From 86837c5a5fe7e5c7dd5ea9dc4b655cb8e0564b5c Mon Sep 17 00:00:00 2001
From: chrchr-github <christian.riesch@live.com>
Date: Wed, 12 Jun 2024 23:08:05 +0200
Subject: [PATCH] Fix  #8159 FN unusedFunction: sole recursive call

---
 lib/checkunusedfunctions.cpp |  7 ++++++-
 test/testunusedfunctions.cpp | 21 +++++++++++++++------
 2 files changed, 21 insertions(+), 7 deletions(-)

diff --git a/lib/checkunusedfunctions.cpp b/lib/checkunusedfunctions.cpp
index f538b3a3544..8310dafaa1f 100644
--- a/lib/checkunusedfunctions.cpp
+++ b/lib/checkunusedfunctions.cpp
@@ -59,6 +59,11 @@ static std::string stripTemplateParameters(const std::string& funcName) {
 // FUNCTION USAGE - Check for unused functions etc
 //---------------------------------------------------------------------------
 
+static bool isRecursiveCall(const Token* ftok)
+{
+    return ftok->function() && ftok->function() == Scope::nestedInFunction(ftok->scope());
+}
+
 void CheckUnusedFunctions::parseTokens(const Tokenizer &tokenizer, const Settings &settings)
 {
     const char * const FileName = tokenizer.list.getFiles().front().c_str();
@@ -251,7 +256,7 @@ void CheckUnusedFunctions::parseTokens(const Tokenizer &tokenizer, const Setting
 
             if (func.filename.empty() || func.filename == "+" || func.filename != called_from_file)
                 func.usedOtherFile = true;
-            else
+            else if (!isRecursiveCall(funcname))
                 func.usedSameFile = true;
 
             mFunctionCalls.insert(baseName);
diff --git a/test/testunusedfunctions.cpp b/test/testunusedfunctions.cpp
index 91f1c1e11bf..0faae42bc03 100644
--- a/test/testunusedfunctions.cpp
+++ b/test/testunusedfunctions.cpp
@@ -67,6 +67,7 @@ class TestUnusedFunctions : public TestFixture {
         TEST_CASE(member_function_ternary);
         TEST_CASE(boost);
         TEST_CASE(enumValues);
+        TEST_CASE(recursive);
 
         TEST_CASE(multipleFiles);   // same function name in multiple files
 
@@ -116,7 +117,7 @@ class TestUnusedFunctions : public TestFixture {
               "    if (f1())\n"
               "    { }\n"
               "}");
-        ASSERT_EQUALS("", errout_str());
+        ASSERT_EQUALS("[test.cpp:1]: (style) The function 'f1' is never used.\n", errout_str());
     }
 
     void return1() {
@@ -124,7 +125,7 @@ class TestUnusedFunctions : public TestFixture {
               "{\n"
               "    return f1();\n"
               "}");
-        ASSERT_EQUALS("", errout_str());
+        ASSERT_EQUALS("[test.cpp:1]: (style) The function 'f1' is never used.\n", errout_str());
     }
 
     void return2() {
@@ -132,7 +133,7 @@ class TestUnusedFunctions : public TestFixture {
               "{\n"
               "    return *foo();\n"
               "}");
-        ASSERT_EQUALS("", errout_str());
+        ASSERT_EQUALS("[test.cpp:1]: (style) The function 'foo' is never used.\n", errout_str());
     }
 
     void return3() {
@@ -180,7 +181,7 @@ class TestUnusedFunctions : public TestFixture {
               "    if (cond) ;\n"
               "    else f1();\n"
               "}");
-        ASSERT_EQUALS("", errout_str());
+        ASSERT_EQUALS("[test.cpp:1]: (style) The function 'foo' is never used.\n", errout_str());
     }
 
     void functionpointer() {
@@ -255,7 +256,7 @@ class TestUnusedFunctions : public TestFixture {
               "}\n"
               "\n"
               "void h() { g<int>(); h(); }");
-        ASSERT_EQUALS("", errout_str());
+        ASSERT_EQUALS("[test.cpp:8]: (style) The function 'h' is never used.\n", errout_str());
     }
 
     void template3() { // #4701
@@ -286,7 +287,7 @@ class TestUnusedFunctions : public TestFixture {
               "        test();\n"
               "    }\n"
               "};");
-        ASSERT_EQUALS("", errout_str());
+        ASSERT_EQUALS("[test.cpp:11]: (style) The function 'test' is never used.\n", errout_str());
     }
 
     void template5() { // #9220
@@ -541,6 +542,14 @@ class TestUnusedFunctions : public TestFixture {
                       errout_str());
     }
 
+    void recursive() {
+        check("void f() {\n" // #8159
+              "    f();\n"
+              "}\n");
+        ASSERT_EQUALS("[test.cpp:1]: (style) The function 'f' is never used.\n",
+                      errout_str());
+    }
+
     void multipleFiles() {
         CheckUnusedFunctions c;