haskell - cabal install --avoid-reinstalls 到底做了什么？

Question

我发现 --avoid-reinstalls 可以在 cabal 失败的地方构建软件包。它到底在做什么？ Cabal 是否已经尝试避免重新安装，或者不应该这样做？

Answer 1

这个邮件列表帖子解释得很好:http://www.haskell.org/pipermail/beginners/2011-June/007502.html

The dependency resolution algorithm will try to make a consistent install plan that allows gitit to be run. However, in order to achieve that, it may decide that it's necessary to reinstall some existing packages in a new configuration (with other dependency or flag settings). Such reinstalls will then overwrite the previous package in the store, and if that previous package was depended on by something else, these other things will break.

--avoid-reinstalls 标志完全可以防止这种行为。