Add shared rule A3-1-1 for RULE-6-2-4 linkage2 and improve A3-1-1

knewbury01 · knewbury01 · commit 9f48c75ac9c4 · 2026-01-26T16:57:32.000-05:00
diff --git a/.vscode/tasks.json b/.vscode/tasks.json
@@ -259,6 +259,8 @@
                 "Language1",
                 "Language2",
                 "Language3",
+                "Linkage1",
+                "Linkage2",
                 "Literals",
                 "Loops",
                 "Macros",
diff --git a/change_notes/2026-01-26-a3-1-1-extern-to-full.md b/change_notes/2026-01-26-a3-1-1-extern-to-full.md
@@ -0,0 +1,2 @@
+- `A3-1-1` - `ViolationsOfOneDefinitionRule.ql`:
+  - The query previously would incorrectly allow cases where something was defined with `extern` and did not use the defined external linkage library to find external linkage. This change may result in the query finding more results.
diff --git a/cpp/autosar/src/rules/A3-1-1/ViolationsOfOneDefinitionRule.ql b/cpp/autosar/src/rules/A3-1-1/ViolationsOfOneDefinitionRule.ql
@@ -20,67 +20,10 @@
 
 import cpp
 import codingstandards.cpp.autosar
-import codingstandards.cpp.AcceptableHeader
+import codingstandards.cpp.rules.violationsofonedefinitionrule.ViolationsOfOneDefinitionRule
 
-predicate isInline(Function decl) {
-  exists(Specifier spec |
-    spec = decl.getASpecifier() and
-    (
-      spec.hasName("inline") or
-      spec.hasName("constexpr")
-    )
-  )
+class ViolationsOfOneDefinitionRuleQuery extends ViolationsOfOneDefinitionRuleSharedQuery {
+  ViolationsOfOneDefinitionRuleQuery() {
+    this = IncludesPackage::violationsOfOneDefinitionRuleQuery()
+  }
 }
-
-predicate isExtern(FunctionDeclarationEntry decl) {
-  exists(string spec |
-    spec = decl.getASpecifier() and
-    spec = "extern"
-  )
-}
-
-from DeclarationEntry decl, string case, string name
-where
-  (
-    //a non-inline/non-extern function defined in a header
-    exists(FunctionDeclarationEntry fn |
-      fn.isDefinition() and
-      not (
-        isInline(fn.getDeclaration())
-        or
-        isExtern(fn)
-        or
-        //any (defined) templates do not violate the ODR
-        fn.isFromUninstantiatedTemplate(_)
-        or
-        fn.isFromTemplateInstantiation(_) and
-        //except for specializations, those do violate ODR
-        not fn.isSpecialization()
-        or
-        fn.getDeclaration().isStatic()
-      ) and
-      decl = fn and
-      case = "function"
-    )
-    or
-    //an non-const object defined in a header
-    exists(GlobalOrNamespaceVariable object |
-      object.hasDefinition() and
-      not (
-        object.isConstexpr()
-        or
-        object.isConst()
-        or
-        object.isStatic()
-      ) and
-      decl = object.getDefinition() and
-      case = "object"
-    )
-  ) and
-  not decl.getDeclaration().getNamespace().isAnonymous() and
-  decl.getFile() instanceof AcceptableHeader and
-  not isExcluded(decl, IncludesPackage::violationsOfOneDefinitionRuleQuery()) and
-  name = decl.getName()
-select decl,
-  "Header file $@ contains " + case + " " + name + " that lead to One Defintion Rule violation.",
-  decl.getFile(), decl.getFile().getBaseName()
diff --git a/cpp/autosar/test/rules/A3-1-1/ViolationsOfOneDefinitionRule.expected b/cpp/autosar/test/rules/A3-1-1/ViolationsOfOneDefinitionRule.expected
diff --git a/cpp/autosar/test/rules/A3-1-1/ViolationsOfOneDefinitionRule.qlref b/cpp/autosar/test/rules/A3-1-1/ViolationsOfOneDefinitionRule.qlref
diff --git a/cpp/autosar/test/rules/A3-1-1/ViolationsOfOneDefinitionRule.testref b/cpp/autosar/test/rules/A3-1-1/ViolationsOfOneDefinitionRule.testref
@@ -0,0 +1 @@
+cpp/common/test/rules/violationsofonedefinitionrule/ViolationsOfOneDefinitionRule.ql
diff --git a/cpp/autosar/test/rules/A3-1-1/test.hpp b/cpp/autosar/test/rules/A3-1-1/test.hpp
diff --git a/cpp/common/src/codingstandards/cpp/exclusions/cpp/Linkage2.qll b/cpp/common/src/codingstandards/cpp/exclusions/cpp/Linkage2.qll
@@ -4,16 +4,16 @@ import RuleMetadata
 import codingstandards.cpp.exclusions.RuleMetadata
 
