id	summary	reporter	owner	description	type	status	priority	milestone	version	resolution	keywords	cc
180	Should not “succeed” if all installed libraries’ interface files are of the wrong version	wjt		"I find myself with two versions of Haddock installed: the Debian-supplied 2.9.2 in /usr/bin, and a cabal-install-provided 2.4.2 in ~/.cabal/bin, which is first in my $PATH. (Presumably this was due to some package depending on a newer version of Haddock than Debian provided in the distant past.)

As a result, when I install any package (with 'documentation: True' in my ~/.cabal/config), I receive warnings as follows:

{{{
Installing executable(s) in /tmp/hmph/bin
Updating documentation index /tmp/hmph/share/doc/index.html
Warning: Cannot read /usr/lib/ghc-doc/haddock/Cabal-1.10.2.0/Cabal.haddock:
   ""Interface file is of wrong version: /usr/lib/ghc-doc/haddock/Cabal-1.10.2.0/Cabal.haddock""
Skipping this interface.
Warning: Cannot read /usr/lib/ghc-doc/haddock/hunit-1.2.2.3/HUnit.haddock:
   ""Interface file is of wrong version: /usr/lib/ghc-doc/haddock/hunit-1.2.2.3/HUnit.haddock""
Skipping this interface.
... and so on, for every installed library
}}}

Since all of my installed libraries' .haddock files are of the wrong version, it might be nice if haddock failed, rather than succeeding but writing an [http://willthompson.co.uk/misc/empty-docs/ empty documentation index]."	enhancement	new	trivial		2.4.2