“season” not rendered from one of the CSL-YAML date formats

[njbart]

The “season” component of a date is rendered correctly when using the pandoc-specific CSL-YAML date format, but it isn’t when using the generic CSL-YAML date format.

This is an example from the 2011 citeproc-js specs (archive link):

{  "issued" : {
      "date-parts" : [
         [ 1950 ]
      ],
      "season" : "1"
   }
}

Its (generic) CSL-YAML equivalent is this:

issued:
  date-parts:
  - - 1950
  season: '1'

Its pandoc-specific CSL-YAML counterpart is this:

  issued:
    - year: 1950
      season: 1

Trying this with:

pandoc -s -F pandoc-citeproc -t plain << EOT

Foo [@item1].

---
references:
- id: item1
  type: article-journal
  author:
  - family: Theauthor
    given: A. B.
  issued:
    date-parts:
    - - 1950
    season: '1'
#   issued:
#     - year: 1950
#       season: 1
  title: The title
  container-title: The Journal
  page: 123-145
  volume: 77
  language: en-US
...
EOT

Output is:

Theauthor, A. B. 1950. “The Title.” The Journal 77:123–45.

When replacing the issued part with the commented-out lines, the (expected) output is this:

Theauthor, A. B. 1950. “The Title.” The Journal 77 (Spring):123–45.

My impression so far has been that pandoc-citeproc is supposed to be able to deal with both CSL-YAML flavours. If so, its behaviour when using generic CSL-YAML should be fixed.