A message like: 'The following REQUIRED_USE flag constraints are unsatisfied:' Doesn't tell anything useful to solve the problem, which seems to be that if you have one use flag, you can't have the other one also active. To get to that conclusion, I had to check on internet about the message and part of the ebuild documentation, like: https://dev.gentoo.org/~zmedico/portage/doc/ch05s03s05.html#package-ebuild-eapi-4-metadata-required-use So the things is, the work of putting a message to alert the user about a problem has been done already, which is good, but the message is unclear, which makes things really bad. Reproducible: Always Steps to Reproduce: 1. emerge --pretend vlc 2. with cddb active in /etc/portage/package without cdda set Actual Results: Can't emerge the package. In this case vlc, but it would be the same with any other package and the same situation. Expected Results: the package should be merged into the system. I got the message the first time doing an emerge --pretend --update world and then I tried manually with emerge --pretend vlc. After checking on Internet, and the ebuild, I changed /etc/portage/package.use and added cdda to vlc. __________ __________ __________ __________ __________ Portage 2.1.10.49 (default/linux/amd64/10.0, gcc-4.5.3, glibc-2.14.1-r3, 3.2.1-gentoo-r2 x86_64) ================================================================= System uname: Linux-3.2.1-gentoo-r2-x86_64-Intel-R-_Core-TM-_i5-2500K_CPU_@_3.30GHz-with-gentoo-2.1 Timestamp of tree: Sat, 16 Jun 2012 08:45:01 +0000 app-shells/bash: 4.2_p20 dev-java/java-config: 2.1.11-r3 dev-lang/python: 2.7.3-r2, 3.2.3 dev-util/cmake: 2.8.7-r5 dev-util/pkgconfig: 0.26 sys-apps/baselayout: 2.1-r1 sys-apps/openrc: 0.9.8.4 sys-apps/sandbox: 2.5 sys-devel/autoconf: 2.13, 2.68 sys-devel/automake: 1.9.6-r3, 1.10.3, 1.11.1 sys-devel/binutils: 2.21.1-r1 sys-devel/gcc: 4.5.3-r2 sys-devel/gcc-config: 1.6 sys-devel/libtool: 2.4-r1 sys-devel/make: 3.82-r1 sys-kernel/linux-headers: 3.1 (virtual/os-headers) sys-libs/glibc: 2.14.1-r3 Repositories: gentoo location: /usr/portage sync: rsync://rsync.ca.gentoo.org/gentoo-portage priority: -1000 ABI="amd64" ACCEPT_KEYWORDS="amd64" ACCEPT_LICENSE="*" ACCEPT_PROPERTIES="*" ALSA_CARDS="ali5451 als4000 atiixp atiixp-modem bt87x ca0106 cmipci emu10k1x ens1370 ens1371 es1938 es1968 fm801 hda-intel intel8x0 intel8x0m maestro3 trident usb-audio via82xx via82xx-modem ymfpci" ALSA_PCM_PLUGINS="adpcm alaw asym copy dmix dshare dsnoop empty extplug file hooks iec958 ioplug ladspa lfloat linear meter mmap_emul mulaw multi null plug rate route share shm softvol" APACHE2_MODULES="actions alias auth_basic authn_alias authn_anon authn_dbm authn_default authn_file authz_dbm authz_default authz_groupfile authz_host authz_owner authz_user autoindex cache cgi cgid dav dav_fs dav_lock deflate dir disk_cache env expires ext_filter file_cache filter headers include info log_config logio mem_cache mime mime_magic negotiation rewrite setenvif speling status unique_id userdir