* merge of the debian-expermental-ma branch

  
* debian/control:
  - add dependency on zlib-dev for libapt-pkg-dev
* apt-pkg/cacheset.cc:
  - [ABI BREAK] add an ErrorType option to CacheSetHelper
* cmdline/apt-cache.cc:
  - use Notice instead of Error in the CacheSetHelper messages
    for compat reasons. Otherwise tools like sbuild blow up
  - return success in show if a virtual package was given
* debian/control:
  - remove libcurl3-gnutls-dev alternative as the package is gone
  - increase needed version of libcurl4-gnutls-dev to >= 7.19.0
    as we use CURLOPT_{ISSUERCERT,CRLFILE} (Closes: #589642)
* apt-pkg/deb/dpkgpm.cc:
  - Write architecture information to history file.
  - Add to history whether a change was automatic or not.
* apt-pkg/contrib/fileutl.cc:
  - Add FileFd::OpenDescriptor() (needed for python-apt's #383617).
* cmdline/apt-get.cc:
  - Support large filesystems by using statvfs64() instead of statvfs()
    and statfs64() instead of statfs() (Closes: #590513).
* apt-pkg/cdrom.cc:
  - Use link() instead of rename() for creating the CD database backup;
    otherwise there would be a short time without any database.
* apt-pkg/depcache.cc:
  - handle "circular" conflicts for "all" packages correctly
* cmdline/apt-cache.cc:
  - be able to omit dependency types in (r)depends (Closes: #319006)
  - show in (r)depends the canidate per default instead of newest
  - share the (r)depends code instead of codecopy
* apt-pkg/cacheset.cc:
  - move them back to the library as they look stable now
  - add a 'newest' pseudo target release as in pkg/newest
* apt-pkg/pkgcache.cc:
  - prefer non-virtual packages in FindPreferredPkg (Closes: #590041)
* test/integration/*:
  - add with bug#590041 testcase a small test "framework"
* apt-pkg/orderlist.cc:
  - try to install another or-group member in DepRemove before
    breaking the or group (Closes: #590438)
  - configure also the replacement before remove by adding Immediate flag

* apt-pkg/contrib/error.{cc,h}
  - docstring cleanup
  - add inline DumpError() to avoid subtle API break
* apt-pkg/contrib/error.{cc,h}:
  - remove constness of va_list parameter to fix build on amd64 and co
    Thanks Eric Valette! (Closes: #588610)
* apt-pkg/deb/debmetaindex.cc:
  - do not query each architecture for flat file archives
  - fix typo preventing display of architecture in Info()
* methods/bzip2.cc:
  - add a copycat of the old gzip.cc as we need it for bzip2 and lzma
* debian/rules:
  - Make DEB_BUILD_OPTIONS=noopt actually work by passing the right
    CXXFLAGS.
* apt-pkg/contrib/fileutl.{h,cc}:
  - Add support for reading of gzipped files with the new "ReadOnlyGzip"
    OpenMode. (Closes: #188407)
  - Link against zlib (in apt-pkg/makefile) and add zlib build dependency.
  - [ABI BREAK] This adds a new private member to FileFd, but its
    initialization is in the public header file.
* configure.in:
  - Check for zlib library and headers.
* apt-pkg/acquire-item.cc, apt-pkg/deb/debindexfile.cc,
  apt-pkg/deb/debrecords.cc, apt-pkg/deb/debsrcrecords.h,
  cmdline/apt-cache.cc:
  - Open Packages, Sources, and Translations indexes in "ReadOnlyGzip" mode.
* apt-pkg/deb/debindexfile.cc:
  - If we do not find uncompressed package/source/translation indexes, look
    for gzip compressed ones.
* apt-pkg/acquire-item.cc:
  - If the Acquire::GzipIndexes option is true and we download a gzipped
    index file, keep it as it is (and rename to .gz) instead of
    uncompressing it.
* doc/apt.conf.5.xml:
  - Document the new Acquire::GzipIndexes option.
* doc/po/apt-doc.pot, doc/po/de.po:
  - German translation of new Acquire::GzipIndexes option.
* Add test/test-indexes.sh:
  - Test behaviour of index retrieval and usage, in particular with
    uncompressed and gzip compressed indexes.
* methods/gzip.cc: With FileFd now being able to read gzipped files, there
  is no need for the gzip method any more to spawn an external gzip process.
  Rewrite it to use FileFd directly, which makes the code a lot simpler, and
  also using less memory and overhead.
