Merge lp:~jelmer/brz/git-switch into lp:brz

[Jelmer Vernooij]

Fix 'brz switch' in git repositories.

Fix 'brz switch' in git repositories.

[Martin Packman (gz)]

Okay. This is pretty hairy but was previously as well.

review: Approve

[The Breezy Bot (the-breezy-bot)]

Merging failed
https://ci.breezy-vcs.org/job/brz/job/brz-land/58/

=== modified file 'breezy/git/tests/test_blackbox.py'
--- breezy/git/tests/test_blackbox.py	2018-11-16 19:47:19 +0000
+++ breezy/git/tests/test_blackbox.py	2018-11-16 23:29:29 +0000
@@ -30,6 +30,7 @@
     )
 
 from ...tests.blackbox import ExternalBase
+from ...workingtree import WorkingTree
 
 from .. import (
     tests,
@@ -338,6 +339,37 @@
         self.assertEqual(output, 'VERSION_INFO \n')
 
 
+class SwitchTests(ExternalBase):
+
+    def test_switch_branch(self):
+        # Create a git repository with a revision.
+        repo = GitRepo.init(self.test_dir)
+        builder = tests.GitBranchBuilder()
+        builder.set_branch(b'refs/heads/oldbranch')
+        builder.set_file('a', b'text for a\n', False)
+        builder.commit(b'Joe Foo <[e-mail]>', u'<The commit message>')
+        builder.set_branch(b'refs/heads/newbranch')
+        builder.reset()
+        builder.set_file('a', b'text for new a\n', False)
+        builder.commit(b'Joe Foo <[e-mail]>', u'<The commit message>')
+        builder.finish()
+
+        repo.refs.set_symbolic_ref(b'HEAD', b'refs/heads/newbranch')
+
+        repo.reset_index()
+
+        output, error = self.run_bzr('switch oldbranch')
+        self.assertEqual(output, '')
+        self.assertTrue(error.startswith('Updated to revision 1.\n'), error)
+
+        self.assertFileEqual("text for a\n", 'a')
+        tree = WorkingTree.open('.')
+        with tree.lock_read():
+            basis_tree = tree.basis_tree()
+            with basis_tree.lock_read():
+                self.assertEqual([], list(tree.iter_changes(basis_tree)))
+
+
 class GrepTests(ExternalBase):
 
     def test_simple_grep(self):
 
=== modified file 'breezy/switch.py'
--- breezy/switch.py	2018-11-12 01:41:38 +0000
+++ breezy/switch.py	2018-11-16 23:29:29 +0000
@@ -50,42 +50,74 @@
     :param store_uncommitted: If True, store uncommitted changes in the
         branch.
     """
-    _check_pending_merges(control_dir, force)
-    try:
-        source_repository = control_dir.open_branch().repository
-    except errors.NotBranchError:
-        source_repository = to_branch.repository
-    if store_uncommitted:
-        with lock.write_locked(control_dir.open_workingtree()) as tree:
+    try:
+        tree = control_dir.open_workingtree()
+    except errors.NotBranchError as ex:
+        # Lightweight checkout and branch is no longer there
+        if not force or store_uncommitted:
+            raise ex
+        else:
+            tree = None
+    else:
+        if store_uncommitted or tree.branch.get_bound_location():
+            tree.lock_write()
+        else:
+            tree.lock_tree_write()
+    try:
+        if tree is not None:
+            parent_ids = tree.get_parent_ids()
+            if len(parent_ids) > 1:
+                raise errors.BzrCommandError(
+                    gettext('Pending merges must be '
+                            'committed or reverted before using switch.'))
+
+        if store_uncommitted:
             tree.store_uncommitted()
+        if tree is None:
+            source_repository = to_branch.repository
+            base_revision_id = None
+        else:
+            source_repository = tree.branch.repository
+            # Attempt to retrieve the base_revision_id now, since some
+            # working tree formats (i.e. git) don't have their own
+            # last_revision but just use that of the currently active branch.
+            base_revision_id = tree.last_revision()
+    finally:
+        if tree is not None:
+            tree.unlock()
     with to_branch.lock_read():
-        _set_branch_location(control_dir, to_branch, force)
+        _set_branch_location(control_dir, to_branch, tree.branch if tree else None, force)
     tree = control_dir.open_workingtree()
-    _update(tree, source_repository, quiet, revision_id, store_uncommitted)
-    _run_post_switch_hooks(control_dir, to_branch, force, revision_id)
-
-
-def _check_pending_merges(control, force=False):
-    """Check that there are no outstanding pending merges before switching.
-
-    :param control: ControlDir of the branch to check
-    """
+    if store_uncommitted:
+        tree.lock_write()
+    else:
+        tree.lock_tree_write()
     try:
-        tree = control.open_workingtree()
-    except errors.NotBranchError as ex:
-        # Lightweight checkout and branch is no longer there
-        if force:
-            return
+        if base_revision_id is None:
+            # If we couldn't get to the tree's last_revision earlier, perhaps
+            # we can now.
+            base_revision_id = tree.last_revision()
+        if revision_id is None:
+            revision_id = to_branch.last_revision()
+        if base_revision_id == revision_id:
+            if not quiet:
+                note(gettext("Tree is up to date at revision %d."),
+                     to_branch.revno())
         else:
-            raise ex
-    # XXX: Should the tree be locked for get_parent_ids?
-    existing_pending_merges = tree.get_parent_ids()[1:]
-    if len(existing_pending_merges) > 0:
-        raise errors.BzrCommandError(gettext('Pending merges must be '
-                                             'committed or reverted before using switch.'))
-
-
-def _set_branch_location(control, to_branch, force=False):
+            base_tree = source_repository.revision_tree(base_revision_id)
+            target_tree = to_branch.repository.revision_tree(revision_id)
+            merge.Merge3Merger(tree, tree, base_tree, target_tree)
+            tree.set_last_revision(revision_id)
+            if not quiet:
+                note(gettext('Updated to revision %d.') % to_branch.revno())
+        if store_uncommitted:
+            tree.restore_uncommitted()
+        _run_post_switch_hooks(control_dir, to_branch, force, revision_id)
+    finally:
+        tree.unlock()
+
+
+def _set_branch_location(control, to_branch, current_branch, force=False):
     """Set location value of a branch reference.
 
