Yuan HOng wrote:
If I have a utility component whose initializaiton depends on the
availability of another utility, the initialization fails with a
Component Lookup Error. It seems that in the ZCML file, the utility
components are first created, and then at the end of the whole
configuration, they are registered.
So if in the initilization code of utility B I need to look up a
utility A, the ZCML configuration will fail.
That's why you shouldn't look up any components in __init__ :)
The problem is that although the z3c eninge object is created before
the 'utility' directive is executed, it is not registered and
therefore can not be looked up when the 'utility' directive tries to
create the MyUtility object.
How does one usually solve such interdependencies?
Look up the utility when you actually *need* it. This is a general rule
of thumb, because you always want to preserve the possibility of local
utilities coming from some local sites, and those aren't available
during some initialization code.
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