When I specify
Build-Depends: base, parsec, HaXml >= 1.19.4
in xml-parsec.cabal
it does install correctly.
I guess what happens is that cabal install takes the earliest version
of a package registered to try to build. I guess that's a reasonable
default.
What seems unreasonable to me is that cabal continued to take the
earlier version even after I hid it with ghc-pkg hide.
My advice would be to improve the error message to read
"... Could not find module `Text.XML.HaXml.Posn':
it is a member of package HaXml-1.19.4, which is hidden
It can be unhidden by adding
Build-Depends: HaXml >= 1.19.4
to xml-parsec.cabal"
That leaves the issue of cabal upgrade not upgrading to the latest
version available on hackage, which still feels like a real bug to me.
Best, Thomas.
2008/11/15 Thomas Hartman
I was upgrading happstutorial.com to ghc 6.10.1 when I came across a cabal install issue.
Somewhere in day 1 (probably as a HAppS dependency), HaXml 1.13.1 got installed.
On day 2, I wanted the latest version of HaXml (1.19.4), a dependency for for xml-parsec.
cabal install HaXml gave me: already installed. cabal upgrade HaXml gave me: some installing action, but in the end I wound up with 1.13.1 again.
cabal install HaXml-1.19.4 gave me what I want, the latest version.
But even then, when I do cabal install xml-parsec I get
Text/ParserCombinators/Parsec/XML.hs:18:7: Could not find module `Text.XML.HaXml.Posn': it is a member of package HaXml-1.19.4, which is hidden
The cabal file has
Build-Depends: base, parsec, HaXml
ghc-pkg latest HaXml says HaXml-1.19.4
Even after ghc-pkg hide HaXml-1.13.3
I get the same result, so I'm not even sure if the problems I'm having are a result of the having two versions of the same package installed.
This is a bug right?
Any advice on how to get xml-parsec installed?
thomas.