Fix #11776 (False positive: uninitialized variable, struct array member initialized in function) (#5165)

lib/astutils.cpp

@@ -3105,6 +3105,10 @@ static ExprUsage getFunctionUsage(const Token* tok, int indirect, const Settings
         }
         if (!args.empty() && indirect == 0 && !addressOf)
             return ExprUsage::Used;
+    } else if (ftok->isControlFlowKeyword()) {
+        return ExprUsage::Used;
+    } else if (ftok->str() == "{") {
+        return ExprUsage::Used;
     } else {
         const bool isnullbad = settings->library.isnullargbad(ftok, argnr + 1);
         if (indirect == 0 && astIsPointer(tok) && !addressOf && isnullbad)

lib/checkuninitvar.cpp

@@ -1621,6 +1621,8 @@ void CheckUninitVar::valueFlowUninit()
                 if (tok->variable()) {
                     bool unknown;
                     const bool isarray = tok->variable()->isArray();
+                    if (isarray && tok->variable()->isMember())
+                        continue; // Todo: this is a bailout
                     const bool ispointer = astIsPointer(tok) && !isarray;
                     const bool deref = CheckNullPointer::isPointerDeRef(tok, unknown, mSettings);
                     if (ispointer && v->indirect == 1 && !deref)
@@ -1633,7 +1635,7 @@ void CheckUninitVar::valueFlowUninit()
                         continue;
                 }
                 const ExprUsage usage = getExprUsage(tok, v->indirect, mSettings);
-                if (usage == ExprUsage::NotUsed)
+                if (usage == ExprUsage::NotUsed || usage == ExprUsage::Inconclusive)
                     continue;
                 if (!v->subexpressions.empty() && usage == ExprUsage::PassedByReference)
                     continue;

test/cfg/posix.c

@@ -1261,7 +1261,7 @@ void timet_h(struct timespec* ptp1)
     clock_settime(clk_id2, ptp1);
 
     struct timespec tp;
-    // cppcheck-suppress uninitvar
+    // FIXME cppcheck-suppress uninitvar
     clock_settime(CLOCK_REALTIME, &tp); // #6577 - false negative
     // cppcheck-suppress uninitvar
     clock_settime(clk_id3, &tp);

test/testuninitvar.cpp

@@ -5268,7 +5268,7 @@ private:
                         "    s.x = 42;\n"
                         "    bar(&s);\n"
                         "}");
-        ASSERT_EQUALS("[test.cpp:18]: (error) Uninitialized variable: &s.flag\n", errout.str());
+        ASSERT_EQUALS("[test.cpp:18] -> [test.cpp:12] -> [test.cpp:8]: (warning) Uninitialized variable: s->flag\n", errout.str());
 
         // Ticket #2207 - False negative
         valueFlowUninit("void foo() {\n"
@@ -6136,7 +6136,7 @@ private:
                         "    someType_t gVar;\n"
                         "    bar(&gVar);\n"
                         "}");
-        ASSERT_EQUALS("[test.cpp:9]: (error) Uninitialized variable: &gVar\n", errout.str());
+        ASSERT_EQUALS("[test.cpp:9] -> [test.cpp:5]: (warning) Uninitialized variable: p->flags\n", errout.str());
 
         valueFlowUninit("typedef struct\n"
                         "{\n"
@@ -6146,7 +6146,8 @@ private:
                         "        someType_t gVar;\n"
                         "        if(gVar.flags[1] == 42){}\n"
                         "}");
-        ASSERT_EQUALS("[test.cpp:7]: (error) Uninitialized variable: gVar.flags\n", errout.str());
+        // TODO : find bugs for member arrays
+        TODO_ASSERT_EQUALS("[test.cpp:7]: (error) Uninitialized variable: gVar.flags\n", "", errout.str());
 
         valueFlowUninit("void foo() {\n" // #10293
                         "  union {\n"
@@ -6667,7 +6668,7 @@ private:
                         "  foo(123, &abc);\n"
                         "  return abc.b;\n"
                         "}");
-        ASSERT_EQUALS("[test.cpp:5]: (error) Uninitialized variable: &abc\n", errout.str());
+        ASSERT_EQUALS("[test.cpp:6]: (error) Uninitialized variable: abc.b\n", errout.str());
 
         valueFlowUninit("struct ABC { int a; int b; int c; };\n"
                         "void foo() {\n"
@@ -6899,7 +6900,7 @@ private:
                         "    abc.a = 1;\n"
                         "    setabc(123, &abc);\n"
                         "}\n");
-        ASSERT_EQUALS("[test.cpp:8]: (error) Uninitialized variables: &abc.b, &abc.c\n", errout.str());
+        ASSERT_EQUALS("[test.cpp:8] -> [test.cpp:3]: (warning) Uninitialized variable: abc->b\n", errout.str());
 
         valueFlowUninit("struct S { int* p; };\n" // #10463
                         "void f(S* in) {\n"
@@ -6942,6 +6943,41 @@ private:
                         "    if (f < s.offset + sizeof(s)) {}\n"
                         "}\n");
         ASSERT_EQUALS("", errout.str());
+
+        // #11776 - function call initialises struct array member
+        valueFlowUninit("typedef struct {\n"
+                        "  int arr[1];\n"
+                        "  int count;\n"
+                        "} arr_struct;\n"
+                        "\n"
+                        "void init(int *a, int b);\n"
+                        "\n"
+                        "void foo(arr_struct const *var);\n" // <- inconclusive if var->count is used
+                        "\n"
+                        "void uninitvar_FP7() {\n"
+                        "  arr_struct my_st;\n"
+                        "  init(my_st.arr, 12);\n" // <- assume that my_st.arr is written
+                        "  foo(&my_st);\n"
+                        "}\n");
+        ASSERT_EQUALS("", errout.str());
+
+        valueFlowUninit("typedef struct {\n"
+                        "  int arr[1];\n"
+                        "  int count;\n"
+                        "} arr_struct;\n"
+                        "\n"
+                        "void init(int *a, int b);\n"
+                        "\n"
+                        "void foo(arr_struct const *var) {\n"
+                        "  x = var->arr[0];\n"
+                        "}\n"
+                        "\n"
+                        "void uninitvar_FP7() {\n"
+                        "  arr_struct my_st;\n"
+                        "  init(my_st.arr, 12);\n" // <- assume that my_st.arr is written
+                        "  foo(&my_st);\n"
+                        "}\n");
+        ASSERT_EQUALS("", errout.str());
     }
 
     void uninitvar_memberfunction() {