Remove base map in vignette

[olivroy]

to fix CI.

I was able to isolate the issue to the call to tm_basemap() in the vignettte. Unfortunately, similar failures happen in examples now..

[olivroy]

Unfortunately, there is still something strange happening with tm_basemap() / tm_tiles()` since 749128c in other circumstances under CRAN checks, which I can't reproduce.
Now, we can see example failures with the same error message.

I have a trace back available, but I don't find it very informative...

Quitting from lines 115-123 [unnamed-chunk-3] (tmap_vv.Rmd)
Error in grid.Call.graphics(C_raster, x$raster, x$x, x$y, x$width, x$height,  : 
  LOGICAL() can only be applied to a 'logical', not a 'NULL'
Error: 
! in callr subprocess.
Caused by error in `grid.Call.graphics(C_raster, x$raster, x$x, x$y, x$width, x$height, …`:
! LOGICAL() can only be applied to a 'logical', not a 'NULL'
ℹ See `$stdout` for standard output.
Type .Last.error to see the more details.
> .Last.error
<callr_error/rlib_error_3_0/rlib_error/error>
Error: 
! in callr subprocess.
Caused by error in `grid.Call.graphics(C_raster, x$raster, x$x, x$y, x$width, x$height, …`:
! LOGICAL() can only be applied to a 'logical', not a 'NULL'
ℹ See `$stdout` for standard output.
---
Backtrace:
1. devtools::build_rmd("vignettes/tmap_vv.Rmd")
2. callr::r_safe(function(...) rmarkdown::render(...), args = list(input = path, …
3. callr:::get_result(output = out, options)
4. callr:::throw(callr_remote_error(remerr, output), parent = fix_msg(remerr[[3]]))
---
Subprocess backtrace:
 1. rmarkdown::render(...)
 2. knitr::knit(knit_input, knit_output, envir = envir, quiet = quiet)
 3. knitr:::process_file(text, output)
 4. xfun:::handle_error(withCallingHandlers(if (tangle) process_tangle(group) else process_group(group), …
 5. base::withCallingHandlers(expr, error = function(e) { …
 6. base::withCallingHandlers(if (tangle) process_tangle(group) else process_group(group), …
 7. knitr:::process_group(group)
 8. knitr:::call_block(x)
 9. knitr:::block_exec(params)
10. knitr:::eng_r(options)
11. knitr:::in_input_dir(evaluate(code, envir = env, new_device = FALSE, …
12. knitr:::in_dir(input_dir(), expr)
13. local evaluate(code, envir = env, new_device = FALSE, keep_warning = if (is.numeric(options$warning)) TRUE else options$warning, …
14. evaluate::evaluate(...)
15. evaluate:::evaluate_call(expr, parsed$src[[i]], envir = envir, enclos = enclos, …
16. base::handle(pv <- withCallingHandlers(withVisible(value_fun(ev$value, …
17. base::withCallingHandlers(withVisible(value_fun(ev$value, ev$visible)), …
18. base::withVisible(value_fun(ev$value, ev$visible))
19. local value_fun(ev$value, ev$visible)
20. local fun(x, options = options)
21. base::withVisible(knit_print(x, ...))
22. knitr::knit_print(x, ...)
23. tmap:::knit_print.tmap(x, ...)
24. tmap:::print.tmap(x, knit = TRUE, options = options, ...)
25. tmap:::step4_plot(x4, vp = vp, return.asp = return.asp, show = show, …
26. base::do.call(FUNrun, list(o = o, show = show, knit = knit, args))
27. tmap:::tmapGridRun(o = list(modes = list(plot = list(name = "Grid", …
28. base::mapply(function(gt, i) { …
29. (function (gt, i) …
30. grid::grid.draw(gt)
31. grid:::grid.draw.gTree(gt)
32. grDevices::recordGraphics(drawGTree(x), list(x = x), getNamespace("grid"))
33. grid:::drawGTree(x)
34. grid::grid.draw(x$children[[i]], recording = FALSE)
35. grid:::grid.draw.gTree(x$children[[i]], recording = FALSE)
36. grDevices::recordGraphics(drawGTree(x), list(x = x), getNamespace("grid"))
37. grid:::drawGTree(x)
38. grid::grid.draw(x$children[[i]], recording = FALSE)
39. grid:::grid.draw.gTree(x$children[[i]], recording = FALSE)
40. grDevices::recordGraphics(drawGTree(x), list(x = x), getNamespace("grid"))
41. grid:::drawGTree(x)
42. grid::grid.draw(x$children[[i]], recording = FALSE)
43. grid:::grid.draw.grob(x$children[[i]], recording = FALSE)
44. grDevices::recordGraphics(drawGrob(x), list(x = x), getNamespace("grid"))
45. grid:::drawGrob(x)
46. grid::drawDetails(x, recording = FALSE)
47. grid:::drawDetails.rastergrob(x, recording = FALSE)
48. grid:::grid.Call.graphics(C_raster, x$raster, x$x, x$y, x$width, x$height, …
49. base::.handleSimpleError(function (e) …
50. local h(simpleError(msg, call))
51. rlang::entrace(e)
52. rlang::cnd_signal(entraced)
53. rlang:::signal_abort(cnd)
54. base::signalCondition(cnd)
55. global (function (e) …

[olivroy]

This old ggplot2 issue seems similar tidyverse/ggplot2#943. Was about a continuous scale and a single color

. It looks like the color scale is not drawn correctly when the continuous scale uses only one color. The code below works: