[Netconf] test-option default

[Andy Bierman <andy at netconfcentral.com>]

Hi,

The <test-option> parameter to the <edit-config> operation
has 2 different defaults:

  test: if :validate not supported
  test-then-set: if :validate is supported

Not only is this confusing, but it is actually wasteful and
may cause false errors, if the default used is 'test-then-set'.

There is no point in validating the <running> config.
This should always be valid.  The agent uses 'test-then-set'
all the time if :writable-running is supported.

If the <edit-config> target is <candidate>, then incremental edits are
to be expected, so validating the entire <candidate> database by default
may lead to false errors and scripts that normally work
will break if :validate is supported by the agent.
This is unacceptable.

I propose that the default for <test-option> always be 'test'
in the new :validate.1.1 capability (will be in next 4741bis draft).
I would like to alter the :validate.1.0 behavior to match, if that
is OK.  Hopefully, no managers rely on, or want, an automatic
validate of the <candidate> each time it is written.


Andy