fix(runtime): write-granular change triggers, unordered composite entry, entry-action transition effects

changes/unreleased/entry-transition-effects.added.md

@@ -0,0 +1 @@
+- **Transitions out of a named entry action run effects and routes.** `entry action boot; transition boot do { … } then s;` runs its effect after the entry action and before `s` is entered, and may target a junction or choice of the same body, whose route is resolved after the entry action; availability checks only the incoming transition's own route, and a dead nested default-entry junction fails with a typed run error when its separate entry transition is taken. In a region of a parallel state the effect, like a compound transition's segment effect inside the region it enters, interleaves with the sibling regions' entries, and `-schedule explore` reaches every order. A trigger on such a transition, or an effect on the shorthand `entry; then s;`, is still rejected.

changes/unreleased/state-change-trigger-writes.fixed.md

@@ -0,0 +1 @@
+- **Change triggers observe every completed write.** A state machine's `accept when <condition>` is re-evaluated after each completed feature write that touches a feature the condition reads, and every false-to-true rise queues one change signal, so a condition that becomes true and false again within one run-to-completion step still fires; a value one assignment writes and replaces before it completes raises no rise. Snapshots, held images, replay and `-schedule explore` carry the observed and pending rises.

docs/internals/design/pseudostates.md

@@ -24,7 +24,10 @@ Pseudostates are transient vertices in state machines that enable complex contro
 - Used to merge multiple incoming transitions or split paths
 - Several enabled branches are a transition choice point (`ChoiceTaken` at the junction,
   enumerated by `explore`); an unguarded branch is the else branch
-- No enabled branch disables the compound transition (PSSM *Junction 002*)
+- No enabled branch on the transition's own route disables it; a junction on a composite's
+  nested default entry belongs to a separate transition out of `entry`, is read after the outer
+  effect and composite entry, and fails at run time with a typed no-way-through error if no
+  branch is enabled (SM46; PSSM *Junction 002* differs by design)
 
 ### Semantics
 
@@ -134,11 +137,14 @@ choice point at the junction the schedule policy draws and records only as the t
 candidate another region's reaction disarms draws nothing; the unguarded segments are the
 default when no guard holds — and goes on until the route reaches a state or a choice. The
 guards read the data as it stands before the incoming transition's effect. If no static
-branch is available, only `errNoWayThrough` leaves the compound transition unenabled before
-selection; the occurrence remains available to another enabled transition, deferral, or unmatched
-discard. A completion with no path is dropped. A history default route is checked this way only
-when the source is outside the history owner, because leaving the owner may record the history
-before its default route is read (see the precise-semantics alignment note, SM29 and SM32).
+branch is available on the transition's own route, only `errNoWayThrough` leaves that transition
+unenabled before selection; the occurrence remains available to another enabled transition,
+deferral, or unmatched discard. A completion with no path is dropped. A junction on a composite's
+nested default entry is read when its separate entry transition is taken, after the outer effect
+and composite entry; if no branch is enabled, the run fails with a typed no-way-through error
+(SM46). A history default route is checked this way only when the source is outside the history
+owner, because leaving the owner may record the history before its default route is read (see the
+precise-semantics alignment note, SM29, SM32 and SM46).
 
 **Choice evaluation** is dynamic. `followOut` leaves the route open at a choice. Firing
 (`travel`) then exits the states every branch of the open choice leaves — the source's ancestors
@@ -256,9 +262,10 @@ package JunctionTest {
 2. **Junction:**
    - Guards read before the incoming transition fires, in definition order; several holding is a
      recorded choice point, as at a choice
-   - No way through leaves the compound transition unenabled before selection, so the occurrence
-     is handled as unmatched: another enabled transition may take it, it may be deferred, or it
-     may be discarded; a completion with no way through is dropped
+   - No way through on the transition's own route leaves it unenabled before selection, so the
+     occurrence is handled as unmatched: another enabled transition may take it, it may be
+     deferred, or it may be discarded; a completion with no way through is dropped. A dead
+     junction on a nested default entry instead fails when that entry transition is taken (SM46)
    - Only `errNoWayThrough` disables; route cycles, unevaluable guards and binding failures remain
      run errors, and static route checking stops at the first choice
 

docs/internals/design/region-order-scheduling.md

@@ -655,6 +655,14 @@ an empty `StatePerformance` and a completion like any other) and PSSM contradict
 event is dispatched after the step whatever the source performs). That is a special case of the
 translation's shape, not a semantics.
 
+*Since resolved for these three.* The spelling argument above holds for the shorthand
+`EntryTransitionMember` only. A transition out of a named entry action is a `TransitionUsage`
+whose source is an action, a `NonStateTransitionPerformance` (`TransitionPerformances.kerml`):
+it follows the entry action within the entry and runs its effect before the target's entry,
+which is the entry-unit row exactly. The emitter now writes the initial transition that way, the
+effect is a unit of its region's queue on the entry front, and *Entering 010*, *Entering 011* and
+*Junction 005* pass with no runtime rule about completions.
+
 **The first halves of the History tests are about the pool's order.** Both regions enter a
 silent state whose completion is enabled at once. PSSM's pool holds the two completion events in
 the order they were generated — §8.5.9, "a new `CompletionEventOccurrence` is placed into the

docs/project/behavior-semantic-oracle.md

@@ -1730,6 +1730,36 @@ which is drawn against the branches' remaining target entries, six outcomes.
 `state_do_step_machine_before_top_entries` is the same shape at the machine, whose do behavior
 begins before its top regions are entered: six outcomes.
 
