Use cabal-doctest only during CI

[hvr]

Proof of concept for using build-type:custom only during CI

[kazu-yamamoto]

You should also take care of AppVeyor. Can the shell script run on Windows?
Or should we implement and use a Haskell script?

[hvr]

@kazu-yamamoto I intentionally used a shell script so we can run it via bash (you'll notice there's already one bash call in the appveyor script) on Appveyor too

PS: I'm on it!

[hvr]

@kazu-yamamoto done; you should take a look now. I also noticed there was some non-idiomatic manual installation lib:cabal-doctest which made no sense (as new-build wouldn't be able to see it anyway)

[kazu-yamamoto]

Great!

[kazu-yamamoto]

Q1) Don't we need a default Setup.hs?
Q2) On macOS, bash enable_doctest.sh results in:

sed: 1: "network.cabal": extra characters at the end of n command
sed: 1: "network.cabal": extra characters at the end of n command
sed: 1: "network.cabal": extra characters at the end of n command

[hvr]

Q1) Don't we need a default Setup.hs?

They're only needed for compliant source-tarballs -- and cabal sdist will include a default Setup.hs automatically; in other words, it's redundant (and somewhat error-prone as there's no checks in place to verify that for build-type:{Simple,Configure} the Setup.hs contents is consistent) to place an explicit default Setup.hs into Git. The only case where you need to provide an explicit one is for build-type:Custom.

Q2) On macOS, bash enable_doctest.sh results in:

Right... the sed invocations assumed GNU sed; but on macOS you have BSD sed which lacks the some of the extensions I used...

Do you need the script to support BSD? If so, I can find an alternative way to perform the transformations.

[kazu-yamamoto]

I would suggest to prepare network.cabal.doctest and copy it to network.cabal instead using sed.

[kazu-yamamoto]

Supporting this sounds crazy:

https://stackoverflow.com/questions/5694228/sed-in-place-flag-that-works-both-on-mac-bsd-and-linux

[hvr]

I would suggest to prepare network.cabal.doctest and copy it to network.cabal instead using sed.

the problem with that approach is that you need to keep the two files manually synced up which can become annoying to do.

Also, I've tweaked the sed invocation a bit to be POSIX compatible.

[llelf]

@hvr s/bash/sh/ then? :)

[hvr]

@llelf the script is already a #!/bin/sh script...? :-)

[llelf]

@hvr yes, but you run it with bash ;)
Think of those poor *BSD systems!

[kazu-yamamoto]

Awesome!

[kazu-yamamoto]

Merged.
Thank you for your contribution!