[SPARK-23073] Fix incorrect R doc page header for generated sql functions

• Type: Documentation
• Status: Resolved
• Priority: Minor
• Resolution: Incomplete
• Affects Version/s: 2.2.1, 2.3.0
• Component/s: SparkR
• Labels: bulk-closed
• Assignee: Unassigned
• Reporter: Felix Cheung
• Created: 14/Jan/18 19:10
• Updated: 08/Oct/19 05:44
• Resolved: 08/Oct/19 05:44

Description

See title says

asc {SparkR}

https://dist.apache.org/repos/dist/dev/spark/v2.3.0-rc1-docs/_site/api/R/columnfunctions.html
http://spark.apache.org/docs/latest/api/R/columnfunctions.html

asc, contains etc are functions generated at runtime. Because of that, their doc entries are dependent on the Generics.R file. Unfortunately, ROxygen2 picks the doc page title from the first function name by default, in the presence of any function it can parse.

An attempt to fix here https://github.com/apache/spark/pull/20263/commits/d433dc930021de85aa338c5017a223bae3526df3#diff-8e3d61ff66c9ffcd6ffb7a8eedc08409R824

#' @rdname columnfunctions
  #' @export
 +#' @name NULL
  setGeneric("asc", function(x) { standardGeneric("asc") })

But it cause a more severe issue to fail CRAN checks

* checking for missing documentation entries ... WARNING
Undocumented code objects:
  'asc' 'contains' 'desc' 'getField' 'getItem' 'isNaN' 'isNotNull'
  'isNull' 'like' 'rlike'
All user-level objects in a package should have documentation entries.
See the chapter 'Writing R documentation files' in the 'Writing R
Extensions' manual.
* checking for code/documentation mismatches ... OK
* checking Rd \usage sections ... WARNING
Objects in \usage without \alias in documentation object 'columnfunctions':
  'asc' 'contains' 'desc' 'getField' 'getItem' 'isNaN' 'isNull'
  'isNotNull' 'like' 'rlike'

To follow up we should

• look for a way to set the doc page title
• http://spark.apache.org/docs/latest/api/R/columnfunctions.html is really barebone and we should explicitly add a doc page with content (which could also address the first point)