 newtype Linkage2Query =
-  THeaderDefinitionsExternalLinkageQuery() or
+  TViolationsOfOneDefinitionRuleMisraQuery() or
   TInternalLinkageSpecifiedAppropriatelyQuery()
 
 predicate isLinkage2QueryMetadata(Query query, string queryId, string ruleId, string category) {
   query =
-    // `Query` instance for the `headerDefinitionsExternalLinkage` query
-    Linkage2Package::headerDefinitionsExternalLinkageQuery() and
+    // `Query` instance for the `violationsOfOneDefinitionRuleMisra` query
+    Linkage2Package::violationsOfOneDefinitionRuleMisraQuery() and
   queryId =
-    // `@id` for the `headerDefinitionsExternalLinkage` query
-    "cpp/misra/header-definitions-external-linkage" and
+    // `@id` for the `violationsOfOneDefinitionRuleMisra` query
+    "cpp/misra/violations-of-one-definition-rule-misra" and
   ruleId = "RULE-6-2-4" and
   category = "required"
   or
@@ -28,11 +28,11 @@ predicate isLinkage2QueryMetadata(Query query, string queryId, string ruleId, st
 }
 
 module Linkage2Package {
-  Query headerDefinitionsExternalLinkageQuery() {
+  Query violationsOfOneDefinitionRuleMisraQuery() {
     //autogenerate `Query` type
     result =
-      // `Query` type for `headerDefinitionsExternalLinkage` query
-      TQueryCPP(TLinkage2PackageQuery(THeaderDefinitionsExternalLinkageQuery()))
+      // `Query` type for `violationsOfOneDefinitionRuleMisra` query
+      TQueryCPP(TLinkage2PackageQuery(TViolationsOfOneDefinitionRuleMisraQuery()))
   }
 
