Right now use-case nodes cannot be associated with actors and subjects. They need to be made subject/actor stakeholders

The graphical notation lacks clear differentiation between the various types of flows in the language: flow, succession flows, and message flow (see also SYSML2-59).
In addition, the BNF was overly restrictive and did not allow flow connections on structural diagrams, except for flows on connections.
Flows on connections also need to include messages and succession flows.
It needs to be corrected in the BNF in the relevant clauses
8.2.3.9 - Occurrences (SD notation)
8.2.3.13 - Connections
8.2.3.14 - Interfaces
8.2.3.16 - Actions

Keywords introduced in the graphical notation BNF are surrounded by guillemets («...»). However, the graphical notation also uses snippets of textual notation in many places, often by referencing productions from the textual notation BNF, which does not put guillemets around keywords. In some cases, though, the graphical BNF will include productions for text that introduce keywords that parallel the textual notation, but don't directly use textual notation BNF productions. The resolution to SYSML2-59 includes such productions for message-label and flow-label that include the «of» keyword surrounded by guillemets, but other such productions in the graphical BNF do not put guillemets around keywords. There needs to be a consistent rule on how guillemets are to be used in the graphical notation.

The reuse of KerML BNF productions in the SysML textual notation grammar is not described sufficiently. It is not clear which productions are reused and which not. Reused productions are simply missing from the SysML definitions.

(This issue was originally reported as part of SYSML2-635.)

The genera textual notation for (binary) connections (see 8.2.2.13.1 Connection Definition and Usage) allows for both a "short form" (connect...to...;) and a "long form", in which the ends are explicitly declared within the connection body. The notations for binding connections (see 8.2.2.13.2 Binding Connectors) and successions (see 8.2.2.13.3 Successions) also have their own "short forms" (bind...=...; and first...then...;)). However, even though both notations allow for connection bodies, the short-form part is required, so it is not possible to declare the ends within the bodies. (Note that the corresponding KerML notations do allow fully "long form" declarations for bindings and successions; see 8.2.5.5.2 and 8.2.5.5.3 in the KerML specification.)

In the SysML v2 the graphical notation for use cases is a box with rounded corners containing the stereotype "use case" and the use case name.
From the very beginning of UML and SysML v1.x use cases are visualized as elliptic elements. Nearly all people that have ever used or seen UML or SysML in the past are familiar with that notation. So why change it for SysML v2 here? It is not necessary from my perspective.
A box with many textual things inside is not a good idea for a graphical language. Graphical languages should use as less text as possible. Instead they should use different graphical shapes, different stroke widths, stroke types and icons to express the semantics and what is modeled.
A user should be able to recognize a diagram element on a first side, looking at a diagram drawing form far away. It should not be necessary to read all details to recognize that is a use case diagram and not any other diagram by reading the stereotype text elements first!

[From Mr. Ryan Noguchi] In the SysML v2 spec, section 7.8.1:

An enumeration definition may not specialize another enumeration definition. This is because the semantics of specialization require that the set of instances classified by a definition be a subset of the instances of classified by any definition it specializes. The enumerated values defined in an enumeration definition, however, would add to the set of enumerated values allowed by any enumeration definition it specialized, which is inconsistent with the semantics of specialization.

To comply with the Liskov Substitution Principle, a specialization of an enumeration definition should only remove literals, not add them. Why can’t the specialization’s definition either simply remove existing literals from the general definition or list the applicable literals—resulting in a syntax error if this list includes anything not present in the general definition? As a concrete example:

enum def ClassificationLevel {
   enum unclassified;
   enum cui;
   enum secret;
   enum top_secret;
}

enum def ClassificationLevelClassified :> ClassificationLevel {
    enum secret;
    enum top_secret;
}

Both Enumeration and ValueType have main mappings and their specified filters do prevent a double match

The direction of a PortUsage can be specified like that of any other feature. However, this does not really seem to make sense. The direction of a PortUsage should be determined by the direction of features within it, consistent with the visualization of directions on ports shown, e.g., in the Representative Notation table in 7.11.1 Parts Overview.

State shall be able to have proxy nodes on their boundaries. Currently not covered by the GBNF

According to the KerML specification, "Structures and behaviors do not overlap". Consistent with this, the approved resolution to KERML-43 added validations to disallow a structure from specializing a behavior and vice versa.

ConnectionDefinitions in SysML are kinds of PartDefinitions, which are (indirectly) kinds of KerML Structures. But FlowConnectionDefinitions are both ConnectionDefinitions and ActionDefinitions, and ActionDefinitions are kinds of KerML Behaviors. This means that FlowConnectionDefinitions are both Structures and Behaviors, violating the restrictions of KerML.

