From 432360485391cfa37588624891bb367f7312f083 Mon Sep 17 00:00:00 2001
From: ambujsingh <ambuj.singh@bti.bmwgroup.com>
Date: Mon, 13 Jul 2026 15:52:23 +0530
Subject: [PATCH] [rules score] refactor requirements model to use abstract
 base types

Replace inline union types with abstract base types in the TRLC
requirements model for cleaner polymorphism and extensibility:

- Add abstract CompReqSource; AssumedSystemReq/FeatReq extend it and
  CompReqSourceId.item references the base instead of
  [FeatReq, AssumedSystemReq].
- Add abstract Measure; ControlMeasure/PreventiveMeasure/Mitigation
  extend it, replacing the tuple Measure union.
- Root PreventiveMeasure and Mitigation in RequirementSafety (fixing
  Mitigation's incorrect AssumedSystemReq parent and PreventiveMeasure
  having no safety classification).
- Drop mitigates from ControlMeasure (tracing is implicit via FTA
  name-matching); keep mitigates on AoU; give Mitigation an optional
  rationale.
- Add mandatory safety/description/version to the SomePreventiveMeasure
  test fixture, which the new hierarchy now requires.
---
 .../seooc_test/safety_measures_fixtures.trlc  |  3 ++
 .../trlc/config/score_requirements_model.rsl  | 30 +++++++++----------
 2 files changed, 18 insertions(+), 15 deletions(-)

diff --git a/bazel/rules/rules_score/test/fixtures/seooc_test/safety_measures_fixtures.trlc b/bazel/rules/rules_score/test/fixtures/seooc_test/safety_measures_fixtures.trlc
index c81da33e..e42fe2ca 100644
--- a/bazel/rules/rules_score/test/fixtures/seooc_test/safety_measures_fixtures.trlc
+++ b/bazel/rules/rules_score/test/fixtures/seooc_test/safety_measures_fixtures.trlc
@@ -29,6 +29,9 @@ ScoreReq.ControlMeasure SomeBasicEvent {
 }
 
 ScoreReq.PreventiveMeasure SomePreventiveMeasure {
+    safety      = ScoreReq.Asil.B
+    description = "A preventive measure that stops a failure mode from occurring (no mitigates field)"
+    version     = 1
 }
 
 ScoreReq.Mitigation SomeMitigation {
diff --git a/bazel/rules/rules_score/trlc/config/score_requirements_model.rsl b/bazel/rules/rules_score/trlc/config/score_requirements_model.rsl
index 3a2d44ce..67ae8959 100644
--- a/bazel/rules/rules_score/trlc/config/score_requirements_model.rsl
+++ b/bazel/rules/rules_score/trlc/config/score_requirements_model.rsl
@@ -44,11 +44,14 @@ abstract type RequirementSafety "Extension of Requirement that carries an ASIL c
            Asil
 }
 
+abstract type CompReqSource "Base type for requirements that may serve as a source for a component requirement." extends RequirementSafety {
+}
+
 ///////////////////////////////
 // S-Core Requirements Model
 ///////////////////////////////
 
-type AssumedSystemReq "System-level requirement received from the wider operational context (e.g. platform)." extends RequirementSafety {
+type AssumedSystemReq "System-level requirement received from the wider operational context (e.g. platform)." extends CompReqSource {
     rationale "Explanation of why this system-level requirement exists and how it was derived."
               String
 }
@@ -59,7 +62,7 @@ tuple AssumedSystemReqId {
     version Integer
 }
 
-type FeatReq "High-level feature requirement derived from one or more AssumedSystemReq items." extends RequirementSafety {
+type FeatReq "High-level feature requirement derived from one or more AssumedSystemReq items." extends CompReqSource {
     derived_from "One or more versioned references to the AssumedSystemReq items this feature requirement is derived from."
                  AssumedSystemReqId[1 .. *]
 }
@@ -71,7 +74,7 @@ tuple FeatReqId {
 }
 
 tuple CompReqSourceId {
-    item    [FeatReq, AssumedSystemReq]
+    item    CompReqSource
     separator @
     version Integer
 }
@@ -154,26 +157,23 @@ type FailureMode "A potential failure of a system function, described using one
                    optional String
 }
 
-type ControlMeasure "A design or operational measure that detects, prevents, or limits a failure mode." extends RequirementSafety {
-    mitigates    "Reference to the FailureMode or safety concern that this requirement mitigates."
-                 optional String
+abstract type Measure "Base type for safety measures referenced from safety analyses." extends RequirementSafety {
 }
 
-type PreventiveMeasure "A measure that prevents a failure mode from occurring in the first place." {
+type ControlMeasure "A design or operational measure that detects, prevents, or limits a failure mode." extends Measure {
 }
 
-type Mitigation "A measure that reduces the severity or probability of a failure mode's effect." extends AssumedSystemReq {
-    mitigates    "Reference to the FailureMode or safety concern that this requirement mitigates."
-                 optional String
+type PreventiveMeasure "A measure that prevents a failure mode from occurring in the first place." extends Measure {
 }
 
-type AoU "Assumption of Use — a safety-relevant condition that a user must fulfil." extends ControlMeasure {
+type Mitigation "A measure that reduces the severity or probability of a failure mode's effect." extends Measure {
+    rationale    "Explanation of why this mitigation is considered effective or necessary."
+                 optional String
 }
 
-tuple Measure {
-    item    [ControlMeasure, PreventiveMeasure, Mitigation]
-    separator @
-    version Integer
+type AoU "Assumption of Use — a safety-relevant condition that a user must fulfil." extends ControlMeasure {
+    mitigates    "Reference to the FailureMode or safety concern that this requirement mitigates."
+                 optional String
 }
 
 ///////////////////////////////