json: allow empty .jsonl files (WEB-49403)

Also, allow empty .json files to make creating a new JSON file more pleasant.

GitOrigin-RevId: 707361a11b025917c06758f5c058c144f18eee4f

json/gen/com/intellij/json/JsonParser.java

@@ -115,19 +115,15 @@ public class JsonParser implements PsiParser, LightPsiParser {
   }
 
   /* ********************************************************** */
-  // value+
+  // value*
   static boolean json(PsiBuilder b, int l) {
     if (!recursion_guard_(b, l, "json")) return false;
-    boolean r;
-    Marker m = enter_section_(b);
-    r = value(b, l + 1);
-    while (r) {
+    while (true) {
       int c = current_position_(b);
       if (!value(b, l + 1)) break;
       if (!empty_element_parsed_guard_(b, "json", c)) break;
     }
-    exit_section_(b, m, null, r);
-    return r;
+    return true;
   }
 
   /* ********************************************************** */

json/json.bnf

@@ -59,7 +59,8 @@
 }
 
 // For compatibility we allow any value at root level (see JsonStandardComplianceAnnotator)
-json ::= value+
+// Empty file is also allowed
+json ::= value*
 
 object ::= '{' object_element* '}' {
   pin=1

json/tests/test/com/intellij/json/JsonHighlightingTest.java

@@ -45,6 +45,16 @@ public class JsonHighlightingTest extends JsonHighlightingTestBase {
     doTestHighlightingForJsonLines(false, true, true);
   }
 
+  public void testJsonLinesEmptyFile() {
+    enableStandardComplianceInspection(true, true);
+    doTestHighlightingForJsonLines(false, true, true);
+  }
+
+  public void testEmptyFile() {
+    enableStandardComplianceInspection(true, true);
+    doTestHighlighting(false, true, true);
+  }
+
   public void testDuplicatePropertyKeys() {
     myFixture.enableInspections(JsonDuplicatePropertyKeysInspection.class);
     doTestHighlighting(false, true, true);