**Please help..
I cannot migrate from latest 3.x.xx to version 4.
Here is the screen log i captured from my terminal
Best Wishes
TArdi**

Linux Test101 3.2.0-4-amd64 #1 SMP Debian 3.2.60-1+deb7u3 x86_64

The programs included with the Debian GNU/Linux system are free software;
the exact distribution terms for each program are described in the
individual files in /usr/share/doc/*/copyright.

Debian GNU/Linux comes with ABSOLUTELY NO WARRANTY, to the extent
permitted by applicable law.
Last login: Wed Nov 12 06:04:42 2014 from 139.192.199.250
erpnext@Test101:~$ sudo pip install -e bench-repo
[sudo] password for erpnext:
erpnext@Test101:~$ cd /home/erpnext
erpnext@Test101:~$ git clone https://github.com/frappe/bench bench-repo
fatal: destination path 'bench-repo' already exists and is not an empty directory.
erpnext@Test101:~$ rm bench-repo/
rm: cannot remove `bench-repo/': Is a directory
erpnext@Test101:~$ sudo pip install -e bench-repo
[sudo] password for erpnext:
Obtaining file:///home/erpnext/bench-repo
  Running setup.py egg_info for package from file:///home/erpnext/bench-repo

    file bench.py (for module bench) not found
Requirement already satisfied (use --upgrade to upgrade): Click in /usr/local/lib/python2.7/dist-packages (from bench==0.1)
Requirement already satisfied (use --upgrade to upgrade): jinja2 in /usr/local/lib/python2.7/dist-packages (from bench==0.1)
Requirement already satisfied (use --upgrade to upgrade): virtualenv in /usr/local/lib/python2.7/dist-packages/virtualenv-1.10.1-py2.7.egg (from bench==0.1)
Requirement already satisfied (use --upgrade to upgrade): requests in /usr/local/lib/python2.7/dist-packages (from bench==0.1)
Requirement already satisfied (use --upgrade to upgrade): honcho in /usr/local/lib/python2.7/dist-packages (from bench==0.1)
Requirement already satisfied (use --upgrade to upgrade): semantic-version in /usr/local/lib/python2.7/dist-packages (from bench==0.1)
Requirement already satisfied (use --upgrade to upgrade): GitPython==0.3.2.RC1 in /usr/local/lib/python2.7/dist-packages (from bench==0.1)
Requirement already satisfied (use --upgrade to upgrade): markupsafe in /usr/local/lib/python2.7/dist-packages (from jinja2->bench==0.1)
Requirement already satisfied (use --upgrade to upgrade): gitdb>=0.5.1 in /usr/local/lib/python2.7/dist-packages (from GitPython==0.3.2.RC1->bench==0.1)
Requirement already satisfied (use --upgrade to upgrade): async>=0.6.1 in /usr/local/lib/python2.7/dist-packages (from gitdb>=0.5.1->GitPython==0.3.2.RC1->bench==0.1)
Requirement already satisfied (use --upgrade to upgrade): smmap>=0.8.0 in /usr/local/lib/python2.7/dist-packages (from gitdb>=0.5.1->GitPython==0.3.2.RC1->bench==0.1)
Installing collected packages: bench
  Running setup.py develop for bench

    file bench.py (for module bench) not found
    Creating /usr/local/lib/python2.7/dist-packages/bench.egg-link (link to .)
    bench 0.1 is already the active version in easy-install.pth
    Installing bench script to /usr/local/bin

