@Julien
The patch already uses the system bubblewrap, see the
--with-system-bubblewrap argument.

@Danny
Thanks for sharing your work! Unfortunately it fixed neither the
documentation nor the tests for me. I think the source might have
changed too much. The "--with-xml-catalog" argument no longer exists
and the tests still error on trying to copy something.

I don't think the rest is necessary. I got both GIMP and Firefox 
nightly working. Make sure you use the --user parameter though, or
you'll need root.

For the record, this is how I got Firefox running:
$ flatpak remote-add --user --if-not-exists flathub https://flathub.org/repo/flathub.flatpakrepo 
$ flatpak install --user --from https://firefox-flatpak.mojefedora.cz/org.mozilla.FirefoxNightly.flatpakref
$ flatpak run org.mozilla.FirefoxNightly/x86_64/master

OK to push?

On Tue, 18 Dec 2018 20:45:35 +0100
Julien Lepiller <julien@lepiller.eu> wrote:

> Le Tue, 18 Dec 2018 19:01:53 +0100,
> Danny Milosavljevic <dannym@scratchpost.org> a écrit :
> 
> > Hi Rutger,
> > 
> > On Tue, 18 Dec 2018 16:12:49 +0100
> > Rutger Helling <rhelling@mykolab.com> wrote:
> >   
> > > this patch adds Flatpak.    
> > 
> > Try
> > 
> >              (string-append "--with-xml-catalog="
> >                             (assoc-ref %build-inputs "docbook-xml")
> >                             "/xml/dtd/docbook/catalog.xml"))
> > 
> > and
> > 
> >          (add-before 'configure 'fix-docbook
> >            (lambda* (#:key inputs #:allow-other-keys)
> >              (substitute* "configure"
> >                ;; The configure check is overzealous about making
> > sure that ;; things are in place -- it uses the xmlcatalog tool to
> > make ;; sure that docbook-xsl is available, but this tool can only
> >                ;; look in one catalog file, unlike the
> > $XML_CATALOG_FILES ;; variable that Guix defines.  Fool the test by
> > using the ;; docbook-xsl catalog explicitly and get on with life.
> >                (("\"\\$XML_CATALOG_FILE\" \
> > \"http://docbook.sourceforge.net/release/xsl/")
> >                 (string-append (car (find-files (assoc-ref inputs
> > "docbook-xsl") "^catalog.xml$"))
> >                                "
> > \"http://docbook.sourceforge.net/release/xsl/"))) #t))
> > 
> > Also, try patching the tests like this:
> > 
> >          (add-after 'unpack 'patch-/var/tmp
> >            (lambda _
> >              (substitute* '("tests/libtest.sh"
> >                             "tests/test-run.sh"
> >                             "tests/testlibrary.c"
> >                             "buildutil/tap-test"
> >                             ; ./common/flatpak-dir.c
> >                             ; ./common/flatpak-run.c
> >                             )
> >                (("/var/tmp") "/tmp"))
> >              (substitute* "tests/libtest.sh"
> >               (("/usr/bin/") "")
> >               (("/bin/") ""))
> >              #t))
> > 
> > Also, in an earlier iteration I needed the following, but if it
> > works without, then fine!
> > 
> >          (add-before 'check 'set-environment-up
> >            (lambda _
> >              ;(mkdir-p "/tmp/b")
> >              (setenv "HOME" "/tmp")
> >              ;; Note: needs xattr support.
> >              (setenv "TMPDIR" "/tmp")
> >              ;;; TODO /dev/fuse
> >              (mkdir-p "/tmp/ldconfig.d")
> >              (call-with-output-file "/tmp/ldconfig.d/ldconfig"
> >                (lambda (port)
> >                  (display "#!/bin/sh\nexit 0\n" port)))
> >              (chmod "/tmp/ldconfig.d/ldconfig" #o755)
> >              (setenv "PATH" (string-append
> > "/tmp/ldconfig.d:" (getenv "PATH"))) #t)))))
> > 
> > Additional inputs may be needed.  I had those:
> > 
> >     (inputs
> >      `(("appstream-glib" ,appstream-glib)
> >        ("attr" ,attr)
> >        ("fuse" ,fuse)
> >        ("glib" ,glib)
> >        ("gpgme" ,gpgme)
> >        ("json-glib" ,json-glib)
> >        ("libarchive" ,libarchive)
> >        ("libcap" ,libcap)
> >        ("libseccomp" ,libseccomp)
> >        ("libsoup" ,libsoup)
> >        ("libxml2" ,libxml2)
> >        ("libxau" ,libxau)
> >        ("nettle" ,nettle)
> >        ("libostree" ,libostree)
> >        ("polkit" ,polkit)))
> >     (native-inputs
> >      `(("autoconf" ,autoconf)
> >        ("automake" ,automake)
> >        ("dbus" ,dbus) ; for the tests
> >        ("docbook-xml" ,docbook-xml-4.1.2)
> >        ("docbook-xsl" ,docbook-xsl)
> >        ("fuse" ,fuse) ; for the tests
> >        ("gettext-minimal" ,gettext-minimal)
> >        ;("git" ,git)
> >        ("glib" ,glib "bin")
> >        ("gnupg" ,gnupg)
> >        ("gobject-introspection" ,gobject-introspection)
> >        ("gtk-doc" ,gtk-doc)
> >        ("libtool" ,libtool)
> >        ("pkg-config" ,pkg-config)
> >        ("which" ,which)
> >        ("libglnx" ,(origin
> >              (method git-fetch)
> >              (uri (git-reference
> >                    (url "https://github.com/GNOME/libglnx.git")
> >                    (commit
> > "6f1ee5db1400b13a9a0fa0b2274ae34e8710c1aa"))) (sha256
> >               (base32
> >                "137329m4lm3ssmxyyr1cin0xmlpsz4kfk26ydq6i4zf7qz81n64s"))))
> >        ("bubblewrap" ,(origin
> >         (method url-fetch)
> >         (uri (string-append
> > "https://github.com/projectatomic/bubblewrap/archive/"
> > "v0.2.0.tar.gz"))
> > 
> >         (sha256
> >           (base32
> >             "17796rqhp5wn3q2lspgqbyk7nk1ixns9m2kgw82j2h2yfyi15mjh"))))  
> 
> Just so you know, we already have a bubblewrap package. Maybe you can
> use it instead of bundling the sources?
> 
> >        ("xmltproc" ,libxslt)))
> >     (home-page "https://www.flatpak.org/")
> >     (synopsis "Flatpak")
> >     (description "Flatpak")
> >     (license license:lgpl2.1+)))
> > 
> > And I fiddled with libglnx:
> > 
> >            (lambda* (#:key inputs #:allow-other-keys)
> >              (use-modules (system repl debug))
> >              (set! terminal-width (lambda () 1000000))
> >              (delete-file-recursively "libglnx")
> >              (copy-recursively (assoc-ref inputs "libglnx")
> > "libglnx") (delete-file-recursively "bsdiff")
> >              ;(symlink "bsdiff-4.3-endsley" "bsdiff")
> >              (copy-recursively (assoc-ref inputs "bsdiff") "bsdiff")
> >              (setenv "NOCONFIGURE" "1")
> >              (invoke "sh" "autogen.sh"))))))
> > 
> > If it works without, your version may be fine as is.  I just wanted
> > to share the parts I already had to try.  
>