+### Effects on the way into the regions of a parallel state: each precedes its own target's entry, the regions interleave
+
+Fixtures: `state_entry_transition_effect_regions` (golden, explored, checked),
+`state_junction_inside_orthogonal_region` (golden, explored, checked).
+
+A transition out of a named entry action, `entry action boot; transition boot do { … } then s;`,
+is a `TransitionUsage` whose source is an action rather than a state, so its performance is a
+`NonStateTransitionPerformance` (`TransitionPerformances.kerml`; `Actions.sysml`
+`DecisionTransitionAction`, `Action::decisionTransitions`): `transitionLinkSource then effect`
+and `effect then transitionLink.laterOccurrence` place the effect after the entry action and
+before the target's `StatePerformance` begins, and `succession transitionLinkSource then
+Performance::self` makes the transition part of the entry, not a step dispatched after it. It
+has no trigger: an accepter needs a state source (the pilot's
+`validateTransitionUsageTriggerActions`). The shorthand `entry; then s;` (§7.18.3
+`EntryTransitionMember`, a `GuardedTargetSuccession`) still carries a guard at most. A segment
+of a compound transition that continues inside a region of the parallel state it enters is the
+same shape one level down: its effect is a `TransitionPerformance` step between the
+pseudostate's predecessor and its target's entry.
+
+The regions of a parallel state are `middle` steps of its `StatePerformance`
+(`StatePerformances.kerml` `succession entry then middle`), concurrent with each other, and
+nothing in either library orders one region's transition performance against another
+region's. So the parallel state's own entry comes first, each region's effect precedes its own
+target's entry, and the regions' chains interleave in every way: for a region whose chain is an
+effect then an entry beside one whose chain is a single entry, three orders. PSSM's *Entering
+010*, *Entering 011* and *Junction 005* admit exactly these linearizations. The executor
+offers each effect as a unit of its region's queue on the entry front
+(`state_unit_front.go` `entryTransitionEffectHead`, `state_region_entry.go` `enterRegion`), so
+`-schedule explore` reaches each order.
+
 ### A succession outside a behavior body orders the performances it relates, wherever they run
 
 Fixtures: `namespace_succession_chain_ends` (golden), `type_succession_performed_actions`

