[regression] Mir server command line options are unpredictable/nondeterministic (--vt is sometimes not recognised)

[Daniel van Vugt]

Mir server platform command line options are unpredictable/non-deterministic.

I keep thinking I'm imagining things. Sometimes --vt works and sometimes it doesn't (from a Gnome Terminal). Well both are true. Now I have two separate wily machines with the same packages. One fails but the other works:

FAILING MACHINE:

$ sudo mir_proving_server --vt 1
[1444966151.185585] mirplatform: Found graphics driver: mesa-x11
[1444966151.187021] mirplatform: Found graphics driver: mesa-kms
Unknown command line options: --vt 1
$ dpkg -l | grep mir-demos
ii mir-demos 0.16.0+15.10.20150921.1-0ubuntu1 amd64 Display server for Ubuntu - demonstration programs

WORKING MACHINE:

$ sudo mir_proving_server --vt 1
[1444965570.300933] mirplatform: Found graphics driver: mesa-kms
[1444965570.302119] mirplatform: Found graphics driver: mesa-x11
[1444965570.304409] mircommon: Loading modules from: /usr/lib/x86_64-linux-gnu/mir/server-platform
[1444965570.304465] mircommon: Loading module: /usr/lib/x86_64-linux-gnu/mir/server-platform/graphics-mesa-kms.so.5
[1444965570.304486] mircommon: Loading module: /usr/lib/x86_64-linux-gnu/mir/server-platform/server-mesa-x11.so.5
[1444965570.305801] mirplatform: Found graphics driver: mesa-kms
[1444965570.306531] mirplatform: Found graphics driver: mesa-x11
[1444965570.306617] mirserver: Selected driver: mesa-kms (version 0.16.0)
...
$ dpkg -l | grep mir-demos
ii mir-demos 0.16.0+15.10.20150921.1-0ubuntu1 amd64 Display server for Ubuntu - demonstration programs

It appears the unpredictability might be arising from which driver it finds on the filesystem first.

[Daniel van Vugt (vanvugt)]

I think the problem came from this:

------------------------------------------------------------
revno: 2756 [merge]
author: Cemil Azizoglu <email address hidden>
committer: Tarmac
branch nick: development-branch
timestamp: Sun 2015-07-19 01:26:23 +0000
message:
  Use command line options during platform probe.

  Introduce a new PlatformPriority value (dummy) which is lower than what real platforms use (supported/best). Return best when a platform-specific option is passed in. This will help in differentiating between Mesa and X11 platforms when the server is launched from an xterm depending on the presence of the "--vt" option.

  Approved by PS Jenkins bot, Alberto Aguirre.
------------------------------------------------------------

[PS Jenkins bot (ps-jenkins)]

Fix committed into lp:mir at revision None, scheduled for release in mir, milestone 0.18.0

[Daniel van Vugt (vanvugt)]

Fix removed in lp:mir/0.18 r3182. And soon to be removed from lp:mir too.

[PS Jenkins bot (ps-jenkins)]

Fix committed into lp:mir at revision 3198, scheduled for release in mir, milestone 0.19.0

[Daniel van Vugt (vanvugt)]

A new potential fix has landed in lp:mir/0.18 r3184.

[PS Jenkins bot (ps-jenkins)]

Fix committed into lp:mir at revision None, scheduled for release in mir, milestone 0.19.0

[Daniel van Vugt (vanvugt)]

Fix Released in Mir 0.18.0. Although it's good to mention this bug got different fixes between the 0.18 and 0.19 branches, it's probably still best to only mention it in the changelog for one of them.