The strL data type is clearly useful, but the fact that it can't be used for a merge is breaking
backward compatibility with Stata 15 and earlier. I don't know if strL is new to Stata16, or if
Stata16 is just more aggressive about using it as a data type.

My prior code is breaking because variables that were formerly `str##` are now being read by Stata
as `strL`, so they cannot be used as merge keys. My research team has written about 200,000 lines of
Stata code over the last 10 years, and these breakages are happening left and right. In many cases,
the efficiency replacement is not remotely worth it-- today some code broke while running a string
replacement using a replacement file that was only 10 strings in length.

In this specific case, the 10-line string file was imported with `import delimited`, and Stata
defaulted the key string to strL, breaking the merge.

I know I can recast these to the `str##` format, but I would like to avoid updating our codebase in
thousands of places.

Ideally, I would like to ask Stata to avoid using the `strL` format except when I specifically
request it. Alternately, to avoid using the `strL` in cases when the string length is less than some
character length, like 100.

Can this be done?

Thank you!

-p