From 7f193fb7a14af162ac86f038e1066a9ffcf50f68 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Daniel=20Marjam=C3=A4ki?= <danielm77@spray.se>
Date: Sat, 30 Jul 2011 19:51:06 +0200
Subject: [PATCH] Fixed #2788 (null pointer: dereference and then check 'if
 (abc->a == 3) { } if (!abc) ..')

---
 lib/checknullpointer.cpp | 14 +++++++++++++-
 test/testnullpointer.cpp |  4 ++--
 2 files changed, 15 insertions(+), 3 deletions(-)

diff --git a/lib/checknullpointer.cpp b/lib/checknullpointer.cpp
index 545af92e5..6b0f0f0dd 100644
--- a/lib/checknullpointer.cpp
+++ b/lib/checknullpointer.cpp
@@ -378,6 +378,12 @@ void CheckNullPointer::nullPointerStructByDeRefAndChec()
             tok1 = tok1->tokAt(3);
         }
 
+        // dereference in condition
+        else if (Token::Match(tok1, "if ( %var% ."))
+        {
+            tok1 = tok1->tokAt(2);
+        }
+
         // dereference in function call (but not sizeof|decltype)
         else if ((Token::Match(tok1->tokAt(-2), "%var% ( %var% . %var%") && !Token::Match(tok1->tokAt(-2), "sizeof|decltype ( %var% . %var%")) ||
                  Token::Match(tok1->previous(), ", %var% . %var%"))
@@ -441,7 +447,7 @@ void CheckNullPointer::nullPointerStructByDeRefAndChec()
 
             else if (tok2->str() == "}")
             {
-                if (indentlevel2 <= 1)
+                if (indentlevel2 == 0)
                     break;
                 --indentlevel2;
             }
@@ -454,7 +460,13 @@ void CheckNullPointer::nullPointerStructByDeRefAndChec()
             else if (tok2->varId() == varid1)
             {
                 if (tok2->next()->str() == "=")
+                {
+                    // Avoid false positives when there is 'else if'
+                    // TODO: can this be handled better?
+                    if (tok1->strAt(-2) == "if")
+                        skipvar.insert(varid1);
                     break;
+                }
                 if (Token::Match(tok2->tokAt(-2), "[,(] &"))
                     break;
             }
diff --git a/test/testnullpointer.cpp b/test/testnullpointer.cpp
index 005c25657..ce9c17a7f 100644
--- a/test/testnullpointer.cpp
+++ b/test/testnullpointer.cpp
@@ -229,7 +229,7 @@ private:
               "    }\n"
               "    if (abc) {}\n"
               "}");
-        TODO_ASSERT_EQUALS("[test.cpp:2]: (error) Possible null pointer dereference: abc - otherwise it is redundant to check if abc is null at line 5\n", "", errout.str());
+        ASSERT_EQUALS("[test.cpp:2]: (error) Possible null pointer dereference: abc - otherwise it is redundant to check if abc is null at line 5\n", errout.str());
 
         // TODO: False negative if member of member is dereferenced
         check("void foo(ABC *abc) {\n"
@@ -516,7 +516,7 @@ private:
               "    a = b ? c : d;\n"
               "    if (item) { }\n"
               "}\n");
-        TODO_ASSERT_EQUALS("error", "", errout.str());
+        ASSERT_EQUALS("[test.cpp:2]: (error) Possible null pointer dereference: item - otherwise it is redundant to check if item is null at line 4\n", errout.str());
 
         check("BOOL GotoFlyAnchor()\n"  // #2243
               "{\n"