[Zope-CMF] RFC: Being more forgiving when importing toolset.xml
Maurits van Rees
m.van.rees at zestsoftware.nl
Mon Dec 26 22:56:29 UTC 2011
The toolset registry of portal_setup can get out of touch with reality:
a product may have installed a tool a while ago and made it required,
but meanwhile the product author has unthinkingly renamed the class or
module of the tool; or the product has been removed from the buildout
without being uninstalled; or the uninstall does not take care of
cleaning up the required tools from the registry.
Now the admin of this website installs a second product which is totally
unrelated. It has its own required tool, which it registers in
toolset.xml. On install, the admin gets a traceback:
Module Products.GenericSetup.tool, line 123, in importToolset
TypeError: 'NoneType' object is not callable
This is because the tool of the first product is still in the required
tools list. The admin does not understand this and files a bug report
for the second product as it cannot be installed. Sample bug reports
And a thread on how to fix it when it has already gone wrong:
I propose to not break in this case, but give a warning and continue
with the next tool, much like was already done for missing import steps.
This should lower the number of sites where installs of new products
fail for a reason that has nothing to do with that product. It should
consequently also bring down the number of misdirected support requests.
Downside could be that when you are developing a new product and make a
typo in the class name in toolset.xml it does not break anymore but only
print a warning message that may be easily overlooked.
I would say the benefit outweighs the downside.
Currently the code in Products/GenericSetup/tool.py starts like this:
for info in toolset.listRequiredToolInfo():
tool_id = str(info['id'])
tool_class = _resolveDottedName(info['class'])
if tool_class is None:
logger.info('Class %(class)s not found for '
'tool %(id)s' % info)
# code that may break when tool_class is None
The code that is executed in the 'tool_class is None' condition should
logger.warning("Not creating required tool %(id)s, because "
"class %(class)s is not found." % info)
Tests on CMF trunk and CMF 2.2 pass with this.
Would this change be acceptable on trunk and branch 1.6?
Maurits van Rees http://maurits.vanrees.org/
Web App Programmer at Zest Software: http://zestsoftware.nl
"Logical thinking shows conclusively that logical thinking
is inconclusive." - My summary of Gödel, Escher, Bach
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