From c4c2d88feb74645fcd6f827a7b1eb02e98f5e316 Mon Sep 17 00:00:00 2001
From: chrchr <christian.riesch@live.com>
Date: Wed, 23 Aug 2023 15:33:46 +0200
Subject: [PATCH] Fix FP incorrectStringBooleanError with unknown macro

---
 lib/checkstring.cpp | 21 ++++++++++++++++++---
 test/teststring.cpp |  7 +++++++
 2 files changed, 25 insertions(+), 3 deletions(-)

diff --git a/lib/checkstring.cpp b/lib/checkstring.cpp
index e58f065185c..90784e3bcb8 100644
--- a/lib/checkstring.cpp
+++ b/lib/checkstring.cpp
@@ -246,6 +246,21 @@ void CheckString::strPlusCharError(const Token *tok)
     reportError(tok, Severity::error, "strPlusChar", "Unusual pointer arithmetic. A value of type '" + charType +"' is added to a string literal.", CWE665, Certainty::normal);
 }
 
+static bool isMacroUsage(const Token* tok)
+{
+    if (const Token* parent = tok->astParent()) {
+        if (parent->isExpandedMacro())
+            return true;
+        if (parent->isUnaryOp("!")) {
+            int argn{};
+            const Token* ftok = getTokenArgumentFunction(parent, argn);
+            if (ftok && !ftok->function())
+                return true;
+        }
+    }
+    return false;
+}
+
 //---------------------------------------------------------------------------
 // Implicit casts of string literals to bool
 // Comparing string literal with strlen() with wrong length
@@ -288,9 +303,9 @@ void CheckString::checkIncorrectStringCompare()
                         incorrectStringCompareError(tok->next(), "substr", end->strAt(1));
                     }
                 }
-            } else if (Token::Match(tok, "%str%|%char%") &&
-                       !(tok->astParent() && tok->astParent()->isExpandedMacro()) &&
-                       isUsedAsBool(tok))
+            } else if (Token::Match(tok, "%str%|%char%") &&                       
+                       isUsedAsBool(tok) &&
+                       !isMacroUsage(tok))
                 incorrectStringBooleanError(tok, tok->str());
         }
     }
diff --git a/test/teststring.cpp b/test/teststring.cpp
index 56e886afdc1..05e88abd135 100644
--- a/test/teststring.cpp
+++ b/test/teststring.cpp
@@ -785,6 +785,13 @@ class TestString : public TestFixture {
               "	  ERROR(\"abc\")\n"
               "}\n");
         ASSERT_EQUALS("", errout.str());
+
+        check("void g(int, bool);\n"
+              "void f() {\n"
+              "    MyAssert(!\"abc\");\n"
+              "    g(2, !\"def\");\n"
+              "}\n");
+        ASSERT_EQUALS("[test.cpp:4]: (warning) Conversion of string literal \"def\" to bool always evaluates to true.\n", errout.str());
     }
 
     void deadStrcmp() {