As a result, the specializations in the declarations of MessageConnection and FlowConnection in the Systems Library model Connections now violate the new validateStructureSpecialization and validateBehaviorSpecialization constraints added by the resolution to KERML-43.

The current specification is not computable in some cases (where the "any" OCL iterator find no value). E.g. : MIWG Test Case#27

In some cases (e.g. MIWG test case #11) it is unable to compute the requested type.

As a consequence SysMLv literals generated by the transformation have no value defined

The current algorithm crashes if the data type provided has no name defined or if the type is not defined

A requirement should include a text body to capture the shall statement or other human readable requirement statement. The doc annotating element is one way to accomplish this. However, a doc element on a requirement definition is inherited by its requirement usages, but it cannot be redefined on its usage. (Note: The texts of a RequirementUsage are the bodies of the documentation of the RequirementUsage.)

The proposal is to add a distinguished attribute to capture the text body of a requirement that would replace the derived text attribute/documentation. This distinguished attribute can be redefined. This avoids a requirement usage from having both the original text in the requirement definition and the modified text in the usage.

The concrete syntax should be updated accordingly.

The multiplicities that the transformation specifies are wrong when the source element has the default multiplicity in the source model.
Shall be fixed: MultiplicityUpperBoundOwningMembership_Mapping and MultiplicityLowerBoundOwningMembership_Mapping
Shall be removed : DefaultLowerBound_Mapping and DefaultUpperBound_Mapping

Factories for LiteralInteger, LiteralInfinity are required

The following cases in the textual notation allow "shorthand" then notations for SuccessionAsUsages:

1. In 8.2.2.9.3 Occurrence Successions, the production SourceSuccession creates a SuccessionAsUsage that has a source end with no related feature and no target end.
2. In 8.2.2.16.7 Action Successions, the production TargetSuccession creates a SuccessionAsUsage that has a source end as in SourceSuccession, but it has a full ConnectorEndMember for its target end, including an explicit related element.

In both cases, the intent is that the implied related feature of the source end of the SuccessionAsUsage is a feature lexically previous to the declaration of the SuccessionAsUsage. In the first case, the implied related feature for the target end of the SuccessionAsUsage is a feature lexically following the SuccessionAsUsage. However, there are no semantic constraints given in 8.3.13.8 SuccessionAsUsage to enforce these implied relationships.

ownedRelationship() operation. There is the following code:

   else if from.oclIsTypeOf(UML::FlowFinalNode) then
       ObjectFlowItemFlowEndRedefinition_Factory.create(ElementMain_Mapping.getMapped(SysMLv2::ActionUsage.allInstances()->any(e | e.qualifiedName =  'Actions::Action::done')))

The point is that the parameter of a getMapped operation shall be an element form the source model, while the code above povide a SysMLv2 element from a library. This makes the MIWIG test case #27 failing

Duplicated operations can be removed by adding a common abstract root class. This will simplify the model and ease the maintenance

The filter operations defined for the mapping specified from an OpaqueBehavior prevent those owned by another kind of element to be transformed, like in MWIG test cases 7 and 35

According to the SysML Specification, 8.2.2.16.4 Send and Accept Actions, the general textual notation for a send action has the form

send payloadExpression via senderExpression to receiverExpression

In this syntax, the via and to parts are optional, but the payloadExpression is not. Since the result of the required payloadExpression is bound to the payload parameter of the send action, this makes it difficult to model a case in which, e.g., it is desired use a flow to provide the value of the payload, rather than the result of an expression. It also makes it difficult to model a general send action with the payload not specified (or defaulted), with the actual payload bound in a specialization of the general action.

While it is possible to get around these limitations by modeling the send action using a regular action usage typed by Actions::SendAction, this is no longer syntactically a send action usage and so, e.g., would not be rendered as such in the graphical notation. It would be better if the textual notation allowed the payloadExpression to be optional, while still declaring syntactic send action usage.

The MWIG test case #8 fails because it contains a property that is typed by an Actor while the transformatiosn currently defined do not support it

Clause 8.3.9.5 (OccurrenceUsage), Constraints, says

checkOccurrenceUsageTypeFeaturing
If the portionKind of an OccurrenceUsage is not empty, then, for each occurrenceDefinition of the OccurrenceUsage, there must be a featuringType of the OccurrenceUsage which either is the occurrenceDefinition or directly or indirectly specializes it.

portionKind <> null implies
  occurrenceDefinition->forAll(occ |
    featuringType->exists(specializes(occ)))

For example, adapted from 7.13.5 (Successions as Usages):

occurrence def Flight {
  timeslice preflight : Preflight [1];
  then timeslice inflight : Inflight [1];
  then timeslice postflight : Postflight[1];

checkOccurrenceUsageTypeFeaturing requires Flight to specialize each of Pre/In/Postflight, even though these would typically be disjoint with Flight, leading to:

• all features defined in Pre/In/Postflight "inheriting" to Flight, eg, PreFlight::refuel, would inherit to Flight, with a separate value potentially unconstrained in time from the one happening in preflight.

