awvwgk
commented
2 years ago This decisions mainly depends on your user base and how much effort you want to put into regression testing those version.
For testing TOML Fortran I started testing and supporting from GCC 5 upwards, however it become more and more difficult to install GCC 5 up to the point that I had to drop it from testing. Similar with GCC 6 which I only test via homebrew. Going forward it seems best to follow the latest three GCC versions, as those will get continuously bug fixes and keep support for older versions as long as it is feasible and they don't break.
Note: the CI is currently only testing Gfortran 7, 8, 9, 10. There are various "hacks" in the code to deal with bugs in earlier Gfortran compilers (the library used to work with 4.9, but that hasn't been tested in a while, at least by me). Some of these hacks are slowing things down a bit, so I would like to remove them. Since I'm not testing anything older than 7, if I remove some of them I'm not really going to know if it breaks anything in those old compilers.
What is the oldest Gfortran version I should be worrying about?
Alternatively I could change the preprocessor hacks to check for specific Gfortran versions, but that seems more complicated, and I don't really want to do it.