Uninformative summary when checks time out

[xrobin]

While checking my pROC package with

revdep_check(num_workers = 4)

several packages failed with the following data in revdep/failures.md:

# Biocomb

<details>

* Version:
* Source code: ???
* URL: http://expasy.org/tools/pROC/
* BugReports: https://github.com/xrobin/pROC/issues
* Number of recursive dependencies: 0

Run `revdep_details(,"")` for more info

</details>

## Error before installation

### Devel

```






```
### CRAN

```






```

This message is repeated several times for several packages that failed. The 6 blank lines are verbatim in failures.md.

Typing revdep_details(,"") as instructed results in the following error:

> revdep_details(,"")
Error in db_results(pkg, revdep)[[1]] : subscript out of bounds
2: structure(db_results(pkg, revdep)[[1]], class = "revdepcheck_details")
1: revdep_details(, "")

I installed revdepcheck yesterday just before running the tests with source("https://install-github.me/r-lib/revdepcheck").

> sessionInfo()
R Under development (unstable) (2019-05-20 r76548)
Platform: x86_64-pc-linux-gnu (64-bit)
Running under: CentOS Linux 7 (Core)

Matrix products: default
BLAS:   /home/zohixe92/build/R-devel-svn/lib/libRblas.so
LAPACK: /home/zohixe92/build/R-devel-svn/lib/libRlapack.so

Random number generation:
 RNG:     Mersenne-Twister 
 Normal:  Inversion 
 Sample:  Rounding 
 
locale:
 [1] LC_CTYPE=en_US.UTF-8       LC_NUMERIC=C              
 [3] LC_TIME=en_US.UTF-8        LC_COLLATE=en_US.UTF-8    
 [5] LC_MONETARY=en_US.UTF-8    LC_MESSAGES=en_US.UTF-8   
 [7] LC_PAPER=en_US.UTF-8       LC_NAME=C                 
 [9] LC_ADDRESS=C               LC_TELEPHONE=C            
[11] LC_MEASUREMENT=en_US.UTF-8 LC_IDENTIFICATION=C       

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

other attached packages:
[1] pROC_1.14.0            revdepcheck_1.0.0.9001 fortunes_1.5-4        
[4] Cairo_1.5-10          

loaded via a namespace (and not attached):
 [1] Rcpp_1.0.1           plyr_1.8.4           highr_0.8           
 [4] compiler_3.7.0       pillar_1.4.0         remotes_2.0.4       
 [7] progress_1.2.2       prettyunits_1.0.2    base64enc_0.1-3     
[10] tools_3.7.0          pkgbuild_1.0.3       digest_0.6.19       
[13] bit_1.1-14           jsonlite_1.6         RSQLite_2.1.1       
[16] memoise_1.1.0        tibble_2.1.1         debugme_1.1.0       
[19] pkgconfig_2.0.2      rlang_0.3.4          whoami_1.3.0        
[22] DBI_1.0.0            cli_1.1.0            yaml_2.2.0          
[25] curl_3.3             xopen_1.0.0          xfun_0.7            
[28] withr_2.1.2          gmailr_0.7.1         httr_1.4.0          
[31] knitr_1.23           hms_0.4.2            desc_1.2.0          
[34] rappdirs_0.3.1       rprojroot_1.3-2      bit64_0.9-7         
[37] glue_1.3.1           crancache_0.0.0.9001 parsedate_1.2.0     
[40] R6_2.4.0             processx_3.3.1       rcmdcheck_1.3.3.9000
[43] sessioninfo_1.1.1    callr_3.2.0          blob_1.1.1          
[46] rematch2_2.0.1       magrittr_1.5         backports_1.1.4     
[49] clisymbols_1.2.0     ps_1.3.0             assertthat_0.2.1    
[52] cranlike_1.0.2       crayon_1.3.4        

[burgerga]

In my case this was caused by revdep timing out (by default after 10 minutes), try again by increasing the timeout

revdepcheck::revdep_check(num_workers = 4, timeout = as.difftime(360,units = "mins"))

[xrobin]

Indeed after increasing the timeout I no longer get these empty error messages.

It would be nice if the failure message included information about the timeout.

Also it makes this bug easy to reproduce by setting a timeout of 0 seconds:

revdep_check(timeout = 0)

All the packages fail (as expected) with the features described above (blank message and subscript out of bounds error in db_results).

A simple workaround would be to increase the default timeout a bit.