Fix #3510 (Improve error message for --suppressions-list)

http://sourceforge.net/apps/trac/cppcheck/ticket/3510
Print additional info to error message if we suspect that multiple files were given.

cli/cmdlineparser.cpp

@@ -16,6 +16,7 @@
  * along with this program.  If not, see <http://www.gnu.org/licenses/>.
  */
 
+#include <algorithm>
 #include <iostream>
 #include <sstream>
 #include <fstream>
@@ -178,6 +179,15 @@ bool CmdLineParser::ParseFromArgs(int argc, const char* const argv[])
                 std::string message("cppcheck: Couldn't open the file: \"");
                 message += std::string(filename);
                 message += "\".";
+                if (count(filename.begin(), filename.end(), ',') > 0 ||
+                    count(filename.begin(), filename.end(), '.') > 1) {
+                    // If user tried to pass multiple files (we can only guess that)
+                    // e.g. like this: --suppressions-list=a.txt,b.txt
+                    // print more detailed error message to tell user how he can solve the problem
+                    message += "\nIf you want to pass two files, you can do it e.g. like this:";
+                    message += "\n    cppcheck --suppressions-list=a.txt --suppressions-list=b.txt file.cpp";
+                }
+
                 PrintMessage(message);
                 return false;
             }

test/redirect.h

@@ -50,6 +50,17 @@ public:
         output << _out.str();
     }
 
+    /** Return what would be printed to cout. See also clearOutput() */
+    std::string getOutput() {
+        return _out.str();
+    }
+
+    /** Normally called after getOutput() to prevent same text to be returned
+    twice. */
+    void clearOutput() {
+        _out.str("");
+    }
+
 private:
     std::stringstream _out;
     std::stringstream _err;
@@ -58,5 +69,7 @@ private:
 };
 
 #define REDIRECT RedirectOutputError redir;
+#define GET_REDIRECT_OUTPUT redir.getOutput()
+#define CLEAR_REDIRECT_OUTPUT redir.clearOutput()
 
 #endif

test/testcmdlineparser.cpp

@@ -665,12 +665,33 @@ private:
     }
 
     void suppressionsNoFile() {
-        // TODO: Fails because there is no suppr.txt file!
         REDIRECT;
+        {
+            CLEAR_REDIRECT_OUTPUT;
             const char *argv[] = {"cppcheck", "--suppressions-list=", "file.cpp"};
             Settings settings;
             CmdLineParser parser(&settings);
-        TODO_ASSERT_EQUALS(true, false, parser.ParseFromArgs(3, argv));
+            ASSERT_EQUALS(false, parser.ParseFromArgs(3, argv));
+            ASSERT_EQUALS(false, GET_REDIRECT_OUTPUT.find("If you want to pass two files") != std::string::npos);
+        }
+
+        {
+            CLEAR_REDIRECT_OUTPUT;
+            const char *argv[] = {"cppcheck", "--suppressions-list=a.suppr,b.suppr", "file.cpp"};
+            Settings settings;
+            CmdLineParser parser(&settings);
+            ASSERT_EQUALS(false, parser.ParseFromArgs(3, argv));
+            ASSERT_EQUALS(true, GET_REDIRECT_OUTPUT.find("If you want to pass two files") != std::string::npos);
+        }
+
+        {
+            CLEAR_REDIRECT_OUTPUT;
+            const char *argv[] = {"cppcheck", "--suppressions-list=a.suppr b.suppr", "file.cpp"};
+            Settings settings;
+            CmdLineParser parser(&settings);
+            ASSERT_EQUALS(false, parser.ParseFromArgs(3, argv));
+            ASSERT_EQUALS(true, GET_REDIRECT_OUTPUT.find("If you want to pass two files") != std::string::npos);
+        }
     }
 
     void suppressionSingle() {