* doc/apt.conf.5.xml:
  - add and document APT::Cache-{Start,Grow,Limit} options for mmap control
* apt-pkg/contrib/fileutl.cc:
  - do not fail von double close()
* cmdline/cacheset.cc:
  - doesn't include it in the library for now as it is too volatile
  - get the candidate either from an already built depcache
    or use the policy which is a bit faster than depcache generation
  - get packages by task^ with FromTask()
  - only print errors if all tries to get a package by string failed
  - factor out code to get a single package FromName()
  - check in Grouped* first without modifier interpretation
* cmdline/apt-get.cc:
  - use the cachsets in the install commands
  - make the specify order of packages irrelevant (Closes: #196021)
* apt-pkg/orderlist.cc:
  - untouched packages are never missing
* apt-pkg/packagemanager.cc:
  - packages that are not touched doesn't need to be unpacked
* debian/control:
  - remove intltool's dependency as it is an ubuntu artefact
* apt-pkg/depcache.cc:
  - SetCandidateVer for all pseudo packages
  - SetReInstall for the "all" package of a pseudo package
  - use the new MatchAgainstConfig for the DefaultRootSetFunc
  - always mark the all package if a pseudo package is marked for install
* apt-pkg/contrib/error.{cc,h}:
  - complete rewrite but use the same API
  - add NOTICE and DEBUG as new types of a message
  - add a simple stack handling to be able to delay error handling
* apt-pkg/aptconfiguration.cc:
  - show a deprecation notice for APT::Acquire::Translation
* apt-pkg/contrib/configuration.{cc,h}:
  - add a wrapper to match strings against configurable regex patterns
* apt-pkg/contrib/fileutl.cc:
  - show notice about ignored file instead of being always silent
  - add a Dir::Ignore-Files-Silently list option to control the notice
* apt-pkg/policy.h:
  - add another round of const& madness as the previous round accidentally
    NOT overrides the virtual GetCandidateVer() method (Closes: #587725)
* apt-pkg/pkgcachegen.{cc,h}:
  - make the used MMap moveable (and therefore dynamic resizeable) by
    applying (some) mad pointer magic (Closes: #195018)
* apt-pkg/deb/dpkgpm.cc:
  - make the apt/term.log output unbuffered (thanks to Matt Zimmerman)
* methods/ftp.h:
  - Handle different logins on the same server (Closes: #586904).
* apt-pkg/deb/deblistparser.cc:
  - Handle architecture wildcards (Closes: #547724).
* apt-pkg/versionmatch.cc:
  - Support matching pins by regular expressions or glob() like patterns,
    regular expressions have to be put between to slashes; for example,
    /.*/.
* apt-pkg/contrib/fileutl.cc:
  - Make FileFd replace files atomically in WriteTemp mode (for cache, etc).
* debian/control:
  - Set Standards-Version to 3.9.0
* apt-pkg/cachefile.h:
  - make pkgPolicy public again, libapt-pkg-perl (and probably
    others) get unhappy without that
* merge the remaining Ubuntu change:
  - on gpg verification failure warn and restore the last known
    good state
  - on failure display the IP of the server (useful for servers
    that use round robin DNS)
  - support Original-Maintainer in RewritePackageOrder
  - enable cdrom autodetection via libudev by default
  - show message about Vcs in use when apt-get source is run for
    packages maintained in a Vcs
  - better support transitional packages with mark auto-installed. 
    when the transitional package is in "oldlibs" the new package
    is not marked auto installed (same is true for section
    metapackages)
  - provide new "deb mirror://archive.foo/mirrors.list sid main"
    method expects a list of mirrors (generated on the server e.g.
    via geoip) and will use that, including cycle on failure
  - write apport crash file on package failure (disabled by default
    on debian until apport is available)
  - support mirror failure reporting (disabled by default on debian)

* apt-pkg/deb/dpkgpm.cc:
  - write Disappeared also to the history.log
  - forward manual-installed bit on package disappearance
* apt-pkg/deb/debsystem.cc:
  - add better config item for extended_states file
* apt-pkg/pkgcache.h:
  - switch {,Install-}Size to unsigned long long
* apt-pkg/depcache.cc:
  - do the autoremove mark process also for required packages to handle
    these illegally depending on lower priority packages (Closes: #583517)
  - try harder to find the other pseudo versions for autoremove multiarch
  - correct "Dangerous iterator usage" pointed out by cppcheck
  - deal with long long, not with int to remove 2GB Limit (LP: #250909)
  - deprecate AddSize with Multiplier as it is unused and switch to
    boolean instead to handle the sizes more gracefully.
