From f398d09b23496cbd85d4e0b199fba93194cd7d8b Mon Sep 17 00:00:00 2001
From: Benjamin Berg <bberg@redhat.com>
Date: Wed, 30 Jun 2021 12:09:30 +0200
Subject: [PATCH] device: Delete existing print in EnrollStart

gnome-control-center expects to be able to re-enroll an existing print
when calling EnrollStart without deleting it first. As such, implicitly
delete the existing print rather than throwing an error.

Ideally, we'll change the API, but we need to give API users time to
adjust to the world.
---
 src/device.c     | 24 ++++++++++++++----------
 tests/fprintd.py | 16 ++++++++++++++--
 2 files changed, 28 insertions(+), 12 deletions(-)

diff --git a/src/device.c b/src/device.c
index 010bfc5..49cbdd5 100644
--- a/src/device.c
+++ b/src/device.c
@@ -54,6 +54,11 @@ static gboolean action_authorization_handler (GDBusInterfaceSkeleton *,
                                               GDBusMethodInvocation *,
                                               gpointer user_data);
 
+static gboolean delete_enrolled_fingers (FprintDevice *rdev,
+                                         const char   *user,
+                                         FpFinger      finger,
+                                         GError      **error);
+
 static GQuark quark_auth_user = 0;
 
 typedef enum {
@@ -1979,22 +1984,21 @@ fprint_device_enroll_start (FprintDBusDevice      *dbus_dev,
   store.print_data_load (priv->dev, finger,
                          session->username, &existing_print);
 
-  if (existing_print)
-    {
-      g_set_error (&error, FPRINT_ERROR, FPRINT_ERROR_FINGER_ALREADY_ENROLLED,
-                   "Finger %d has already been enrolled for user %s", finger, session->username);
-      g_dbus_method_invocation_return_gerror (invocation,
-                                              error);
-      return TRUE;
-    }
-
-
   if (!can_start_action (rdev, &error))
     {
       g_dbus_method_invocation_return_gerror (invocation, error);
       return TRUE;
     }
 
+  if (existing_print)
+    {
+      if (!delete_enrolled_fingers (rdev, session->username, finger, &error))
+        {
+          g_dbus_method_invocation_return_gerror (invocation, error);
+          return TRUE;
+        }
+    }
+
   g_debug ("start enrollment device %d finger %d", priv->id, finger);
 
   priv->current_cancellable = g_cancellable_new ();
diff --git a/tests/fprintd.py b/tests/fprintd.py
index e35ac88..1f8faee 100644
--- a/tests/fprintd.py
+++ b/tests/fprintd.py
@@ -2315,9 +2315,21 @@ class FPrintdVirtualDeviceEnrollTests(FPrintdVirtualDeviceBaseTest):
     def test_enroll_already_enrolled_finger(self):
         self.enroll_image('whorl', start=False)
 
+        # We can enroll a new image deleting the first
+        self.device.EnrollStart('(s)', 'left-middle-finger')
+        self.enroll_image('arch', start=False)
         self.stop_on_teardown = False
-        with self.assertFprintError('FingerAlreadyEnrolled'):
-            self.device.EnrollStart('(s)', 'left-middle-finger')
+
+        # If we verify, 'arch' will match, 'whorl' will not match
+        self.device.VerifyStart('(s)', 'any')
+        self.send_image('whorl')
+        self.assertVerifyNoMatch()
+        self.device.VerifyStop()
+
+        self.device.VerifyStart('(s)', 'any')
+        self.send_image('arch')
+        self.assertVerifyMatch()
+        self.device.VerifyStop()
 
     def test_enroll_duplicate_image(self):
         self.enroll_image('whorl', finger='left-thumb', start=False)