Partial fix for #12922 FN uninitvar with std::array::at() (cppcheck-opensource#6589)

chrchr-github · web-flow · commit 7aa5e4ace8eb · 2024-07-12T22:05:02.000+02:00
diff --git a/lib/valueflow.cpp b/lib/valueflow.cpp
@@ -7077,6 +7077,15 @@ static bool needsInitialization(const Variable* var)
             return true;
         if (var->valueType()->type == ValueType::Type::ITERATOR)
             return true;
+        if (var->isStlType() && var->isArray()) {
+            if (const Token* ctt = var->valueType()->containerTypeToken) {
+                if (ctt->isStandardType())
+                    return true;
+                const Type* ct = ctt->type();
+                if (ct && ct->needInitialization == Type::NeedInitialization::True)
+                    return true;
+            }
+        }
     }
     return false;
 }
diff --git a/test/testuninitvar.cpp b/test/testuninitvar.cpp
@@ -6520,6 +6520,28 @@ class TestUninitVar : public TestFixture {
                         "    printf(\"%s\", p);\n"
                         "}\n");
         ASSERT_EQUALS("", errout_str());
+
+        valueFlowUninit("std::string f() {\n" // #12922
+                        "    std::string a[2];\n"
+                        "    std::array<std::string, 2> b;\n"
+                        "    return a[1] + b.at(1);\n" // don't warn
+                        "}\n"
+                        "struct S { int i; };\n"
+                        "struct T { int i = 0; };\n"
+                        "int g() {\n"
+                        "    std::array<int, 2> a;\n"
+                        "    std::array<S, 2> b;\n"
+                        "    std::array<T, 2> c;\n" // don't warn
+                        "    return a.at(1) + b.at(1).i + c.at(1).i;\n"
+                        "}\n"
+                        "int h() {\n"
+                        "    std::array<int, 2> a;\n"
+                        "    return a[1];\n"
+                        "}\n");
+        ASSERT_EQUALS("[test.cpp:12]: (error) Uninitialized variable: a\n"
+                      "[test.cpp:12]: (error) Uninitialized variable: b\n"
+                      "[test.cpp:16]: (error) Uninitialized variable: a\n",
+                      errout_str());
     }
 
     void valueFlowUninitBreak() { // Do not show duplicate warnings about the same uninitialized value
diff --git a/test/testvalueflow.cpp b/test/testvalueflow.cpp
@@ -6304,7 +6304,7 @@ class TestValueFlow : public TestFixture {
                "  std::array<int,10> ints;\n" // Array size is 10
                "  ints.front();\n"
                "}";
-        ASSERT_EQUALS("", isKnownContainerSizeValue(tokenValues(code, "ints . front"), 10));
+        ASSERT_EQUALS("values.size():2", isKnownContainerSizeValue(tokenValues(code, "ints . front"), 10)); // uninit value
 
         code = "void f() {\n"
                "  std::string s;\n"
