问rvm升级错误，显示'command gem pristine --extensions debugger --version 1.6.0 failed‘

EN

Error running '__rvm_with ruby-2.1.5 gemset_pristine',
showing last 15 lines of /Users/snowcrash/.rvm/log/1419348453/gemset.pristine-ruby-2.1.5.log
+ gem pristine --extensions yard --version 0.8.6.2
+ read _gem _version _platforms
+ ((  1 > 0  ))
+ rvm_error '\n'\''command gem pristine --extensions debugger --version 1.6.0'\'' failed, you need to fix this gems manually.'
+ rvm_pretty_print stderr
+ case "${rvm_pretty_print_flag:=auto}" in
+ case "${TERM:-dumb}" in
+ case "$1" in
+ [[ -t 2 ]]
+ return 1
+ printf %b '\n'\''command gem pristine --extensions debugger --version 1.6.0'\'' failed, you need to fix this gems manually.\n'

'command gem pristine --extensions debugger --version 1.6.0' failed, you need to fix this gems manually.
+ return 1