• valid traces where all the pre/in/postflight values are instances of Flight, which are all required to have pre/in/postflight timeslices.

which probably aren't intended in this exampe.

The MIWIG test case #11 fails because it assumes that the client of a SysML::Satisfy relationship, that is a Block, is owned by something that is mapped to a SysMLv2 Type.

This is unlikely to happen since in most cases (like in this test case) Blocks are owned by Packages

GenericToStateUsage_Mapping is missing a default rule for isParallel

GenericToElement_Mapping is missing default rules for:

• owningRelationship
• aliasIds
• declaredShortName
• isImpliedIncluded

A Namespace shall own the relationships that defined its members (either owned or not) and its import relationships.
Instead the ownedImport() operation is useless since Namespace::ownedImport is a derived property

Comment_Mapping is missing a default rule locale

The body condition specified for this operation is wrong. It should be an empty set.

GenericToRelationship_Mapping should provide default rules for

• owningRelatedElement
• isImplied

A graphical BNF production should be added that specifies that keywords may optionally be included on edges.

A graphical BNF production should be added that specifies that it is mandatory to include the applicable user-defined keyword in the notation for a library extension element.

Clause 8.4.5.2 (Occurrence Usages) says

If an OccurrenceUsage has a non-null portionKind, then it is also required to have a portioningFeature with the same portionKind. The following semantic constraints apply to a PortioningFeature:
...

and the code example at the end of 8.4.5.2 has comments identifying some features as "Portioning", with text below it referring to portioningFeature

However, portioningFeature doesn't appear in Figure 12 (Occurrence Definition and Usage) or anywhere else in the document.

Currently it is not possible to use action control nodes (Fork/Join/Decision/Merge) as sources/targets of a transition in a state definition or usage.

GenericToRequirementUsage_Mapping is missing a default rule for reqId

Documentation should be added that bolding of keywords in the graphical notation is optional, and may be used for visual prominence. For example, in representative notation table 16 in subclause 7.17.1 in the actions compartment of a state the keywords entry, do and exit are bolded.

Definition elements incorrectly appear in graphical BNF productions for interconnection-element. Remove the following from interconnection-element productions: part-def in 8.2.3.11, port-def in 8.2.3.12, connection-def in 8.2.3.13, constraint-def in 8.2.3.19, requirement-def and concern-def in 8.2.3.20, viewpoint-def and view-def in 8.2.3.25.

Notation table shows item flows on interface connections. This is not enabled by the graphical BNF

Right now use-case nodes cannot be associated with actors and subjects. They need to be made subject/actor stakeholders

The intent of "initializer" classes is to factorize the opeations that provide default values for the properties of a target class so that it can be used for both mapping and factory classes. Initializers that do not generalize both a mapping and a factory class are useless and should be remove for clarity

The redefinition of ownedRelationship() is missing the "class" part, i.e. what is defined in its Class aspect

Events and event occurrences are supported by the textual syntax, but not by the graphical syntax.
It is also not mentioned in the representative notation tables

Graphical BNF specifies a flow connection. It is not clearly mapped to a semantic language concept. Should it be merged with a message specified as part of occurences?

Informal specification of requirements is realized as body of the documentation.
Informal requirement specification often contains text formatting and images as illustrations. To facilitate exchange of requirements between different organizations and proper rendering, the used formatting language, the relative root path for included images and their allowed formats have to be aligned.

• add optional 'language' keyword to doc
• define the folder containing the sysml file as root for references made from documentation elements within this file

To provide guidance for users on common formatting

• reference jpg and png as suggested image formats
• reference markdown "md" or other low-complex language as suggested formatting language

example:
requirement def SomeRequirement

The transformation ignores the entry, do, and exit behavior of a state.

Sub-clause 8.2.3.3 (dependencies) uses element-node as the source and target of a dependency.
element-node is not defined anywhere

Concern_Mapping is a main mapping that calls ConcernOwningMemberships_Mapping in its ownedRelationship() operation, which itself calls ConcernDocumentation_Mapping. However, the one defined in its ancestor Comment_Mapping should do the job without them.
The redefinition should then be removed and both ConcernOwningMemberships_Mapping and ConcernDocumentation_Mapping are useless and should be replace by a simpler version of the ownedRelationship() operation.

