Bug: numbers converted to string get the letter "g" added to the end if about 10^19 in general format with over 20 decimal places

[Tyson Banks]

I'm using Stata MP 19.5 for Mac. When I run:

clear all
set obs 1
gen double glitched_tostring = 10^19
tostring glitched_tostring, format("%50.21g") replace force
di glitched_tostring[1]

The output is:

1000000000000000000.g

Which seems to have a random letter g added to the end. This seems to only happen when:

*The number is at least 10^19, and smaller than 10^20
*The format specifies more than 20 decimals
*The format type ends in g or gc

[Tyson Banks]

Huh, I just noticed that the actual output minus the ".g" is no longer on the order of 10^19, and is now 10^18.

So it's not that ".g" gets appended onto the end, but it actually replaces the last digit.

[Hua Peng (StataCorp)]

We are able to reproduce it and am looking into the issue.