E&S CVS Commit: Trellis - Fix a lurking problem with dependencies: circular dependencies couldn'

[pje at eby-sarna.com]

Author: pje
Date: Tue Jul 10 20:43:23 2007
New Revision: 2342

URL: http://svn.eby-sarna.com?rev=2342&view=rev
Log:
Fix a lurking problem with dependencies: circular dependencies couldn't
be reliably observed by rules that weren't part of the circle!  Strangely,
last year's version of the trellis code had a fix for this, using doubly-
indirected links, but there were no tests that covered the behavior, so
I didn't keep it in the rewrite.  But now, there's a test that covers it.
The issue is that only the cell that depends on a cell, should ever
remove itself as a listener from the target, because only the depender
knows when it's finished depending on something! (i.e., when it
recalculates itself, or becomes a Constant)

Modified:
    Trellis/README.txt
    Trellis/peak/events/trellis.py