[SPARK-30493][PYTHON][ML] Remove OneVsRestModel setClassifier, setLabelCol and setWeightCol methods

[zero323]

What changes were proposed in this pull request?

Removal of OneVsRestModel.setClassifier, OneVsRestModel.setLabelCol and OneVsRestModel.setWeightCol methods.

Why are the changes needed?

Aforementioned methods shouldn't by included by SPARK-29093, as they're not present in Scala OneVsRestModel and have no practical application.

Does this PR introduce any user-facing change?

Not beyond scope of SPARK-29093].

How was this patch tested?

Existing tests.

CC @huaxingao @zhengruifeng

[SparkQA]

Test build #116574 has finished for PR 27181 at commit 180a592.

• This patch passes all tests.
• This patch merges cleanly.
• This patch adds no public classes.

[SparkQA]

Test build #116576 has finished for PR 27181 at commit a727e3f.

• This patch fails PySpark unit tests.
• This patch merges cleanly.
• This patch adds no public classes.

[huaxingao]

setLabelCol is still required. The other two should be removed.
Thanks for catching the problem!

[zero323]

setLabelCol is still required.

Is it really? Doesn't seem like Scala counterpart has one. And ignoring that ‒ when would a Model use it?

[huaxingao]

setLabelCol is called in OneVsRestModel._from_java

[SparkQA]

Test build #116579 has finished for PR 27181 at commit a727e3f.

• This patch fails PySpark unit tests.
• This patch merges cleanly.
• This patch adds no public classes.

[huaxingao]

actually, should use _set instead of setLabelCol in OneVsRestModel._from_java.

[zero323]

Shouldn't weightCol be set as well?

[huaxingao]

Yes, I think weightCol should be set as well for OneVsRestModel._from_java/_to_java and OneVsRest._from_java/_to_java

[SparkQA]

Test build #116581 has finished for PR 27181 at commit 82367a3.

• This patch passes all tests.
• This patch merges cleanly.
• This patch adds no public classes.

[HyukjinKwon]

@zero323, please keep and follow the PR template - https://github.com/apache/spark/blob/master/.github/PULL_REQUEST_TEMPLATE

[zhengruifeng]

looks reasonably straightforward
@huaxingao Seem we do not need those setter in OVRModel?

[huaxingao]

@zhengruifeng Yes. These setters can be removed. The internal methods can use _set to set classifier, labelCol and weightCol

[HyukjinKwon]

Before merging it, can we update PR description properly please? It's best to avoid having bad PR examples.

[zhengruifeng]

Merged to master, thanks all!

[zero323]

@zero323, please keep and follow the PR template - https://github.com/apache/spark/blob/master/.github/PULL_REQUEST_TEMPLATE

Sorry @HyukjinKwon, it felt more like a follow-up / cleanup, than a full proposal.

[zero323]

Yes, I think weightCol should be set as well for OneVsRestModel._from_java/_to_java and OneVsRest._from_java/_to_java

FYI I've opened SPARK-30504.