From 255f273c46074d79a782cd7f2b0a88d69383ec45 Mon Sep 17 00:00:00 2001
From: Paul Fultz II <pfultz2@yahoo.com>
Date: Fri, 9 Apr 2021 00:43:54 -0500
Subject: [PATCH] Fix issue 10088: ValueFlow: Array size, wrong known value
 (#3204)

---
 lib/valueflow.cpp      | 29 ++++++++++++++++++++++-------
 test/testvalueflow.cpp | 16 ++++++++++++++++
 2 files changed, 38 insertions(+), 7 deletions(-)

diff --git a/lib/valueflow.cpp b/lib/valueflow.cpp
index 8d13e8503..570fd9bc1 100644
--- a/lib/valueflow.cpp
+++ b/lib/valueflow.cpp
@@ -4476,7 +4476,6 @@ struct ConditionHandler {
                 // start token of conditional code
                 Token* startTokens[] = {nullptr, nullptr};
 
-                bool inverted = false;
                 // if astParent is "!" we need to invert codeblock
                 {
                     const Token* tok2 = tok;
@@ -4484,10 +4483,8 @@ struct ConditionHandler {
                         const Token* parent = tok2->astParent();
                         while (parent && parent->str() == "&&")
                             parent = parent->astParent();
-                        if (parent && (parent->str() == "!" || Token::simpleMatch(parent, "== false"))) {
-                            inverted = true;
+                        if (parent && (parent->str() == "!" || Token::simpleMatch(parent, "== false")))
                             std::swap(thenValues, elseValues);
-                        }
                         tok2 = parent;
                     }
                 }
@@ -4569,8 +4566,25 @@ struct ConditionHandler {
                                      std::mem_fn(&ValueFlow::Value::isPossible));
                     }
 
+                    if (values.empty())
+                        return;
+
                     if (dead_if || dead_else) {
-                        if (!inverted && Token::Match(tok->astParent(), "&&|&")) {
+                        const Token* parent = tok->astParent();
+                        // Skip the not operator
+                        while (Token::simpleMatch(parent, "!"))
+                            parent = parent->astParent();
+                        bool possible = false;
+                        if (Token::Match(parent, "&&|%oror%")) {
+                            std::string op = parent->str();
+                            while (parent && parent->str() == op)
+                                parent = parent->astParent();
+                            if (Token::simpleMatch(parent, "!") || Token::simpleMatch(parent, "== false"))
+                                possible = op == "||";
+                            else
+                                possible = op == "&&";
+                        }
+                        if (possible) {
                             values.remove_if(std::mem_fn(&ValueFlow::Value::isImpossible));
                             changeKnownToPossible(values);
                         } else {
@@ -4578,8 +4592,9 @@ struct ConditionHandler {
                             valueFlowSetConditionToKnown(tok, values, false);
                         }
                     }
-                    if (!values.empty())
-                        forward(after, scope->bodyEnd, cond.vartok, values, tokenlist, settings);
+                    if (values.empty())
+                        return;
+                    forward(after, scope->bodyEnd, cond.vartok, values, tokenlist, settings);
                 }
             }
         });
diff --git a/test/testvalueflow.cpp b/test/testvalueflow.cpp
index 935be5156..638c24e80 100644
--- a/test/testvalueflow.cpp
+++ b/test/testvalueflow.cpp
@@ -5063,6 +5063,22 @@ private:
         ASSERT_EQUALS("",
                       isKnownContainerSizeValue(tokenValues(code, "a . front", ValueFlow::Value::ValueType::CONTAINER_SIZE), 10));
 
+        code = "int f(const std::vector<int>& x) {\n"
+               "    if (!x.empty() && x[0] == 0)\n"
+               "        return 2;\n"
+               "    return x.front();\n"
+               "}\n";
+        ASSERT_EQUALS("",
+                      isPossibleContainerSizeValue(tokenValues(code, "x . front", ValueFlow::Value::ValueType::CONTAINER_SIZE), 0));
+
+        code = "int f(const std::vector<int>& x) {\n"
+               "    if (!(x.empty() || x[0] != 0))\n"
+               "        return 2;\n"
+               "    return x.front();\n"
+               "}\n";
+        ASSERT_EQUALS("",
+                      isPossibleContainerSizeValue(tokenValues(code, "x . front", ValueFlow::Value::ValueType::CONTAINER_SIZE), 0));
+
         code = "void f(std::string str) {\n"
                "    if (str == \"123\") {\n"
                "        bool x = (str == \"\");\n"