haskell - 堆栈构建工具: compatibility issue with LTS resolver

Question

被宣传为 Haskell 工具的突破，我尝试从 Cabal 切换到 Stack。但是，我仍然遇到一个问题，即让项目与使用 cabal 运行的堆栈一起运行。我认为问题在于解析器设置的全局约束(例如堆栈中的长期支持包)不符合本地包依赖性。

举个具体的例子，我在0.14.0.6版本中使用了snap框架( http://snapframework.com/ )。使用 snap init 创建完整的 snap 项目后，我尝试使用 stack init 从 cabal 文件实例化堆栈构建计划。然而，堆栈没有找到满足约束的构建计划。另一方面，cabal install 成功构建了项目。

我对栈的理解有误吗？如何解决这一问题？

完整的错误日志如下所示，其中项目名称为 SnapFull:

Checking against build plan lts-3.7

* Build plan did not match your requirements:
    base version 4.8.1.0 found
    - SnapFull requires >=4 && <4.4

    lens version 4.12.3 found
    - SnapFull requires >=3.7.6 && <3.8

    snap-loader-dynamic not found
    - SnapFull requires ==0.10.*

    snap-loader-static not found
    - SnapFull requires >=0.9 && <0.10


Checking against build plan lts-2.22

* Build plan did not match your requirements:
    base version 4.7.0.2 found
    - SnapFull requires >=4 && <4.4

    lens version 4.7.0.1 found
    - SnapFull requires >=3.7.6 && <3.8

    snap-loader-dynamic not found
    - SnapFull requires ==0.10.*

    snap-loader-static not found
    - SnapFull requires >=0.9 && <0.10


Checking against build plan lts-3.8

* Build plan did not match your requirements:
    base version 4.8.1.0 found
    - SnapFull requires >=4 && <4.4

    lens version 4.12.3 found
    - SnapFull requires >=3.7.6 && <3.8

    snap-loader-dynamic not found
    - SnapFull requires ==0.10.*

    snap-loader-static not found
    - SnapFull requires >=0.9 && <0.10


Checking against build plan nightly-2015-10-09

* Build plan did not match your requirements:
    base version 4.8.1.0 found
    - SnapFull requires >=4 && <4.4

    lens version 4.12.3 found
    - SnapFull requires >=3.7.6 && <3.8

    snap-loader-dynamic not found
    - SnapFull requires ==0.10.*

    snap-loader-static not found
    - SnapFull requires >=0.9 && <0.10


There was no snapshot found that matched the package bounds in your .cabal files.
Please choose one of the following commands to get started.

    stack init --resolver lts-3.7
    stack init --resolver lts-2.22
    stack init --resolver lts-3.8
    stack init --resolver nightly-2015-10-09

You'll then need to add some extra-deps. See:

    https://github.com/commercialhaskell/stack/blob/master/doc/yaml_configuration.md#extra-deps

You can also try falling back to a dependency solver with:

    stack init --solver

Answer 1

我建议尝试一下非 LTS 求解器:

$ stack init --resolver=ghc-7.10 --force

或

$ stack init --resolver=ghc-7.8 --force

这通常比 lts-* 更容易给出工作结果。解算器，但您无法从 LTS 的稳定性中受益。但既然你来自 Cabal，无论如何你之前都没有 LTS，所以你不妨从常规的 ghc-7.10 开始。或ghc-7.8解析器并查看稍后是否可以迁移到 LTS。

P.S.您还可以尝试夜间 sleep ，介于 lts-* 之间。和ghc-*我猜，但我自己没有尝试过。

编辑:在stack init之后您通常还需要运行 stack solver --modify-stack-yaml 命令填充extra-deps您的 stack.yaml 部分具有根据 build-depends 计算的构建依赖项您的 .cabal 部分文件。我认为正在发生的事情是init仅使用指定的求解器配置项目，但不调用实际的依赖项解析。 (如果对此信息有任何更正，我将不胜感激。)