Deprecate "dry run" mode

[jaraco]

As I'm working to eliminate the reliance of distutils.compilers on distutils (as part of pypa/setuptools#3622), I find the "dry run" functionality binds everything together. Spawn has its own behavior to account for dry-run. Each command and compiler has a .execute method to honor dry run.

And it got me thinking - does anybody use this functionality? My guess is probably not, especially now that most of this is handled in isolated environments and as part of build backends.

So let's explore just removing it.

[jaraco]

I did a search, and it does seem there are quite a few references to --dry-run being used. Most of them seem like casual use. I couldn't find anything that looked like popular and programmatic use. And since setup.py is deprecated, it should be safe to remove features of setup.py without warning.

[Avasam]

Your query link seems to be messed-up and double-encoded, this should be correct: https://github.com/search?q=content%3A%2Fsetup%5C.py.*--dry-run%2F&type=code

As for programatic usage: https://github.com/search?q=content%3A.dry_run+path%3Asetup.py&type=code

Glad to say this is no longer a concern for pywin32 as of https://github.com/mhammond/pywin32/pull/2390/files#diff-60f61ab7a8d1910d86d9fda2261620314edcae5894d5aaa236b821c7256badd7L871 😄