Regenerate the client id / first run date if needed

Old builds of products using glean, which were already
executed once, once updated, might not correctly report
the client id and the first run date. Since these are
likely low number of developer builds, we simply regenerate
these fields.

components/service/glean/src/main/java/mozilla/components/service/glean/Glean.kt

@@ -216,8 +216,17 @@ open class GleanInternalAPI internal constructor () {
         val newClientId = uuidClientInfoSnapshot?.get("client_id")
         if (newClientId == null) {
             val uuidPingInfoSnapshot = UuidsStorageEngine.getSnapshot("glean_ping_info", false)
-            uuidPingInfoSnapshot?.get("client_id")?.let {
-                UuidsStorageEngine.record(GleanInternalMetrics.clientId, it)
+            val legacyClientId = uuidPingInfoSnapshot?.get("client_id")
+            if (legacyClientId != null) {
+                UuidsStorageEngine.record(GleanInternalMetrics.clientId, legacyClientId)
+            } else {
+                // Apparently, this is a very old build that was already run
+                // at least once and has a different name for the underlying
+                // UUID storage engine persistence (i.e. UuidStorageEngine.xml
+                // vs using the full class name with the namespace).
+                // This should be mostly devs and super early adopters, so just regenerate
+                // the data.
+                UuidsStorageEngine.record(GleanInternalMetrics.clientId, UUID.randomUUID())
             }
         }
 
@@ -225,11 +234,23 @@ open class GleanInternalAPI internal constructor () {
         val newFirstRunDate = datetimeClientInfoSnapshot?.get("first_run_date")
         if (newFirstRunDate == null) {
             val datetimePingInfoSnapshot = DatetimesStorageEngine.getSnapshot("glean_ping_info", false)
+            var firstRunDateSet = false
             datetimePingInfoSnapshot?.get("first_run_date")?.let {
-                parseISOTimeString(it)?.let {
-                    DatetimesStorageEngine.set(GleanInternalMetrics.firstRunDate, it)
+                parseISOTimeString(it)?.let { parsedDate ->
+                    DatetimesStorageEngine.set(GleanInternalMetrics.firstRunDate, parsedDate)
+                    firstRunDateSet = true
                 }
             }
+
+            if (!firstRunDateSet) {
+                // Apparently, this is a very old build that was already run
+                // at least once and has a different name for the underlying
+                // Datetime storage engine persistence (i.e. DatetimeStorageEngine.xml
+                // vs using the full class name with the namespace).
+                // This should be mostly devs and super early adopters, so just regenerate
+                // the data.
+                DatetimesStorageEngine.set(GleanInternalMetrics.firstRunDate)
+            }
         }
     }
 

components/service/glean/src/test/java/mozilla/components/service/glean/GleanTest.kt

@@ -15,6 +15,7 @@ import kotlinx.coroutines.ObsoleteCoroutinesApi
 import kotlinx.coroutines.runBlocking
 import mozilla.components.service.glean.GleanMetrics.GleanInternalMetrics
 import mozilla.components.service.glean.config.Configuration
+import mozilla.components.service.glean.firstrun.FileFirstRunDetector
 import mozilla.components.service.glean.private.DatetimeMetricType
 import mozilla.components.service.glean.private.EventMetricType
 import mozilla.components.service.glean.private.Lifetime
@@ -394,6 +395,35 @@ class GleanTest {
         assertNotEquals(firstRunDateMetric.testGetValue(), GleanInternalMetrics.firstRunDate.testGetValue())
     }
 
+    @Test
+    fun `client_id and first_run_date must be generated if not available after the first start`() {
+        // 1539480 BACKWARD COMPATIBILITY HACK
+
+        // The resetGlean called right before this function will add client_id
+        // and first_run_date to the new location in glean_client_info.  We
+        // need to clear those out again so we can test what happens when they
+        // are missing.
+        StorageEngineManager(
+            applicationContext = ApplicationProvider.getApplicationContext()
+        ).clearAllStores()
+
+        assertFalse(GleanInternalMetrics.clientId.testHasValue())
+        assertFalse(GleanInternalMetrics.firstRunDate.testHasValue())
+
+        // Set this to be a non-first start with missing clientId/firstRunDate.
+        val gleanDataDir =
+            File(ApplicationProvider.getApplicationContext<Context>().applicationInfo.dataDir, Glean.GLEAN_DATA_DIR)
+        val firstRunDetector = FileFirstRunDetector(gleanDataDir)
+        firstRunDetector.createFirstRunFile()
+
+        // This should copy the values to their new locations
+        Glean.initialized = false
+        Glean.initialize(ApplicationProvider.getApplicationContext())
+
+        assertTrue(GleanInternalMetrics.clientId.testHasValue())
+        assertTrue(GleanInternalMetrics.firstRunDate.testHasValue())
+    }
+
     @Test
     fun `getLanguageTag() reports the tag for the default locale`() {
         val defaultLanguageTag = getLocaleTag()