[MERGE] Content filtering (EOL part 2 of 3)

[Ian Clatworthy]

Robert Collins wrote:

> This would seem to allow me to wedge my working tree state between bzr
> versions (e.g. a NFS mounted tree is at high risk of triggering this).
> 
> It needs some mechanism to prevent this IMO.
> 
> bb:resubmit

The mechanism which poolie and I have discussed & proposed is to add
a section to .bzrrules which specifies the requirements needed to work
on a branch. The trouble is that content filtering on its own is only
a small part of the problem: ensuring other users - or other bzr
instances on your own computer - also have the right versions of
the right plugins is arguably necessary.

So .bzrrules will end up looking like (for example) ...

  [requires]
  bzr = 1.6
  bzr-eol = 0.2

  [name *.bat]
  eol = dos

We believe this mechanism is both clean and powerful. For example,
teams can use it to ensure plugins enforcing required hooks and
policies are installed by team members while working on relevant
code bases.

There is undoubtedly devil in the detail, particularly when to comes
to how this interacts with the smart server and remote branches in
particular. We ought to take the time to get this feature right.

I don't agree however that this mechanism needs to land in order
for us to land content filtering. To begin with, no plugin using
content filtering will even load on versions of Bazaar without
content filtering in the core - the registration API will be
absent.

Don't retract your resubmit vote though. The patch is buggy and
I'm working on a fixed version. :-(

Ian C.