Zero Range for HMS object

[muschellij2]

The use case for this bug is at tidyverse/ggplot2#6134

The zero_range internal function has different behavior for hms and all difftime objects if there is a "midnight" in there aka 00:00:00 hms value.

Simple Example

Let's say a function calculated a range of hms objects and midnight not in there:

range = structure(c(1234, 7380), class = "difftime", units = "secs")
scales:::zero_range(range)
#> Error in `/.difftime`((x[1] - x[2]), m): second argument of / cannot be a "difftime" object

The error happens at

scales/R/bounds.R

Line 397 in 6e5e4c3

abs((x[1] - x[2]) / m) < tol

and m in this case is a difftime object.

Create a sequence that crosses midnight, range has a 0 in there, so no error.
The error is “resolved” because

scales/R/bounds.R

Line 391 in 6e5e4c3

if (m == 0) {

exits with FALSE.

range_with_zero = structure(c(0, 7380), class = "difftime", units = "secs")
scales:::zero_range(range_with_zero)
#> [1] FALSE