Created attachment 203979 [details] [review]
gobject: loosen property override flag restrictions

GObject enforces the following restrictions on property overrides:

  - must only add abilities: if the parent class supports
    readability/writability then the subclass must also support them.
    Subclasses are free to add readability/writability.

  - must not add additional restrictions: if the parent class doesn't
    have construct/construct-only restrictions then the subclass must
    not add them.  Subclasses are free to remove restrictions.

The problem with the previous implementation is that the check against
adding construct/construct-only restrictions was being done even if the
property was not previously writable.  As an example:

  "readable" and "writable only on construct"

was considered as being more restrictive than

  "read only".

This patch tweaks the check to allow the addition of
construct/construct-only restrictions for properties that were
previously read-only and are now being made writable.

Created attachment 203980 [details] [review]
GAction: back out changes to property flags

41e5ba86a791a17bb560dd7813ad7e849e0230dc introduced some changes to the
property flags of GAction.  These changes were not a reflection of the
actual interface of GAction but were necessary due to GObject being
overly-sensitive to flag changes on property overrides.

Now that the GObject bug is fixed, we can restore the GAction flags to
their correct values.

Review of attachment 203979 [details] [review]:

No objections to this. I was not following the irc discussion closely enough, it seems.

Review of attachment 203979 [details] [review]:

The commit message is excellent.   Following the logic in the implementation is a little awkward with deeply nested negations and && and || mixed with bit logic |.  Maybe split it out like:

if (class_pspec)
 { 
   if (pspecs[n]->flags & WRITABLE)
    {
      if (!SUBSET()) { error }
    }
   if (!SUBSET()) { error }

}

?

Attachment 203979 [details] pushed as af24dbc - gobject: loosen property override flag restrictions
Attachment 203980 [details] pushed as ebf572c - GAction: back out changes to property flags