[Fix] do not colorize output in a pipe, unless --colors is passed

Fixes 2497

nvm.sh

@@ -2994,14 +2994,29 @@ nvm() {
     case $i in
       --) break ;;
       '-h'|'help'|'--help')
-        NVM_NO_COLORS=""
-        for j in "$@"; do
-          if [ "${j}" = '--no-colors' ]; then
-            NVM_NO_COLORS="${j}"
-            break
-          fi
+        local NVM_NO_COLORS
+        NVM_NO_COLORS=''
+        local NVM_YES_COLORS
+        NVM_YES_COLORS=0
+
+        while [ $# -ne 0 ]; do
+          case "${1}" in
+            --colors) NVM_YES_COLORS=1 ;;
+            --no-colors) NVM_NO_COLORS='--no-colors' ;;
+            --) ;;
+          esac
+          shift
         done
 
+        if [ $NVM_YES_COLORS -eq 1 ]; then
+          if [ "${NVM_NO_COLORS-}" = '--no-colors' ]; then
+            nvm_err '--colors and --no-colors are mutually exclusive'
+            return 55
+          fi
+        elif ! nvm_stdout_is_terminal; then
+          NVM_NO_COLORS='--no-colors'
+        fi
+
         local NVM_IOJS_PREFIX
         NVM_IOJS_PREFIX="$(nvm_iojs_prefix)"
         local NVM_NODE_PREFIX
@@ -3598,6 +3613,7 @@ nvm() {
 
       return $EXIT_CODE
     ;;
+
     "uninstall")
       if [ $# -ne 1 ]; then
         >&2 nvm --help
@@ -3678,6 +3694,7 @@ nvm() {
         nvm unalias "$(command basename "${ALIAS}")"
       done
     ;;
+
     "deactivate")
       local NVM_SILENT
       while [ $# -ne 0 ]; do
@@ -3727,6 +3744,7 @@ nvm() {
       unset NVM_BIN
       unset NVM_INC
     ;;
+
     "use")
       local PROVIDED_VERSION
       local NVM_SILENT
@@ -3864,6 +3882,7 @@ nvm() {
         nvm_echo "${NVM_USE_OUTPUT}"
       fi
     ;;
+
     "run")
       local provided_version
       local has_checked_nvmrc
@@ -3948,6 +3967,7 @@ nvm() {
       EXIT_CODE="$?"
       return $EXIT_CODE
     ;;
+
     "exec")
       local NVM_SILENT
       local NVM_LTS
@@ -4008,14 +4028,18 @@ nvm() {
       fi
       NODE_VERSION="${VERSION}" "${NVM_DIR}/nvm-exec" "$@"
     ;;
+
     "ls" | "list")
       local PATTERN
       local NVM_NO_COLORS
+      local NVM_YES_COLORS
+      NVM_YES_COLORS=0
       local NVM_NO_ALIAS
 
       while [ $# -gt 0 ]; do
         case "${1}" in
           --) ;;
+          --colors) NVM_YES_COLORS=1 ;;
           --no-colors) NVM_NO_COLORS="${1}" ;;
           --no-alias) NVM_NO_ALIAS="${1}" ;;
           --*)
@@ -4028,6 +4052,16 @@ nvm() {
         esac
         shift
       done
+
+      if [ $NVM_YES_COLORS -eq 1 ]; then
+        if [ "${NVM_NO_COLORS-}" = '--no-colors' ]; then
+          nvm_err '--colors and --no-colors are mutually exclusive'
+          return 55
+        fi
+      elif ! nvm_stdout_is_terminal; then
+        NVM_NO_COLORS='--no-colors'
+      fi
+
       if [ -n "${PATTERN-}" ] && [ -n "${NVM_NO_ALIAS-}" ]; then
         nvm_err '`--no-alias` is not supported when a pattern is provided.'
         return 55
@@ -4046,10 +4080,13 @@ nvm() {
       fi
       return $NVM_LS_EXIT_CODE
     ;;
+
     "ls-remote" | "list-remote")
       local NVM_LTS
       local PATTERN
       local NVM_NO_COLORS
+      local NVM_YES_COLORS
+      NVM_YES_COLORS=0
 
       while [ $# -gt 0 ]; do
         case "${1-}" in
@@ -4060,6 +4097,7 @@ nvm() {
           --lts=*)
             NVM_LTS="${1##--lts=}"
           ;;
+          --colors) NVM_YES_COLORS=1 ;;
           --no-colors) NVM_NO_COLORS="${1}" ;;
           --*)
             nvm_err "Unsupported option \"${1}\"."
@@ -4086,6 +4124,15 @@ nvm() {
         shift
       done
 
