"bzr update" in checkout of empty branch fails and breaks dirstate

[Andrew Bennetts]

The following shell script:

"""
# Make a branch with zero revisions.
bzr init master
# Check it out
bzr co master slave
# Make a local commit
cd slave
bzr ci --local --unchanged -m "Empty commit."
# Update. Boom!
bzr update
"""

Will trigger the following traceback:

bzr: ERROR: exceptions.TypeError: sequence item 1: expected string, NoneType found

Traceback (most recent call last):
  File "/home/andrew/code/bzr/bzrlib/commands.py", line 717, in run_bzr_catch_errors
    return run_bzr(argv)
  File "/home/andrew/code/bzr/bzrlib/commands.py", line 678, in run_bzr
    ret = run(*run_argv)
  File "/home/andrew/code/bzr/bzrlib/commands.py", line 375, in run_argv_aliases
    return self.run(**all_cmd_args)
  File "/home/andrew/code/bzr/bzrlib/builtins.py", line 1045, in run
    tree.unlock()
  File "/home/andrew/code/bzr/bzrlib/workingtree_4.py", line 1119, in unlock
    self.flush()
  File "/home/andrew/code/bzr/bzrlib/workingtree_4.py", line 311, in flush
    self.current_dirstate().save()
  File "/home/andrew/code/bzr/bzrlib/dirstate.py", line 1728, in save
    self._state_file.writelines(self.get_lines())
  File "/home/andrew/code/bzr/bzrlib/dirstate.py", line 1221, in get_lines
    lines.append(self._get_parents_line(self.get_parent_ids()))
  File "/home/andrew/code/bzr/bzrlib/dirstate.py", line 1233, in _get_parents_line
    return '\0'.join([str(len(parent_ids))] + parent_ids)
TypeError: sequence item 1: expected string, NoneType found

bzr 0.18.0dev0 on python 2.5.1.final.0 (linux2)
arguments: ['/home/andrew/code/bzr/bzr', 'update']

I've reproduced this with current bzr.dev.

A use case that prompts this is An obvious way to create a start a branch for a new project that you want to host remotely is to "bzr init REMOTE_URL" then immediately "bzr checkout REMOTE_URL LOCAL_CHECKOUT".

A workaround would be to do "bzr init LOCAL_CHECKOUT", and once there's at least one revision there, then do "bzr push REMOTE_URL; bzr bind" to create the remote branch and convert the local branch into a checkout.

[Mary Gardiner (puzzlement)]

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[Wouter van Heyst (larstiq)]

Same symptom as 127115, different cause.

[Martin Pool (mbp)]

What's worse is that this also seems to do an incorrect merge against the empty revision, causing any locally added files to be deleted.

[Martin Pool (mbp)]

bug 127115 is now fixed, but as of 0.91 this one is not.

[Martin Pool (mbp)]

bug 127115 is now fixed, but as of 0.91 this one is not.

There is a workaround for this: do a blank (or non-blank) commit on the main branch before doing the local commits.

[James Westby (james-w)]

On (14/09/07 16:54), Martin Pool wrote:
> This is https://bugs.launchpad.net/bzr/+bug/120968 "bzr update" in
> checkout of empty branch fails and breaks dirstate

The sequence at the top now fails with the following error instead:

All changes applied successfully.
bzr: ERROR: bzrlib.errors.ReservedId: Reserved revision-id {null:}

