StackOverflow2013

Note that there are some explanatory texts on larger screens.

plurals

PO
text
Body
copied!<p>I haven't run into this specific issue, but the error message looks like it's a simple question of GHC being unable to find version 3.0.3.2 the package "base." This version has been buildable since GHC 6.9, so you should have it. Try running the following command:</p> <pre><code>ghc-pkg check </code></pre> <p>This will tell you if there is something wrong with your packages. Cabal can be a bit of a nightmare for dependencies -- partly, it seems, because a lot of Haskell developers underestimate the extent to which their underlying libraries will shift in the future. So they will define a dependency as ">= [version of package x]" without limiting the max version to the one presently available. Or they just leave out version-limiting altogether.</p> <p>Yesod, I'm happy to say, doesn't fall into this trap. But several of the libraries it depends on do. When you start developing in Haskell, learn this lesson: never assume that future versions of a library won't break your code. They will. A lot. </p> <p>If ghc-pkg comes up with broken packages, you may need to clean up/uninstall/reinstall these packages until they are either cleaned up or hidden. (Just do <code>ghc-pkg hide [package name]</code> to tell ghc to ignore that package.</p> <p>Your next problem is that hidden base package. Try the following:</p> <pre><code>ghc-pkg list | grep base </code></pre> <p>If you see brackets around the library, that means it's hidden. The package base-3.0.3.2 might show up as hidden (although that's a bit unlikely, as that's where the backward-compatible Prelude lives). If it is hidden, try to unhide it with the following command:</p> <pre><code>ghc-pkg expose base-3.0.3.2 </code></pre> <p>Now try re-running <code>yesod devel</code> and see how it goes. Best case scenario is that it works. If not, let us know.</p>

Querying!

Guidance

An individual column

Larger individual text columns get their own page to allow for proper reading.

SQuiL has stopped working due to an internal error.

If you are curious you may find further information in the browser console, which is accessible through the devtools (F12).

Reload