usertrack vhost_alias" ARCH="amd64" AUTOCLEAN="yes" BOOTSTRAP_USE="cxx unicode multilib" CALLIGRA_FEATURES="kexi words flow plan sheets stage tables krita karbon braindump" CAMERAS="ptp2" CBUILD="x86_64-pc-linux-gnu" CFLAGS="-march=core2 -mtune=generic -O2 -pipe" CFLAGS_amd64="-m64" CFLAGS_x32="-mx32" CFLAGS_x86="-m32" CHOST="x86_64-pc-linux-gnu" CHOST_amd64="x86_64-pc-linux-gnu" CHOST_x32="x86_64-pc-linux-gnu" CHOST_x86="i686-pc-linux-gnu" CLEAN_DELAY="5" COLLECTD_PLUGINS="df interface irq load memory rrdtool swap syslog" COLLISION_IGNORE="/lib/modules" CONFIG_PROTECT="/etc /usr/share/config /usr/share/gnupg/qualified.txt" CONFIG_PROTECT_MASK="/etc/ca-certificates.conf /etc/env.d /etc/env.d/java/ /etc/fonts/fonts.conf /etc/gconf /etc/gentoo-release /etc/php/apache2-php5.3/ext-active/ /etc/php/cgi-php5.3/ext-active/ /etc/php/cli-php5.3/ext-active/ /etc/revdep-rebuild /etc/sandbox.d /etc/terminfo" CXXFLAGS="-march=core2 -mtune=generic -O2 -pipe" DBUS_SESSION_BUS_ADDRESS="unix:abstract=/tmp/dbus-fKWCRfBdCN,guid=63c0d8af291970b4e896861100007e35" DEFAULT_ABI="amd64" DISPLAY=":0.0" DISTDIR="/usr/portage/distfiles" EDITOR="/bin/nano" ELIBC="glibc" EMERGE_DEFAULT_OPTS="--columns --complete-graph=y --deep --jobs=8 --load-average=7 --verbose --with-bdeps=y" EMERGE_LOG_DIR="/var/log/emerge" EMERGE_WARNING_DELAY="10" EPREFIX="" EROOT="/" FCFLAGS="" FEATURES="assume-digests binpkg-logs clean-logs distlocks ebuild-locks fail-clean fixlafiles news nodoc parallel-fetch protect-owned sandbox sfperms strict unknown-features-warn unmerge-logs unmerge-orphans userfetch usersandbox" FETCHCOMMAND="wget -t 3 -T 60 --passive-ftp -O "${DISTDIR}/${FILE}" "${URI}"" FETCHCOMMAND_RSYNC="rsync -avP "${URI}" "${DISTDIR}/${FILE}"" FETCHCOMMAND_SFTP="bash -c "x=\${2#sftp://} ; host=\${x%%/*} ; port=\${host##*:} ; host=\${host%:*} ; [[ \${host} = \${port} ]] && port=22 ; exec sftp -P \${port} \"\${host}:/\${x#*/}\" \"\$1\"" sftp "${DISTDIR}/${FILE}" "${URI}"" FETCHCOMMAND_SSH="bash -c "x=\${2#ssh://} ; host=\${x%%/*} ; port=\${host##*:} ; host=\${host%:*} ; [[ \${host} = \${port} ]] && port=22 ; exec rsync --rsh=\"ssh -p\${port}\" -avP \"\${host}:/\${x#*/}\" \"\$1\"" rsync "${DISTDIR}/${FILE}" "${URI}"" FFLAGS="" GCC_SPECS="" GDK_USE_XFT="1" GENTOO_MIRRORS="http://ftp.swin.edu.au/gentoo ftp://ftp.swin.edu.au/gentoo http://gentoo.gg3.net/ ftp://gg3.net/pub/linux/gentoo/ ftp://gentoo.tiscali.nl/pub/mirror/gentoo/ http://gentoo.tiscali.nl/ http://ftp.df.lth.se/pub/gentoo/ ftp://ftp.df.lth.se/pub/gentoo/ ftp://ftp.twaren.net/Linux/Gentoo/ http://ftp.twaren.net/Linux/Gentoo/" GPSD_PROTOCOLS="ashtech aivdm earthmate evermore fv18 garmin garmintxt gpsclock itrax mtk3301 nmea ntrip navcom oceanserver oldstyle oncore rtcm104v2 rtcm104v3 sirf superstar2 timing tsip tripmate tnt