226 lines
9.1 KiB
Markdown
226 lines
9.1 KiB
Markdown
# About
|
|
|
|
All you wanted to know about GHCup.
|
|
|
|
## Team
|
|
|
|
### Author and Maintainer
|
|
|
|
* [Julian Ospald](https://github.com/hasufell) (aka: maerwald, hasufell)
|
|
|
|
### Collaborators
|
|
|
|
* [Arjun Kathuria](https://github.com/arjunkathuria)
|
|
* [Ben Gamari](https://github.com/bgamari)
|
|
* [Javier Neira](https://github.com/jneira)
|
|
|
|
### Contributors
|
|
|
|
* amesgen
|
|
* Chris Smith
|
|
* Anton-Latukha
|
|
* Brian McKenna
|
|
* Huw campbell
|
|
* Tom Ellis
|
|
* Sigmund Vestergaard
|
|
* Ron Toland
|
|
* Paolo Martini
|
|
* Mario Lang
|
|
* Jan Hrček
|
|
* vglfr
|
|
* Fendor
|
|
* Enrico Maria De Angelis
|
|
* Emily Pillmore
|
|
* Colin Barrett
|
|
* Artur Gajowy
|
|
|
|
### Sponsors
|
|
|
|
* All [opencollective](https://opencollective.com/ghcup#category-CONTRIBUTE) contributors
|
|
* [haskell.org](https://www.haskell.org/haskell-org-committee/) via CI and infrastructure
|
|
* [Haskell Foundation](https://haskell.foundation/affiliates/) via affiliation
|
|
|
|
## How to help
|
|
|
|
* if you want to contribute code or documentation, check out the [issue tracker](https://gitlab.haskell.org/haskell/ghcup-hs/-/issues) and the [Development guide](./dev.md)
|
|
* if you want to propose features or write user feedback, feel free to [open a ticket](https://gitlab.haskell.org/haskell/ghcup-hs/-/issues/new?issue)
|
|
* if you want to donate to the project, visit our [opencollective](https://opencollective.com/ghcup#category-CONTRIBUTE) page
|
|
|
|
## Design goals
|
|
|
|
1. simplicity
|
|
2. non-interactive CLI interface
|
|
3. portable
|
|
4. do one thing and do it well (UNIX philosophy)
|
|
|
|
## Non-goals
|
|
|
|
1. invoking `sudo`, `apt-get` or *any* package manager
|
|
2. handling system packages
|
|
3. handling cabal projects
|
|
4. being a stack alternative
|
|
|
|
## How
|
|
|
|
Installs a specified GHC version into `~/.ghcup/ghc/<ver>`, and places `ghc-<ver>` symlinks in `~/.ghcup/bin/`.
|
|
|
|
Optionally, an unversioned `ghc` link can point to a default version of your choice.
|
|
|
|
This uses precompiled GHC binaries that have been compiled on fedora/debian by [upstream GHC](https://www.haskell.org/ghc/download_ghc_8_6_1.html#binaries).
|
|
|
|
Alternatively, you can also tell it to compile from source (note that this might fail due to missing requirements).
|
|
|
|
cabal-install/HLS/stack are installed in `~/.ghcup/bin/<tool>-<ver>` and have unversioned symlinks to the latest version by default (`~/.ghcup/bin/<tool>-<ver>`).
|
|
|
|
## Known users
|
|
|
|
* CI:
|
|
- [Github actions/virtual-environments](https://github.com/actions/virtual-environments)
|
|
- [Github haskell/actions/setup](https://github.com/haskell/actions/tree/main/setup)
|
|
- [haskell-ci](https://github.com/haskell-CI/haskell-ci)
|
|
* mirrors:
|
|
- [sjtug](https://mirror.sjtu.edu.cn/docs/ghcup)
|
|
* tools:
|
|
- [vscode-haskell](https://github.com/haskell/vscode-haskell)
|
|
- [nvim-lsp-installer](https://github.com/williamboman/nvim-lsp-installer)
|
|
- [vabal](https://github.com/Franciman/vabal)
|
|
|
|
## Known problems
|
|
|
|
### Custom ghc version names
|
|
|
|
When installing ghc bindists with custom version names as outlined in
|
|
[installing custom bindists](#installing-custom-bindists), then cabal might
|
|
be unable to find the correct `ghc-pkg` (also see [#73](https://gitlab.haskell.org/haskell/ghcup-hs/-/issues/73))
|
|
if you use `cabal build --with-compiler=ghc-foo`. Instead, point it to the full path, such as:
|
|
`cabal build --with-compiler=$HOME/.ghcup/ghc/<version-name>/bin/ghc` or set that GHC version
|
|
as the current one via: `ghcup set ghc <version-name>`.
|
|
|
|
This problem doesn't exist for regularly installed GHC versions.
|
|
|
|
### Limited distributions supported
|
|
|
|
Currently only GNU/Linux distributions compatible with the [upstream GHC](https://www.haskell.org/ghc/download_ghc_8_6_1.html#binaries) binaries are supported.
|
|
|
|
### Precompiled binaries
|
|
|
|
Since this uses precompiled binaries you may run into
|
|
several problems.
|
|
|
|
#### Missing libtinfo (ncurses)
|
|
|
|
You may run into problems with *ncurses* and **missing libtinfo**, in case
|
|
your distribution doesn't use the legacy way of building
|
|
ncurses and has no compatibility symlinks in place.
|
|
|
|
Ask your distributor on how to solve this or
|
|
try to compile from source via `ghcup compile <version>`.
