Import A5-6-1 division/mod by zero

Author: MichaelRFairhurst

change_notes/2026-03-16-share-divisor-equal-to-zero-query.md

@@ -0,0 +1,2 @@
+ - `A5-6-1` - `DivisorEqualToZero.ql`:
+   - Refactored query logic into a shared library (`DivisorEqualToZeroShared.qll`) to enable reuse by MISRA C++ `RULE-4-1-3`. The query logic is unchanged and no visible changes to results or performance are expected.

cpp/autosar/src/rules/A5-6-1/DivisorEqualToZero.ql

@@ -15,10 +15,10 @@
 
 import cpp
 import codingstandards.cpp.autosar
+import codingstandards.cpp.rules.divisorequaltozeroshared.DivisorEqualToZeroShared
 
-from BinaryArithmeticOperation bao
-where
-  not isExcluded(bao, ExpressionsPackage::divisorEqualToZeroQuery()) and
-  (bao instanceof DivExpr or bao instanceof RemExpr) and
-  bao.getRightOperand().getValue().toFloat() = 0 // `toFloat()` holds for both integer and float literals.
-select bao, "Divisor is zero."
+module DivisorEqualToZeroConfig implements DivisorEqualToZeroSharedConfigSig {
+  Query getQuery() { result = ExpressionsPackage::divisorEqualToZeroQuery() }
+}
+
+import DivisorEqualToZeroShared<DivisorEqualToZeroConfig>

cpp/autosar/test/rules/A5-6-1/DivisorEqualToZero.qlref

@@ -0,0 +1 @@
+cpp/common/test/rules/divisorequaltozeroshared/DivisorEqualToZeroShared.ql

cpp/autosar/test/rules/A5-6-1/DivisorEqualToZero.testref

@@ -8,7 +8,8 @@ newtype UndefinedQuery =
   TCriticalUnspecifiedBehaviorQuery() or
   TUndefinedBehaviorAuditQuery() or
   TCriticalUnspecifiedBehaviorAuditQuery() or
-  TPossibleDataRaceBetweenThreadsQuery()
+  TPossibleDataRaceBetweenThreadsQuery() or
+  TDivisionByZeroUndefinedBehaviorQuery()
 
 predicate isUndefinedQueryMetadata(Query query, string queryId, string ruleId, string category) {
   query =
@@ -55,6 +56,15 @@ predicate isUndefinedQueryMetadata(Query query, string queryId, string ruleId, s
     "cpp/misra/possible-data-race-between-threads" and
   ruleId = "RULE-4-1-3" and
   category = "required"
+  or
+  query =
+    // `Query` instance for the `divisionByZeroUndefinedBehavior` query
+    UndefinedPackage::divisionByZeroUndefinedBehaviorQuery() and
+  queryId =
+    // `@id` for the `divisionByZeroUndefinedBehavior` query
+    "cpp/misra/division-by-zero-undefined-behavior" and
+  ruleId = "RULE-4-1-3" and
+  category = "required"
 }
 
 module UndefinedPackage {
@@ -92,4 +102,11 @@ module UndefinedPackage {
       // `Query` type for `possibleDataRaceBetweenThreads` query
       TQueryCPP(TUndefinedPackageQuery(TPossibleDataRaceBetweenThreadsQuery()))
   }
+
+  Query divisionByZeroUndefinedBehaviorQuery() {
+    //autogenerate `Query` type
+    result =
+      // `Query` type for `divisionByZeroUndefinedBehavior` query
+      TQueryCPP(TUndefinedPackageQuery(TDivisionByZeroUndefinedBehaviorQuery()))
+  }
 }

