On 2008.06.13 22:22:06 +0100, Duncan Coutts
On Fri, 2008-06-13 at 11:19 -0400, Darrin Thompson wrote:
Cabal-install is looking good. It now, for the record, has only two deps outside of Cabal-1.4.
I installed cabal-install-0.5 on ubuntu with the haskell.org linux binary for ghc 6.8.2.
I then tried cabal-install yi
Got this output: ... many successful installs ... Registering vty-3.0.1... Reading package info from "dist/installed-pkg-config" ... done. Saving old package config file... done. Writing new package config file... done. Downloading yi-0.3... [1 of 1] Compiling Main ( Setup.hs, dist/setup/Main.o )
Setup.hs:9:0: Warning: Deprecated use of `showPackageId' (imported from Distribution.Simple, but defined in Distribution.Package): use the Text class instead Linking dist/setup/setup ... Warning: defaultUserHooks in Setup script is deprecated. Configuring yi-0.3... Warning: Instead of 'ghc-options: -DDYNAMIC -DFRONTEND_VTY' use 'cpp-options: -DDYNAMIC -DFRONTEND_VTY' setup: alex version >=2.0.1 && <3 is required but it could not be found. cabal: Error: some packages failed to install: yi-0.3 failed during the configure step. The exception was: exit: ExitFailure 1
Is this a cabal problem of package problem? I would have expected it to fail immediately instead of discover this problem so far into process.
So it's failing when configuring yi because alex is not installed.
So the question is when should this get checked? I think it's not unreasonable to have the check where it is now though perhaps we could do better by bringing it forward.
The point is, cabal-install only checks that haskell packages are available before beginning to install stuff. It leaves all the other checks (build tools, C libs, custom checks in Setup.hs script etc) to be done at the configure phase of each package.
In theory it's not impossible to imagine doing the configure phase of every package before doing the build phase of any package but it's not clear that it gains us that much and it's a bit more complex to do it that way.
Duncan
I think this may be Cabal's fault anyway. The yi.cabal includes the line: build-tools: alex >= 2.0.1 && < 3 in the 'executable yi' section, right after the build-depends, so Yi is being straightforward and upfront about its needs. Now, Cabal is obviously checking that the build-depends is satisfied first, but why isn't it checking that alex is available when it has the information it needs to check, presumably anything in build-tools is *required*, and the field name suggests that it would be checked? -- gwern watchers 5.0i Fax UXO NORAD Consulting meta Gatt of data