Prevent contact records from being resynced from unrelated changes.

app/src/main/java/org/thoughtcrime/securesms/database/RecipientTable.kt

@@ -1977,8 +1977,13 @@ open class RecipientTable(context: Context, databaseHelper: SignalDatabase) : Da
   /**
    * Applies multiple profile fields in a single UPDATE statement. Calls [rotateStorageId] and
    * [notifyRecipientChanged] at most once. Designed for bulk profile fetches.
+   *
+   * Of these fields, only the profile name and username live on the storage service contact record, so
+   * the storage id is only rotated when one of those actually changes.
    */
   fun applyProfileUpdate(id: RecipientId, update: ProfileUpdate) {
+    val clearsUsername = update.clearUsername && hasUsername(id)
+
     val contentValues = ContentValues().apply {
       update.profileName?.let {
         put(PROFILE_GIVEN_NAME, it.givenName.nullIfBlank())
@@ -2009,7 +2014,7 @@ open class RecipientTable(context: Context, databaseHelper: SignalDatabase) : Da
           .build()
         put(EXPIRING_PROFILE_KEY_CREDENTIAL, Base64.encodeWithPadding(columnData.encode()))
       }
-      if (update.clearUsername) {
+      if (clearsUsername) {
         putNull(USERNAME)
       }
     }
@@ -2019,7 +2024,7 @@ open class RecipientTable(context: Context, databaseHelper: SignalDatabase) : Da
     }
 
     if (update(id, contentValues)) {
-      val needsStorageRotation = update.profileName != null || update.clearUsername
+      val needsStorageRotation = update.profileName != null || clearsUsername
       if (needsStorageRotation) {
         rotateStorageId(id)
       }
@@ -2027,6 +2032,13 @@ open class RecipientTable(context: Context, databaseHelper: SignalDatabase) : Da
     }
   }
 
+  private fun hasUsername(id: RecipientId): Boolean {
+    return readableDatabase
+      .exists(TABLE_NAME)
+      .where("$ID = ? AND $USERNAME NOT NULL", id.serialize())
+      .run()
+  }
+
   fun setProfileName(id: RecipientId, profileName: ProfileName) {
     val contentValues = ContentValues(1).apply {
       put(PROFILE_GIVEN_NAME, profileName.givenName.nullIfBlank())

app/src/main/java/org/thoughtcrime/securesms/jobs/RetrieveProfileJob.kt

@@ -313,7 +313,7 @@ class RetrieveProfileJob private constructor(parameters: Parameters, private val
       val profileNameResult = resolveProfileName(recipient, recipientProfileKey, profile.name)
       val aboutResult = resolveProfileAbout(recipientProfileKey, profile.about, profile.aboutEmoji)
       val phoneNumberSharing = resolvePhoneNumberSharing(recipient, recipientProfileKey, profile.phoneNumberSharing)
-      val clearUsername = recipient.hasNonUsernameDisplayName(context) || profileNameResult?.changed == true
+      val clearUsername = (recipient.username.isPresent && recipient.hasNonUsernameDisplayName(context)) || profileNameResult?.changed == true
 
       val update = RecipientTable.ProfileUpdate(
         profileName = if (profileNameResult?.changed == true) profileNameResult.remoteProfileName else null,

app/src/test/java/org/thoughtcrime/securesms/database/RecipientTableTest.kt

@@ -13,6 +13,8 @@ import org.junit.Assert.assertEquals
 import org.junit.Assert.assertFalse
 import org.junit.Assert.assertNotEquals
 import org.junit.Assert.assertNotNull
+import org.junit.Assert.assertNull
+import org.junit.Assert.assertTrue
 import org.junit.Before
 import org.junit.Rule
 import org.junit.Test
@@ -231,6 +233,70 @@ class RecipientTableTest {
     assertThat(uncategorized).isEmpty()
   }
 
+  @Test
+  fun givenAContactWithNoUsername_whenAProfileUpdateOnlyChangesFieldsAbsentFromTheContactRecord_thenIExpectNoStorageIdRotation() {
+    SignalDatabase.recipients.setStorageIdIfNotSet(target)
+    val originalStorageId: ByteArray? = SignalDatabase.recipients.getRecord(target).storageId
+    assertNotNull("Precondition: contact should have a storage id", originalStorageId)
+    assertNull("Precondition: contact should have no username", SignalDatabase.recipients.getUsername(target))
+
+    // WHEN a profile fetch reports a new sealed sender mode, which the contact record does not carry
+    SignalDatabase.recipients.applyProfileUpdate(
+      target,
+      RecipientTable.ProfileUpdate(
+        sealedSenderAccessMode = RecipientTable.SealedSenderAccessMode.ENABLED,
+        clearUsername = true
+      )
+    )
+
+    assertEquals(RecipientTable.SealedSenderAccessMode.ENABLED, SignalDatabase.recipients.getRecord(target).sealedSenderAccessMode)
+    assertTrue(
+      "Storage id must not rotate for fields absent from the contact record, otherwise we republish identical content under a fresh id",
+      originalStorageId!!.contentEquals(SignalDatabase.recipients.getRecord(target).storageId)
+    )
+  }
+
+  @Test
+  fun givenAContactWithAUsername_whenAProfileUpdateClearsIt_thenIExpectAStorageIdRotation() {
+    SignalDatabase.recipients.setUsername(target, "target.01")
+    SignalDatabase.recipients.setStorageIdIfNotSet(target)
+
+    val originalStorageId: ByteArray? = SignalDatabase.recipients.getRecord(target).storageId
+    assertNotNull("Precondition: contact should have a storage id", originalStorageId)
+
+    SignalDatabase.recipients.applyProfileUpdate(
+      target,
+      RecipientTable.ProfileUpdate(
+        sealedSenderAccessMode = RecipientTable.SealedSenderAccessMode.ENABLED,
+        clearUsername = true
+      )
+    )
+
+    assertNull(SignalDatabase.recipients.getUsername(target))
+    assertFalse(
+      "Storage id should rotate when the username is actually cleared",
+      originalStorageId!!.contentEquals(SignalDatabase.recipients.getRecord(target).storageId)
+    )
+  }
+
+  @Test
+  fun givenASyncedContact_whenAProfileUpdateChangesTheProfileName_thenIExpectAStorageIdRotation() {
+    SignalDatabase.recipients.setStorageIdIfNotSet(target)
+    val originalStorageId: ByteArray? = SignalDatabase.recipients.getRecord(target).storageId
+    assertNotNull("Precondition: contact should have a storage id", originalStorageId)
+
+    // WHEN a profile fetch reports a new profile name, which the contact record does carry
+    SignalDatabase.recipients.applyProfileUpdate(
+      target,
+      RecipientTable.ProfileUpdate(profileName = ProfileName.fromParts("Renamed", "Person"))
+    )
+
+    assertFalse(
+      "Storage id should rotate when the profile name changes",
+      originalStorageId!!.contentEquals(SignalDatabase.recipients.getRecord(target).storageId)
+    )
+  }
+
   companion object {
     val ACI_A = ACI.from(UUID.fromString("aaaa0000-5a76-47fa-a98a-7e72c948a82e"))
     val PNI_A = PNI.from(UUID.fromString("aaaa1111-c960-4f6c-8385-671ad2ffb999"))