Proj4Leaflet-TMS.R example is broken; broken TMS in Leaflet is possibly the culprit!

[olyerickson]

The Proj4Leaflet-TMS.R example in this github at...

inst/examples/proj4Leaflet-TMS.R

...does not work; in particular, it does not successfully retrieve tiles from the TMS provider when TMS=TRUE.

Base on my testing this week with other known TMS providers, I believe leaflet's handling of TMS=TRUE and the alternative, {-y}, is broken somehow.

[olyerickson]

UPDATE: One of the TMS = TRUE examples in the TMS example file does work, BUT I am still not convinced Leaflet's TMS implementation is correct (at least for R); setting TMS = TRUE for the Mars M20 endpoint does not work as expect (but does in native JavaScript)

[olyerickson]

This apparently is a known and unsolved issue; see #788