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GOTCHA: Cameo 2026x: SysMLv2 Plugin: A "transition" from an empty entry entry is interpreted (consistently) as a succession not a transition (LIKELY A SPEC EXAMPLES ISSUE). WORKAROUND: Use start:StateAction

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icon_class
far fa-sticky-note
icon_class_computed
far fa-sticky-note
Note kind
GOTCHA
TOOL
Policy level
INFORMATIVE
Specification keywords
SysMLv2
SysMLv2 keywords
State
Transition
Succession
entry
then
Keywords
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[2026-05-15 UPDATE: After more analysis Webel IT has concluded that the spec itself has multiple inconsistent examples. The Webel SysMLv2 course has a series of slides investigating the issue and suggesting Just use start:stateAction]

For the latest analysis and workaround visit instead

SysML2.0: ERROR: The Specification body, Annex and multiple SysMLv2 PILOT Github samples show or use in code an incorrect transition from an (empty) entry action of a state (breaks the rules for transitions). Prefer transition from start:StateAction!

Former slide analysis above is PARTIALLY OBSOLETE

Cameo 2026x SysMLv2 interprets a then from an empty entry actions as a Succession (not a Transition). Further analysis indicates this actually correct (transitions can only be between state usages).

Both Cameo2026x and Cameo2026xHF2 struggle to interpret this wrong code formulation, but have different (necessarily incorrect) interpretations of the error:

entry action initial;
transition first initial then ...

In Cameo 2026xHotFix2 now turns that into a succession with an else! as shown here:

05-State-based Behavior: 5-State-based Behavior-1.sysml [WITH MODELLING DISCUSSION]

It seem that the form shown in the SysMLv2.0 spec p.115 and p118 is itself incorrect and that form is not used in the OMG SysMLv2 sample ptc-25-04-31.sysml.

ISSUE: SysMLv2.0 spec: States: Inconsistent concerning use of entry action and notation for a "start state" in examples (cf. p.115)
Relates to
05-State-based Behavior: 5-State-based Behavior-1.sysml [WITH MODELLING DISCUSSION]
Related notes
[ISSUE, LIMITATION, MODELLING, TOOL]{INFORMATIVE} Dr Darren's Cameo2026x SysMLv2 Plugin and SysMLv2 Evaluation Plugin quick review notes: Tips, issues, workarounds, wishlist.
[ISSUE]{INFORMATIVE} ISSUE: SysMLv2.0 spec: States: Inconsistent concerning use of entry action and notation for a "start state" in examples (cf. p.115)
Related notes (backlinks)
Related snippets (extracts)
  [SysMLv2] State usages can be connected by transition usages, which can activate and deactivate the state usages. The triggering of a transition usage from its source state usage to its target state usage deactivates the source state and activates the target state.
  [SysMLv2] The source of a transition usage must be a state usage, but its target may be an action usage other than a state usage.
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