   Query internalLinkageSpecifiedAppropriatelyQuery() {
diff --git a/cpp/common/src/codingstandards/cpp/rules/violationsofonedefinitionrule/ViolationsOfOneDefinitionRule.qll b/cpp/common/src/codingstandards/cpp/rules/violationsofonedefinitionrule/ViolationsOfOneDefinitionRule.qll
@@ -0,0 +1,74 @@
+/**
+ * Provides a library with a `problems` predicate for the following issue:
+ * Placing the definitions of functions or objects that are non-inline and have
+ * external linkage can lead to violations of the ODR and can lead to undefined
+ * behaviour.
+ */
+
+import cpp
+import codingstandards.cpp.Customizations
+import codingstandards.cpp.Exclusions
+import codingstandards.cpp.AcceptableHeader
+import codingstandards.cpp.Linkage
+
+predicate isInline(Function decl) {
+  exists(Specifier spec |
+    spec = decl.getASpecifier() and
+    (
+      spec.hasName("inline") or
+      spec.hasName("constexpr")
+    )
+  )
+}
+
+abstract class ViolationsOfOneDefinitionRuleSharedQuery extends Query { }
+
+Query getQuery() { result instanceof ViolationsOfOneDefinitionRuleSharedQuery }
+
+query predicate problems(DeclarationEntry decl, string message, File declFile, string secondmessage) {
+  exists(string case |
+    not isExcluded(decl, getQuery()) and
+    declFile = decl.getFile() and
+    secondmessage = decl.getFile().getBaseName() and
+    message =
+      "Header file $@ contains " + case + " " + decl.getName() +
+        " that lead to One Defintion Rule violation." and
+    hasExternalLinkage(decl.getDeclaration()) and
+    (
+      //a non-inline/non-extern function defined in a header
+      exists(FunctionDeclarationEntry fn |
+        fn.isDefinition() and
+        not (
+          isInline(fn.getDeclaration())
+          or
+          //any (defined) templates do not violate the ODR
+          fn.isFromUninstantiatedTemplate(_)
+          or
+          fn.isFromTemplateInstantiation(_) and
+          //except for specializations, those do violate ODR
+          not fn.isSpecialization()
+          or
+          //static/nonstatic member functions should still not be defined (so do not exclude here)
+          fn.getDeclaration().isStatic() and not fn.getFunction() instanceof MemberFunction
+        ) and
+        decl = fn and
+        case = "function"
+      )
+      or
+      //an non-const object defined in a header
+      exists(Variable object |
+        not (
+          object.isConstexpr()
+          or
+          object.isConst()
+          or
+          object.isStatic()
+        ) and
+        decl = object.getDefinition() and
+        case = "object"
+      )
+    ) and
+    not decl.getDeclaration().getNamespace().isAnonymous() and
+    decl.getFile() instanceof AcceptableHeader
+  )
+}
diff --git a/cpp/common/test/rules/violationsofonedefinitionrule/ViolationsOfOneDefinitionRule.expected b/cpp/common/test/rules/violationsofonedefinitionrule/ViolationsOfOneDefinitionRule.expected
@@ -0,0 +1,3 @@
+| test.hpp:3:6:3:7 | definition of f1 | Header file $@ contains function f1 that lead to One Defintion Rule violation. | test.hpp:0:0:0:0 | test.hpp | test.hpp |
+| test.hpp:8:5:8:5 | definition of i | Header file $@ contains object i that lead to One Defintion Rule violation. | test.hpp:0:0:0:0 | test.hpp | test.hpp |
+| test.hpp:9:12:9:13 | definition of i1 | Header file $@ contains object i1 that lead to One Defintion Rule violation. | test.hpp:0:0:0:0 | test.hpp | test.hpp |
diff --git a/cpp/common/test/rules/violationsofonedefinitionrule/ViolationsOfOneDefinitionRule.ql b/cpp/common/test/rules/violationsofonedefinitionrule/ViolationsOfOneDefinitionRule.ql
@@ -0,0 +1,4 @@
+// GENERATED FILE - DO NOT MODIFY
+import codingstandards.cpp.rules.violationsofonedefinitionrule.ViolationsOfOneDefinitionRule
+
+class TestFileQuery extends ViolationsOfOneDefinitionRuleSharedQuery, TestQuery { }
diff --git a/cpp/common/test/rules/violationsofonedefinitionrule/test.cpp b/cpp/common/test/rules/violationsofonedefinitionrule/test.cpp
diff --git a/cpp/common/test/rules/violationsofonedefinitionrule/test.hpp b/cpp/common/test/rules/violationsofonedefinitionrule/test.hpp
@@ -0,0 +1,26 @@
+void f(); // COMPLIANT
+
+void f1() {}        // NON_COMPLIANT
+inline void f2() {} // COMPLIANT
+
+template <typename T> void f3(T){}; // COMPLIANT - implicitly inline
+
+int i;             // NON_COMPLIANT
+extern int i1 = 1; // NON_COMPLIANT
+
+constexpr auto i2{1}; // COMPLIANT - not external linkage
+
+struct S {
+  int i;                         // COMPLIANT - no linkage
+  inline static const int i1{1}; // COMPLIANT - inline
+};
+
+class C {
+  static int m(); // COMPLIANT
+  int m1();       // COMPLIANT
+};
+
+int C::m() {}  // NON_COMPLIANT[FALSE_NEGATIVE] - external linkage library
+               // issue/namespace of class not found
+int C::m1() {} // NON_COMPLIANT[FALSE_NEGATIVE] - external linkage library
+               // issue/namespace of class not found
diff --git a/cpp/misra/src/rules/RULE-6-2-4/ViolationsOfOneDefinitionRuleMisra.ql b/cpp/misra/src/rules/RULE-6-2-4/ViolationsOfOneDefinitionRuleMisra.ql
@@ -0,0 +1,27 @@
+/**
+ * @id cpp/misra/violations-of-one-definition-rule-misra
+ * @name RULE-6-2-4: A header file shall not contain definitions of functions or objects that are non-inline and have external linkage
+ * @description Placing the definitions of functions or objects that are non-inline and have
+ *              external linkage can lead to violations of the ODR and can lead to undefined
+ *              behaviour.
+ * @kind problem
+ * @precision very-high
+ * @problem.severity error
+ * @tags external/misra/id/rule-6-2-4
+ *       correctness
+ *       maintainability
+ *       readability
+ *       scope/single-translation-unit
+ *       external/misra/enforcement/decidable
+ *       external/misra/obligation/required
+ */
+
+import cpp
+import codingstandards.cpp.misra
+import codingstandards.cpp.rules.violationsofonedefinitionrule.ViolationsOfOneDefinitionRule
+
+class ViolationsOfOneDefinitionRuleMisraQuery extends ViolationsOfOneDefinitionRuleSharedQuery {
+  ViolationsOfOneDefinitionRuleMisraQuery() {
+    this = Linkage2Package::violationsOfOneDefinitionRuleMisraQuery()
+  }
+}
diff --git a/cpp/misra/test/rules/RULE-6-2-4/ViolationsOfOneDefinitionRuleMisra.testref b/cpp/misra/test/rules/RULE-6-2-4/ViolationsOfOneDefinitionRuleMisra.testref
@@ -0,0 +1 @@
+cpp/common/test/rules/violationsofonedefinitionrule/ViolationsOfOneDefinitionRule.ql
diff --git a/rule_packages/cpp/Includes.json b/rule_packages/cpp/Includes.json
@@ -42,6 +42,7 @@
           "precision": "very-high",
           "severity": "warning",
           "short_name": "ViolationsOfOneDefinitionRule",
+          "shared_implementation_short_name": "ViolationsOfOneDefinitionRule",
           "tags": [
             "correctness",
             "maintainability",
diff --git a/rule_packages/cpp/Linkage2.json b/rule_packages/cpp/Linkage2.json
@@ -12,7 +12,8 @@
           "name": "A header file shall not contain definitions of functions or objects that are non-inline and have external linkage",
           "precision": "very-high",
           "severity": "error",
-          "short_name": "HeaderDefinitionsExternalLinkage",
+          "short_name": "ViolationsOfOneDefinitionRuleMisra",
+          "shared_implementation_short_name": "ViolationsOfOneDefinitionRule",
           "tags": [
             "correctness",
             "maintainability",
diff --git a/rules.csv b/rules.csv
@@ -856,7 +856,7 @@ cpp,MISRA-C++-2023,RULE-6-0-4,Yes,Required,Decidable,Single Translation Unit,The
 cpp,MISRA-C++-2023,RULE-6-2-1,Yes,Required,Decidable,System,The one-definition rule shall not be violated,M3-2-2,ImportMisra23,Import,
 cpp,MISRA-C++-2023,RULE-6-2-2,Yes,Required,Decidable,System,All declarations of a variable or function shall have the same type,"M3-9-1,DCL40-C",Declarations2,Easy,
 cpp,MISRA-C++-2023,RULE-6-2-3,Yes,Required,Decidable,System,The source code used to implement an entity shall appear only once,,Declarations2,Medium,
-cpp,MISRA-C++-2023,RULE-6-2-4,Yes,Required,Decidable,Single Translation Unit,A header file shall not contain definitions of functions or objects that are non-inline and have external linkage,M3-2-4,Linkage2,Easy,
+cpp,MISRA-C++-2023,RULE-6-2-4,Yes,Required,Decidable,Single Translation Unit,A header file shall not contain definitions of functions or objects that are non-inline and have external linkage,A3-1-1,Linkage2,Import,
 cpp,MISRA-C++-2023,RULE-6-4-1,Yes,Required,Decidable,Single Translation Unit,A variable declared in an inner scope shall not hide a variable declared in an outer scope,A2-10-1,ImportMisra23,Import,
 cpp,MISRA-C++-2023,RULE-6-4-2,Yes,Required,Decidable,Single Translation Unit,Derived classes shall not conceal functions that are inherited from their bases,A7-3-1,ImportMisra23,Import,
 cpp,MISRA-C++-2023,RULE-6-4-3,Yes,Required,Decidable,Single Translation Unit,A name that is present in a dependent base shall not be resolved by unqualified lookup,M14-6-1,ImportMisra23,Import,

