From fc6de74ea7a3dc2a6f5315c49e01f7930bf0b879 Mon Sep 17 00:00:00 2001
From: chrchr-github <78114321+chrchr-github@users.noreply.github.com>
Date: Wed, 24 Jul 2024 15:58:44 +0200
Subject: [PATCH] Fix #12958 reopened Stack overflow with using namespace
 (#6639)

---
 lib/symboldatabase.cpp      | 13 ++++++++-----
 test/testsymboldatabase.cpp | 14 ++++++++++++++
 2 files changed, 22 insertions(+), 5 deletions(-)

diff --git a/lib/symboldatabase.cpp b/lib/symboldatabase.cpp
index 4082a894e2f..9bdff3f622c 100644
--- a/lib/symboldatabase.cpp
+++ b/lib/symboldatabase.cpp
@@ -6123,7 +6123,7 @@ const Scope *SymbolDatabase::findScopeByName(const std::string& name) const
 //---------------------------------------------------------------------------
 
 template<class S, class T, REQUIRES("S must be a Scope class", std::is_convertible<S*, const Scope*> ), REQUIRES("T must be a Type class", std::is_convertible<T*, const Type*> )>
-S* findRecordInNestedListImpl(S& thisScope, const std::string & name, bool isC)
+S* findRecordInNestedListImpl(S& thisScope, const std::string& name, bool isC, std::set<const Scope*>& visited)
 {
     for (S* scope: thisScope.nestedList) {
         if (scope->className == name && scope->type != Scope::eFunction)
@@ -6136,9 +6136,10 @@ S* findRecordInNestedListImpl(S& thisScope, const std::string & name, bool isC)
     }
 
     for (const auto& u : thisScope.usingList) {
-        if (!u.scope || u.scope == &thisScope)
+        if (!u.scope || u.scope == &thisScope || visited.find(u.scope) != visited.end())
             continue;
-        S* nestedScope = const_cast<S*>(u.scope)->findRecordInNestedList(name, false);
+        visited.emplace(u.scope);
+        S* nestedScope = findRecordInNestedListImpl<S, T>(const_cast<S&>(*u.scope), name, false, visited);
         if (nestedScope)
             return nestedScope;
     }
@@ -6158,12 +6159,14 @@ S* findRecordInNestedListImpl(S& thisScope, const std::string & name, bool isC)
 
 const Scope* Scope::findRecordInNestedList(const std::string & name, bool isC) const
 {
-    return findRecordInNestedListImpl<const Scope, const Type>(*this, name, isC);
+    std::set<const Scope*> visited;
+    return findRecordInNestedListImpl<const Scope, const Type>(*this, name, isC, visited);
 }
 
 Scope* Scope::findRecordInNestedList(const std::string & name, bool isC)
 {
-    return findRecordInNestedListImpl<Scope, Type>(*this, name, isC);
+    std::set<const Scope*> visited;
+    return findRecordInNestedListImpl<Scope, Type>(*this, name, isC, visited);
 }
 
 //---------------------------------------------------------------------------
diff --git a/test/testsymboldatabase.cpp b/test/testsymboldatabase.cpp
index baa847d5dd9..5a69a402fbe 100644
--- a/test/testsymboldatabase.cpp
+++ b/test/testsymboldatabase.cpp
@@ -5609,6 +5609,20 @@ class TestSymbolDatabase : public TestFixture {
             ASSERT(db != nullptr);
             ASSERT_EQUALS("", errout_str());
         }
+        {
+            GET_SYMBOL_DB_DBG("namespace N {\n"
+                              "    struct S {};\n"
+                              "}\n"
+                              "namespace O {\n"
+                              "    using namespace N;\n"
+                              "}\n"
+                              "namespace N {\n"
+                              "    using namespace O;\n"
+                              "    struct T {};\n"
+                              "}\n");
+            ASSERT(db != nullptr);
+            ASSERT_EQUALS("", errout_str());
+        }
     }
 
     void createSymbolDatabaseFindAllScopes1() {