From b4d78e3d053da3d4aabcc1b736dd541883c42c9b Mon Sep 17 00:00:00 2001
From: Kamil Dudka <kdudka@redhat.com>
Date: Sat, 15 Sep 2012 09:34:41 +0200
Subject: [PATCH] Fixed #3651 (Preprocessor: Wrong handling of #elif)

---
 lib/preprocessor.cpp      |  7 ++++++-
 test/testpreprocessor.cpp | 29 +++++++++++++++++++++++++++--
 2 files changed, 33 insertions(+), 3 deletions(-)

diff --git a/lib/preprocessor.cpp b/lib/preprocessor.cpp
index db023ea71..1b1870d30 100644
--- a/lib/preprocessor.cpp
+++ b/lib/preprocessor.cpp
@@ -1832,7 +1832,7 @@ std::string Preprocessor::handleIncludes(const std::string &code, const std::str
 
     // has there been a true #if condition at the current indentmatch level?
     // then no more #elif or #else can be true before the #endif is seen.
-    bool elseIsTrue = true;
+    std::vector<bool> elseIsTrueStack;
 
     unsigned int linenr = 0;
 
@@ -1845,6 +1845,11 @@ std::string Preprocessor::handleIncludes(const std::string &code, const std::str
     while (std::getline(istr,line)) {
         ++linenr;
 
+        // has there been a true #if condition at the current indentmatch level?
+        // then no more #elif or #else can be true before the #endif is seen.
+        elseIsTrueStack.resize(1U + indentmatch, true);
+        std::vector<bool>::reference elseIsTrue = elseIsTrueStack[indentmatch];
+
         if (line.compare(0,7,"#ifdef ") == 0) {
             if (indent == indentmatch) {
                 const std::string tag = getdef(line,true);
diff --git a/test/testpreprocessor.cpp b/test/testpreprocessor.cpp
index 7be607525..f3b2e42e9 100644
--- a/test/testpreprocessor.cpp
+++ b/test/testpreprocessor.cpp
@@ -256,7 +256,8 @@ private:
         // Defines are given: test Preprocessor::handleIncludes
         TEST_CASE(def_handleIncludes);
         TEST_CASE(def_missingInclude);
-        TEST_CASE(def_handleIncludes_ifelse);   // problems in handleIncludes for #else
+        TEST_CASE(def_handleIncludes_ifelse1);   // problems in handleIncludes for #else
+        TEST_CASE(def_handleIncludes_ifelse2);
 
         TEST_CASE(def_valueWithParenthesis); // #3531
 
@@ -3078,6 +3079,7 @@ private:
         ASSERT_EQUALS("\n123\n\n", preprocessor.getcode(code, "X=123", "test.cpp"));
     }
 
+
     void simplifyCondition() {
         // Ticket #2794
         std::map<std::string, std::string> cfg;
@@ -3279,7 +3281,7 @@ private:
         }
     }
 
-    void def_handleIncludes_ifelse() {
+    void def_handleIncludes_ifelse1() {
         const std::string filePath("test.c");
         const std::list<std::string> includePaths;
         std::map<std::string,std::string> defs;
@@ -3334,6 +3336,29 @@ private:
         }
     }
 
+    void def_handleIncludes_ifelse2() { // #3651
+        const char code[] = "#if defined(A)\n"
+                            "\n"
+                            "#if defined(B)\n"
+                            "#endif\n"
+                            "\n"
+                            "#elif defined(C)\n"
+                            "\n"
+                            "#else\n"
+                            "\n"
+                            "123\n"
+                            "\n"
+                            "#endif";
+
+        Preprocessor preprocessor(NULL, this);
+
+        const std::list<std::string> includePaths;
+        std::map<std::string,std::string> defs;
+        defs["A"] = "1";
+        ASSERT_EQUALS(std::string::npos,  // No "123" in the output
+                      preprocessor.handleIncludes(code, "test.c", includePaths, defs).find("123"));
+    }
+
     void def_valueWithParenthesis() {
         // #define should introduce a new symbol regardless of parenthesis in the value
         // and regardless of white space in weird places (people do this for some reason).