r - 当measure.vars包含不在data.table中的变量时，melt.data.table可能会崩溃

Question

以下代码在我的安装中崩溃:

library(data.table)
library(reshape2)
x = data.table(a=c(1,2),b=c(2,3),c=c(3,4))
melt(x,id.vars="a") # OK
melt(x,id.vars="a",measure.vars=c("c","d")) # Crashes

消息如下:

*** caught segfault ***
address 0x21000038, cause 'memory not mapped'
Traceback:
1: melt.data.table(x, id.vars = "a", measure.vars = c("c", "d"))
2: melt(x, id.vars = "a", measure.vars = c("c", "d"))

这是sessionInfo()

R version 3.1.0 (2014-04-10)
Platform: x86_64-pc-linux-gnu (64-bit)

locale:
 [1] LC_CTYPE=en_US.UTF-8       LC_NUMERIC=C              
 [3] LC_TIME=ro_RO.UTF-8        LC_COLLATE=en_US.UTF-8    
 [5] LC_MONETARY=ro_RO.UTF-8    LC_MESSAGES=en_US.UTF-8   
 [7] LC_PAPER=ro_RO.UTF-8       LC_NAME=C                 
 [9] LC_ADDRESS=C               LC_TELEPHONE=C            
[11] LC_MEASUREMENT=ro_RO.UTF-8 LC_IDENTIFICATION=C       

attached base packages:
[1] stats     graphics  grDevices utils     datasets  methods   base     
> library(data.table)
data.table 1.9.2  For help type: help("data.table")
> library(reshape2)
> sessionInfo()
R version 3.1.0 (2014-04-10)
Platform: x86_64-pc-linux-gnu (64-bit)

locale:
 [1] LC_CTYPE=en_US.UTF-8       LC_NUMERIC=C              
 [3] LC_TIME=ro_RO.UTF-8        LC_COLLATE=en_US.UTF-8    
 [5] LC_MONETARY=ro_RO.UTF-8    LC_MESSAGES=en_US.UTF-8   
 [7] LC_PAPER=ro_RO.UTF-8       LC_NAME=C                 
 [9] LC_ADDRESS=C               LC_TELEPHONE=C            
[11] LC_MEASUREMENT=ro_RO.UTF-8 LC_IDENTIFICATION=C       

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

other attached packages:
[1] reshape2_1.4     data.table_1.9.2

loaded via a namespace (and not attached):
[1] plyr_1.8.1    Rcpp_0.11.1   stringr_0.6.2

这里可能报告了相同的问题: melting data.table seems to crash RStudio?

Answer 1

感谢您的发布和错误报告。现在，此问题已通过v1.9.3的commit 1261修复。从NEWS:

• melt now returns friendly error when meaure.vars are not in data instead of segfault. Closes #699. Thanks to vsalmendra for this post on SO and the subsequent bug report.

如果问题仍然存在，请回信。