avoid a crash in eden doctor if any active mounts are unconfigured

Summary:
My stale mounts check regressed eden doctor's handling of
unconfigured mounts.  For now, just skip them, and add a test that
eden doctor doesn't crash.

Reviewed By: simpkins

Differential Revision: D6801445

fbshipit-source-id: 65d2f9028af651ef487a7ce6c334f387b541492d

eden/cli/doctor.py

@@ -89,6 +89,13 @@ def cure_what_ails_you(
 
     watchman_roots = _get_watch_roots_for_watchman()
     for mount_path in active_mount_points:
+        if mount_path not in config.get_mount_paths():
+            # TODO: if there are mounts in active_mount_points that aren't in
+            # config.get_mount_paths(), should we try to add them to the config?
+            # I've only seen this happen in the wild if a clone fails partway, for
+            # example, if a post-clone hook fails.
+            continue
+
         # For now, we assume that each mount_path is actively mounted. We should
         # update the listMounts() Thrift API to return information that notes
         # whether a mount point is active and use it here.

eden/cli/test/doctor_test.py

@@ -475,6 +475,63 @@ All is well.
 
         mock_rpm_q.assert_has_calls(calls)
 
+    def test_unconfigured_mounts_dont_crash(self):
+        # If Eden advertises that a mount is active, but it is not in the
+        # configuration, then at least don't throw an exception.
+        tmp_dir = tempfile.mkdtemp(prefix='eden_test.')
+        try:
+            edenfs_path1 = os.path.join(tmp_dir, 'path1')
+            edenfs_path2 = os.path.join(tmp_dir, 'path2')
+
+            mount_paths = OrderedDict()
+            mount_paths[edenfs_path1] = {
+                'bind-mounts': {},
+                'mount': edenfs_path1,
+                'scm_type': 'hg',
+                'snapshot': 'abcd' * 10,
+                'client-dir': '/I_DO_NOT_EXIST1'
+            }
+            # path2 is not configured in the config...
+            config = FakeConfig(mount_paths, is_healthy=True)
+            # ... but is advertised by the daemon...
+            config.get_thrift_client()._mounts = [
+                eden_ttypes.MountInfo(mountPoint=edenfs_path1),
+                eden_ttypes.MountInfo(mountPoint=edenfs_path2),
+            ]
+
+            # ... and is in the system mount table.
+            mount_table = FakeMountTable()
+            mount_table.stats[edenfs_path1] = mtab.MTStat(
+                st_uid=os.getuid(),
+                st_dev=11)
+            mount_table.stats[edenfs_path2] = mtab.MTStat(
+                st_uid=os.getuid(),
+                st_dev=12)
+
+            os.mkdir(edenfs_path1)
+            hg_dir = os.path.join(edenfs_path1, '.hg')
+            os.mkdir(hg_dir)
+            dirstate = os.path.join(hg_dir, 'dirstate')
+            dirstate_hash = b'\xab\xcd' * 10
+            parents = (dirstate_hash, b'\x00' * 20)
+            with open(dirstate, 'wb') as f:
+                eden.dirstate.write(f, parents, tuples_dict={}, copymap={})
+
+            dry_run = False
+            out = io.StringIO()
+            exit_code = doctor.cure_what_ails_you(
+                config, dry_run, out, mount_table)
+        finally:
+            shutil.rmtree(tmp_dir)
+
+        self.assertEqual(
+            f'''\
+Performing 3 checks for {edenfs_path1}.
+All is well.
+''', out.getvalue()
+        )
+        self.assertEqual(0, exit_code)
+
 
 class StaleMountsCheckTest(unittest.TestCase):
     maxDiff = None