Add a new parseJabRefComment with unit test

src/main/java/org/jabref/logic/importer/fileformat/BibtexParser.java

@@ -20,6 +20,7 @@
 import java.util.Optional;
 import java.util.Set;
 import java.util.function.Predicate;
+import java.util.regex.Matcher;
 import java.util.regex.Pattern;
 
 import javax.xml.parsers.DocumentBuilderFactory;
@@ -58,6 +59,10 @@
 import com.dd.plist.BinaryPropertyListParser;
 import com.dd.plist.NSDictionary;
 import com.dd.plist.NSString;
+import com.google.gson.Gson;
+import com.google.gson.JsonObject;
+import com.google.gson.JsonParser;
+import com.google.gson.JsonSyntaxException;
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
 import org.w3c.dom.Document;
@@ -339,7 +344,7 @@ private void parseAndAddEntry(String type) {
         }
     }
 
-    private void parseJabRefComment(Map<String, String> meta) {
+    void parseJabRefComment(Map<String, String> meta) {
         StringBuilder buffer;
         try {
             buffer = parseBracketedFieldContent();
@@ -354,6 +359,7 @@ private void parseJabRefComment(Map<String, String> meta) {
         // We remove all line breaks in the metadata
         // These have been inserted to prevent too long lines when the file was saved, and are not part of the data.
         String comment = buffer.toString().replaceAll("[\\x0d\\x0a]", "");
+
         if (comment.substring(0, Math.min(comment.length(), MetaData.META_FLAG.length())).equals(MetaData.META_FLAG)) {
             if (comment.startsWith(MetaData.META_FLAG)) {
                 String rest = comment.substring(MetaData.META_FLAG.length());
@@ -386,6 +392,36 @@ private void parseJabRefComment(Map<String, String> meta) {
             } catch (ParseException ex) {
                 parserResult.addException(ex);
             }
+        } else if (isValidJson(comment)) {
+            parseCommentToJson(comment);
+        }
+    }
+
+    public static boolean isValidJson(String jsonString) {
+        try {
+            String[] target = jsonString.split("\\{", 2);
+            if (target.length < 2) {
+                return false;
+            }
+            JsonParser.parseString("{" + target[1]);
+            return true;
+        } catch (
+                JsonSyntaxException e) {
+            return false;
+        }
+    }
+
+    private void parseCommentToJson(String comment) {
+        Pattern pattern = Pattern.compile("\\{.*}", Pattern.DOTALL);
+        Matcher matcher = pattern.matcher(comment);
+        if (matcher.find()) {
+            String jsonString = matcher.group();
+            Gson gson = new Gson();
+            JsonObject jsonObject = gson.fromJson(jsonString, JsonObject.class);
+            String jsonResult = gson.toJson(jsonObject);
+            BibEntry entry = new BibEntry();
+            entry.setField(StandardField.COMMENT, jsonResult);
+            database.insertEntry(entry);
         }
     }
 

src/test/java/org/jabref/logic/importer/fileformat/BibtexParserTest.java

@@ -2238,4 +2238,26 @@ void parseInvalidBibDeskFilesResultsInWarnings() throws IOException {
 
         assertEquals(List.of(firstEntry, secondEntry), result.getDatabase().getEntries());
     }
+
+    @Test
+    void parseJabRefSingleJsonComment() throws IOException {
+        String entries =
+        """
+            @Comment{jabref-meta-0.1.0
+                {
+                    "saveActions" :
+                    {
+                        "state": true,
+                        "date": ["normalize_date", "action2"],
+                        "pages" : ["normalize_page_numbers"],
+                        "month" : ["normalize_month"]
+                    }
+                }
+            }
+        """;
+        ParserResult result = parser.parse(new StringReader(entries));
+        BibEntry expectedEntry = new BibEntry();
+        expectedEntry.setField(StandardField.COMMENT, "{\"saveActions\":{\"state\":true,\"date\":[\"normalize_date\",\"action2\"],\"pages\":[\"normalize_page_numbers\"],\"month\":[\"normalize_month\"]}}");
+        assertEquals(expectedEntry, result.getDatabase().getEntries().getFirst());
+    }
 }