|
|
|
|
#### Libnuma required
|
|
|
|
This was a [bug](https://ghc.haskell.org/trac/ghc/ticket/15688) in the build system of some GHC versions that lead to
|
|
unconditionally enabled libnuma support. To mitigate this you might have to install the libnuma
|
|
package of your distribution. See [here](https://gitlab.haskell.org/haskell/ghcup/issues/58) for a discussion.
|
|
|
|
### Compilation
|
|
|
|
Although this script can compile GHC for you, it's just a very thin
|
|
wrapper around the build system. It makes no effort in trying
|
|
to figure out whether you have the correct toolchain and
|
|
the correct dependencies. Refer to [the official docs](https://ghc.haskell.org/trac/ghc/wiki/Building/Preparation/Linux)
|
|
on how to prepare your environment for building GHC.
|
|
|
|
### Stack support
|
|
|
|
There may be a number of bugs when trying to make ghcup installed GHC versions work with stack,
|
|
such as:
|
|
|
|
- https://gitlab.haskell.org/haskell/ghcup-hs/-/issues/188
|
|
|
|
Further, stack's upgrade procedure may break/confuse ghcup. There are a number of integration
|
|
issues discussed here:
|
|
|
|
- https://gitlab.haskell.org/haskell/ghcup-hs/-/issues/153
|
|
|
|
### Windows support
|
|
|
|
Windows support is in early stages. Since windows doesn't support symbolic links properly,
|
|
ghcup uses a [shimgen wrapper](https://github.com/71/scoop-better-shimexe). It seems to work
|
|
well, but there may be unknown issues with that approach.
|
|
|
|
Windows 7 and Powershell 2.0 aren't well supported at the moment, also see:
|
|
|
|
- https://gitlab.haskell.org/haskell/ghcup-hs/-/issues/140
|
|
- https://gitlab.haskell.org/haskell/ghcup-hs/-/issues/197
|
|
|
|
## FAQ
|
|
|
|
### Why reimplement stack?
|
|
|
|
GHCup is not a reimplementation of stack. The only common part is automatic installation of GHC,
|
|
but even that differs in scope and design.
|
|
|
|
### Why should I use ghcup over stack?
|
|
|
|
GHCup is not a replacement for stack. Instead, it supports installing and managing stack versions.
|
|
It does the same for cabal, GHC and HLS. As such, It doesn't make a workflow choice for you.
|
|
|
|
### Why should I let ghcup manage stack?
|
|
|
|
You don't need to. However, some users seem to prefer to have a central tool that manages cabal and stack
|
|
at the same time. Additionally, it can allow better sharing of GHC installation across these tools.
|
|
Also see:
|
|
|
|
* https://docs.haskellstack.org/en/stable/yaml_configuration/#system-ghc
|
|
* https://github.com/commercialhaskell/stack/pull/5585
|
|
|
|
### Why does ghcup not use stack code?
|
|
|
|
1. GHCup started as a shell script. At the time of rewriting it in Haskell, the authors didn't even know that stack exposes *some* of its [installation API](https://hackage.haskell.org/package/stack-2.5.1.1/docs/Stack-Setup.html)
|
|
2. it doesn't support cabal installation, which was the main motivation behind GHCup back then
|
|
3. depending on a codebase as big as stack for a central part of one's application without having a short contribution pipeline would likely have caused stagnation or resulted in simply copy-pasting the relevant code in order to adjust it
|
|
4. it's not clear how GHCup would have been implemented with the provided API. It seems the codebases are fairly different. GHCup does a lot of symlink handling to expose a central `bin/` directory that users can easily put in PATH, without having to worry about anything more. It also provides explicit removal functionality, GHC cross-compilation, a TUI, etc etc.
|
|
|
|
### Why not unify...
|
|
|
|
#### ...stack and Cabal and do away with standalone installers
|
|
|
|
GHCup is not involved in such decisions. cabal-install and stack might have a
|
|
sufficiently different user experience to warrant having a choice.
|
|
|
|
#### ...installer implementations and have a common library
|
|
|
|
This sounds like an interesting goal. However, GHC installation isn't a hard engineering problem
|
|
and the shared code wouldn't be too exciting. For such an effort to make sense, all involved
|
|
parties would need to collaborate and have a short pipeline to get patches in.
|
|
|
|
It's true this would solve the integration problem, but following unix principles, we can
|
|
do similar via **hooks**. Both cabal and stack can support installation hooks. These hooks
|
|
can then call into ghcup or anything else, also see:
|
|
|
|
* https://github.com/haskell/cabal/issues/7394
|
|
* https://github.com/commercialhaskell/stack/pull/5585
|
|
|
|
#### ...installers (like, all of it)
|
|
|
|
So far, there hasn't been an open discussion about this. Is this even a good idea?
|
|
Sometimes projects converge eventually if their overlap is big enough, sometimes they don't.
|
|
|
|
While unification sounds like a simplification of the ecosystem, it also takes away choice.
|
|
Take `curl` and `wget` as an example.
|
|
|
|
### Why not support windows?
|
|
|
|
Windows is supported since GHCup version 0.1.15.1.
|
|
|
|
### Why the haskell reimplementation?
|
|
|
|
GHCup started as a portable posix shell script of maybe 50 LOC. GHC installation itself can be carried out in
|
|
about ~3 lines of shell code (download, unpack , configure+make install). However, much convenient functionality
|
|
has been added since, as well as ensuring that all operations are safe and correct. The shell script ended up with
|
|
over 2k LOC, which was very hard to maintain.
|
|
|
|
The main concern when switching from a portable shell script to haskell was platform/architecture support.
|
|
However, ghcup now re-uses GHCs CI infrastructure and as such is perfectly in sync with all platforms that
|
|
GHC supports.
|