ubx" GRUB_PLATFORMS="" GSETTINGS_BACKEND="gconf" GS_LIB="/root/.fonts" GTK2_RC_FILES="/etc/gtk-2.0/gtkrc:/root/.gtkrc-2.0:/root/.kde4/share/config/gtkrc-2.0" GTK_RC_FILES="/etc/gtk/gtkrc:/root/.gtkrc:/root/.kde4/share/config/gtkrc" HOME="/root" HUSHLOGIN="FALSE" INFOPATH="/usr/share/info:/usr/share/gcc-data/x86_64-pc-linux-gnu/4.5.3/info:/usr/share/binutils-data/x86_64-pc-linux-gnu/2.21.1/info" INPUT_DEVICES="evdev" JAVAC="/etc/java-config-2/current-system-vm/bin/javac" JAVA_HOME="/etc/java-config-2/current-system-vm" JDK_HOME="/etc/java-config-2/current-system-vm" KDE_FULL_SESSION="true" KDE_MULTIHEAD="true" KDE_SESSION_UID="0" KDE_SESSION_VERSION="4" KERNEL="linux" LCD_DEVICES="bayrad cfontz cfontz633 glk hd44780 lb216 lcdm001 mtxorb ncurses text" LDFLAGS="-Wl,-O1 -Wl,--as-needed" LDFLAGS_amd64="-m elf_x86_64" LDFLAGS_x32="-m elf32_x86_64" LDFLAGS_x86="-m elf_i386" LESS="-R -M --shift 5" LESSOPEN="|lesspipe %s" LIBDIR_amd64="lib64" LIBDIR_amd64_fbsd="lib64" LIBDIR_n32="lib32" LIBDIR_n64="lib64" LIBDIR_o32="lib" LIBDIR_ppc="lib32" LIBDIR_ppc64="lib64" LIBDIR_s390="lib32" LIBDIR_s390x="lib64" LIBDIR_sparc32="lib32" LIBDIR_sparc64="lib64" LIBDIR_x32="libx32" LIBDIR_x86="lib32" LIBDIR_x86_fbsd="lib32" LIBGL_DRIVERS_PATH="/usr/lib64/dri:/usr/lib32/dri" LIBREOFFICE_EXTENSIONS="presenter-console presenter-minimizer" LINGUAS="es es_ES en en_GB" LOGNAME="root" LS_COLORS="rs=0:di=01;34:ln=01;36:mh=00:pi=40;33:so=01;35:do=01;35:bd=40;33;01:cd=40;33;01:or=01;05;37;41:mi=01;05;37;41:su=37;41:sg=30;43:ca=30;41:tw=30;42:ow=34;42:st=37;44:ex=01;32:*.tar=01;31:*.tgz=01;31:*.arj=01;31:*.taz=01;31:*.lzh=01;31:*.lzma=01;31:*.tlz=01;31:*.txz=01;31:*.zip=01;31:*.z=01;31:*.Z=01;31:*.dz=01;31:*.gz=01;31:*.lz=01;31:*.xz=01;31:*.bz2=01;31:*.bz=01;31:*.tbz=01;31:*.tbz2=01;31:*.tz=01;31:*.deb=01;31:*.rpm=01;31:*.jar=01;31:*.war=01;31:*.ear=01;31:*.sar=01;31:*.rar=01;31:*.ace=01;31:*.zoo=01;31:*.cpio=01;31:*.7z=01;31:*.rz=01;31:*.jpg=01;35:*.jpeg=01;35:*.gif=01;35:*.bmp=01;35:*.pbm=01;35:*.pgm=01;35:*.ppm=01;35:*.tga=01;35:*.xbm=01;35:*.xpm=01;35:*.tif=01;35:*.tiff=01;35:*.png=01;35:*.svg=01;35:*.svgz=01;35:*.mng=01;35:*.pcx=01;35:*.mov=01;35:*.mpg=01;35:*.mpeg=01;35:*.m2v=01;35:*.mkv=01;35:*.webm=01;35:*.ogm=01;35:*.mp4=01;35:*.m4v=01;35:*.mp4v=01;35:*.vob=01;35:*.qt=01;35:*.nuv=01;35:*.wmv=01;35:*.asf=01;35:*.rm=01;35:*.rmvb=01;35:*.flc=01;35:*.avi=01;35:*.fli=01;35:*.flv=01;35:*.gl=01;35:*.dl=01;35:*.xcf=01;35:*.xwd=01;35:*.yuv=01;35:*.cgm=01;35:*.emf=01;35:*.axv=01;35:*.anx=01;35:*.ogv=01;35:*.ogx=01;35:*.pdf=00;32:*.ps=00;32:*.txt=00;32:*.patch=00;32:*.diff=00;32:*.log=00;32:*.tex=00;32:*.doc=00;32:*.aac=00;36:*.au=00;36:*.flac=00;36:*.mid=00;36:*.midi=00;36:*.mka=00;36:*.mp3=00;36:*.mpc=00;36:*.ogg=00;36:*.ra=00;36:*.wav=00;36:*.axa=00;36:*.oga=00;36:*.spx=00;36:*.xspf=00;36:" MAIL="/var/mail/root" MAKEOPTS="-j8" MANPATH="/etc/java-config-2/current-system-vm/man:/usr/local/share/man:/usr/share/man:/usr/share/gcc-data/x86_64-pc-linux-gnu/4.5.3/man:/usr/share/binutils-data/x86_64-pc-linux-gnu/2.21.1/man:/etc/java-config/system-vm/man/:/usr/lib64/php5.3/man/" MULTILIB_ABIS="amd64 x86" MULTILIB_STRICT_DENY="64-bit.