  - switch i{Download,Usr}Size from double to (un)signed long long
* apt-pkg/aptconfiguration.cc:
  - remove duplicate architectures in getArchitectures()
* apt-pkg/indexrecords.{cc,h}:
  - backport forgotten Valid-Until patch from the obsolete experimental
    branch to prevent replay attacks better, thanks to Thomas Viehmann
    for the initial patch! (Closes: #499897)
  - add a constant Exists check for MetaKeys
* apt-pkg/acquire-item.cc:
  - do not try PDiff if it is not listed in the Meta file
  - sent Last-Modified header also for Translation files
* apt-pkg/cacheiterator.h:
  - let pkgCache::Iterator inherent std::iterator
* ftparchive/writer.h:
  - add a virtual destructor to FTWScanner class (for cppcheck)
* apt-pkg/cacheset.{cc,h}:
  - add simple wrapper around std::set for cache structures
  - move regex magic from apt-get to new FromRegEx method
  - move cmdline parsing from apt-cache to new FromCommandLine method
  - support special release-modifier 'installed' and 'candidate'
* apt-pkg/contrib/cmdline.cc:
  - fix segfault in SaveInConfig caused by writing over char[] sizes
* apt-pkg/pkgcache.cc:
  - get the best matching arch package from a group with FindPreferredPkg
* cmdline/apt-cache.cc:
  - make the search multiarch compatible by using GrpIterator instead
  - use pkgCacheFile and the new CacheSets all over the place
  - add --target-release option (Closes: #115520)
  - accept pkg/release and pkg=version in show and co. (Closes: #236270)
  - accept package versions in the unmet command
* cmdline/apt-get.cc:
  - use unsigned long long instead of double to store values it gets
* apt-pkg/cachefile.{cc,h}:
  - split Open() into submethods to be able to build only parts
  - make the OpProgress optional in the Cache buildprocess
  - store also the SourceList we use internally for export
* doc/apt.conf.5.xml:
  - document the new Valid-Until related options
* apt-pkg/contrib/strutl.cc:
  - split StrToTime() into HTTP1.1 and FTP date parser methods and
    use strptime() instead of some self-made scanf mangling
  - use the portable timegm shown in his manpage instead of a strange
    looking code copycat from wget
* ftparchive/writer.cc:
  - add ValidTime option to generate a Valid-Until header in Release file
* apt-pkg/policy.cc:
  - get the candidate right for a not-installed pseudo package if
    his non-pseudo friend is installed
* apt-pkg/indexcopy.cc:
  - move the gpg codecopy to a new method and use it also in methods/gpgv.cc
* cmdline/apt-get.cc:
  - rerun dpkg-source in source if --fix-broken is given (Closes: #576752)
  - don't suggest held packages as they are installed (Closes: #578135)
  - handle multiple --{tar,diff,dsc}-only options correctly
  - show at the end of the install process a list of disappeared packages
* cmdline/apt-cache.cc:
  - use GroupCount for package names in stats and add a package struct line
* methods/rred.cc:
  - use the patchfile modification time instead of the one from the
    "old" file - thanks to Philipp Weis for noticing! (Closes: #571541)
* debian/rules:
  - remove targets referring to CVS or arch as they are useless
  - use $(CURDIR) instead of $(pwd)
  - use dpkg-buildflags if available for CXXFLAGS
* README.arch:
  - remove the file completely as it has no use nowadays
* apt-pkg/depcache.cc:
  - be doublesure that the killer query is empty before starting reinstall
* methods/gpgv.cc:
  - remove the keyrings count limit by using vector magic
* contrib/mmap.cc:
  - clarify "MMap reached size limit" error message, thanks Ivan Masár!
