Operations as processing instructions don't work in granule list FDML

[lindholc]

For example:

<?xml version="1.0" encoding="UTF-8"?>

<dataset id="nrl2_ssi_prelim_P1D">

  <source>
    <dataset>
      <adapter class="latis.input.FileListAdapter"
               pattern="ssi_v02r01-preliminary_daily_s(2020\d{4})_e\d{8}_c\d{8}.nc$"/>
      <source uri="file:///lisird/lasp/nrl2/v02r01-prelim_ncdc/"/>
      <function>
        <scalar id="time"
                units="yyyyMMdd"
                type="string"
                class="latis.time.Time"/>
        <scalar id="uri" type="string"/>
      </function>
    </dataset>
  </source>

  <adapter class="latis.input.GranuleListAppendAdapter">
    <adapter class="latis.input.NetcdfAdapter"/>
  </adapter>

  <function>
    <tuple>
      <scalar id="time"
              units="days since 1610-01-01"
              type="int"
              class="latis.time.Time"/>
      <scalar id="wavelength" type="double" units="nm"/>
    </tuple>
    <tuple>
      <scalar id="SSI" type="double" units="W/m^2/nm"/>
      <scalar id="SSI_UNC" type="double" units="W/m^2/nm"/>
    </tuple>
  </function>

  <?latis-operation expression="curry(1)"?>
</dataset>

Note that the model is correct when reading the dataset:

scala> FdmlReader.read(new java.net.URI("file:///.../nrl2_ssi_prelim_P1D.fdml"), validate=false)
val res9: latis.dataset.Dataset = nrl2_ssi_prelim_P1D: time -> wavelength -> (SSI, SSI_UNC)

But there's an error when we try to write the dataset:

scala> (new TextEncoder()).encode(res10).compile.toVector.unsafeRunSync()
java.util.NoSuchElementException: empty collection

The stack trace is just IO/Stream internals.

Using the curry operation from the REPL works fine.

Selections didn't work either, but they didn't throw an exception. I wonder if neither operation is being applied to the data, and the reason we only see an error with curry is that curry changes the model and a selection does not.