GHC 8.4: compiler and package fixes #34023

deepfire · 2018-01-18T20:51:16Z

Motivation for this change

This provides GHC 8.4.1-alpha in Nixpkgs, along with many necessary package overrides.

Things done

Tested using sandboxing (nix.useSandbox on NixOS, or option build-use-sandbox in nix.conf on non-NixOS)
Built on platform(s)
- NixOS
- macOS
- other Linux distributions
Tested via one or more NixOS test(s) if existing and applicable for the change (look inside nixos/tests)
Tested compilation of all pkgs that depend on this change using nix-shell -p nox --run "nox-review wip"
Tested execution of all binary files (usually in ./result/bin/)
Fits CONTRIBUTING.md.

deepfire · 2018-01-18T20:51:44Z

cc @peti

peti · 2018-01-19T10:28:08Z

pkgs/development/haskell-modules/configuration-ghc-8.4.x.nix

+  # Use the latest LLVM.
+  inherit (pkgs) llvmPackages;
+
+  # Disable GHC 7.11.x core libraries.


This comment makes me suspicious. :-) Did you actually check which core libraries GHC 8.4.x provides and adopt this list accordingly?

@peti, pushed an attempt at this update. One question is -- what is bin-package-db -- did previous GHC's indeed used to have this package or not? I retained its entry, because it sounded magical enough..

peti · 2018-01-19T10:28:56Z

pkgs/development/haskell-modules/configuration-ghc-8.4.x.nix

+  bytestring-builder = dontHaddock super.bytestring-builder;
+
+  # We have time 1.5
+  aeson = disableCabalFlag super.aeson "old-locale";


This override is actually necessary???

I've started with the ghcHEAD definition and extended that. So I didn't really check the inherited old entries.

What do you think is the best way to go forward?

The problem is that we end up having a ton of overrides with no documentation, no ticket URLs, not explanation of why they exist ... so who is ever going to clean that up?

Personally, I'd start with an empty configuration-ghc-8.4.x.nix file and add only those overrides that I find are actually required. It's also a good idea to add comments every now and then to document why you're adding the overrides you do.

Indeed.. I was planning to track a short one-liner explanation in the Elaborate Set of Bash Scripts, so that information is available.

Thank you!

peti · 2018-01-19T10:31:37Z

pkgs/development/haskell-modules/configuration-ghc-8.4.x.nix

+
+# Non-code change
+
+  adjunctions = overrideCabal super.adjunctions (drv: {


Why don't you use doJailbreak?

I use an Elaborate Set of Bash Scripts to generate the list of overrides, and this has consequences, that adding a line entry is easier than adding a wrapping set of parentheses..

Just out of curiosity, how did those shell scripts know which version to pick for overriding blaze-markup etc.?

@peti, the figuring out was manual work, of course -- but the maintenance (hash updates, state changes) is supported by those scripts.

There is an angle to this, however -- the dataset is structured in such a way, that paring the set of overrides down automatically is not infeasible.

peti · 2018-01-19T11:44:16Z

What is bin-package-db?

This used to be a core package in GHC 6.x, I think. It never existed on Hackage, so we should probably keep the assignment to "null" because some packages refer to it as a dependency and the package set won't evaluate if the name is missing.

peti

I would be happy to merge a version of this PR that adds the compiler plus an empty configuration-ghc-8.4.x.nix file that defines nothing but the core packages. The version with all those overrides defined, however, scares me because it's seems like a really bad idea totally intransparent where these settings come from and how they are going to be maintained in the future.

peti · 2018-01-19T11:55:12Z

pkgs/development/haskell-modules/configuration-ghc-8.4.x.nix

+  hashable = doJailbreak super.hashable;
+
+  # Great Fire of China
+  blaze-markup = overrideCabal super.blaze-markup (drv: {


Why don't you use self.blaze-markup_0_8_2_0?

Oversight : -)

peti · 2018-01-19T11:56:48Z

pkgs/development/haskell-modules/configuration-ghc-8.4.x.nix

+
+# Upstreamed
+
+  constraints = overrideCabal super.constraints (drv: {


I really don't like these overrides because they unconditionally override whatever version hackage-packages.nix provides -- even if the version in there is actually newer than the one we hard-code here. I'd very much prefer to have these overrides import the relevant patches, because then we'd at least notice when they cease to apply to the upstream version.