A UML4SysML::ConstraintProperty is currently mapped to a ItemUsage, but should be an AssertConstraintUsage.

Clause 7.13.3 (Bindings as Usages) says

The end features of a binding always have multiplicity [1..1].

and Clause 8.3.17.9 (TransitionUsage) includes a constraint requiring a (1 to 1) binding between its succession and transitionLink:

checkTransitionUsageSuccessionBindingConnector
A TransitionUsage must have an ownedMember that is a BindingConnector between its succession and the
inherited Feature TransitionPerformances::TransitionPerformance::transitionLink.
ownedMember->selectByKind(BindingConnector)->exists(b |
b.relatedFeatures->includes(succession) and
b.relatedFeatures->includes(resolveGlobal(
'TransitionPerformances::TransitionPerformance::transitionLink')))

with similar text in 8.4.13.3 (Transition Usages). A succession will typically have fewer values than its transition usage, because the succession won't be traversed for every value (occurrence) of its source feature, while its transition usage will have the same number of values as the source feature, conflicting with the 1-1 end multiplicities. Compare to the modeling pattern in KerML Clause 9.2.10.1 (Transition Performances Overview), excerpted in KERML-157.

Subclause 8.2.3.13, specifies the productions for connections. Ballot 3 added a production for n-ary connection usage, but n-ary connection definition (graphical) is still missing

In the textual notation, a change event can be represented by an accept action with a when condition. The example below is from the vehicle model.
transition normal_To_degraded
first normal
accept when senseTemperature.temp > Tmax
do send OverTemp() via targetPort
then degraded;

In the textual notation, a time event can be represented by an accept action with an at or after condition. The example below is from the vehicle model.
transition normal_To_maintenance
first normal
accept at maintenanceTime
then maintenance;

Clause 8.4.12.4 (Control Nodes), under the Join and Fork headings says:

validateJoinNodeIncomingSuccessions constraint requires that all incoming Successions to a JoinNode have source multiplicity 1..1.

validateForkNodeOutgoingSuccessions requires that all outgoing Successions from a ForkNode have target multiplicity 1..1.

but the validation rules are missing from 8.3.16.11 (JoinNode) and 8.3.16.8 (ForkNode), respectively.

Any execution of the CommentAnnotation_Mapping transformation rule shall result in the same instance of SysMLv2 Annotation for a given (Comment, annotatedElement) pair provided. I.e. it should specialize the Foundations::UniqueMapping class.

Add feature modifiers (e.g. ordered for [1..*] timestamps) to "Portion Membership" examples in representative notation tables for Occurrences.

The representative notation example "Package with members compartment" shows the members compartment which is the default compartment and does not require a compartment label. Change members compartment label to the requirements compartment label and adjust the package content and textual notation accordingly, i.e. with requirement elements.

Actor and subject are parameters of a use case (and also requirement in case of subject). The current notation suggests symbols completely outside the contour of the use case/requirements linked by a line segment. This is different from V1 where actors and subjects were not parameters. Ultimately the modeler is interested to see the binding of those parameters being the concrete occurrences standing for them. The parameter bindings can be graphically represented by binding connections to those external symbols. Would be more effective to treat those predefined parameters using on contour symbols like ports and parameters and bind to those.

Decision/MergeNodes are (indirectly) typed by KerML:Decision/MergePerformance (via specialization of Actions::Action::decisions/merges), which KerML Clause 9.2.9.1 (Control Performances Overview) requires:

Successions going out of Steps typed by DecisionPerformance or its specializations must:
• ...
• be included in a Feature of its featuringBehavior that unions (see 7.3.2.7) all the outgoing Successions, and is bound to the outgoingHBLink of the Step (see 7.3.4.6 on feature chaining).

