Merge pull request #12951 from asgerf/js/json-with-comments

JS: Stop complaining about comments in JSON files

Author: asgerf

javascript/extractor/src/com/semmle/js/parser/JSONParser.java

@@ -21,6 +21,7 @@
 import com.semmle.util.io.WholeIO;
 import java.io.File;
 import java.util.ArrayList;
+import java.util.Collections;
 import java.util.List;
 import java.util.regex.Matcher;
 import java.util.regex.Pattern;
@@ -32,7 +33,6 @@ public class JSONParser {
   private int offset;
   private int length;
   private String src;
-  private List<ParseError> recoverableErrors;
 
   public static Pair<JSONValue, List<ParseError>> parseValue(String json) throws ParseError {
     JSONParser parser = new JSONParser(json);
@@ -41,14 +41,13 @@ public static Pair<JSONValue, List<ParseError>> parseValue(String json) throws P
     parser.consumeWhitespace();
     if (parser.offset < parser.length) parser.raise("Expected end of input");
 
-    return Pair.make(value, parser.recoverableErrors);
+    return Pair.make(value, Collections.emptyList());
   }
 
   private JSONParser(String json) throws ParseError {
     this.line = 1;
     this.column = 0;
     this.offset = 0;
-    this.recoverableErrors = new ArrayList<ParseError>();
 
     if (json == null) raise("Input string may not be null");
     this.length = json.length();
@@ -351,17 +350,16 @@ private void consumeWhitespace() throws ParseError {
     }
   }
 
-  /** Skips the line comment starting at the current position and records a recoverable error. */
+  /** Skips the line comment starting at the current position. */
   private void skipLineComment() throws ParseError {
     Position pos = new Position(line, column, offset);
     char c;
     next();
     next();
     while ((c = peek()) != '\r' && c != '\n' && c != -1) next();
-    recoverableErrors.add(new ParseError("Comments are not legal in JSON.", pos));
   }
 
-  /** Skips the block comment starting at the current position and records a recoverable error. */
+  /** Skips the block comment starting at the current position. */
   private void skipBlockComment() throws ParseError {
     Position pos = new Position(line, column, offset);
     char c;
@@ -376,7 +374,6 @@ private void skipBlockComment() throws ParseError {
         break;
       }
     } while (true);
-    recoverableErrors.add(new ParseError("Comments are not legal in JSON.", pos));
   }
 
   private void consume(char token) throws ParseError {

javascript/extractor/tests/json/output/trap/comments.json.trap

@@ -18,15 +18,5 @@ locations_default(#20003,#10000,3,12,3,18)
 json_locations(#20002,#20003)
 json_literals("world","""world""",#20002)
 json_properties(#20000,"hello",#20002)
-#20004=*
-json_errors(#20004,"Error: Comments are not legal in JSON.")
-#20005=@"loc,{#10000},2,3,2,3"
-locations_default(#20005,#10000,2,3,2,3)
-json_locations(#20004,#20005)
-#20006=*
-json_errors(#20006,"Error: Comments are not legal in JSON.")
-#20007=@"loc,{#10000},4,3,4,3"
-locations_default(#20007,#10000,4,3,4,3)
-json_locations(#20006,#20007)
 numlines(#10000,5,0,0)
 filetype(#10000,"json")

javascript/ql/src/change-notes/2023-04-28-json-with-comments.md

@@ -0,0 +1,5 @@
+---
+category: fix
+---
+* Fixed a spurious diagnostic warning about comments in JSON files being illegal.
+  Comments in JSON files are in fact fully supported, and the diagnostic message was misleading.

javascript/ql/test/library-tests/JSON/JSONError.expected

@@ -1 +0,0 @@
-| invalid.json:3:1:3:1 | Error: Comments are not legal in JSON. |