Original file line number	Diff line number	Diff line change
`@@ -0,0 +1,2 @@`
	`1`	+- `A3-1-1` - `ViolationsOfOneDefinitionRule.ql`:
	`2`	+ - The query previously would incorrectly allow cases where something was defined with `extern` and did not use the defined external linkage library to find external linkage. This change may result in the query finding more results.
Original file line number	Diff line number	Diff line change
`@@ -0,0 +1 @@`
	`1`	`+cpp/common/test/rules/violationsofonedefinitionrule/ViolationsOfOneDefinitionRule.ql`
Original file line number	Diff line number	Diff line change
`@@ -0,0 +1,3 @@`
	`1`	`+\| test.hpp:3:6:3:7 \| definition of f1 \| Header file $@ contains function f1 that lead to One Defintion Rule violation. \| test.hpp:0:0:0:0 \| test.hpp \| test.hpp \|`
	`2`	`+\| test.hpp:8:5:8:5 \| definition of i \| Header file $@ contains object i that lead to One Defintion Rule violation. \| test.hpp:0:0:0:0 \| test.hpp \| test.hpp \|`
	`3`	`+\| test.hpp:9:12:9:13 \| definition of i1 \| Header file $@ contains object i1 that lead to One Defintion Rule violation. \| test.hpp:0:0:0:0 \| test.hpp \| test.hpp \|`