next_cursor overflow in get_friends

[aaronrudkin]

Problem

The next_cursor attribute (and thus, function) generated from get_friends occasionally overflows because something in the code is not properly using next_cursor_str.

Expected behavior

next_cursor returns a cursor to the next page of query results.

Reproduce the problem

library(tidyverse)
library(rtweet)

# create_token(...)

my_token = rtweet:::check_token(NULL)
next_token = -1
full_results = 1:20 %>% map(function(x) {
  print(paste("Working on page", x, "of verified users."))
  print(paste("Next cursor", next_token))
  current_rate_limit = rate_limit(my_token, "friends/ids")
  if(current_rate_limit$remaining == 0) {
    message("Waiting because out of rate limit")
    Sys.sleep(as.numeric(current_rate_limit$reset, "secs") + 2)
  }
  
  results = get_friends(users = "verified", 
                        n = 5000,
                        retryonratelimit = TRUE, 
                        page = next_token)

  next_token <<- next_cursor(results)
  results
}) %>% bind_rows()

Observe that after 16 pages, the next_cursor function returns an integer large enough to overflow into scientific notation. I believe this is because the code in get_friends_ which copies the next_cursor value into the table attribute uses next_cursor instead of next_cursor_str. I do notice that the next_cursor() S3 methods correctly check for next_cursor_str, but get_friends circumvents the next_cursor() function and directly sets the attribute from the [["next_cursor"]] item in the response.

rtweet version

0.6.8

[aaronrudkin]

This PR should fix the narrow issue, although please note I did not check any other API methods for the same bug, and so it may be worth doing so.