* doc/apt.ent
  - add entities for the current oldstable/stable/testing codenames
* doc/sources.list.5.xml:
  - use stable-codename instead of stable in the examples (Closes: #531492)
* doc/apt_preferences.5.xml:
  - adapt some examples here to use current codenames as well
  - add "NotAutomatic: yes" handling, thanks Osamu Aoki (Closes: #490347)
* debian/libapt-pkg-doc.doc-base.cache:
  - remove yet another reference to the removed cache.sgml
* doc/apt-get.8.xml:
  - do not say explicit target_release_{name,version,codename}, it should
    be clear by itself and 'man' can break lines again (Closes: #566166)
  - remove the gnome-apt reference as it is removed from unstable
* apt-pkg/deb/dpkgpm.cc:
  - add 'disappear' to the known processing states, thanks Jonathan Nieder
* apt-pkg/packagemanager.h:
  - export info about disappeared packages with GetDisappearedPackages()
* methods/http.{cc,h}:
  - code cleanup, use enums instead of magic ints

* debian/rules:
  - spell out some less known options to reduce manpage consultation-rate
  - Use POSIX command substitution: $(<command sequence>)
  - Remove EOL whitespace (Closes: #577804)
* apt-pkg/acquire-item.cc:
  - Fix pkgAcqFile::Custom600Headers() to always return something.

* apt-pkg/depcache.cc:
  - rewrite the pseudo package reinstaller to be more intelligent
    in his package choices
* apt-pkg/packagemanager.cc:
  - don't try to "unpack" pseudo packages twice
* apt-pkg/contrib/fileutl.cc:
  - add a parent-guarded "mkdir -p" as CreateDirectory()
* apt-pkg/acquire.{cc,h}:
  - add a delayed constructor with Setup() for success reporting
  - check for and create directories in Setup if needed instead of
    error out unfriendly in the Constructor (Closes: #523920, #525783)
  - optional handle a lock file in Setup()
* apt-pkg/acquire-item.cc:
  - Acquire::ForceHash to force method for expected hash
* cmdline/apt-get.cc:
  - remove the lock file handling and let Acquire take care of it instead
  - display MD5Sum in --print-uris if not forced to use another method
    instead of displaying the strongest available (Closes: #576420)
  - regex for package names executed on Grp- not PkgIterator
  - show non-candidates as fallback for virtual packages (Closes: #578385)
  - set also "all" to this version for pseudo packages in TryToChangeVer
* apt-pkg/deb/dpkgpm.cc:
  - remove Chroot-Directory from files passed to install commands.
    Thanks to Kel Modderman for report & patch! (Closes: #577226)
* ftparchive/writer.cc:
  - remove 999 chars Files and Checksums rewrite limit (Closes: #577759)
* cmdline/apt-cache.cc:
  - align Installed and Candidate Version in policy so they can be compared
    easier, thanks Ralf Gesellensetter for the pointer! (Closes: #578657)
* doc/apt.ent:
  - Add a note about APT_CONFIG in the -c description (Closes: #578267)
* doc/po/de.po:
  - correct typos in german apt_preferences manpage, thanks Chris Leick!
* apt-pkg/sourcelist.cc:
  - be less strict and accept [option=value] as well
* apt-pkg/contrib/configuration.cc:
  - error out if #clear directive has no argument
* doc/files.sgml:
  - sync documentation with status quo, regarding files/directories in
    use, extended_states and uri schemes.
* doc/cache.sgml:
  - drop the file in favor of inplace documentation with doxygen
* apt-pkg/pkgcache.h:
  - enhance the Groups ABI by providing a ID as the other structs does
  - check also the size of the Group struct then checking for the others
* cmdline/apt-get.cc:
  - replace backticks with single quotes around fix-broken command
    in the broken packages message. (Closes: #577168)
* dselect/install:
  - modernize if-statements not to use 'x' (Closes: #577117)
  - replace backticks with POSIX $() (Closes: #577116)
* cmdline/apt-get.cc:
  - fix crash when pkg.VersionList() is empty
  - install html doxygen in libapt-pkg-doc 
* debian/control:
  - build-depend on doxygen
* apt-pkg/contrib/weakptr.h:
  - add a class WeakPointable which allows one to register weak pointers to
    an object which will be set to NULL when the object is deallocated.
* [ABI break] apt-pkg/acquire{-worker,-item,}.h:
  - subclass pkgAcquire::{Worker,Item,ItemDesc} from WeakPointable.
* apt-pkg/pkgcache.cc:
  - Merge fix from David to correct handling in single-arch environments.
* cmdline/apt-cache.cc:
  - Add a showauto command to apt-cache.
* cmdline/apt-get.cc:
  - Add apt-get markauto and unmarkauto commands.
