inconsistencies in the way to detect a missing attribute
| Affects | Status | Importance | Assigned to | Milestone | |
|---|---|---|---|---|---|
| Zope 2 |
Fix Released
|
Medium
|
Unassigned | ||
Bug Description
When catalogging/
The problem is that each plugin index and the metadata extraction use different methods:
1) metadata (see recordify in Catalog.py) uses MV from Missing to indicate a missing attribute
2) UnIndex (and all indexes derived from it) uses an private attribute _marker defined as []
3) KeywordIndex uses () as a missing attribute and just catalogs everything
The problem is that if the attribute is provided by (e.g.) a python script, it's impossible for the python script to indicate a missing attribute, or it has to be done in several different methods:
a) for metadata is possible to return MV from Missing to indicate a missing attribute
b) for indexes deriving from UnIndex is impossible to indicate a missing attribute (since _marker is private)
c) for keyword indexes one has to return ()
d) even if it was possible to import the private _merker, it's not the same _marker for each index.
I think the solution would be to use the same value everywhere to detect a missing attribute, and this value should be useable from external method, like, e.g., MV from Missing, or a non private attribute imported from the same module.
| Toby Dickenson (htrd) wrote | #1 |
| Casey Duncan (caseman) wrote | #2 |
| Toby Dickenson (htrd) wrote | #3 |
| Tres Seaver (tseaver) wrote | #4 |
| tags: |
added: bugday removed: bug |
| Changed in zope2: | |
| status: | New → Triaged |
| Changed in zope2: | |
| assignee: | nobody → Jens Vagelpohl (jens-dataflake) |
| Jens Vagelpohl (dataflake-deactivatedaccount-deactivatedaccount) wrote | #5 |
| Changed in zope2: | |
| status: | Triaged → Fix Committed |
| Changed in zope2: | |
| milestone: | none → 2.12.7 |
| Changed in zope2: | |
| status: | Fix Committed → Fix Released |
Status: Pending => Accepted
Supporters added: htrd
> 1) metadata (see recordify in Catalog.py) uses MV from Missing to
> indicate a missing attribute
>
> 2) UnIndex (and all indexes derived from it) uses an private attribute
> _marker defined as []
For both of these two you are describing implementation details that you dont need to know to be able to achieve what you want. Just raise an AttributeError and it *should* just work.
It looks like metadata (see recordify in Catalog.py) wont handle an AttributeError inside an accessor method. I think *this* is a bug.
> 3) KeywordIndex uses () as a missing attribute and just catalogs everything
Yes. KeywordIndex has switched this behaviour several times in its history, and I agree that the current behaviour is wrong. I believe an AttributeError 'should' cause the object to not appear in the index, rather than be indexed with no properties.