Guard the whole boundary ring, not only the parse (Copilot on #141)

JSON.parse succeeding does not make coordinates[0] a ring of number pairs;
an undefined or malformed ring would throw at .map inside the submit
listener, exactly the failure mode the guard removes. Test pins it.

Author: dkastl

assets/javascripts/gtt_fiware_form.js

@@ -191,11 +191,15 @@
         try {
           ring = JSON.parse(mode.dataset.geom).geometry.coordinates[0];
         } catch (err) {
-          // data-geom is server-rendered; if it is missing or malformed,
-          // leave the stored triple untouched rather than submitting a
-          // half-written one from inside a throwing submit listener.
-          return;
+          ring = null;
         }
+        // data-geom is server-rendered; if it is missing, malformed or not
+        // a ring of number pairs, leave the stored triple untouched rather
+        // than throwing from inside the submit listener.
+        var isPair = function(c) {
+          return Array.isArray(c) && typeof c[0] === 'number' && typeof c[1] === 'number';
+        };
+        if (!Array.isArray(ring) || ring.length === 0 || !ring.every(isPair)) { return; }
         var geom = ring
           .map(function(c) { return [Number(c[1].toFixed(5)), Number(c[0].toFixed(5))]; })
           .join(';');

test/javascripts/serialization.test.js

@@ -139,6 +139,19 @@ describe('geographic area', () => {
       .toBe('35.67,139.69;35.68,139.7;35.675,139.695;35.67,139.69');
   });
 
+  // data-geom is server-rendered, but a malformed value must not throw from
+  // inside the submit listener (the submit proceeds regardless), and must
+  // leave the stored triple alone rather than half-writing it.
+  it('boundary with a malformed data-geom leaves the triple untouched', () => {
+    buildForm({ geoMode: 'boundary' });
+    initForm();
+    document.querySelector('input[value="boundary"]').dataset.geom = '{"geometry":{"coordinates":[]}}';
+    field('subscription_template_expression_georel').value = 'kept';
+    expect(() => submitForm()).not.toThrow();
+    expect(field('subscription_template_expression_georel').value).toBe('kept');
+    expect(field('subscription_template_expression_geometry').value).toBe('');
+  });
+
   it('custom leaves the triple untouched', () => {
     buildForm({ geoMode: 'custom' });
     initForm();