Explain condition for copy_names() in str_sub() and str_pad().

Author: jonovik

R/pad.R

@@ -44,5 +44,6 @@ str_pad <- function(
     right = stri_pad_right(string, width, pad = pad, use_length = !use_width),
     both = stri_pad_both(string, width, pad = pad, use_length = !use_width)
   )
+  # Preserve names unless `string` is recycled
   if (length(out) == length(string)) copy_names(string, out) else out
 }

R/sub.R

@@ -69,6 +69,7 @@ str_sub <- function(string, start = 1L, end = -1L) {
   } else {
     stri_sub(string, from = start, to = end)
   }
+  # Preserve names unless `string` is recycled
   if (length(out) == length(string)) copy_names(string, out) else out
 }