*shared object" MULTILIB_STRICT_DIRS="/lib32 /lib /usr/lib32 /usr/lib /usr/kde/*/lib32 /usr/kde/*/lib /usr/qt/*/lib32 /usr/qt/*/lib /usr/X11R6/lib32 /usr/X11R6/lib" MULTILIB_STRICT_EXEMPT="(perl5|gcc|gcc-lib|binutils|eclipse-3|debug|portage|udev)" NETBEANS="apisupport cnd groovy gsf harness ide identity j2ee java mobility nb php profiler soa visualweb webcommon websvccommon xml" NOCOLOR="true" OPENCL_PROFILE="amd" OPENGL_PROFILE="ati" PAGER="/usr/bin/less" PATH="/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin:/opt/bin:/usr/x86_64-pc-linux-gnu/gcc-bin/4.5.3" PHP_TARGETS="php5-3" PKGDIR="/usr/portage/packages" PORTAGE_ARCHLIST="ppc sparc64-freebsd ppc-openbsd x86-openbsd ppc64 x86-winnt x86-fbsd ppc-aix alpha arm x86-freebsd s390 amd64 arm-linux x86-macos x64-openbsd ia64-hpux hppa x86-netbsd ppc64-linux x86-cygwin amd64-linux ia64-linux x86 sparc-solaris x64-freebsd sparc64-solaris x86-linux x64-macos sparc m68k-mint ia64 mips ppc-macos x86-interix hppa-hpux amd64-fbsd x64-solaris m68k sh x86-solaris sparc-fbsd" PORTAGE_BINHOST_CHUNKSIZE="3000" PORTAGE_BIN_PATH="/usr/lib64/portage/bin" PORTAGE_COMPRESS_EXCLUDE_SUFFIXES="css gif htm[l]? jp[e]?g js pdf png" PORTAGE_CONFIGROOT="/" PORTAGE_DEBUG="0" PORTAGE_DEPCACHEDIR="/var/cache/edb/dep" PORTAGE_ELOG_CLASSES="warn error log" PORTAGE_ELOG_MAILFROM="portage@localhost" PORTAGE_ELOG_MAILSUBJECT="[portage] ebuild log for ${PACKAGE} on ${HOST}" PORTAGE_ELOG_MAILURI="root" PORTAGE_ELOG_SYSTEM="save" PORTAGE_FETCH_CHECKSUM_TRY_MIRRORS="5" PORTAGE_FETCH_RESUME_MIN_SIZE="350K" PORTAGE_GID="250" PORTAGE_GPG_SIGNING_COMMAND="gpg --sign --clearsign --yes --default-key "${PORTAGE_GPG_KEY}" --homedir "${PORTAGE_GPG_DIR}" "${FILE}"" PORTAGE_INST_GID="0" PORTAGE_INST_UID="0" PORTAGE_OVERRIDE_EPREFIX="" PORTAGE_PYM_PATH="/usr/lib64/portage/pym" PORTAGE_RSYNC_OPTS="--recursive --links --safe-links --perms --times --compress --force --whole-file --delete --stats --human-readable --timeout=180 --exclude=/distfiles --exclude=/local --exclude=/packages" PORTAGE_RSYNC_RETRIES="-1" PORTAGE_SYNC_STALE="30" PORTAGE_TMPDIR="/tmp" PORTAGE_VERBOSE="1" PORTAGE_WORKDIR_MODE="0700" PORTDIR="/usr/portage" PORTDIR_OVERLAY="" PORT_LOGDIR="/var/log/portage" PORT_LOGDIR_CLEAN="find "${PORT_LOGDIR}" -type f ! -name "summary.log*" -mtime +7 -delete" PRELINK_PATH_MASK="/usr/lib64/libfreebl3.so:/usr/lib64/libnssdbm3.so:/usr/lib64/libsoftokn3.so" PROFILE_ONLY_VARIABLES="ARCH ELIBC KERNEL USERLAND" PWD="/root" PYTHONDONTWRITEBYTECODE="1" PYTHON_TARGETS="python3_2 python2_7" QT_GRAPHICSSYSTEM="raster" QT_PLUGIN_PATH="/usr/lib64/kde4/plugins:/root/.kde4/lib64/kde4/plugins/:/usr/lib64/kde4/plugins/" RESUMECOMMAND="wget -c -t 3 -T 60 --passive-ftp -O "${DISTDIR}/${FILE}" "${URI}"" RESUMECOMMAND_RSYNC="rsync -avP "${URI}" "${DISTDIR}/${FILE}"" RESUMECOMMAND_SSH="bash -c "x=\${2#ssh://} ; host=\${x%%/*} ; port=\${host##*:} ; host=\${host%:*} ; [[ \${host} = \${port} ]] && port=22 ; exec rsync --rsh=\"ssh -p\${port}\" -avP \"\${host}:/\${x#*/}\" \"\$1\"" rsync "${DISTDIR}/${FILE}" "${URI}"" ROOT="/" ROOTPATH="/opt/bin:/usr/x86_64-pc-linux-gnu/gcc-bin/4.5.3" RPMDIR="/usr/portage/rpm" RUBY_TARGETS="ruby18 