[
https://issues.apache.org/jira/browse/LUCENE-8292?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16763797#comment-16763797
]
David Smiley commented on LUCENE-8292:
--------------------------------------
Adrien last said:
{quote}In general, we do not delegate methods that have a default
implementation because the default implementation is correct regardless of what
the wrapper class does. Overriding these methods in FilterTermsEnum to delegate
to the wrapped instance would make room for bugs by requiring more methods to
be overridden for the wrapper to be correct.
{quote}
CC [~simonw] curious about your thoughts too
_In general_ I can see this. For the case of termState() and
seekExact(termState) in particular, I don't. Hypothetically what could go
wrong if FilterTermsEnum delegated? When I think of filtering a TermsEnum, I
think of something that might match a subset of terms from the underlying
TermsEnum. The TermsEnum must be positioned to something that matches when
termState is called. If seekExact(termState) in the underlying TermsEnum
receives some termState impl it doesn't identify (isn't of a class it knows),
then you get the default functional behavior, which is safe. I'm looking at
the 6 subclasses of FilterTermsEnum we have in Lucene and I don't see an issue.
(Interestingly, 3 of them are in the UnifiedHighlighter). I checked that
delegating these two methods doesn't result in test failures too, aside from
TestFilterLeafReader.testOverrideMethods which expressly tests our policy.
> Fix FilterLeafReader.FilterTermsEnum to delegate all seekExact methods
> ----------------------------------------------------------------------
>
> Key: LUCENE-8292
> URL: https://issues.apache.org/jira/browse/LUCENE-8292
> Project: Lucene - Core
> Issue Type: Bug
> Components: core/index
> Affects Versions: 7.2.1
> Reporter: Bruno Roustant
> Priority: Major
> Fix For: trunk
>
> Attachments:
> 0001-Fix-FilterLeafReader.FilterTermsEnum-to-delegate-see.patch,
> LUCENE-8292.patch
>
>
> FilterLeafReader#FilterTermsEnum wraps another TermsEnum and delegates many
> methods.
> It misses some seekExact() methods, thus it is not possible to the delegate
> to override these methods to have specific behavior (unlike the TermsEnum API
> which allows that).
> The fix is straightforward: simply override these seekExact() methods and
> delegate.
--
This message was sent by Atlassian JIRA
(v7.6.3#76005)
---------------------------------------------------------------------
To unsubscribe, e-mail: [email protected]
For additional commands, e-mail: [email protected]
