Travis build is failing

[Robinlovelace]

Due to new dependency on RWeka it seems:

https://travis-ci.org/Robinlovelace/geocompr/jobs/635999896#L15302

[Robinlovelace]

Heads-up @jannes-m (as it's in c 11) I can also reproduce this locally:

rmarkdown::render("~/geocompr/geocompr/11-spatial-cv.Rmd")
#> processing file: 11-spatial-cv.Rmd
#> Linking to GEOS 3.8.0, GDAL 3.0.2, PROJ 6.2.1
#> Loading required package: sp
#> Loading required package: ParamHelpers
#> 
#> Attaching package: 'ParamHelpers'
#> The following object is masked from 'package:raster':
#> 
#>     getValues
#> 
#> Attaching package: 'mlr'
#> The following object is masked from 'package:raster':
#> 
#>     resample
#> 
#> Attaching package: 'dplyr'
#> The following objects are masked from 'package:raster':
#> 
#>     intersect, select, union
#> The following objects are masked from 'package:stats':
#> 
#>     filter, lag
#> The following objects are masked from 'package:base':
#> 
#>     intersect, setdiff, setequal, union
#> Warning in kableExtra::kable_styling(., latex_options = "scale_down"): Please
#> specify format in kable. kableExtra can customize either HTML or LaTeX outputs.
#> See https://haozhu233.github.io/kableExtra/ for details.
#> Setting levels: control = FALSE, case = TRUE
#> Setting direction: controls < cases
#> Setting levels: control = FALSE, case = TRUE
#> Setting direction: controls < cases
#> Quitting from lines 362-370 (11-spatial-cv.Rmd)
#> Error in loadNamespace(name): there is no package called 'RWeka'

^{Created on 2020-01-12 by the reprex package (v0.3.0)}

[Robinlovelace]

This is the culprit:

lrns_df = 
  listLearners(task, warn.missing.packages = FALSE) %>%
  dplyr::select(Class = class, Name = name, `Short name` = short.name, Package = package) %>% 
  head()

[Robinlovelace]

Also depends on package mda:

Error in loadNamespace(name) : there is no package called ‘mda’

[Robinlovelace]

Now failing due to this it seems: https://github.com/rstudio/bookdown/issues/15

[Robinlovelace]

https://travis-ci.org/Robinlovelace/geocompr/jobs/636019908#L8250

[Robinlovelace]

On travis-fix branch creating this book is the last issue:

[Nowosad]

@Robinlovelace there is one minor issue to fix - can you take a look at it:

pandoc-citeproc: reference jafari_investigation_2015 not found