Completely agreed -- my plan was to submit early, and then pare down the Hackage-sourced overrides, as they're overtaken by the hackage-packages regeneration.

peti · 2018-01-19T11:57:48Z

pkgs/development/haskell-modules/configuration-ghc-8.4.x.nix

+  conduit-extras = overrideCabal super.conduit-extras (drv: {
+    src = pkgs.fetchgit {
+      url    = "https://github.com//conduit-extras";
+      rev    = "";


This doesn't seem like a good idea.

Whoops, thank you! It's a bit odd the resulting package set works here.. Hmm.

deepfire · 2018-01-19T12:57:13Z

@peti, done -- the PR now has only the minimum required to provide the following experience:

deepfire@andromedae:~/nixpkgs$ nix-shell -p haskell.compiler.ghc841

[nix-shell:~/nixpkgs]$ ghc --version
The Glorious Glasgow Haskell Compilation System, version 8.4.20180115

I hope to work with you to submit the rest in a subsequent PR.

peti · 2018-01-19T14:12:10Z

Yes, I am curious to play with 8.4.x, too! I'd say let's add overrides incrementally and make sure each of them is (a) necessary, (b) known to upstream, and (c) somewhat documented. :-) I'll enable a bunch of Hydra builds for 8.4.x at https://hydra.nixos.org/jobset/nixpkgs/haskell-updates so that we can get a feel for the general state of the package set. That jobset builds the haskell-updates branch of https://github.com/peti/nixpkgs where I usually push all changes for testing before they go to master.

DanBurton · 2018-01-23T00:21:09Z

pkgs/development/compilers/ghc/8.4.1.nix

+  # library instead of the faster but GPLed integer-gmp library.
+  enableIntegerSimple ? false, gmp ? null
+
+, version ? "8.4.20180115"


Nitpick, not sure how important this is, but shouldn't this be 8.4.0.20180115? (with the .0 between 8.4 and the date).

I don't really have an opinion, having taken ghcHEAD (which currently carries "8.5.20180118") as basis..

The difference is that HEAD is going to be released as 8.6.1, so that new version number will be higher than 8.5.x no matter what "x" is. In case of the 8.4.1 pre-release, the final version is going to be 8.4.1, which will be a version that's lower than what we currently use for the alpha. Arguably, 8.4.0.x would be a better choice for the alpha.

Having said that, I don't really care about this issue, because I don't think it makes any difference in practice. :-) People who use the 8.4.1-alpha tend to know what they are doing and won't be confused by this issue, I think.

deepfire requested a review from peti as a code owner January 18, 2018 20:51

GrahamcOfBorg added 10.rebuild-darwin: 1-10 10.rebuild-linux: 1-10 labels Jan 18, 2018

deepfire mentioned this pull request Jan 19, 2018

Inconistent Haskell Binaries #7792

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peti requested changes Jan 19, 2018

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deepfire force-pushed the x-ghc-8.4-master branch 4 times, most recently from 137ec1d to 9f0a492 Compare January 19, 2018 11:06

peti requested changes Jan 19, 2018

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deepfire force-pushed the x-ghc-8.4-master branch from 9f0a492 to 75b2c01 Compare January 19, 2018 12:56

ghc841: GHC 8.4.1: nix-shell -p haskell.compiler.ghc841

8d027c1

deepfire force-pushed the x-ghc-8.4-master branch from 75b2c01 to 8d027c1 Compare January 19, 2018 13:06

peti merged commit 766bfd6 into NixOS:master Jan 19, 2018

peti mentioned this pull request Jan 19, 2018

haskell infra: Fix cross compilation to work with new system #26799

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DanBurton reviewed Jan 23, 2018

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deepfire mentioned this pull request Jan 30, 2018

GHC 8.4 package overrides #34404

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GHC 8.4: compiler and package fixes #34023

GHC 8.4: compiler and package fixes #34023

deepfire commented Jan 18, 2018

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deepfire commented Jan 19, 2018 •

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DanBurton Jan 23, 2018

deepfire Jan 23, 2018 •

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peti Jan 23, 2018


		# Non-code change

		adjunctions = overrideCabal super.adjunctions (drv: {


		# Upstreamed

		constraints = overrideCabal super.constraints (drv: {

GHC 8.4: compiler and package fixes #34023

GHC 8.4: compiler and package fixes #34023

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deepfire commented Jan 18, 2018

Motivation for this change

Things done

deepfire commented Jan 18, 2018

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deepfire commented Jan 19, 2018 • edited

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