* [BREAK] merge MultiArch-ABI. We don't support MultiArch,
  but we support the usage of the new ABI so libapt users
  can start to prepare for MultiArch (Closes: #536029)
* Ignore :qualifiers after package name in build dependencies
  in the library by default, but try to honour them in apt-get
  as we have some sort of MultiArch support ready (Closes: #558103)
* add translation of the manpages to PT (portuguese)
  Thanks to Américo Monteiro!
* Switch to dpkg-source 3.0 (native) format
* apt-pkg/depcache.cc:
  - remove Auto-Installed information from extended_states
    together with the package itself (Closes: #572364)
* cmdline/apt-mark:
  - don't crash if no arguments are given (Closes: #570962)
* debian/control:
  - remove some years old and obsolete Replaces
  - add automake/conf build-depends/conflicts as recommend by
    the autotools-dev README (Closes: #572615)
* apt-pkg/contrib/mmap.{h,cc}:
  - add char[] fallback for filesystems without shared writable
    mmap() like JFFS2. Thanks to Marius Vollmer for writing
    and to Loïc Minier for pointing to the patch! (Closes: #314334)
* doc/apt_preferences.5.xml:
  - fix two typos and be more verbose in the novice warning.
    Thanks to Osamu Aoki for pointing it out! (Closes: #567669)
  - fix a=sid vs. n=sid typo, thanks Ansgar Burchardt!
  - origin can be used to match a hostname (Closes: #352667)
  - remove wrong pin-priority is optional remark (Closes: #574944)
* apt-pkg/deb/dpkgpm.cc:
  - fix error message construction in OpenLog()
  - if available store the Commandline in the history
* cmdline/apt-get.cc:
  - add a --only-upgrade flag to install command (Closes: #572259)
  - fix memory leaks in error conditions in DoSource()
  - try version match in FindSrc first exact than fuzzy (LP: #551178)
* apt-pkg/contrib/cmndline.cc:
  - save Commandline in Commandline::AsString for logging
* apt-pkg/deb/debversion.cc:
  - consider absent of debian revision equivalent to 0 (Closes: #573592)
* doc/makefile, doc/*:
  - generate subdirectories for building the manpages in on the fly
    depending on the po files we have.
* apt-pkg/pkgcachegen.cc:
  - merge versions correctly even if multiple different versions
    with the same version number are available.
    Thanks to Magnus Holmgren for the patch! (Closes: #351056)
* ftparchive/writer.cc:
  - write LongDescriptions if they shouldn't be included in Packages
    file into i18n/Translation-en by default.
* doc/po/de.po:
  - correct a few typos in the german manpage translation.
    Thanks to Chris Leick and Georg Koppen! (Closes: #574962)
* apt-pkg/contrib/strutl.cc:
  - convert all toupper calls to tolower_ascii for a little speedup
* apt-pkg/contrib/strutl.cc:
  - always escape '%' (LP: #130289) (Closes: #500560)
  - unescape '%' sequence only if followed by 2 hex digit
  - username/password are urlencoded in proxy string (RFC 3986)

1 files changed, 113 insertions, 0 deletions

diff --git a/README.MultiArch b/README.MultiArch
new file mode 100644
index 000000000..b2964ac38
--- /dev/null
+++ b/README.MultiArch
@@ -0,0 +1,113 @@
+Before we start with this topic: Note that MultiArch is not yet ready for
+prime time and/or for the casual user. The implementation is so far widely
+untested and only useful for developers of packagemanagment tools which
+use APT and his friends and maintainers of (upcoming) MultiArch packages.
+This README is especially NOT written for the casual user and is NOT a
+usage guide - you have been warned. It is assumed that the reader has
+at least a bit of knowledge about APT internals, dependency relations
+and the MultiArch spec [0].
+
+Note also that the toolchain isn't ready yet, e.g. while you can simulate
+the installation of MultiArch packages they will more sooner than later
+cause enormous problems if really installed as dpkg can't handle MultiArch
+yet (no, --force-{overwrite,architecture} aren't good options here).
+Other parts of the big picture are missing and/or untested too.
+You have been warned!
+
+
+The implementation is focused on NOT breaking existing singleArch-only
+applications and/or systems as this is the current status-quo for all
+systems. Also, many systems don't need (or can't make use of) MultiArch,
+so APT will proceed in thinking SingleArch as long as it is not explicitly
+told to handle MultiArch:
+To activate MultiArch handling you need to specify architectures you
+want to be considered by APT with the config list APT::Architectures
+(Insert architectures in order of preference).
