Must _p_mtime activate a ghost?

[tseaver]

The C implementation does forcibly activate it, while the pure-Python version (until #20) did not.

See: #20

[jamadden]

Is there any other reliable way to know that an object has definitively been saved at least once, besides the fact that it has a _p_mtime? That's what our code uses it for.

It's a convenience, in that case, that _p_mtime activates the object. If it did not, code like this:

if obj._p_mtime:
   # we've been saved before
else:
   # we're a brand new object, do first-time stuff

has to become:

obj._p_activate()
if obj._p_mtime:
   # ...
...

Could that code be changed everywhere? Sure. Would it be moderately annoying and an easily-missed source of bugs? Sure.

[tseaver]

I believe the consensus answer is "Yes, _p_mtime must activate the object." I don't know that we every got the rationale documented, but #20 makes it so for pure-Python.