Summarise crashes

[hadley]

library(dplyr)
mtcars_cyl_am <- summarise(group_by(mtcars, cyl, gear), m1 = mean(mpg))
summarise(mtcars_cyl_am, m2 = mean(mpg))

[romainfrancois]

Ouch. Probably a bad use of boost hash maps :/

> summarise(mtcars_cyl_am, m2 = mean(mpg))
Process 20015 stopped
* thread #1: tid = 0xe8903, 0x0000000106ebed60 dplyr.so`dplyr::LazyGroupedSubsets::get_variable(SEXPREC*) const [inlined] boost::unordered::iterator_detail::iterator<boost::unordered::detail::ptr_node<std::__1::pair<SEXPREC* const, dplyr::GroupedSubset*> >*, std::__1::pair<SEXPREC* const, dplyr::GroupedSubset*> >::operator++() + 1 at buckets.hpp:369, queue = 'com.apple.main-thread, stop reason = EXC_BAD_ACCESS (code=1, address=0x0)
    frame #0: 0x0000000106ebed60 dplyr.so`dplyr::LazyGroupedSubsets::get_variable(SEXPREC*) const [inlined] boost::unordered::iterator_detail::iterator<boost::unordered::detail::ptr_node<std::__1::pair<SEXPREC* const, dplyr::GroupedSubset*> >*, std::__1::pair<SEXPREC* const, dplyr::GroupedSubset*> >::operator++() + 1 at buckets.hpp:369
   366          }
   367
   368          iterator& operator++() {
-> 369              node_ = static_cast<node_pointer>(node_->next_);
   370              return *this;
   371          }
   372

[kevinushey]

Isn't the problem just that mpg is not defined in mtcars_cyl_am? Can't you check for the existence of symbols passed early on?

[romainfrancois]

That was it. Fixed now.