Bug 1657909 - Improve calculation of fields telemetry for Credit Card Autofill. r=abr

Differential Revision: https://phabricator.services.mozilla.com/D86410

browser/extensions/formautofill/FormAutofillContent.jsm

@@ -553,14 +553,34 @@ var FormAutofillContent = {
     }
 
     records.creditCard.forEach(record => {
-      let totalCount = handler.form.elements.length;
-      let autofilledCount = Object.keys(record.record).length;
-      let unmodifiedCount = record.untouchedFields.length;
-      const extra = {
-        fields_not_auto: (totalCount - autofilledCount).toString(),
-        fields_auto: autofilledCount.toString(),
-        fields_modified: (autofilledCount - unmodifiedCount).toString(),
+      let extra = {
+        // Fields which have been filled manually.
+        fields_not_auto: "0",
+        // Fields which have been autofilled.
+        fields_auto: "0",
+        // Fields which have been autofilled and then modified.
+        fields_modified: "0",
       };
+
+      if (record.guid !== null) {
+        // If the `guid` is not null, it means we're editing an existing record.
+        // In that case, all fields in the record are autofilled, and fields in
+        // `untouchedFields` are unmodified.
+        let totalCount = handler.form.elements.length;
+        let autofilledCount = Object.keys(record.record).length;
+        let unmodifiedCount = record.untouchedFields.length;
+
+        extra.fields_not_auto = (totalCount - autofilledCount).toString();
+        extra.fields_auto = autofilledCount.toString();
+        extra.fields_modified = (autofilledCount - unmodifiedCount).toString();
+      } else {
+        // If the `guid` is null, we're filling a new form.
+        // In that case, all not-null fields are manually filled.
+        extra.fields_not_auto = Array.from(handler.form.elements)
+          .filter(element => !!element.value.trim().length)
+          .length.toString();
+      }
+
       Services.telemetry.recordEvent(
         "creditcard",
         "submitted",

browser/extensions/formautofill/test/browser/creditCard/browser_creditCard_telemetry.js

@@ -232,9 +232,10 @@ add_task(async function test_submit_creditCard_new() {
       "cc_form",
       undefined,
       {
-        fields_not_auto: "3",
-        fields_auto: "5",
-        fields_modified: "5",
+        // 5 fields plus submit button
+        fields_not_auto: "6",
+        fields_auto: "0",
+        fields_modified: "0",
       },
     ],
   ];