cpp/common/src/codingstandards/cpp/exclusions/cpp/Undefined.qll

@@ -0,0 +1,23 @@
+/**
+ * Provides a configurable module DivisorEqualToZeroShared with a `problems` predicate
+ * for the following issue:
+ * The result is undefined if the right hand operand of the integer division or the
+ * remainder operator is zero.
+ */
+
+import cpp
+import codingstandards.cpp.Customizations
+import codingstandards.cpp.Exclusions
+
+signature module DivisorEqualToZeroSharedConfigSig {
+  Query getQuery();
+}
+
+module DivisorEqualToZeroShared<DivisorEqualToZeroSharedConfigSig Config> {
+  query predicate problems(BinaryArithmeticOperation bao, string message) {
+    not isExcluded(bao, Config::getQuery()) and
+    (bao instanceof DivExpr or bao instanceof RemExpr) and
+    bao.getRightOperand().getValue().toFloat() = 0 and // `toFloat()` holds for both integer and float literals.
+    message = "Divisor is zero."
+  }
+}

cpp/common/src/codingstandards/cpp/rules/divisorequaltozeroshared/DivisorEqualToZeroShared.qll

@@ -10,4 +10,4 @@
 | test.cpp:28:11:28:18 | ... / ... | Divisor is zero. |
 | test.cpp:29:11:29:18 | ... % ... | Divisor is zero. |
 | test.cpp:30:11:30:18 | ... / ... | Divisor is zero. |
-| test.cpp:31:11:31:18 | ... % ... | Divisor is zero. |
+| test.cpp:31:11:31:18 | ... % ... | Divisor is zero. |

…rules/A5-6-1/DivisorEqualToZero.expected …shared/DivisorEqualToZeroShared.expectedcpp/autosar/test/rules/A5-6-1/DivisorEqualToZero.expected renamed to cpp/common/test/rules/divisorequaltozeroshared/DivisorEqualToZeroShared.expected cpp/autosar/test/rules/A5-6-1/DivisorEqualToZero.expected renamed to cpp/common/test/rules/divisorequaltozeroshared/DivisorEqualToZeroShared.expected

@@ -0,0 +1,8 @@
+// GENERATED FILE - DO NOT MODIFY
+import codingstandards.cpp.rules.divisorequaltozeroshared.DivisorEqualToZeroShared
+
+module TestFileConfig implements DivisorEqualToZeroSharedConfigSig {
+  Query getQuery() { result instanceof TestQuery }
+}
+
+import DivisorEqualToZeroShared<TestFileConfig>

cpp/common/test/rules/divisorequaltozeroshared/DivisorEqualToZeroShared.ql

@@ -35,4 +35,4 @@ void test_macro() {
   int f = 1 % ONE;   // COMPLIANT
   int g = 1 / ID(1); // COMPLIANT
   int h = 1 % ID(1); // COMPLIANT
-}
+}

cpp/autosar/test/rules/A5-6-1/test.cpp …/rules/divisorequaltozeroshared/test.cppcpp/autosar/test/rules/A5-6-1/test.cpp renamed to cpp/common/test/rules/divisorequaltozeroshared/test.cpp cpp/autosar/test/rules/A5-6-1/test.cpp renamed to cpp/common/test/rules/divisorequaltozeroshared/test.cpp

@@ -0,0 +1,23 @@
+/**
+ * @id cpp/misra/division-by-zero-undefined-behavior
+ * @name RULE-4-1-3: Division or modulo by zero leads to undefined behavior
+ * @description Division or remainder by zero results in undefined behavior.
+ * @kind problem
+ * @precision high
+ * @problem.severity error
+ * @tags external/misra/id/rule-4-1-3
+ *       correctness
+ *       scope/system
+ *       external/misra/enforcement/undecidable
+ *       external/misra/obligation/required
+ */
+
+import cpp
+import codingstandards.cpp.misra
+import codingstandards.cpp.rules.divisorequaltozeroshared.DivisorEqualToZeroShared
+
+module DivisionByZeroUndefinedBehaviorConfig implements DivisorEqualToZeroSharedConfigSig {
+  Query getQuery() { result = UndefinedPackage::divisionByZeroUndefinedBehaviorQuery() }
+}
+
+import DivisorEqualToZeroShared<DivisionByZeroUndefinedBehaviorConfig>