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Committer:
Colin Watson
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Date:
2022-03-16 16:59:21 UTC
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Revision ID:
cjwatson@canonical.com-20220316165921-8g0y1bnpe3qx0w70
Clarify exception for a property with allow_none=False and default=None.
Creating a property with `allow_none=False, default=None` doesn't make
sense, but it's sometimes easy to set things up that way by accident
during refactoring. Storm immediately raises `NoneError` when creating
the variable in that case. However, it's not obvious that the exception
is due to the bad default, and I spent some time with a colleague today
debugging a situation that turned out to be due to this.
Change the exception message from "None isn't acceptable as a value" to
"None isn't acceptable as a default value" in this case, to clue future
travellers into the fact that the problem relates to the default.