Traceback (most recent call last):
  File "/home/jw2328/devel/bzr/bzr.dev/bzrlib/commands.py", line 800, in run_bzr_catch_errors
    return run_bzr(argv)
  File "/home/jw2328/devel/bzr/bzr.dev/bzrlib/commands.py", line 758, in run_bzr
    ret = run(*run_argv)
  File "/home/jw2328/devel/bzr/bzr.dev/bzrlib/commands.py", line 492, in run_argv_aliases
    return self.run(**all_cmd_args)
  File "/home/jw2328/devel/bzr/bzr.dev/bzrlib/builtins.py", line 1039, in run
    possible_transports=possible_transports)
  File "/home/jw2328/devel/bzr/bzr.dev/bzrlib/workingtree.py", line 2061, in update
    return self._update_tree(old_tip, change_reporter)
  File "/home/jw2328/devel/bzr/bzr.dev/bzrlib/mutabletree.py", line 50, in tree_write_locked
    return unbound(self, *args, **kwargs)
  File "/home/jw2328/devel/bzr/bzr.dev/bzrlib/workingtree.py", line 2119, in _update_tree
    self.set_parent_trees(parent_trees)
  File "/home/jw2328/devel/bzr/bzr.dev/bzrlib/mutabletree.py", line 50, in tree_write_locked
    return unbound(self, *args, **kwargs)
  File "/home/jw2328/devel/bzr/bzr.dev/bzrlib/workingtree_4.py", line 1099, in set_parent_trees
    _mod_revision.check_not_reserved_id(rev_id)
  File "/home/jw2328/devel/bzr/bzr.dev/bzrlib/revision.py", line 451, in check_not_reserved_id
    raise errors.ReservedId(revision_id)
ReservedId: Reserved revision-id {null:}

presumably with Aaron's null: changes.

Here is a testcase to exercise this bug:

=== modified file 'bzrlib/tests/blackbox/test_update.py'
--- bzrlib/tests/blackbox/test_update.py 2007-08-08 02:01:10 +0000
+++ bzrlib/tests/blackbox/test_update.py 2007-09-14 16:36:30 +0000
@@ -210,3 +210,11 @@
                                                    lightweight=True)
         tree.commit('empty commit')
         self.run_bzr('update checkout')
+
+ def test_update_checkout_of_empty_branch(self):
+ """Run update in a checkout of an empty branch: #438137."""
+ tree = self.make_branch_and_tree('branch')
+ checkout = tree.branch.create_checkout('checkout', lightweight=False)
+ checkout.commit('empty commit', local=True)
+ self.run_bzr('update checkout')
+

--
  James Westby -- GPG Key ID: B577FE13 -- http://jameswestby.net/
  seccure key - (3+)k7|M*edCX/.A:n*N!>|&7U.L#9E)Tu)T0>AM - secp256r1/nistp256

[Aaron Bentley (abentley)]

-----BEGIN PGP SIGNED MESSAGE-----
Hash: SHA1

James Westby wrote:
> On (14/09/07 16:54), Martin Pool wrote:
>> This is https://bugs.launchpad.net/bzr/+bug/120968 "bzr update" in
>> checkout of empty branch fails and breaks dirstate
> ReservedId: Reserved revision-id {null:}
>
> presumably with Aaron's null: changes.

The error here is correct; if the parent is null, you should do
set_parent_trees([]).

Aaron
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Comment: Using GnuPG with Mozilla - http://enigmail.mozdev.org

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[Wouter van Heyst (larstiq)]

This seems to work fine with 1.5, I'll get back to checking up and closing it after reporting a related bug.

[Otaci Martins (otaci)]

Same problem to me.

My specs:

- Bazaar 1.9
- Fedora 10
- Kernel 2.6.27.7-134

Steps:

In central host:

    # bzr init-repo myprojetc
    # cd myproject
    # bzr init trunk

In developer's laptop:

     # bzr init-repo myproject
     # cd myproject
     # bzr branch sftp://centralhost/projects/myproject/trunk
     # bzr branch trunk v1.0
     # cd v1.0
     # (hack, hack, hack)
     # bzr commit
     # cd ../trunk
     # bzr pull
     # bzr merge ../v1.0
     # bzr status
         working tree is out of date, run 'bzr update'
      # bzr update
          (deletes some files)
          bzr: ERROR: Reserved revision-id {null:}

[Robert Collins (lifeless)]

Don't know how, don't know who, don't know when, but the sample snippet works.