Merge pull request #4831 from geoffw0/printfunknown

C++: Fix Printf.qll specsAreKnown

Author: jbj

cpp/ql/src/semmle/code/cpp/commons/Printf.qll

@@ -900,6 +900,7 @@ class FormatLiteral extends Literal {
    */
   int getNumArgNeeded(int n) {
     exists(this.getConvSpecOffset(n)) and
+    exists(this.getConversionChar(n)) and
     result = count(int mode | hasFormatArgumentIndexFor(n, mode))
   }
 

cpp/ql/test/query-tests/Likely Bugs/Format/WrongNumberOfFormatArguments/test.c

@@ -42,4 +42,8 @@ void test(int i, const char *str)
 	}
 
 	printf("%@ %i %i", 1, 2); // GOOD
+
+	printf("%Y", 1, 2); // GOOD (unknown format character, this might be correct)
+	printf("%1.1Y", 1, 2); // GOOD (unknown format character, this might be correct)
+	printf("%*.*Y", 1, 2); // GOOD (unknown format character, this might be correct)
 }