[PEAK] PEAK CVS vs. ZODB CVS :: [pP]ersistence :: Round 1, Fight!

[Bob Ippolito]

On Feb 20, 2004, at 12:16 PM, Phillip J. Eby wrote:

> At 12:11 PM 2/20/04 -0500, Bob Ippolito wrote:
>
>> On Feb 20, 2004, at 11:59 AM, Phillip J. Eby wrote:
>>> However, my plan for alpha 4 was to drop the use of ZODB altogether  
>>> and go with a PEAK-specific persistence mechanism.  But I haven't  
>>> designed that mechanism yet, so it's not a quick fix.
>>
>> I'm pretty sure that the latest ZODB 3.3 doesn't use ExtensionClass,  
>> it uses a new style class (written in C).
>
> I may investigate that if I have the time, but I'm concerned that if  
> the semantics of the 3.3 version are different from ZODB4, I may waste  
> a lot of time hacking how PEAK wraps it that would be better spent  
> replacing it altogether.

On further inspection.. the ZODB  3.3 that I'm using (ZODB in the CVS  
repo) has a module called "persistent" which seems equivalent to the  
"persistence" module that PEAK uses, with a few small changes (i.e. it  
doesn't seem to have the stupid 2.2 hack, so I made the metaclass  
type).  I did have to make a small patch to the persistent module such  
that it gets Interface and Attribute from protocols if ZODB isn't  
available (otherwise it uses garbage old style classes in place).

Index: src/peak/persistence.py
===================================================================
RCS file: /cvsroot/PEAK/src/peak/persistence.py,v
retrieving revision 1.5
diff -u -r1.5 persistence.py
--- src/peak/persistence.py     2003/06/05 16:19:55     1.5
+++ src/peak/persistence.py     2004/02/22 07:04:09
@@ -10,12 +10,12 @@
  import __main__
  md = __main__.__dict__

-Persistent             = importString('persistence:Persistent', md)
-PersistentMetaClass    =  
importString('persistence:PersistentMetaClass', md)
-GHOST                  =  
importString('persistence._persistence:GHOST', md)
-IPersistent            =  
importString('persistence.interfaces:IPersistent', md)
+Persistent             = importString('persistent:Persistent', md)
+PersistentMetaClass    = type
+GHOST                  = importString('persistent:GHOST', md)
+IPersistent            =  
importString('persistent.interfaces:IPersistent', md)
  IPersistentDataManager = importString(
-    'persistence.interfaces:IPersistentDataManager', md
+    'persistent.interfaces:IPersistentDataManager', md
  )

  def isGhost(obj):

I also changed the setup.py to check for ZEO instead of zope.component,  
because ZODB installs ZConfig too -- but that's more of a hack.

All of the tests pass, except one related to ZConfig.. something about  
u'/Library/Python/2.3_PEAK/ZConfig/doc/schema.dtd' not being a valid  
URL type.. on further inspection, it seems that it's not normalizing  
the relative path against the document's base.. it's trying to use  
'../../ZConfig/doc/schema.dtd' directly, instead of os.path.join(base,  
'../../blah') and ends up trying to load it as a url when that fails.   
It actually gets ends up with the correct path when it *does* do the  
normalization, but it doesn't stick "file://" in front of it.  I'm  
going to file a bug against PyXML and maybe Python on this one.

 >  
/System/Library/Frameworks/Python.framework/Versions/2.3/lib/python2.3/ 
site-packages/_xmlplus/sax/saxutils.py(515)prepare_input_source()
-> f = urllib2.urlopen(source.getSystemId())
(Pdb) source.getSystemId()
u'/Library/Python/2.3_PEAK/ZConfig/doc/schema.dtd'

-bob