Calling `first()` in `summarise()` on a non-existent column causes segfault (and crashes R)

[Qzrx]

R version 3.1.0 (2014-04-10) -- "Spring Dance", OSX 64-bit
dplyr 0.2.0.99

If I take a data frame and then try summarizing using first value of a non-existing column, dplyr gets very unhappy. Which is good--it shouldn't silently eat the error!

Unfortunately it doesn't return an error or warning. Instead it just outright crashes the entire R session. Meep.

foo = data.frame(x = 1:10, y = 1:10)
foo %>%
  group_by(x) %>% 
  summarise(first_y = first(y)) # perfectly happy!

foo = data.frame(x = 1:10, y = 1:10)
foo %>%
  group_by(x) %>% 
  summarise(first_y = first(z)) # CRAAAAASH!

[Qzrx]

Full terminal output for usefulness:

> library(dplyr)

Attaching package: ‘dplyr’

The following objects are masked from ‘package:stats’:

    filter, lag

The following objects are masked from ‘package:base’:

    intersect, setdiff, setequal, union

> foo = data.frame(x = 1:10, y = 1:10)
> foo %>%
+   group_by(x) %>% 
+   summarise(first_y = first(z)) 

 *** caught segfault ***
address 0x0, cause 'memory not mapped'

Traceback:
 1: .Call("dplyr_summarise_impl", PACKAGE = "dplyr", df, args, env)
 2: summarise_impl(.data, named_dots(...), environment())
 3: summarise.tbl_df(`foo %>% group_by(x)`, first_y = first(z))
 4: summarise(`foo %>% group_by(x)`, first_y = first(z))
 5: eval(expr, envir, enclos)
 6: eval(e, env)
 7: withVisible(eval(e, env))
 8: foo %>% group_by(x) %>% summarise(first_y = first(z))

Possible actions:
1: abort (with core dump, if enabled)
2: normal R exit
3: exit R without saving workspace
4: exit R saving workspace

[hadley]

Could you please try with the latest version? It should be fixed in d822e0d

[hadley]

@romainfrancois this still crashes for me. Can you please take a look?

[cnjr2]

I still seem to get the segfault using the example from above.

Please find my session output below:

All is good with:

foo = data.frame(x = 1:10, y = 1:10)
foo %>%
  group_by(x) %>% 
  summarise(first_y = first(y)) # perfectly happy!

R version 3.2.2 (2015-08-14) -- "Fire Safety"
Copyright (C) 2015 The R Foundation for Statistical Computing
Platform: x86_64-apple-darwin11.4.2 (64-bit)

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> library("dplyr")

Attaching package: ‘dplyr’

The following objects are masked from ‘package:stats’:

    filter, lag

The following objects are masked from ‘package:base’:

    intersect, setdiff, setequal, union

> 
> foo = data.frame(x = 1:10, y = 1:10)
> foo %>%
+     group_by(x) %>%
+     summarise(first_y = first(y)) # perfectly happy!
Source: local data frame [10 x 2]

       x first_y
   (int)   (int)
1      1       1
2      2       2
3      3       3
4      4       4
5      5       5
6      6       6
7      7       7
8      8       8
9      9       9
10    10      10

But for:

foo = data.frame(x = 1:10, y = 1:10)
foo %>%
  group_by(x) %>% 
  summarise(first_y = first(z)) # CRAAAAASH!

It crashes:

> foo = data.frame(x = 1:10, y = 1:10)
> foo %>%
+   group_by(x) %>% 
+   summarise(first_y = first(z)) # CRAAAAASH!

 *** caught segfault ***
address 0x0, cause 'unknown'

Traceback:
 1: .Call("dplyr_summarise_impl", PACKAGE = "dplyr", df, dots)
 2: summarise_impl(.data, dots)
 3: summarise_.tbl_df(.data, .dots = lazyeval::lazy_dots(...))
 4: summarise_(.data, .dots = lazyeval::lazy_dots(...))
 5: summarise(., first_y = first(z))
 6: function_list[[k]](value)
 7: withVisible(function_list[[k]](value))
 8: freduce(value, `_function_list`)
 9: `_fseq`(`_lhs`)
10: eval(expr, envir, enclos)
11: eval(quote(`_fseq`(`_lhs`)), env, env)
12: withVisible(eval(quote(`_fseq`(`_lhs`)), env, env))
13: foo %>% group_by(x) %>% summarise(first_y = first(z))

Possible actions:
1: abort (with core dump, if enabled)
2: normal R exit
3: exit R without saving workspace
4: exit R saving workspace
Selection: 

Here is also my session info.

> sessionInfo()
R version 3.2.2 (2015-08-14)
Platform: x86_64-apple-darwin11.4.2 (64-bit)
Running under: OS X 10.11.3 (El Capitan)

locale:
[1] en_GB.UTF-8/en_GB.UTF-8/en_GB.UTF-8/C/en_GB.UTF-8/en_GB.UTF-8

attached base packages:
[1] stats     graphics  grDevices utils     datasets  methods   base     

other attached packages:
[1] dplyr_0.4.3

loaded via a namespace (and not attached):
[1] lazyeval_0.1.10 magrittr_1.5    R6_2.1.1        assertthat_0.1  parallel_3.2.2  tools_3.2.2     DBI_0.3.1       Rcpp_0.12.2    

I have installed R via anaconda.

[cnjr2]

Despite my sessionInfo() printing that dplyr_0.4.3 is attached, I upgraded my dplyr in anaconda with:

>conda install -c r r-dplyr
Using Anaconda Cloud api site https://api.anaconda.org
Fetching package metadata: ......
Solving package specifications: .................
Package plan for installation in environment /Users/user/anaconda:

The following packages will be UPDATED:

    r-dplyr: 0.4.1-0 --> 0.4.3-r3.2.2_0
    zlib:    1.2.8-0 --> 1.2.8-1       

Proceed ([y]/n)? y

Unlinking packages ...
[      COMPLETE      ]|###################################################################################################################################################################################################################################################| 100%
Linking packages ...
[      COMPLETE      ]|###################################################################################################################################################################################################################################################| 100%
>

It seems that version 0.4.1-0 was installed afterall... I am not sure where it had the 4.3 from.

Anyways, running the following now works fine!

> foo = data.frame(x = 1:10, y = 1:10)
> foo %>%
+   group_by(x) %>% 
+   summarise(first_y = first(z)) # CRAAAAASH!
Error: variable 'z' not found

Thanks!