Merge pull request #779 from jbj/commented-out-code-braces

C++: Relax commented-out code heuristic for `}`

cpp/ql/src/Documentation/CommentedOutCode.qll

@@ -20,6 +20,18 @@ private predicate looksLikeCode(string line) {
     exists(string trimmed |
            trimmed = line.regexpReplaceAll("(?i)(^\\s+|&#?[a-z0-9]{1,31};|\\s+$)", "") |
            trimmed.regexpMatch(".*[{};]")
+           and (
+              // If this line looks like code because it ends with a closing
+              // brace that's preceded by something other than whitespace ...
+              trimmed.regexpMatch(".*.\\}")
+              implies
+              // ... then there has to be ") {" (with some variation of
+              // whitespace) on the line, suggesting it's a statement like `if`
+              // or a function declaration. Otherwise it's likely to be a
+              // benign use of braces such as a JSON example or explanatory
+              // pseudocode.
+              trimmed.regexpMatch(".*\\)\\s*\\{.*")
+           )
            and not trimmed.regexpMatch("(>.*|.*[\\\\@][{}].*|(optional|repeated) .*;|.*(\\{\\{\\{|\\}\\}\\}).*|\\{[-0-9a-zA-Z]+\\})"))
 }
 

cpp/ql/test/query-tests/Documentation/CommentedOutCode/CommentedOutCode.expected

@@ -1,3 +1,4 @@
+| test2.cpp:37:1:37:39 | // int myFunction() { return myValue; } | This comment appears to contain commented-out code |
 | test.c:2:1:2:22 | // commented out code; | This comment appears to contain commented-out code |
 | test.c:4:1:7:8 | // some; | This comment appears to contain commented-out code |
 | test.c:9:1:13:8 | // also; | This comment appears to contain commented-out code |

cpp/ql/test/query-tests/Documentation/CommentedOutCode/test2.cpp

@@ -0,0 +1,37 @@
+/*
+ * This sentence contains a semicolon;
+ * however, this doesn't make it code.
+ */
+
+// This sentence contains a semicolon;
+// however, this doesn't make it code.
+
+/* Mention a ';' */
+
+/* Mention a '{' */
+
+/* JSON example: {"foo":"bar"} */
+
+/* JSON example in backticks: `{"foo":"bar"}` */
+
+/* JSON example in quotes: '{"foo":"bar"}' */
+
+/*
+ * Code example: `return 0;`.
+ */
+
+// Code example:
+//
+//     return 0;
+
+// Code example:
+//
+// ```
+// return 0;
+// ```
+
+// { 1, 2, 3, 4 }
+
+// Example: { 1, 2, 3, 4 }
+
+// int myFunction() { return myValue; }