ruby19" SANE_BACKENDS="hp" SANE_CONFIG_DIR="/etc/sane.d" SESSION_MANAGER="local/patito.local:@/tmp/.ICE-unix/27975,unix/patito.local:/tmp/.ICE-unix/27975" SHELL="/bin/bash" SHLVL="4" SYMLINK_LIB="yes" SYNC="rsync://rsync.ca.gentoo.org/gentoo-portage" TERM="xterm" USB_DEVFS_PATH="/dev/bus/usb" USE="X acl acpi alsa amd64 apm bzip2 cli consolekit cracklib crypt cups cxx dbus dri fontconfig fortran gif gpm iconv jpeg kde mmx modules mudflap multilib nls nptl opengl openmp pam pcre png policykit pppd python qt3support readline session sse sse2 ssl tcpd threads tiff truetype udev unicode xorg zlib" ALSA_CARDS="ali5451 als4000 atiixp atiixp-modem bt87x ca0106 cmipci emu10k1x ens1370 ens1371 es1938 es1968 fm801 hda-intel intel8x0 intel8x0m maestro3 trident usb-audio via82xx via82xx-modem ymfpci" ALSA_PCM_PLUGINS="adpcm alaw asym copy dmix dshare dsnoop empty extplug file hooks iec958 ioplug ladspa lfloat linear meter mmap_emul mulaw multi null plug rate route share shm softvol" APACHE2_MODULES="actions alias auth_basic authn_alias authn_anon authn_dbm authn_default authn_file authz_dbm authz_default authz_groupfile authz_host authz_owner authz_user autoindex cache cgi cgid dav dav_fs dav_lock deflate dir disk_cache env expires ext_filter file_cache filter headers include info log_config logio mem_cache mime mime_magic negotiation rewrite setenvif speling status unique_id userdir usertrack vhost_alias" CALLIGRA_FEATURES="kexi words flow plan sheets stage tables krita karbon braindump" CAMERAS="ptp2" COLLECTD_PLUGINS="df interface irq load memory rrdtool swap syslog" ELIBC="glibc" GPSD_PROTOCOLS="ashtech aivdm earthmate evermore fv18 garmin garmintxt gpsclock itrax mtk3301 nmea ntrip navcom oceanserver oldstyle oncore rtcm104v2 rtcm104v3 sirf superstar2 timing tsip tripmate tnt ubx" INPUT_DEVICES="evdev" KERNEL="linux" LCD_DEVICES="bayrad cfontz cfontz633 glk hd44780 lb216 lcdm001 mtxorb ncurses text" LIBREOFFICE_EXTENSIONS="presenter-console presenter-minimizer" LINGUAS="es es_ES en en_GB" PHP_TARGETS="php5-3" PYTHON_TARGETS="python3_2 python2_7" RUBY_TARGETS="ruby18 ruby19" SANE_BACKENDS="hp" USERLAND="GNU" VIDEO_CARDS="fglrx" XTABLES_ADDONS="quota2 psd pknock lscan length2 ipv4options ipset ipp2p iface geoip fuzzy condition tee tarpit sysrq steal rawnat logmark ipmark dhcpmac delude chaos account" USER="root" USERLAND="GNU" USE_EXPAND="ALSA_CARDS ALSA_PCM_PLUGINS APACHE2_MODULES APACHE2_MPMS CALLIGRA_FEATURES CAMERAS COLLECTD_PLUGINS CROSSCOMPILE_OPTS CURL_SSL DRACUT_MODULES DVB_CARDS ELIBC FCDSL_CARDS FFTOOLS FOO2ZJS_DEVICES FRITZCAPI_CARDS GPSD_PROTOCOLS GRUB_PLATFORMS INPUT_DEVICES KERNEL LCD_DEVICES LIBREOFFICE_EXTENSIONS LINGUAS LIRC_DEVICES MISDN_CARDS NETBEANS_MODULES NGINX_MODULES_HTTP NGINX_MODULES_MAIL OFED_DRIVERS OPENMPI_FABRICS OPENMPI_OFED_FEATURES OPENMPI_RM PHP_TARGETS PYTHON_TARGETS QEMU_SOFTMMU_TARGETS QEMU_USER_TARGETS RUBY_TARGETS SANE_BACKENDS USERLAND VIDEO_CARDS XFCE_PLUGINS