Why do we have these helper functions? They don't provide any meaningful abstraction over literal strings IMHO.

They don't really, but writing these ifs everywhere would seem cumbersome, if you want to pass the negative flags as well.

According to documentation, the standard autoconf macros --disable-foo and --without-bar are defined as equivalent to --enable-foo=no and --with-bar=no.

So stdenv.lib.withFeatureAs wgetSupport "wget" "${wget}/bin/wget" can become --with-wget=${if wgetSupport then "${wget}/bin/wget" else "no"}. Which has better grep-ability and (at least to me) less cognitional load. I'd get rid of these miniscule helpers.

Yes, sounds nice. It won't be possible to guard against the typo like this PR does :-) but that's a relatively small thing and without the function the typo may be harder to make.

I'm not really in favor of these. I once had to spend a day reverting the previous attempt at such functions (https://github.com/NixOS/nixpkgs/commits/e3356b396d308264ab04cb3e997edc048af2fea2). The problem was that people starting exposing every configure flag as Nix function arguments...

Any updates on this pull request?

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Any updates on this pull request?

I'm not really in favor of these. [..] The problem was that people starting exposing every configure flag as Nix function arguments...

@edolstra What's the rationale for merging it? Did something change in the last 2 years?

EDIT: Change just seems to be about asserting isString feat, I see.