haskell-devscripts is unable to parse the CABAL_VERSION out of some
.cabal files.  This is only recently a problem because prior to the
recent perl changes, builds would not fail if CABAL_VERSION was empty.
An example of a package where the .cabal file cannot be parsed is
haskell-base-prelude.  This results in an error such as this:

haskell-devscripts should be updated to perform parsing of the .cabal
file more reliably.

Hello,

Bug #1012569 in haskell-devscripts reported by you has been fixed in the
Git repository and is awaiting an upload. You can see the commit
message below and you can check the diff of the fix at:

https://salsa.debian.org/haskell-team/haskell-devscripts/-/commit/38ca91d0687ab9037864aa782364c65828b81033
The grep/sed method didn't work for some .cabal files, so just use
Haskell which will necessarily know how to parse it's own files.  This
will be a bit slower, but probably not enough to care too much.
------------------------------------------------------------------------

(this message was generated automatically)
-- 
Greetings

https://bugs.debian.org/1012569

We believe that the bug you reported is fixed in the latest version of
haskell-devscripts, which is due to be installed in the Debian FTP archive.

A summary of the changes between this version and the previous one is
attached.

Thank you for reporting the bug, which will now be closed.  If you
have further comments please address them to 1012569@bugs.debian.org,
and the maintainer will reopen the bug report if appropriate.

Debian distribution maintenance software
pp.
Scott Talbert <swt@techie.net> (supplier of updated haskell-devscripts package)

(This message was generated automatically at their request; if you
believe that there is a problem with it please contact the archive
administrators by mailing ftpmaster@ftp-master.debian.org)
Format: 1.8
Date: Sun, 19 Jun 2022 20:38:23 -0400
Source: haskell-devscripts
Architecture: source
Version: 0.16.20
Distribution: unstable
Urgency: medium
Maintainer: Debian Haskell Group <pkg-haskell-maintainers@lists.alioth.debian.org>
Changed-By: Scott Talbert <swt@techie.net>
Closes: 1012569
Changes:
 haskell-devscripts (0.16.20) unstable; urgency=medium
 .
   * Use Haskell to parse .cabal files (Closes: #1012569)
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