Hi,
On 05/25/12 19:51, Fred Kiefer wrote:
I looked into your problem more deeply and there were two issues
blocking you. One was the change Richard made in the way we store the
item count of an array in archives. Richard improved on that an now
archives store this count in a forward compatible way in most cases,
this means old code will be able to read arrays in archives written by
newer code.
The other issues hasn't been resolved and is unlikely to get resolved.
In the last release we changed the way some classes get archived. This
has happened for almost all gui releases over the last years and there
isn't much we can do about it. We try to implement the new archiving
code in a way that allows us to read old archives, but there is no way
to allow old code to read newer archives, when the format changes.
Now the simplest solution for you would be to switch over to keyed
archives, in this case from Gorm to NIB files. This format is backward
and forward compatible most of the time and for this reason should be
preferred over non-keyed archives.
This essentially means that the option Greg has given in Gorm to save
old file formats is unreliable as soon as there is a bigger change in
the classes.
If this isn't an option for you, your could try to build a hybrid
version of archiving for the classes that are needed for you specific
Gorm files. That is, you move the -encodeWithCoder: back to the last
version and keep the -initWithCoder: method on the new state. This
requires that you find all the classes where this is needed and is is
also a bit dangerous, as you will write out the objects with the wrong
version number if you don't change that number as well.
If you are very sure that your only problem are the unsigned/signed
changes that Sebastian made a while ago, then there is another option,
you could remove the sign check from the base code, or rather make it
a warning. (This is in NSUnarchiver.m in the function typeCheck) This
may even be a change we could keep. But don't expect this to resolve
all your issues with forward compatibility. For example NSTableColumn
and NSTextView were also changed in a incompatible way. If I remember
correctly, this was to fix bugs that you reported.
I transformed the exception in a NSLog() and recompiled a base 1.24
installation with only that change, then I did run Gorm using that base
and the only warning I get (except the version number) is that signed
vs. unsigned and the gorm file opens fine. I resaved it. It seems to
work and essentially for now.
Riccardo
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