Bug#1085518: haskell-xml-conduit-writer:FTBFS:build failure (The variable when is not in scope)

Source: haskell-xml-conduit-writer
Version: 0.1.1.4-1
Severity: serious
Tags: FTBFS, patch
User: debian-riscv@lists.debian.org
Usertags: riscv64
X-Debbugs-Cc: debian-riscv@lists.debian.org

Dear haskell-xml-conduit-writer Maintainer,

The package haskell-xml-conduit-writer build failed on a lot of architectures.The crucial buildd log below:

```

Preprocessing library for xml-conduit-writer-0.1.1.4..
Building library for xml-conduit-writer-0.1.1.4..
[1 of 1] Compiling Text.XML.Writer  ( src/Text/XML/Writer.hs, dist-ghc/build/Text/XML/Writer.o, dist-ghc/build/Text/XML/Writer.dyn_o )

src/Text/XML/Writer.hs:226:5: error: [GHC-88464]
    Variable not in scope:
      when
        :: Bool
           -> XML -> WriterT (DL.DList Node) Data.Functor.Identity.Identity a0
    |
226 |     when (not $ null headerContent) $ do
    |     ^^^^
-e: error: debian/hlibrary.setup build --builddir=dist-ghc returned exit code 1
 at /usr/share/perl5/Debian/Debhelper/Dh_Lib.pm line 877.
	Debian::Debhelper::Dh_Lib::error("debian/hlibrary.setup build --builddir=dist-ghc returned exit"...) called at /usr/share/perl5/Debian/Debhelper/Dh_Lib.pm line 616
	Debian::Debhelper::Dh_Lib::error_exitcode("debian/hlibrary.setup build --builddir=dist-ghc") called at /usr/share/perl5/Debian/Debhelper/Dh_Lib.pm line 479
	Debian::Debhelper::Dh_Lib::doit("debian/hlibrary.setup", "build", "--builddir=dist-ghc") called at /usr/share/perl5/Debian/Debhelper/Buildsystem/Haskell/Recipes.pm line 656
	Debian::Debhelper::Buildsystem::Haskell::Recipes::build_recipe() called at -e line 1
make: *** [/usr/share/cdbs/1/class/hlibrary.mk:158: build-ghc-stamp] Error 25
dpkg-buildpackage: error: debian/rules binary-arch subprocess returned exit status 2

```

The full buildd log is here:

https://buildd.debian.org/status/fetch.php?pkg=haskell-xml-conduit-writer&arch=riscv64&ver=0.1.1.4-1%2Bb4&stamp=1728666470&raw=0

My solution to this issue:

The error is caused by the variable when not being in scope, so importing 'Control.Monad (when)' can fix the issue. I have tested this solution locally,and it works well.The debpatch is in the attachment.Please let me know weather this solution can be accepted.

Gui-Yue

Best Regards