Read error locations in the correct order from XML (#3226)

When ErrorMessage::callStack elements are serialized to XML they are
saved in the reverse order. But when they read back from XML they are
added at the end of the list. Thus the round trip via XML reverses the
order of ErrorMessage::callStack.

From the user point of view it looks like the usage of the
--cppcheck-build-dir option sometimes (when the file wasn't reanalyzed,
but that is hard to spot) results in incorrect location info for some
diagnostic messages.

Moreover, when the first location matches some suppression rule and the
last doesn't match any (or vice versa), usage of --cppcheck-build-dir
results in some diagnostic messages appearing and disappearing seemingly
at random (again, depending on whether the file was reanalyzed or not).

Makefile

@@ -632,7 +632,7 @@ test/testconstructors.o: test/testconstructors.cpp lib/astutils.h lib/check.h li
 test/testcppcheck.o: test/testcppcheck.cpp lib/analyzerinfo.h lib/check.h lib/config.h lib/cppcheck.h lib/errorlogger.h lib/errortypes.h lib/importproject.h lib/library.h lib/mathlib.h lib/platform.h lib/settings.h lib/standards.h lib/suppressions.h lib/timer.h lib/utils.h test/testsuite.h
 	$(CXX) ${INCLUDE_FOR_TEST} $(CPPFLAGS) $(CPPFILESDIR) $(CXXFLAGS) $(UNDEF_STRICT_ANSI) -c -o test/testcppcheck.o test/testcppcheck.cpp
 
-test/testerrorlogger.o: test/testerrorlogger.cpp lib/analyzerinfo.h lib/check.h lib/config.h lib/cppcheck.h lib/errorlogger.h lib/errortypes.h lib/importproject.h lib/library.h lib/mathlib.h lib/platform.h lib/settings.h lib/standards.h lib/suppressions.h lib/timer.h lib/utils.h test/testsuite.h
+test/testerrorlogger.o: test/testerrorlogger.cpp externals/tinyxml2/tinyxml2.h lib/analyzerinfo.h lib/check.h lib/config.h lib/cppcheck.h lib/errorlogger.h lib/errortypes.h lib/importproject.h lib/library.h lib/mathlib.h lib/platform.h lib/settings.h lib/standards.h lib/suppressions.h lib/timer.h lib/utils.h test/testsuite.h
 	$(CXX) ${INCLUDE_FOR_TEST} $(CPPFLAGS) $(CPPFILESDIR) $(CXXFLAGS) $(UNDEF_STRICT_ANSI) -c -o test/testerrorlogger.o test/testerrorlogger.cpp
 
 test/testexceptionsafety.o: test/testexceptionsafety.cpp lib/astutils.h lib/check.h lib/checkexceptionsafety.h lib/config.h lib/errorlogger.h lib/errortypes.h lib/importproject.h lib/library.h lib/mathlib.h lib/platform.h lib/settings.h lib/standards.h lib/suppressions.h lib/templatesimplifier.h lib/timer.h lib/token.h lib/tokenize.h lib/tokenlist.h lib/utils.h lib/valueflow.h test/testsuite.h

lib/errorlogger.cpp

@@ -216,7 +216,7 @@ ErrorMessage::ErrorMessage(const tinyxml2::XMLElement * const errmsg)
             const char *info = strinfo ? strinfo : "";
             const int line = strline ? std::atoi(strline) : 0;
             const int column = strcolumn ? std::atoi(strcolumn) : 0;
-            callStack.emplace_back(file, info, line, column);
+            callStack.emplace_front(file, info, line, column);
         }
     }
 }

test/testerrorlogger.cpp

@@ -22,6 +22,7 @@
 #include "suppressions.h"
 #include "testsuite.h"
 
+#include <tinyxml2.h>
 #include <list>
 #include <string>
 
@@ -49,6 +50,7 @@ private:
         TEST_CASE(ToXmlV2);
         TEST_CASE(ToXmlV2Locations);
         TEST_CASE(ToXmlV2Encoding);
+        TEST_CASE(FromXmlV2);
 
         // Inconclusive results in xml reports..
         TEST_CASE(InconclusiveXml);
@@ -231,6 +233,38 @@ private:
         }
     }
 
+    void FromXmlV2() const {
+        const char xmldata[] = "<?xml version=\"1.0\"?>\n"
+        "<error id=\"errorId\""
+        " severity=\"error\""
+        " cwe=\"123\""
+        " inconclusive=\"true\""
+        " msg=\"Programming error.\""
+        " verbose=\"Verbose error\""
+        " hash=\"456\""
+        ">\n"
+        "  <location file=\"bar.cpp\" line=\"8\" column=\"1\"/>\n"
+        "  <location file=\"foo.cpp\" line=\"5\" column=\"2\"/>\n"
+        "</error>";
+        tinyxml2::XMLDocument doc;
+        doc.Parse(xmldata, sizeof(xmldata));
+        ErrorMessage msg(doc.FirstChildElement());
+        ASSERT_EQUALS("errorId", msg.id);
+        ASSERT_EQUALS(Severity::error, msg.severity);
+        ASSERT_EQUALS(123u, msg.cwe.id);
+        ASSERT_EQUALS(Certainty::inconclusive, msg.certainty);
+        ASSERT_EQUALS("Programming error.", msg.shortMessage());
+        ASSERT_EQUALS("Verbose error", msg.verboseMessage());
+        ASSERT_EQUALS(456u, msg.hash);
+        ASSERT_EQUALS(2u, msg.callStack.size());
+        ASSERT_EQUALS("foo.cpp", msg.callStack.front().getfile());
+        ASSERT_EQUALS(5, msg.callStack.front().line);
+        ASSERT_EQUALS(2u, msg.callStack.front().column);
+        ASSERT_EQUALS("bar.cpp", msg.callStack.back().getfile());
+        ASSERT_EQUALS(8, msg.callStack.back().line);
+        ASSERT_EQUALS(1u, msg.callStack.back().column);
+    }
+
     void InconclusiveXml() const {
         // Location
         std::list<ErrorMessage::FileLocation> locs(1, fooCpp5);