() {
-  return 1
-}
+OLDPATH="$PATH"
+
+# fake curl/wget: `command curl` bypasses shell functions, so the mocks must be executables on PATH
+make_fake_curl "$TEST_BIN" 'exit 1'
+printf '#!/bin/sh\nexit 1\n' > "$TEST_BIN/wget"
+chmod +x "$TEST_BIN/wget"
+
+export PATH="$TEST_BIN:$OLDPATH"
 
 try_err nvm_get_latest
 [ "_$CAPTURED_STDERR" = "_https://latest.nvm.sh did not redirect to the latest release on GitHub" ] \