Rule 043I

[Ale_mm]

Hello,

I've a doubt regarding the rule 043I of SLSF set. The rule tells: "In all flow-charts and graphical functions, exactly one unconditional transition must begin at every junction (except for the last junction). Every decision point (junction) must have a default path."
The problem is about the bounds of this rules, because it'd delimited only for flow-charts. Since a flowchart contains none or one state, the rule is not applied in case that I have a junction, without a default path, between two state.
Therefore my question is, why this rule (and as far as I know, no others) does not check default paths in junctions between states? Or else, why this rule is only flowcharts circumscribed and not statecharts as well?


Many thanks in advance,
any feedback will be really appreciated,

Alessandro

[MISRA Reply]

The case of default path application for junctions residing on transitions between two states is effectively covered by rule 043H.

Rule 043I is most concerned with ensuring there is always a clearly defined path from the start point through to the single end point in a flowchart. On transitions between states there is not the same need to ensure a path through to a single end point and as a result it is not the case that a default transition from a junction is required in all circumstances on state transition paths.

See for instance Example 3 in Rule 043H where the junction does not have or require a default transition. If we were to follow the spirit of Rule 043I here and take a default transition from the mid-point junction back to state A then the statechart will exhibit different execution properties; in the original form if ‘a > C1’ and ‘b

[Ale_mm]

I've clearly understood the main point and the reason/behaviour of the rule 43. Mainly I didn't think about the side-effect of exit and re-enter in a current state.
Many thanks for the reply.

Best Regards,
Alessandro