Add integration test for rebasing in Hg.

Summary:
This is a relatively simple test that takes two branches with no conflicts and
rebases one on top of the other. It also provides modest checks to ensure Eden
does not load a bunch of inodes unnecessarily when updating to the new head.

This also introduces `EdenServerInspector`, which provides convenience methods
for inspecting the Eden server via Thrift.

Reviewed By: simpkins

Differential Revision: D5504741

fbshipit-source-id: 6636c431658f24a850d0e5404d1a0e4f0528a781

eden/fs/service/__init__.py

@@ -8,9 +8,10 @@
 from __future__ import (absolute_import, division,
                         print_function, unicode_literals)
 
-from .client import EdenNotRunningError, create_thrift_client
+from .client import EdenClient, EdenNotRunningError, create_thrift_client
 
 __all__ = [
+    'EdenClient',
     'EdenNotRunningError',
     'create_thrift_client',
 ]

eden/integration/hg/rebase_test.py

@@ -0,0 +1,91 @@
+#!/usr/bin/env python3
+#
+# Copyright (c) 2016-present, Facebook, Inc.
+# All rights reserved.
+#
+# This source code is licensed under the BSD-style license found in the
+# LICENSE file in the root directory of this source tree. An additional grant
+# of patent rights can be found in the PATENTS file in the same directory.
+
+from .lib.hg_extension_test_base import HgExtensionTestBase
+from ..lib import eden_server_inspector
+
+
+class RebaseTest(HgExtensionTestBase):
+    def populate_backing_repo(self, repo):
+        repo.mkdir('numbers')
+        repo.write_file('numbers/README', 'this will have two directories')
+        self._base_commit = repo.commit('commit')
+
+        repo.mkdir('numbers/1')
+        repo.write_file('numbers/1/11', '')
+        self._c11 = repo.commit('c11')
+        repo.write_file('numbers/1/12', '')
+        self._c12 = repo.commit('c12')
+        repo.write_file('numbers/1/13', '')
+        self._c13 = repo.commit('c13')
+        repo.write_file('numbers/1/14', '')
+        self._c14 = repo.commit('c14')
+        repo.write_file('numbers/1/15', '')
+        self._c15 = repo.commit('c15')
+
+        repo.update(self._base_commit)
+        repo.mkdir('numbers/2')
+        repo.write_file('numbers/2/21', '')
+        self._c21 = repo.commit('c21')
+        repo.write_file('numbers/2/22', '')
+        self._c22 = repo.commit('c22')
+        repo.write_file('numbers/2/23', '')
+        self._c23 = repo.commit('c23')
+        repo.write_file('numbers/2/24', '')
+        self._c24 = repo.commit('c24')
+        repo.write_file('numbers/2/25', '')
+        self._c25 = repo.commit('c25')
+
+        repo.update(self._base_commit)
+
+    def test_rebase_commit_with_independent_folder(self):
+        stdout = self.hg('rebase', '-s', self._c11, '-d', self._c25)
+        expected_stdout = f'''\
+rebasing 1:{self._c11[:12]} "c11"
+rebasing 2:{self._c12[:12]} "c12"
+rebasing 3:{self._c13[:12]} "c13"
+rebasing 4:{self._c14[:12]} "c14"
+rebasing 5:{self._c15[:12]} "c15"
+'''
+        self.assertEqual(expected_stdout, stdout)
+
+        # Get the hash of the new head created as a result of the rebase.
+        new_head = self.hg(
+            'log', '-r', f'successors({self._c15})', '-T', '{node}'
+        )
+
+        # Record the pre-update inode count.
+        inspector = eden_server_inspector.EdenServerInspector(self.repo.path)
+        inspector.unload_inode_for_path('numbers')
+        pre_update_count = inspector.get_inode_count('numbers')
+        print(f'loaded inode count before `hg update`: {pre_update_count}')
+
+        # Verify that updating to the new head that was created as a result of
+        # the rebase leaves Hg in the correct state.
+        self.assertEqual(1, len(self.repo.log()), msg=(
+            'At the base commit, `hg log` should have only one entry.'
+        ))
+        self.hg('update', new_head)
+        self.assertEqual(11, len(self.repo.log()), msg=(
+            'The new head should include all the commits.'
+        ))
+
+        # Verify the post-update inode count.
+        post_update_count = inspector.get_inode_count('numbers')
+        print(f'loaded inode count after `hg update`: {post_update_count}')
+        self.assertGreaterEqual(post_update_count, pre_update_count, msg=(
+            'The inode count should not decrease due to `hg update`.'
+        ))
+        num_new_inodes = post_update_count - pre_update_count
+        self.assertLessEqual(num_new_inodes, 2, msg=(
+            'There should be no more than 2 new inodes as a result of the '
+            'update. At the time this test was created, num_new_inodes is 0, '
+            'but if we included unloaded inodes, there would be 2: one for '
+            'numbers/1 and one for numbers/2.'
+        ))

eden/integration/lib/eden_server_inspector.py

@@ -0,0 +1,54 @@
+#!/usr/bin/env python3
+#
+# Copyright (c) 2016-present, Facebook, Inc.
+# All rights reserved.
+#
+# This source code is licensed under the BSD-style license found in the
+# LICENSE file in the root directory of this source tree. An additional grant
+# of patent rights can be found in the PATENTS file in the same directory.
+
+import eden.thrift
+from typing import Iterable
+
+'''Utilities for inspecting the state of the Eden server via Thrift.
+
+This utility is parameterized by a specific mount point so that it need not be
+specified for each instance method.
+'''
+
+
+class EdenServerInspector(object):
+    def __init__(self, mount_point: str) -> None:
+        self._mount_point = mount_point
+
+    def create_thrift_client(self) -> eden.thrift.EdenClient:
+        return eden.thrift.create_thrift_client(mounted_path=self._mount_point)
+
+    def unload_inode_for_path(self, path: str='') -> None:
+        '''path: relative path to a directory under the mount.'''
+        with self.create_thrift_client() as client:
+            client.unloadInodeForPath(self._mount_point, path)
+
+    def get_inode_count(self, path: str='') -> int:
+        '''path: relative path to a directory under the mount.
+
+        Use '' for the root. Note that this will include the inode count for
+        the root .hg and .eden entries.
+        '''
+        with self.create_thrift_client() as client:
+            debug_info = client.debugInodeStatus(self._mount_point, path)
+        count = 0
+        for tree_inode_debug_info in debug_info:
+            count += sum(1 for entry in tree_inode_debug_info.entries
+                         if entry.loaded)
+        return count
+
+    def get_paths_for_inodes(self, path: str='') -> Iterable[str]:
+        '''path: relative path to a directory under the mount.'''
+        with self.create_thrift_client() as client:
+            debug_info = client.debugInodeStatus(self._mount_point, path)
+        for tree_inode_debug_info in debug_info:
+            parent_dir = tree_inode_debug_info.path.decode('utf-8')
+            for entry in tree_inode_debug_info.entries:
+                if entry.loaded:
+                    yield f'{parent_dir}/{entry.name.decode("utf-8")}'