From 5423262bda744861db11339bcea0453399e7fc1f Mon Sep 17 00:00:00 2001
From: chrchr <christian.riesch@live.com>
Date: Mon, 21 Aug 2023 11:35:35 +0200
Subject: [PATCH] Fix #11886 performance regression (hang) in 2.12dev

---
 lib/symboldatabase.cpp | 14 +++++++++++++-
 test/testclass.cpp     | 15 +++++++++++++++
 2 files changed, 28 insertions(+), 1 deletion(-)

diff --git a/lib/symboldatabase.cpp b/lib/symboldatabase.cpp
index f64caa82e27..bb487db8336 100644
--- a/lib/symboldatabase.cpp
+++ b/lib/symboldatabase.cpp
@@ -4350,6 +4350,18 @@ const Function *Function::getOverriddenFunction(bool *foundAllBaseClasses) const
     return getOverriddenFunctionRecursive(nestedIn->definedType, foundAllBaseClasses);
 }
 
+// prevent recursion if base is the same except for different template parameters
+static bool isDerivedFromItself(const std::string& thisName, const std::string& baseName)
+{
+    const auto posThis = thisName.find('<');
+    if (posThis == std::string::npos)
+        return false;
+    const auto posBase = baseName.find('<');
+    if (posBase == std::string::npos)
+        return false;
+    return posThis == posBase && thisName.compare(0, posThis, baseName);
+}
+
 const Function * Function::getOverriddenFunctionRecursive(const ::Type* baseType, bool *foundAllBaseClasses) const
 {
     // check each base class
@@ -4402,7 +4414,7 @@ const Function * Function::getOverriddenFunctionRecursive(const ::Type* baseType
             }
         }
 
-        if (!derivedFromType->derivedFrom.empty() && !derivedFromType->hasCircularDependencies()) {
+        if (!derivedFromType->derivedFrom.empty() && !derivedFromType->hasCircularDependencies() && !isDerivedFromItself(baseType->classScope->className, i.name)) {
             // avoid endless recursion, see #5289 Crash: Stack overflow in isImplicitlyVirtual_rec when checking SVN and
             // #5590 with a loop within the class hierarchy.
             const Function *func = getOverriddenFunctionRecursive(derivedFromType, foundAllBaseClasses);
diff --git a/test/testclass.cpp b/test/testclass.cpp
index b2a343a4446..5413a56c199 100644
--- a/test/testclass.cpp
+++ b/test/testclass.cpp
@@ -183,6 +183,7 @@ class TestClass : public TestFixture {
         TEST_CASE(const89);
         TEST_CASE(const90);
         TEST_CASE(const91);
+        TEST_CASE(const92);
 
         TEST_CASE(const_handleDefaultParameters);
         TEST_CASE(const_passThisToMemberOfOtherClass);
@@ -6654,6 +6655,20 @@ class TestClass : public TestFixture {
         ASSERT_EQUALS("", errout.str());
     }
 
+    void const92() { // #11886
+        checkConst("void g(int);\n"
+                   "template<int n>\n"
+                   "struct S : public S<n - 1> {\n"
+                   "    void f() {\n"
+                   "        g(n - 1);\n"
+                   "    }\n"
+                   "};\n"
+                   "template<>\n"
+                   "struct S<0> {};\n"
+                   "struct D : S<150> {};\n");
+        // don't hang
+    }
+
     void const_handleDefaultParameters() {
         checkConst("struct Foo {\n"
                    "    void foo1(int i, int j = 0) {\n"