Wrong outputs in modelDescription.xml

[Lennart Ochel]

FMUs generated from the attached Modelica model (which is using the PlanarMechanics library) contain 3 variables that are marked as output:

<!-- Index of variable = "14" -->
  <ScalarVariable
    name="der(speed)"
    valueReference="13"
    variability="continuous"
    causality="output"
    initial="exact">
    <Real start="0.0"/>
  </ScalarVariable>
  <!-- Index of variable = "401" -->
  <ScalarVariable
    name="position"
    valueReference="400"
    variability="continuous"
    causality="output"
    initial="exact">
    <Real start="0.0"/>
  </ScalarVariable>
  <!-- Index of variable = "420" -->
  <ScalarVariable
    name="speed"
    valueReference="419"
    variability="continuous"
    causality="output"
    initial="exact">
    <Real start="0.0"/>
  </ScalarVariable>

The Outputs section of the ModelStructure definition list only two of them:

      <Unknown index="401" dependencies="1" dependenciesKind="dependent" />
      <Unknown index="420" dependencies="2" dependenciesKind="dependent" />

The ModelStructure seem to be correct, but the entiremodelDescription.xml becomes invalid due to the previously defined third output.

[Lennart Ochel]

The problem comes from the index reduction, which introduces dummy states derivatives and assigns the causality of the correspondent dummy state to it.

[Lennart Ochel]

The issue is addressed in ​OpenModelica/OMCompiler#2788.