cabal-install不考虑我安装的转换器版本 [英] My installed transformers version is not considered by cabal-install

问题描述

我对Haskell阴谋集团是完全陌生的，我正在努力使yesod正常工作.

I am totally new to Haskell an cabal and I'm trying to make yesod work.

我的阴谋集团版本是阴谋集团安装版本1.20.0.3使用Cabal库的1.20.0.2版本

My cabal version is cabal-install version 1.20.0.3 using version 1.20.0.2 of the Cabal library

这是当我tru安装alex时发生的事情:

This is what happends when I tru to install alex:

$ cabal install alex
Resolving dependencies...
cabal: Could not resolve dependencies:
trying: alex-3.1.4 (user goal)
next goal: QuickCheck (dependency of alex-3.1.4)
rejecting: QuickCheck-2.8.1, 2.8 (global constraint requires ==2.7.6)
trying: QuickCheck-2.7.6
next goal: transformers (dependency of QuickCheck-2.7.6)
rejecting: transformers-0.4.3.0, 0.4.2.0, 0.4.1.0, 0.3.0.0, 0.2.2.1, 0.2.2.0,
0.2.1.0, 0.2.0.0, 0.1.4.0, 0.1.3.0, 0.1.1.0, 0.1.0.1, 0.1.0.0, 0.0.1.0,
0.0.0.0, 0.4.0.0 (global constraint requires installed instance)
Dependency tree exhaustively searched.

第二次尝试:

$ cabal install alex happy yesod-bin --allow-newer
Resolving dependencies...
cabal: Could not resolve dependencies:
trying: alex-3.1.4 (user goal)
trying: QuickCheck-2.7.6/installed-1a8... (dependency of alex-3.1.4)
trying: tf-random-0.5/installed-ef3... (dependency of
QuickCheck-2.7.6/installed-1a8...)
next goal: primitive (dependency of tf-random-0.5/installed-ef3...)
rejecting: primitive-0.5.0.1/installed-8e5... (global constraint requires
==0.6)
rejecting: primitive-0.6 (conflict: tf-random =>
primitive==0.5.0.1/installed-8e5...)
rejecting: primitive-0.5.4.0, 0.5.3.0, 0.5.2.1, 0.5.1.0, 0.5.0.1, 0.5, 0.4.1,
0.4.0.1, 0.4, 0.3.1, 0.3, 0.2.1, 0.2, 0.1 (global constraint requires ==0.6)
Dependency tree exhaustively searched.

我必须做什么来安装alex?

What do I have to do to install alex?

一个相关的问题是: cabal安装---全局约束要求已安装实例

@kosmikus对这个问题的评论是:

The comment by @kosmikus on that question is:

因此Stackage LTS配置文件包含约束转换器已安装，表示仅已存在的版本可以使用变压器.这是合理的，因为GHC随附了特定版本的变压器.对于ghc-7.8，这是变形金刚0.3.0.0.由于某种原因，此安装版本不是由cabal-install考虑.您的部分日志不包含足够的信息以了解原因.

So the Stackage LTS config file contains the constraint transformers installed, meaning that only an already present version of transformers can be used. This is reasonable, because GHC ships with a specific version of transformers. For ghc-7.8, this is transformers-0.3.0.0. For some reason, this installed version is not considered by cabal-install. Your partial log doesn't contain sufficient info to see why.

如何修复Stackage LTS配置文件?在Ubuntu上它在哪里?

How can I fix my Stackage LTS config file? Where is it on Ubuntu?

推荐答案

问题的原因是我的GHC太旧了.我下载了新版本并解决了问题.

The reason of the problem was that my GHC was too old. I downloaded a newer version and solved the problem.

尝试失败(错误)

当前目录中应该有一个 cabal.config 文件.使用任何文本编辑器打开它，并搜索已安装的变形金刚字符串.

You should have a cabal.config file in your current directory. Open it with any text editor and serach for the transformers installed string.

找到它后，将其替换为 transformers == 0.4.3.0 或您喜欢的任何其他版本.

Once you have found it, replace it with transformers ==0.4.3.0 or any other version you like.

这是一个糟糕的解决方案，因为dfeurer写道:

It is a bad solution, because, as dfeurer writes:

transformers 在程序包依赖关系结构中位于非常低的位置.一世相信它仅取决于 base ；我想大多数Hackage上的软件包直接或间接取决于它.如果你升级 transformers ，实际上系统中的每个依赖项都会搞砸了，这与您想要的相反使用Stackage.

transformers sits very far down in the package dependency structure. I believe it depends only on base; I imagine a large majority of packages on Hackage depend, directly or indirectly, on it. If you upgrade transformers, practically every dependency in the system will go screwy, which is the opposite of what you're going for if you're using Stackage.

---

Sibi的清洁解决方案

按原样使用堆叠包装.如果您有一些导致问题的全局软件包，请删除它们并单独使用堆栈.在每个项目中使用沙箱也是一个好主意.

Use the stackage packages as it is. If you have some global package causing problem, then remove them and use stackage exclusively. Also using sandbox for each project is a good idea.

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