Concurrently allocated sessions get into trouble

[Chris Muller]

Hi, thanks for reporting it.  I'd like to incorporate your/a fix into
the pending release.

Can you help me with some of the details?  I gather you are talking
about two Smalltalk Processes each doing:

  MagmaSession openLocal: 'my repository'

at the same time, both leading them through
MagmaRepositoryController>>#openedOn:, where, since the first one
didn't finish yet, the second one also tries to #open: a new one.
Yeah, that's not good.

Magma objects themselves (read: on the instance-side) do guard their
own internals from access between multiple processes.  But this
problem is occurring on the class-side, where there is no
Semaphore/Monitor guard available.  Part of me wants to say this falls
into the responsibility of the end-user app.  It is creating instances
of Magma objects as its own internals, so it should probably maintain
responsibility for guarding access to them if it uses multiple
processes.

I merged Magma server-kph.206, thanks for that, but I did not see any
code addressing this issue.  So what guard did you use to protect the
opening of the sessions?  Did you add a class-var?

Regards,
  Chris

On 6/25/07, Keith Hodges <keith_hodges at yahoo.co.uk> wrote:
> Dear Chris,
>
> I discovered that opening a session, before a prior session had
> completed being opened resulted in two open repositorycontrollers. i.e.
> openedOn: was returning nil for a controller that was already in the
> process of being opened.
>
> This also results in clients being given the same id for multiple sessions.
>
> I solved this by putting a critical block around our #newSession code.
>
> Keith
> _______________________________________________
> Magma mailing list
> Magma at lists.squeakfoundation.org
> http://lists.squeakfoundation.org/mailman/listinfo/magma
>