Bug 1874944: send distinct telemetry data for empty attribution strings r=nalexander

An empty attribution string is a different case from one that exists that cannot be read (they generally point towards different potential causes in our infrastructure). We should send them as distinct errors.

Differential Revision: https://phabricator.services.mozilla.com/D199558

Author: bhearsum

browser/components/attribution/AttributionCode.sys.mjs

@@ -192,7 +192,23 @@ export var AttributionCode = {
         `_getMacAttrDataAsync: getAttributionString: "${attrStr}"`
       );
 
-      gCachedAttrData = this.parseAttributionCode(attrStr);
+      if (attrStr === null) {
+        gCachedAttrData = {};
+
+        lazy.log.debug(`_getMacAttrDataAsync: null attribution string`);
+        Services.telemetry
+          .getHistogramById("BROWSER_ATTRIBUTION_ERRORS")
+          .add("null_error");
+      } else if (attrStr == "") {
+        gCachedAttrData = {};
+
+        lazy.log.debug(`_getMacAttrDataAsync: empty attribution string`);
+        Services.telemetry
+          .getHistogramById("BROWSER_ATTRIBUTION_ERRORS")
+          .add("empty_error");
+      } else {
+        gCachedAttrData = this.parseAttributionCode(attrStr);
+      }
     } catch (ex) {
       // Avoid partial attribution data.
       gCachedAttrData = {};

browser/components/attribution/test/browser/browser_AttributionCode_Mac_telemetry.js

@@ -73,3 +73,49 @@ add_task(async function test_no_attribution() {
     sandbox.restore();
   }
 });
+
+add_task(async function test_empty_attribution() {
+  const sandbox = sinon.createSandbox();
+  await MacAttribution.setAttributionString("");
+
+  AttributionCode._clearCache();
+
+  const histogram = Services.telemetry.getHistogramById(
+    "BROWSER_ATTRIBUTION_ERRORS"
+  );
+  try {
+    // Clear any existing telemetry
+    histogram.clear();
+
+    await AttributionCode.getAttrDataAsync();
+
+    TelemetryTestUtils.assertHistogram(histogram, INDEX_EMPTY_ERROR, 1);
+  } finally {
+    AttributionCode._clearCache();
+    histogram.clear();
+    sandbox.restore();
+  }
+});
+
+add_task(async function test_null_attribution() {
+  const sandbox = sinon.createSandbox();
+  sandbox.stub(MacAttribution, "getAttributionString").resolves(null);
+
+  AttributionCode._clearCache();
+
+  const histogram = Services.telemetry.getHistogramById(
+    "BROWSER_ATTRIBUTION_ERRORS"
+  );
+  try {
+    // Clear any existing telemetry
+    histogram.clear();
+
+    await AttributionCode.getAttrDataAsync();
+
+    TelemetryTestUtils.assertHistogram(histogram, INDEX_NULL_ERROR, 1);
+  } finally {
+    AttributionCode._clearCache();
+    histogram.clear();
+    sandbox.restore();
+  }
+});

browser/components/attribution/test/browser/head.js

@@ -12,6 +12,8 @@ const INDEX_READ_ERROR = 0;
 const INDEX_DECODE_ERROR = 1;
 const INDEX_WRITE_ERROR = 2;
 const INDEX_QUARANTINE_ERROR = 3;
+const INDEX_EMPTY_ERROR = 4;
+const INDEX_NULL_ERROR = 5;
 
 add_setup(function () {
   // AttributionCode._clearCache is only possible in a testing environment

toolkit/components/telemetry/Histograms.json

@@ -12832,10 +12832,17 @@
     "products": ["firefox"],
     "expires_in_version": "never",
     "kind": "categorical",
-    "labels": ["read_error", "decode_error", "write_error", "quarantine_error"],
-    "description": "Count for the number of errors encountered trying to determine attribution data: on Windows, from the installers (stub and full); on macOS, from the quarantine database.",
+    "labels": [
+      "read_error",
+      "decode_error",
+      "write_error",
+      "quarantine_error",
+      "empty_error",
+      "null_error"
+    ],
+    "description": "Count for the number of errors encountered trying to determine attribution data: on Windows, from the installers (stub and full); on macOS, from an extended attributed on the .app bundle.",
     "releaseChannelCollection": "opt-out",
-    "bug_numbers": [1621402, 1525076],
+    "bug_numbers": [1621402, 1525076, 1874944],
     "alert_emails": ["aoprea@mozilla.com"],
     "operating_systems": ["mac", "windows"]
   },