remove installation of Cabal by cabal

[samuelpilz]

The install.hs calls cabal install Cabal-X. This command was copied from the Makefile several months ago.

I have done exhaustive tests on different machies (linux only) and have not seen any effect of this line and hie works even without this command. This PR removes this command from the installation process.

Comments on this change and tests on MacOS and Windows are welcome!

[Anrock]

I'll give it a shot on Windows soon. What should i remove to be sure it's working properly?

[fendor]

Did you measure the installation time? I think, one point was to accelerate the installation.

[samuelpilz]

@Anrock on Linux, hie clearing means roughly:

• remove installed binaries from $HOME/.local/bin: hie, hie-*, cabal, hoogle
• remove all the caches: $HOME/.stack, $HOME/.cabal, $HOME/.hoogle

Installing:

• freshly clone the repository
• stack install.hs build-all
• let run overnight

[samuelpilz]

@fendor It was used to reduce the time during the first startup of hie. However I have noticed no speedup and the first startup was quite quick.

[fendor]

Alright. Then LGTM.

[alanz]

I'm happy to merge this, if anyone complains we will know to add it back, or put in instructions to do it.

[Anrock]

Late to the party, but still - most of hies build just fine with build-all.

[alanz]

So, I found my cabal-helper was not able to work with hie on hie itself anymore, but was reporting that it was building against Cabal-2.4.0.1.

After reverting this commit and re-installing hie, it works again.

So, the reason we did this originally, was to allow cabal-helper to actually work. We need to revert this.

[samuelpilz]

I can do that. However, I have been unable to reproduce that behavior. A clean installation of hie does not make cabal-helper require Cabal on my test-vms, which provide the maximum repeatability and isolation I can provide.

@alanz Can you give me instructions on how to reproduce this error? I will go back to my test-environment and figure out what is going on.

[alanz]

It comes about trying to load hie itself, and shows cabal-helper complaining to stderr that the exe has two mains in it, one of which is Paths_haskell_ide_engine.

So our current tests do not show this as a problem, and perhaps we should add one for this specific case.

[alanz]

And now I am no longer sure about this. I installed hie using this approach, and it now works where it did not before. But the cabal-helper cache has it's exe called cabal-helper0.9.0.0-Cabal2.4.0.1.

[alanz]

So perhaps we should wait for any issues to be raised, and consider this as an option if so.

[samuelpilz]

@alanz, I am also very unsure about this, In my tests in an non-clean environment, I got different results every time and were unable to reproduce any issues reliably.

Could you clarify in what state would you prefer to wait. Should we include cabal v1-install Cabal-X in the meantime?

I have a repository that describes a vagrant-vm I use to test the hie binaries and the required environment. I can work this a bit further and publish it to the collaborators here.

[alanz]

I think we should keep our fix in reserve, and see if anyone raises an issue against 0.9.0.0 in the meantime.