+APT will download Packages files for all these architectures in the
+update step. Exception: In the sourcelist is the optionfield used:
+deb [ arch=amd64,i386 ] http://example.org/ experimental main
+(This optionfield is a NOP in previous apt versions)
+
+Internally in APT a package is represented as a PkgIterator -
+before MultiArch this PkgIterator was architecture unaware,
+only VerIterators include the architecture they came from.
+This is/was a big problem as all versions in a package are
+considered for dependency resolution, so pinning will not work in all cases.
+
+The problem is solved by a conceptional change:
+A PkgIterator is now architecture aware, so the packages
+of foobar for amd64 and for i386 are now for apt internal totally
+different packages. That is a good thing for e.g. pinning, but
+sometimes you need the information that such packages are belonging together:
+All these foobar packages therefore form a Group accessible with GrpIterators.
+Note that the GrpIterator has the same name as all the packages in this group,
+so e.g. apt-cache pkgnames iterates over GrpIterator to get the package names:
+This is compatible to SingleArch as a Group consists only of a single package
+and also to MultiArch as a Group consists of possible many packages which
+all have the same name and are therefore out of interest for pkgnames.
+
+
+Caused by the paragraph "Dependencies involving Architecture: all packages"
+in the MultiArch spec we have a second major conceptional change
+which could even break existing applications, but we hope for the best…
+An Architecture: all package is internally split into pseudo packages
+for all MultiArch Architectures and additional a package with the
+architecture "all" with no dependencies which is a dependency of all
+these architecture depending packages. While the architecture depending
+packages are mainly used for dependency resolution (a package of arch A which
+depends on an arch all package assumes that the dependencies of this package
+are also from arch A. Packages also sometimes change from any to all or v.v.)
+the arch "all" package is used for scheduling download/installation of the
+underlying "real" package. Note that the architecture depending packages can
+be detected with Pseudo() while the "all" package reports exactly this arch
+as package architecture and as pseudo architecture of the versions of this pkg.
+Beware: All versions of a "real" architecture all package will be report "all"
+as their architecture if asked with Arch() regardless if they are the "all" or
+the architecture depending packages. If you want to know the architecture this
+pseudo package was created for call Arch(true). Also, while the spec say that
+arch:all packages are not allowed to have a MultiArch flag APT assigns a
+special value to them: MultiArch: all.
+
+
+As you might guess this arch:all handling has a few problems (but we think so
+far that the problems are minor compared to the problems we would have with
+other implementations.)
+APT doesn't know which pseudo packages of such an arch all package are
+"installed" (to satisfy dependencies), so APT will generate a Cache in which
+all these pseudo packages are installed (e.g. apt-cache policy will display
+them all as installed). Later in the DepCache step it will "remove"
+all pseudo packages whose dependencies are not satisfied.
+The expense is that if the package state is broken APT could come to the
+conclusion to "remove" too many pseudo packages, but in a stable environment
+APT should never end up in a broken system state…
+
+
+Given all these internal changes it is quite interesting that the actual
+implementation of MultiArch is trivial: Some implicit dependencies and a few
+more provides are all changes needed to get it working. Especially noteworthy
+is that it wasn't needed to change the resolver in any way and other parts only
+need to be told about ignoring pseudo packages or using GrpIterator instead of
+PkgIterator, so chances are good that libapt-applications will proceed to work
+without or at least only require minor changes, but your mileage may vary…
+
+
+Known Issues and/or noteworthy stuff:
+* The implementation is mostly untested, so it is very likely that APT will
+  eat your kids if you aren't as lucky as the author of these patches.
+* the (install)size of a pseudo package is always NULL - if you want to know
+  the (install)size you need to get the info from the arch "all" package.
+* It is maybe confusing, but the arch "all" package does have the same versions
+  and in general roughly the same information with one subtil difference:
+  It doesn't have any dependency, regardless of the type. The pseudo packages
+  depend on this package.
+* apt-cache policy foobar on installed architecture all package foobar will
+  report all architecture depending packages as installed. Displaying here the
+  correct information would require to build the complete DepCache…
+* [BUG] An installed package which changes the architecture from any to all
+  (and v.v.) shows up in the NEW packages section instead of UPGRADE.
+* [TODO] Investigate the DepCache pseudo-package killer heuristic:
+  e.g. add more safety guards…
+* [FIXME] a few corner cases/missing features marked as FIXME in the code
+
+
+[0] https://wiki.ubuntu.com/MultiarchSpec