Merge pull request #1141 from castler/fix_8_2_10_false_positive

RULE-8-2-10: Avoid callers of recursive functions being flagged

Author: MichaelRFairhurst

c/misra/test/rules/RULE-17-2/test.c

@@ -8,7 +8,7 @@ void f3() {
   f3(); // NON_COMPLIANT
 }
 void f6() {
-  f3(); // NON_COMPLIANT
+  f3(); // COMPLIANT - merely calls a recursive function
 }
 
 void f5() {

change_notes/2026-06-18-fix-fp-recursive-functions.md

@@ -0,0 +1,2 @@
+`A7-5-2`, `RULE-8-2-10`: `FunctionsCallThemselvesEitherDirectlyOrIndirectly.ql`:
+    - Fix false positives where callers of recursive functions were incorrectly reported as recursive. Only calls that participate in a recursive cycle are now reported.

cpp/common/src/codingstandards/cpp/rules/functionscallthemselveseitherdirectlyorindirectly/FunctionsCallThemselvesEitherDirectlyOrIndirectly.qll

@@ -23,7 +23,7 @@ class RecursiveFunction extends Function {
   RecursiveFunction() { exists(RecursiveCall fc | fc.getEnclosingFunction() = this) }
 }
 
-query predicate problems(FunctionCall fc, string message, RecursiveFunction f, string functionName) {
+query predicate problems(RecursiveCall fc, string message, Function f, string functionName) {
   not isExcluded(fc, getQuery()) and
   f = fc.getTarget() and
   functionName = f.getName() and

cpp/common/test/rules/functionscallthemselveseitherdirectlyorindirectly/FunctionsCallThemselvesEitherDirectlyOrIndirectly.expected

@@ -1,5 +1,4 @@
 | test.cpp:7:13:7:35 | call to test_recursive_function | This call directly invokes its containing function $@. | test.cpp:5:5:5:27 | test_recursive_function | test_recursive_function |
-| test.cpp:21:9:21:31 | call to test_recursive_function | The function test_indirect_recursive_function is indirectly recursive via this call to $@. | test.cpp:5:5:5:27 | test_recursive_function | test_recursive_function |
-| test.cpp:27:5:27:30 | call to test_indirect_recursive_f2 | The function test_indirect_recursive_f1 is indirectly recursive via this call to $@. | test.cpp:36:5:36:30 | test_indirect_recursive_f2 | test_indirect_recursive_f2 |
-| test.cpp:38:9:38:34 | call to test_indirect_recursive_f1 | The function test_indirect_recursive_f2 is indirectly recursive via this call to $@. | test.cpp:25:5:25:30 | test_indirect_recursive_f1 | test_indirect_recursive_f1 |
-| test.cpp:75:10:75:19 | call to operator== | This call directly invokes its containing function $@. | test.cpp:74:6:74:15 | operator== | operator== |
+| test.cpp:33:5:33:30 | call to test_indirect_recursive_f2 | The function test_indirect_recursive_f1 is indirectly recursive via this call to $@. | test.cpp:42:5:42:30 | test_indirect_recursive_f2 | test_indirect_recursive_f2 |
+| test.cpp:44:9:44:34 | call to test_indirect_recursive_f1 | The function test_indirect_recursive_f2 is indirectly recursive via this call to $@. | test.cpp:31:5:31:30 | test_indirect_recursive_f1 | test_indirect_recursive_f1 |
+| test.cpp:81:10:81:19 | call to operator== | This call directly invokes its containing function $@. | test.cpp:80:6:80:15 | operator== | operator== |

cpp/common/test/rules/functionscallthemselveseitherdirectlyorindirectly/test.cpp

@@ -18,10 +18,16 @@ int test_nonrecursive_function(int i) { // COMPLIANT
 
 int test_indirect_recursive_function(int i) {
   if (i > 10) {
-    i = test_recursive_function(i * i); // NON_COMPLIANT
+    i = test_recursive_function(
+        i * i); // COMPLIANT - merely calls a recursive function
   }
 }
 
+int test_calls_recursive_function(int i) {
+  return test_recursive_function(
+      i); // COMPLIANT - not part of a recursive cycle
+}
+
 int test_indirect_recursive_f1(int i) {
   if (i > 10) {
     test_indirect_recursive_f2(i + i); // NON_COMPLIANT