Type issue when checking for diagram existence

Document Generation
1

Hi I’m using capella 1.4.2 and M2Doc 3.2.0 and I encountered weird behaviour for the function isRepresentationDescriptionName().

Most of the time it worked completely fine in my model and document but after I tried to use it to export LABs something weird happened. If I use
self.containedLogicalArchitectures.ownedLogicalComponentPkg.isRepresentationDescriptionName('Logical Architecture Blank')
to check for existing LABs I get an error and the validation file shows
The predicate never evaluates to a boolean type ([Sequence(boolean)])

I interpret this as the function returning a Sequence(boolean) instead of a boolean (which should not happen according to documentation). Now, this problem can be solved by adding ->first() to extract the boolean from the Sequence. However, the error is thrown for all subsequent uses of isRepresentationDescriptionName() regardless of diagram types or usages.

If I do not check for LABs, everything works. If I use the code block, everything AFTER it throws the same Sequence(boolean) error. Currently, I “bypass” the issue in my model by not checking if the diagram exists. I just directly loop the representationByDescriptionName() for the corresponding diagram type…

Below I attached the code I’m using in a minimal test case to reproduce the problem. Uses 1 logical function, one LAB and one LFBD.

// Works fine
m:for LF | self.containedLogicalArchitectures.containedLogicalFunctionPkg.ownedLogicalFunctions
m:LF.name
m:if LF.isRepresentationDescriptionName('Logical Function Breakdown')
m:for rep | LF.representationByDescriptionName('Logical Function Breakdown')
m:rep.name
m:endfor
m:endif
m:endfor

// Introduces problem
m:if self.containedLogicalArchitectures.ownedLogicalComponentPkg.isRepresentationDescriptionName('Logical Architecture Blank')
m:for rep | self.containedLogicalArchitectures.ownedLogicalComponentPkg.representationByDescriptionName('Logical Architecture Blank')
m:rep.name
m:endfor
m:endif

// Does not work anymore (but works if I delete the previous code block)
m:for LF | self.containedLogicalArchitectures.containedLogicalFunctionPkg.ownedLogicalFunctions
m:LF.name
m:if LF.isRepresentationDescriptionName('Logical Function Breakdown')
m:for rep | LF.representationByDescriptionName('Logical Function Breakdown')
m:rep.name
m:endfor
m:endif
m:endfor
2

The AQL expression you are writing creates a collection of objects:

self.containedLogicalArchitectures

At this point you have a collection of objects as the name containedLogicalArchitectures suggest. You can check this by looking at the EReference:

self.eClass().eAllStructuralFeatures->select(f | f.name = 'containedLogicalArchitectures')

The 0…* means many values.

Then AQL continue the evaluation it will collect every navigation result in a Collection. After the ```
isRepresentationDescriptionName() call you get a Collection of Boolean. And the condition of the if must be a Boolean (scalar). That the reason for your error message. Using the first service is not a good idea here, you probably want to know if there is at least one true value in the Collection:

...->exists(b | b)

The last block should still be working even if the second block fails. Do you have the corresponding error message ?

3

Thanks, that explains the first part well!

Yes, the last block shows the same error message: The predicate never evaluates to a boolean type ([Sequence(boolean)]). Although it shouldn’t.

4

This message make sens for this line:

m:if self.containedLogicalArchitectures.ownedLogicalComponentPkg.isRepresentationDescriptionName('Logical Architecture Blank')

But it doesn’t make sens on this line:

m:if LF.isRepresentationDescriptionName('Logical Function Breakdown')

Can you check the message location ?

An other way to do this would be to check if the list of representations is empty or not:

{m:let representations = LF.representationByDescriptionName('Logical Function Breakdown')}
  {m:if not representations->isEmpty()}
    {m:for rep | representations}
      ...
    {m:endfor}
  {m:endif}
{m:endlet}

The let statement is used to cache the list of representations. It’s might be easier to read also.

5

The message location is the third block, even if it doesnt appear in the second block (for example, by using your suggested ->exists(b | b) to check if there is at least one true value in the returned collection).

If I use your suggested solution, I do not get the error message for the third block but I find this unsatisfactory.

If we go to my original example, the code I use is basically the following. Running Block A also prints out the name of the one existing diagram, so I would expect it to still be there when Block A runs a second time.

Block A -> No error
Block B -> Error
Block A -> Error

If I now use either first() or exist() then I get

Block A -> No error
Block B -> No error
Block A -> Error

If I use your let solution (Block C) instead of Block A it works fine, proving that the list of representations is not empty (implicitly proven by Block A as well if we look into the generated document)

Block A -> No error
Block B -> No error
Block C -> No error

But if copy paste the first block at the bottom again the error re-appears

Block A -> No error
Block B -> No error
Block C -> No error
Block A -> Error

If I delete Block B it works fine

Block A -> No error
Block C -> No error
Block A -> No error

That was a lot of cases. Essentially, I’m happy with finding workarounds but the error I experience should not occur. Because I get the impression that calling isRepresentationDescriptionName() on a collection permanently changes its behaviour for all subsequent calls which is of course undesirable.

6

I think something else is getting M2Doc of tracks here. Not sure what in you case but:

  • Word sometime replace quotes while copy/pasting
  • text areas might also break M2Doc parsing

If want me to have a look at your template, you can open an issue here and attach your template. Also add a link to this discussion.

7

I created an issue and attached my example model: https://github.com/ObeoNetwork/M2Doc/issues/454

8

Thank you, I’ll have a look.