    Installed /home/erpnext/bench-repo
Successfully installed bench
Cleaning up...
erpnext@Test101:~$ cd ~
erpnext@Test101:~$ bench init frappe-bench
Already using interpreter /usr/bin/python
Cloning into 'frappe'...
remote: Counting objects: 61784, done.
remote: Compressing objects: 100% (81/81), done.
remote: Total 61784 (delta 27), reused 1 (delta 0)
Receiving objects: 100% (61784/61784), 25.69 MiB | 203 KiB/s, done.
Resolving deltas: 100% (43739/43739), done.
installing frappe
Wrote ./assets/js/frappe-web.min.js - 90k
Wrote ./assets/js/print_format_v3.min.js - 18k
Wrote ./assets/css/frappe.css - 224k
Wrote ./assets/css/frappe-web.css - 163k
Wrote ./assets/js/editor.min.js - 27k
Wrote ./assets/js/frappe.min.js - 609k
Wrote ./assets/js/slickgrid.min.js - 102k
Wrote ./assets/js/canvasResize.min.js - 22k
Bench frappe-bench initialized
erpnext@Test101:~$ cd frappe-bench
erpnext@Test101:~/frappe-bench$ bench get-app erpnext https://github.com/frappe/erpnext
Cloning into 'erpnext'...
remote: Counting objects: 121266, done.
remote: Compressing objects: 100% (72/72), done.
remote: Total 121266 (delta 60), reused 40 (delta 32)
Receiving objects: 100% (121266/121266), 39.77 MiB | 201 KiB/s, done.
Resolving deltas: 100% (86964/86964), done.
installing erpnext
Wrote ./assets/js/frappe-web.min.js - 90k
Wrote ./assets/js/print_format_v3.min.js - 18k
Wrote ./assets/js/erpnext.min.js - 12k
Wrote ./assets/css/frappe.css - 224k
Wrote ./assets/css/frappe-web.css - 163k
Wrote ./assets/js/editor.min.js - 27k
Wrote ./assets/css/erpnext.css - 0k
Wrote ./assets/js/frappe.min.js - 609k
Wrote ./assets/js/erpnext-web.min.js - 0k
Wrote ./assets/js/slickgrid.min.js - 102k
Wrote ./assets/js/canvasResize.min.js - 22k
erpnext@Test101:~/frappe-bench$ bench get-app shopping_cart https://github.com/frappe/shopping-cart
Cloning into 'shopping_cart'...
remote: Counting objects: 1017, done.
remote: Total 1017 (delta 0), reused 0 (delta 0)
Receiving objects: 100% (1017/1017), 289.06 KiB | 69 KiB/s, done.
Resolving deltas: 100% (702/702), done.
installing shopping_cart
Wrote ./assets/js/frappe-web.min.js - 90k
Wrote ./assets/js/shopping-cart-web.min.js - 1k
Wrote ./assets/js/print_format_v3.min.js - 18k
Wrote ./assets/js/erpnext.min.js - 12k
Wrote ./assets/css/frappe.css - 224k
Wrote ./assets/css/frappe-web.css - 163k
Wrote ./assets/css/shopping-cart-web.css - 0k
Wrote ./assets/js/editor.min.js - 27k
Wrote ./assets/css/erpnext.css - 0k
Wrote ./assets/js/frappe.min.js - 609k
Wrote ./assets/js/erpnext-web.min.js - 0k
Wrote ./assets/js/slickgrid.min.js - 102k
Wrote ./assets/js/canvasResize.min.js - 22k
erpnext@Test101:~/frappe-bench$ bench migrate-3to4 /home/erpnext/erpnext
/home/erpnext/erpnext/public
database backup taken - sites/erpnext/private/backups/20141112_2340941_database.sql.gz - on 2014-11-12 06:26:24.469090
Executing execute:frappe.db.sql("""update `tabPatch Log` set patch=replace(patch, '.4_0.', '.v4_0.')""") #2014-05-12 in erpnext (erpnextdb101)
Success
Executing execute:frappe.reload_doc('core', 'doctype', 'doctype', force=True) #2014-01-24 in erpnext (erpnextdb101)
Traceback (most recent call last):
  File "/home/erpnext/bench-repo/bench/migrate3to4.py", line 106, in <module>
    main(args.site)
  File "/home/erpnext/bench-repo/bench/migrate3to4.py", line 39, in main
    migrate(site)
  File "/home/erpnext/bench-repo/bench/migrate3to4.py", line 86, in migrate
    latest()
  File "/home/erpnext/frappe-bench/apps/frappe/frappe/cli.py", line 67, in new_fn
    return fn(*args, **new_kwargs)
  File "/home/erpnext/frappe-bench/apps/frappe/frappe/cli.py", line 423, in latest
    frappe.modules.patch_handler.run_all()
  File "/home/erpnext/frappe-bench/apps/frappe/frappe/modules/patch_handler.py", line 25, in run_all