     :param control: ControlDir of the checkout to change
@@ -97,7 +129,7 @@
         # Lightweight checkout: update the branch reference
         branch_format.set_reference(control, None, to_branch)
     else:
-        b = control.open_branch()
+        b = current_branch
         bound_branch = b.get_bound_location()
         if bound_branch is not None:
             # Heavyweight checkout: check all local commits
@@ -152,36 +184,3 @@
             if not graph.is_ancestor(last_rev, other_last_rev):
                 return True
     return False
-
-
-def _update(tree, source_repository, quiet=False, revision_id=None,
-            restore_uncommitted=False):
-    """Update a working tree to the latest revision of its branch.
-
-    :param tree: the working tree
-    :param source_repository: repository holding the revisions
-    :param restore_uncommitted: restore any uncommitted changes in the branch.
-    """
-    if restore_uncommitted:
-        tree.lock_write()
-    else:
-        tree.lock_tree_write()
-    try:
-        to_branch = tree.branch
-        if revision_id is None:
-            revision_id = to_branch.last_revision()
-        if tree.last_revision() == revision_id:
-            if not quiet:
-                note(gettext("Tree is up to date at revision %d."),
-                     to_branch.revno())
-        else:
-            base_tree = source_repository.revision_tree(tree.last_revision())
-            merge.Merge3Merger(tree, tree, base_tree,
-                               to_branch.repository.revision_tree(revision_id))
-            tree.set_last_revision(to_branch.last_revision())
-            if not quiet:
-                note(gettext('Updated to revision %d.') % to_branch.revno())
-        if restore_uncommitted:
-            tree.restore_uncommitted()
-    finally:
-        tree.unlock()
 
=== modified file 'breezy/tests/blackbox/test_switch.py'
--- breezy/tests/blackbox/test_switch.py	2018-11-16 11:37:47 +0000
+++ breezy/tests/blackbox/test_switch.py	2018-11-16 23:29:29 +0000
@@ -492,8 +492,8 @@
         # being too low. If rpc_count increases, more network roundtrips have
         # become necessary for this use case. Please do not adjust this number
         # upwards without agreement from bzr's network support maintainers.
-        self.assertLength(24, self.hpss_calls)
-        self.assertLength(4, self.hpss_connections)
+        self.assertLength(21, self.hpss_calls)
+        self.assertLength(3, self.hpss_connections)
         self.assertThat(self.hpss_calls, ContainsNoVfsCalls)