Successions coming into Steps typed by MergePerformance or its specializations must:
• ...
• subset a Feature of its featuringBehavior that unions all the incoming Successions, and is bound to the incomingHBLink of the Step.

while constraints in 8.3.16.7 (DecisionNode) and 8.3.16.13 (MergeNode) say

checkDecisionNodeOutgoingSuccessionSpecialization
All outgoing Successions from a DecisionNode must subset the inherited outgoingHBLink feature of the DecisionNode.
sourceConnector->selectByKind(Succession)-> forAll(subsetsChain(this,
resolveGlobal("ControlPerformances::MergePerformance::outgoingHBLink")))

checkMergeNodeIncomingSuccessionSpecialization
All incoming Successions to a MergeNode must subset the inherited incomingHBLink feature of the MergeNode.
targetConnector->selectByKind(Succession)-> forAll(subsetsChain(this,
resolveGlobal("ControlPerformances::MergePerformance::incomingHBLink")))

with similar text in 8.4.12.4 (Control Nodes) under Decision / Merge Nodes. These constraints allow outgoing/incomingHBLink to have values that are not identified by outgoing/incoming successions when none of the successions is traversed. The KerML pattern above introduces a feature unioning the successions and binds it to a chain through decision/merge to outgoing/incomingHBLink, ensuring the HB links are identified by the successions. See Annex A.3.7 (Timing for behaviors, Decisions and merges) for an example, at the end of the model to be executed (first code listing), under "Decision and merge timing constraints".

Add feature modifiers (e.g. ordered, nonunique) to "Feature Membership" examples in representative notation tables for Definitions and Usage.

Example "Package with imported packages (nested packages)" should use dotted instead of dashed outline

Add example package with filter in 7.5.1. The filter should be one of the filters defined in 9.2.19.2.4. Good choice is filter for Requirement.

In examples "Individual Occurrence", "Timeslice", "Snapshot", add attribute to «individual» «occurrence» and redefine the attribute with value in «timeslice» and «snapshot».

Add import qualifier text (* or **) to upper right corner of imported Package

Add graphical notation to represent binding between action inputs and outputs and directed features on ports.

The request is to add a representative notation example to Table 11 that shows how directed features of performed actions in parts can be connected to directed features of ports.

Clarify that the identifier for the metadata declaration is the metadata definition name.

Add representative notation for causation (9.5.2.1) and requirements derivation (9.6.2.1) including n-arys. This (and other representative notation examples for domain library models) should probably go into the respective 9.x Overview subclauses, rather than in Clause 7.

In the param-t production the nesting parameter pdv is missing an optional nested param-t* element.

In SysML v1, an output value of an action that is an input value of more than one action, is often modeled by an object flow and fork node which create object tokens pointing to the value.

The mapping of ObjectFlow in combination with ForkNodes is not covered yet by the transformation.

The mapping of ObjectFlow in combination with DecisionNodes including the decisionInput is not covered yet by the transformation.

The mapping of ObjectFlow in combination with JoinNodes is not covered yet by the transformation.

Add support for defining a metadata definition using the normal definition symbol (e.g., key word metadata def with metadata def name in name compartment). Separate compartment for attribute declarations. Add compartment redefined the annotated elements so they are constrained to be of a certain metaclass. (Note that MetadataDefinition is a kind of ItemDefinition but MetadataFeature (and therefore MetadataUsage) is a kind of AnnotatingElement.)

The mapping of a Unit and a QuantityKind is not covered by the transformation yet.

The way SysML libraries are provided relies on textual notation files on which element declarations do not include the specification of their elementId property.

As consequence, if the elementId is actually generated by the tool, as written in the KerML specification (p226), it is very likely to have a different value from one computer to another and even from one loading to another on the same computer.

Hence, it is impossible to make sure it will "not change during the lifetime of the Element", as required by in the same paragraph of that specification.

Linked to a similar issue raised on KerML

Since Relationship is now an abstract class, ElementOwnership_Mapping has been made abstract as well. A consequence of this, because it is not a "MainMapping", is that it is not possible to invoke the getMapped operation directly on this mapping class.
However there are many body conditions that still that. They have to be fixed.

There are a number of cases in which derived properties require that a referenced feature by of a certain metaclass. For example, the EventOccurrenceUsage::eventOccurrence property is derived as the referencedFeature of the ownedReferenceSubsetting EventOccurrenceUsage (if it has one), but the property is typed as an OccurrenceUsage, so the referencedFeature must be an OccurrenceUsage. This is enforced by the validateEventOccurrenceUsageReference constraint.

Unfortunately, this does not take feature chaining into account. If the referencedFeature has a feature chain, it will be parsed as a plain Feature, not an OccurrenceUsage. However, the last Feature in the chain should be an OccurrenceUsage, and this OccurrenceUsage is what should be the eventOccurrence of the EventOccurrenceUsage, and what is check by validateEventOccurrenceUsageReference.

There are similar problems with at least the "reference" derivation and validation constraints for all the subtypes of EventOccurrenceUsage, and perhaps in other cases, too.

The transformation does not map the Parameter::isStreaming.

The transformation does not specify mapping rules for UML4SysML::ReadLinkAction.

The transformation does not specify mapping rules for UML4SysML::DestroyLinkAction.