docs/project/pssm-referee-baseline.json

@@ -6,14 +6,14 @@
     "url": "https://www.omg.org/spec/PSSM/20181101/PSSM_TestSuite.xmi",
     "suiteDigest": "c355b249c356774377a46b60345019d827af1ce417bde88e533aa5f39206ae07",
     "tests": 103,
-    "recorded": "2026-10-01",
-    "develop": "deca2b0389f796b02fa1c30a387617d0613a034c"
+    "recorded": "2026-10-03",
+    "develop": "3d45ca6fb200339461594cd086004e461633e6d1"
   },
   "buckets": {
-    "differs-by-design": 5,
-    "fail": 11,
+    "differs-by-design": 7,
+    "fail": 6,
     "not-expressible": 34,
-    "pass": 53
+    "pass": 56
   },
   "tests": [
     {
@@ -630,32 +630,24 @@
       "name": "Entering 010",
       "area": "Entering",
       "class": "standard",
-      "bucket": "fail",
-      "reasons": [
-        "admitted trace not reached: S1(entry)::T2.1(effect)::S1.1(entry)::S2.1(entry)",
-        "admitted trace not reached: S1(entry)::T2.1(effect)::S2.1(entry)::S1.1(entry)"
-      ],
+      "bucket": "pass",
       "expected": [
         "S1(entry)::S1.1(entry)::T2.1(effect)::S2.1(entry)",
         "S1(entry)::T2.1(effect)::S1.1(entry)::S2.1(entry)",
         "S1(entry)::T2.1(effect)::S2.1(entry)::S1.1(entry)"
       ],
       "reached": [
-        "S1(entry)::S1.1(entry)::T2.1(effect)::S2.1(entry)"
+        "S1(entry)::S1.1(entry)::T2.1(effect)::S2.1(entry)",
+        "S1(entry)::T2.1(effect)::S1.1(entry)::S2.1(entry)",
+        "S1(entry)::T2.1(effect)::S2.1(entry)::S1.1(entry)"
       ],
-      "runs": 4
+      "runs": 20
     },
     {
       "name": "Entering 011",
       "area": "Entering",
       "class": "standard",
-      "bucket": "fail",
-      "reasons": [
-        "admitted trace not reached: S1(entry)::T1.1(effect)::T2.1(effect)::S1.1(entry)::S1.2(entry)",
-        "admitted trace not reached: S1(entry)::T1.1(effect)::T2.1(effect)::S1.2(entry)::S1.1(entry)",
-        "admitted trace not reached: S1(entry)::T2.1(effect)::T1.1(effect)::S1.1(entry)::S1.2(entry)",
-        "admitted trace not reached: S1(entry)::T2.1(effect)::T1.1(effect)::S1.2(entry)::S1.1(entry)"
-      ],
+      "bucket": "pass",
       "expected": [
         "S1(entry)::T1.1(effect)::S1.1(entry)::T2.1(effect)::S1.2(entry)",
         "S1(entry)::T1.1(effect)::T2.1(effect)::S1.1(entry)::S1.2(entry)",
@@ -666,9 +658,13 @@
       ],
       "reached": [
         "S1(entry)::T1.1(effect)::S1.1(entry)::T2.1(effect)::S1.2(entry)",
-        "S1(entry)::T2.1(effect)::S1.2(entry)::T1.1(effect)::S1.1(entry)"
+        "S1(entry)::T1.1(effect)::T2.1(effect)::S1.1(entry)::S1.2(entry)",
+        "S1(entry)::T1.1(effect)::T2.1(effect)::S1.2(entry)::S1.1(entry)",
+        "S1(entry)::T2.1(effect)::S1.2(entry)::T1.1(effect)::S1.1(entry)",
+        "S1(entry)::T2.1(effect)::T1.1(effect)::S1.1(entry)::S1.2(entry)",
+        "S1(entry)::T2.1(effect)::T1.1(effect)::S1.2(entry)::S1.1(entry)"
       ],
-      "runs": 4
+      "runs": 40
     },
     {
       "name": "Exiting 001",
@@ -1438,20 +1434,17 @@
       "name": "Junction 002",
       "area": "Junction",
       "class": "extension",
-      "row": "SM32",
-      "rowKind": "agrees",
-      "bucket": "fail",
+      "row": "SM46",
+      "rowKind": "differs because v2 differs",
+      "bucket": "differs-by-design",
       "reasons": [
-        "reached a trace the suite does not admit: S1(entry)",
+        "run error: process event: fire transition out of wait: entry transition through junction S1_Junction1: no way through: junction S1_Junction1: no guard evaluated to true",
         "admitted trace not reached: T3(effect)",
-        "reports on SM32 (Junction or join with no path through): agrees"
+        "reports on SM46 (Junction on a nested default entry): differs because v2 differs"
       ],
       "expected": [
         "T3(effect)"
       ],
-      "reached": [
-        "S1(entry)"
-      ],
       "runs": 1
     },
     {
@@ -1473,40 +1466,35 @@
       "name": "Junction 004",
       "area": "Junction",
       "class": "extension",
-      "row": "SM32",
-      "rowKind": "agrees",
-      "bucket": "fail",
+      "row": "SM46",
+      "rowKind": "differs because v2 differs",
+      "bucket": "differs-by-design",
       "reasons": [
-        "reached a trace the suite does not admit: S1(entry)::T1.3(effect)::S1.2(exit)",
+        "run error: process event: fire transition out of wait: enter state: enter starting state in region S1/Region2: entry transition through junction S1_Junction1_2: no way through: junction S1_Junction1_2: no guard evaluated to true",
         "admitted trace not reached: T3(effect)",
-        "reports on SM32 (Junction or join with no path through): agrees"
+        "reports on SM46 (Junction on a nested default entry): differs because v2 differs"
       ],
       "expected": [
         "T3(effect)"
       ],
-      "reached": [
-        "S1(entry)::T1.3(effect)::S1.2(exit)"
-      ],
-      "runs": 2
+      "runs": 6
     },
     {
       "name": "Junction 005",
       "area": "Junction",
       "class": "extension",
-      "bucket": "fail",
-      "reasons": [
-        "admitted trace not reached: S1(entry)::T2.1(effect)::S2.1(entry)::T1.3(effect)::S1.2(exit)::S1(exit)",
-        "admitted trace not reached: S1(entry)::T2.1(effect)::T1.3(effect)::S2.1(entry)::S1.2(exit)::S1(exit)"
-      ],
+      "bucket": "pass",
       "expected": [
         "S1(entry)::T1.3(effect)::T2.1(effect)::S2.1(entry)::S1.2(exit)::S1(exit)",
         "S1(entry)::T2.1(effect)::S2.1(entry)::T1.3(effect)::S1.2(exit)::S1(exit)",
         "S1(entry)::T2.1(effect)::T1.3(effect)::S2.1(entry)::S1.2(exit)::S1(exit)"
       ],
       "reached": [
-        "S1(entry)::T1.3(effect)::T2.1(effect)::S2.1(entry)::S1.2(exit)::S1(exit)"
+        "S1(entry)::T1.3(effect)::T2.1(effect)::S2.1(entry)::S1.2(exit)::S1(exit)",
+        "S1(entry)::T2.1(effect)::S2.1(entry)::T1.3(effect)::S1.2(exit)::S1(exit)",
+        "S1(entry)::T2.1(effect)::T1.3(effect)::S2.1(entry)::S1.2(exit)::S1(exit)"
       ],
-      "runs": 4
+      "runs": 20
     },
     {
       "name": "Junction 006",