TEMPORARY and gross (yuck) workaround for qt not finding platform plugins.

000-README.md

This will only work (as-is) at the root of the same nixpkgs checkout from which you're trying to run a Qt app.

 $ pwd
/my/checkout/nixpkgs
 $ qt-run result/bin/that-qt-software

qt-run

#!/usr/bin/env bash

# THIS ONLY WORKS WHEN USED AT THE ROOT OF A NIXPKGS CHECKOUT
# OR IF YOU MANIPULATE YOUR NIX PATH.

set -e
set -u

_nb() {
        nix-build --no-out-link -A "$@"
}

_qtlibs=(
        qt5.qtbase.bin
        qt5.qtdeclarative.bin
        qt5.qtimageformats.out
        qt5.qtlocation.bin
        qt5.qtmultimedia.bin
        qt5.qtsensors.bin
        qt5.qtsvg.bin
)

for attrpath in "${_qtlibs[@]}"; do
        _p=$(_nb $attrpath)/bin
        PATH="$_p:$PATH"
        unset _p
done

exec "$@"

This (ab)uses the added behaviour from nixpkgs to Qt that uses PATH components to pre-seed the Qt plugin path. Using QT_PLUGIN_PATH would work as well. I, though, preferred using PATH as they are earlier in the selection.

As for which libs, I used this:

nix-locate -1r qt-5.*plugins/.*so | grep -v '^(' | sort -u

And selected those under qt5.*.