[regression] symbol lookup error: /usr/lib/arm-linux-gnueabihf/libmirserver.so.24: undefined symbol: _ZTIN7android7RefBaseE (libmirserver 0.6.1 doesn't work with libmircommon 0.7.0)

This only seems to be a problem on devices with a mix of Mir 0.6 and 0.7. If you flash devel-proposed for example you'll get pure Mir 0.7.0 and no problem.

If the problem is indeed just that we failed to bump MIRCOMMON_ABI then that's understandable. In fact I did bump it and the change got reverted because there wasn't strong evidence of it actually being necessary. Needs more investigation, although it would be relatively harmless to just bump MIRCOMMON_ABI on development-branch right now.

A simple workaround *should* be to just ensure the version of the libmirserver package is the same as libmircommon. That should be possible to force...?

The trivial fix (an ABI bump in Mir 0.8) can't be backported to 0.7 for obvious reasons. And Saviq agrees a fix in 0.7 isn't strictly required, so "Won't Fix" in 0.7.

Fix committed into lp:mir/devel at revision None, scheduled for release in mir, milestone Unknown

This bug was fixed in the package mir - 0.8.0+14.10.20141010-0ubuntu1

---------------
mir (0.8.0+14.10.20141010-0ubuntu1) utopic; urgency=medium

  [ Daniel van Vugt ]
  * New upstream release 0.8.0 (https://launchpad.net/mir/+milestone/0.8.0)
    - Enhancements:
      . Less sensitivity to ABI breaks - many headers unused by external
        projects are now hidden and not installed by -dev packaes. If you
        require any headers that are missing, just ask.
      . Touchspots: --enable-touchspots to servers; visually shows touch
        locations (warning: This affects performance LP: #1373692).
      . Client performance reporting: Any Mir client can now get accurate
        performance information (frame rate, render time, buffer lag etc)
        logged to stdout. Just set env MIR_CLIENT_PERF_REPORT=log
      . Further improved touch responsiveness, with less lag and smoother
        scrolling (so long as you don't enable touchspots).
      . Slightly faster builds using precompiled headers.
      . Turn hardware overlays on by default. When in use, this halves the
        CPU usage of a Mir server. Already enabled in unity-system-compositor.
      . More scripting to detect ABI breaks.
      . Improved src/ tree consistency (renamed "src/shared" to "src/common").
      . Improved fatal signal design: Changed from SIGTERM to SIGHUP delivered
        to clients on unexpected server disconnection.
      . Improved library/package design to allow concurrent installations
        of different Mir versions without conflicts.
      . Fd reception code is now common to client and server.
    - ABI summary: Servers need rebuilding, but clients do not;
      . Mirclient ABI unchanged at 8
      . Mircommon ABI bumped to 2
      . Mirplatform ABI bumped to 3
      . Mirserver ABI bumped to 26
    - API changes between Mir 0.7 and 0.8:
      . Lots of headers removed from the public SDK! We have only hidden
        headers not known to be used by any known projects. Please let us
        know if anything is missing - https://bugs.launchpad.net/mir/+filebug
      . graphics::Platform - interface changed significantly.
      . Lots of server API changes to support touchspots.
      . File descriptors now passed as type Fd instead of int32_t.
    - Bug fixes:
      . [regression] Mir deb packages with versioned names cannot be installed
        simultaneously any more (LP: #1293944)
      . A frozen client can hang the whole server (LP: #1350207)
      . QtMir FTBFS: fatal error: mir/input/input_channel.h: No such file or
        directory (LP: #1365934)
      . [regression] platform-api fails to build against Mir 0.8 (LP: #1368354)
      . Mir FTBFS with gcc 4.9.1-14 (utopic update):
        auto_unblock_thread.h:44:46: error: no matching function for call to
        ‘std::thread::thread(<brace-enclosed initializer list>)’ (LP: #1369389)
      . [regression] Compositing is jerky and stutters during touch events
        (LP: #1372850)
      . unit test fails: AndroidInputReceiverSetup.slow_raw_input_doesnt_cause_
        frameskipping (LP: #1373826)
      . intermittent hang in TestClientInput (LP: #1338612)
      . TestClientInput.scene_obscure_mo...

This bug was fixed in the package mir - 0.8.0+14.10.20141005-0ubuntu1

---------------
mir (0.8.0+14.10.20141005-0ubuntu1) 14.09; urgency=medium

  [ Daniel van Vugt ]
  * New upstream release 0.8.0 (https://launchpad.net/mir/+milestone/0.8.0)
    - Enhancements:
      . Less sensitivity to ABI breaks - many headers unused by external
        projects are now hidden and not installed by -dev packaes. If you
        require any headers that are missing, just ask.
      . Touchspots: --enable-touchspots to servers; visually shows touch
        locations (warning: This affects performance LP: #1373692).
      . Client performance reporting: Any Mir client can now get accurate
        performance information (frame rate, render time, buffer lag etc)
        logged to stdout. Just set env MIR_CLIENT_PERF_REPORT=log
      . Further improved touch responsiveness, with less lag and smoother
        scrolling (so long as you don't enable touchspots).
      . Slightly faster builds using precompiled headers.
      . Turn hardware overlays on by default. When in use, this halves the
        CPU usage of a Mir server. Already enabled in unity-system-compositor.
      . More scripting to detect ABI breaks.
      . Improved src/ tree consistency (renamed "src/shared" to "src/common").
      . Improved fatal signal design: Changed from SIGTERM to SIGHUP delivered
        to clients on unexpected server disconnection.
      . Improved library/package design to allow concurrent installations
        of different Mir versions without conflicts.
      . Fd reception code is now common to client and server.
    - ABI summary: Servers need rebuilding, but clients do not;
      . Mirclient ABI unchanged at 8
      . Mircommon ABI bumped to 2
      . Mirplatform ABI bumped to 3
      . Mirserver ABI bumped to 26
    - API changes between Mir 0.7 and 0.8:
      . Lots of headers removed from the public SDK! We have only hidden
        headers not known to be used by any known projects. Please let us
        know if anything is missing - https://bugs.launchpad.net/mir/+filebug
      . graphics::Platform - interface changed significantly.
      . Lots of server API changes to support touchspots.
      . File descriptors now passed as type Fd instead of int32_t.
    - Bug fixes:
      . [regression] Mir deb packages with versioned names cannot be installed
        simultaneously any more (LP: #1293944)
      . A frozen client can hang the whole server (LP: #1350207)
      . QtMir FTBFS: fatal error: mir/input/input_channel.h: No such file or
        directory (LP: #1365934)
      . [regression] platform-api fails to build against Mir 0.8 (LP: #1368354)
      . Mir FTBFS with gcc 4.9.1-14 (utopic update):
        auto_unblock_thread.h:44:46: error: no matching function for call to
        ‘std::thread::thread(<brace-enclosed initializer list>)’ (LP: #1369389)
      . [regression] Compositing is jerky and stutters during touch events
        (LP: #1372850)
      . unit test fails: AndroidInputReceiverSetup.slow_raw_input_doesnt_cause_
        frameskipping (LP: #1373826)
      . intermittent hang in TestClientInput (LP: #1338612)
      . TestClientInput.scene_obscure_mot...