XTABLES_ADDONS" USE_EXPAND_HIDDEN="CROSSCOMPILE_OPTS ELIBC KERNEL USERLAND" USE_ORDER="env:pkg:conf:defaults:pkginternal:repo:env.d" VBOX_APP_HOME="/usr/lib64/virtualbox" VIDEO_CARDS="fglrx" WINDOWPATH="7" XAUTHORITY="/tmp/kde-root/xauth-0-_0" XCURSOR_THEME="Oxygen_White" XDG_CONFIG_DIRS="/etc/xdg" XDG_DATA_DIRS="/usr/local/share:/usr/share" XDG_SESSION_COOKIE="8abbbf680a5ad523e8df204900000b79-1339638745.295939-2131763161" XTABLES_ADDONS="quota2 psd pknock lscan length2 ipv4options ipset ipp2p iface geoip fuzzy condition tee tarpit sysrq steal rawnat logmark ipmark dhcpmac delude chaos account" _="/usr/bin/emerge" __________ __________ __________ __________ __________
Sorry for posting again, but while I was writing this, I realized that I made a mistake with my original asumption, I wrote: ' Doesn't tell anything useful to solve the problem, which seems to be that if you have one use flag, you can't have the other one also active. ' And it should be: Doesn't tell anything useful to solve the problem, which seems to be that if you have one use flag, you should have the other one also active. Bye
The thing about REQUIRED_USE is that it's possible to write expressions that can't be easily explained in human language. So, the user really needs to be able to understand REQUIRED_USE expressions. Maybe we just need to have it refer to some documentation about REQUIRED_USE expressions? Also see bug 403207, which is about having emerge --autounmask generate REQUIRED_USE solutions automatically.
Hi Well, considering what you mention, maybe a good option would be to set a page in the documentation area, or a page in the wiki (could be an orphan page so the only way to get there is from the error message and have it locked down so can't be spoiled), or something similar with possible solutions and causes for the message. I know that writing documentation could be ... not the most interesting part of developing, but it certainly helps a lot. Thanks for the work and for the answer. Bye
I agree that maybe a wiki page explaining each REQUIRED_USE case and suggesting how to solve them would be useful and that link should be shown in the error. Also, looking to the message: The following REQUIRED_USE flag constraints are unsatisfied: at-most-one-of ( gstreamer ffmpeg ) That come from: def human_readable_required_use(required_use): return required_use.replace("^^", "exactly-one-of").replace("||", "any-of").replace("??", "at-most-one-of") in pym/portage/dep/__init__.py I was wondering if the message could be tweaked to end up being something like: REQUIRED_USE flag constraints are unsatisfied, you need to enable: at-most-one-of ( gstreamer ffmpeg ) USE flags Thanks
After looking to the amount of different bug reports about hard to understand REQUIRED_USE outputs... I was wondering if maybe (for the next EAPI) having a "REQUIRED_USE_MESSAGE=" variable allowing maintainers to write a message to explain the error people will get and how to solve it would be the best option :/ What do you think?