+      if [ $NVM_YES_COLORS -eq 1 ]; then
+        if [ "${NVM_NO_COLORS-}" = '--no-colors' ]; then
+          nvm_err '--colors and --no-colors are mutually exclusive'
+          return 55
+        fi
+      elif ! nvm_stdout_is_terminal; then
+        NVM_NO_COLORS='--no-colors'
+      fi
+
       local NVM_OUTPUT
       local EXIT_CODE
       NVM_OUTPUT="$(NVM_LTS="${NVM_LTS-}" nvm_remote_versions "${PATTERN}" &&:)"
@@ -4166,12 +4213,15 @@ nvm() {
       local ALIAS
       local TARGET
       local NVM_NO_COLORS
+      local NVM_YES_COLORS
+      NVM_YES_COLORS=0
       ALIAS='--'
       TARGET='--'
 
       while [ $# -gt 0 ]; do
         case "${1-}" in
           --) ;;
+          --colors) NVM_YES_COLORS=1 ;;
           --no-colors) NVM_NO_COLORS="${1}" ;;
           --*)
             nvm_err "Unsupported option \"${1}\"."
@@ -4188,6 +4238,15 @@ nvm() {
         shift
       done
 
+      if [ $NVM_YES_COLORS -eq 1 ]; then
+        if [ "${NVM_NO_COLORS-}" = '--no-colors' ]; then
+          nvm_err '--colors and --no-colors are mutually exclusive'
+          return 55
+        fi
+      elif ! nvm_stdout_is_terminal; then
+        NVM_NO_COLORS='--no-colors'
+      fi
+
       if [ -z "${TARGET}" ]; then
         # for some reason the empty string was explicitly passed as the target
         # so, unalias it.
@@ -4216,6 +4275,7 @@ nvm() {
         nvm_list_aliases "${ALIAS-}"
       fi
     ;;
+
     "unalias")
       local NVM_ALIAS_DIR
       NVM_ALIAS_DIR="$(nvm_alias_path)"

test/fast/Set Colors/Using --colors and --no-colors errors

@@ -0,0 +1,12 @@
+#!/bin/sh
+
+die () { echo "$@" ; cleanup ; exit 1; }
+
+\. ../../../nvm.sh
+
+set -ex
+
+nvm ls --colors --no-colors && die "\`nvm ls --colors --no-colors\` did not fail"
+nvm ls-remote --colors --no-colors && die "\`nvm ls-remote --colors --no-colors\` did not fail"
+nvm alias --colors --no-colors && die "\`nvm alias --colors --no-colors\` did not fail"
+nvm --help --colors --no-colors && die "\`nvm --help --colors --no-colors\` did not fail"

test/fast/Set Colors/`--no-colors` is implied in a pipe

@@ -0,0 +1,22 @@
+#!/bin/sh
+
+die () { echo "$@" ; cleanup ; exit 1; }
+
+\. ../../../nvm.sh
+\. ../../common.sh
+
+
+set -ex
+
+for cmd in ls ls-remote alias --help; do
+  NO_COLORS="$(run_in_terminal nvm "${cmd}" --no-colors)"
+  COLORS="$(run_in_terminal nvm "${cmd}" --colors)"
+
+  [ "${COLORS}" != "${NO_COLORS}" ] || die "Expected \`nvm ${cmd} --colors\` to be different from \`nvm ${cmd} --no-colors\`"
+
+  PIPE="$(nvm "${cmd}")"
+  PIPE_COLORS="$(nvm "${cmd}" --colors)"
+
+  [ "${PIPE}" = "${NO_COLORS}" ] || die "Expected \`nvm ${cmd}\` in a pipe to be the same as \`nvm ${cmd} --no-colors\`"
+  [ "${PIPE_COLORS}" = "${COLORS}" ] || die "Expected \`nvm ${cmd} --colors\` in a pipe to be the same as \`nvm ls\` in a terminal (with colors)"
+done