    if not run_single(patchmodule = patch):
  File "/home/erpnext/frappe-bench/apps/frappe/frappe/modules/patch_handler.py", line 50, in run_single
    return execute_patch(patchmodule, method, methodargs)
  File "/home/erpnext/frappe-bench/apps/frappe/frappe/modules/patch_handler.py", line 64, in execute_patch
    exec patchmodule.split("execute:")[1] in globals()
  File "<string>", line 1, in <module>
  File "/home/erpnext/frappe-bench/apps/frappe/frappe/__init__.py", line 368, in reload_doc
    return frappe.modules.reload_doc(module, dt, dn, force=force)
  File "/home/erpnext/frappe-bench/apps/frappe/frappe/modules/__init__.py", line 36, in reload_doc
    return import_files(module, dt, dn, force=force)
  File "/home/erpnext/frappe-bench/apps/frappe/frappe/modules/import_file.py", line 17, in import_files
    return import_file(module, dt, dn, force=force)
  File "/home/erpnext/frappe-bench/apps/frappe/frappe/modules/import_file.py", line 22, in import_file
    ret = import_file_by_path(path, force)
  File "/home/erpnext/frappe-bench/apps/frappe/frappe/modules/import_file.py", line 50, in import_file_by_path
    import_doc(doc, force=force)
  File "/home/erpnext/frappe-bench/apps/frappe/frappe/modules/import_file.py", line 111, in import_doc
    doc.insert()
  File "/home/erpnext/frappe-bench/apps/frappe/frappe/model/document.py", line 162, in insert
    self.run_post_save_methods()
  File "/home/erpnext/frappe-bench/apps/frappe/frappe/model/document.py", line 442, in run_post_save_methods
    self.run_method("on_update")
  File "/home/erpnext/frappe-bench/apps/frappe/frappe/model/document.py", line 412, in run_method
    return Document.hook(fn)(self, *args, **kwargs)
  File "/home/erpnext/frappe-bench/apps/frappe/frappe/model/document.py", line 493, in composer
    return composed(self, method, *args, **kwargs)
  File "/home/erpnext/frappe-bench/apps/frappe/frappe/model/document.py", line 476, in runner
    add_to_return_value(self, fn(self, *args, **kwargs))
  File "/home/erpnext/frappe-bench/apps/frappe/frappe/model/document.py", line 406, in <lambda>
    fn = lambda self, *args, **kwargs: getattr(self, method)(*args, **kwargs)
  File "/home/erpnext/frappe-bench/apps/frappe/frappe/core/doctype/doctype/doctype.py", line 87, in on_update
    updatedb(self.name)
  File "/home/erpnext/frappe-bench/apps/frappe/frappe/model/db_schema.py", line 393, in updatedb
    tab = DbTable(dt, 'tab')
  File "/home/erpnext/frappe-bench/apps/frappe/frappe/model/db_schema.py", line 63, in __init__
    self.get_columns_from_docfields()
  File "/home/erpnext/frappe-bench/apps/frappe/frappe/model/db_schema.py", line 107, in get_columns_from_docfields
    filters={"doc_type": self.doctype, "doctype_or_field": "DocField", "property": "precision"}):
  File "/home/erpnext/frappe-bench/apps/frappe/frappe/__init__.py", line 617, in get_all
    return get_list(doctype, **args)
  File "/home/erpnext/frappe-bench/apps/frappe/frappe/__init__.py", line 613, in get_list
    ignore_permissions=ignore_permissions, user=user)
  File "/home/erpnext/frappe-bench/apps/frappe/frappe/model/db_query.py", line 47, in execute
    return self.build_and_run()
  File "/home/erpnext/frappe-bench/apps/frappe/frappe/model/db_query.py", line 50, in build_and_run
    args = self.prepare_args()
  File "/home/erpnext/frappe-bench/apps/frappe/frappe/model/db_query.py", line 81, in prepare_args
    self.set_order_by(args)
  File "/home/erpnext/frappe-bench/apps/frappe/frappe/model/db_query.py", line 322, in set_order_by
    meta.sort_field or "modified", meta.sort_order or "desc")
AttributeError: 'Meta' object has no attribute 'sort_field'
Error: None
Traceback (most recent call last):
  File "/usr/local/bin/bench", line 9, in <module>
    load_entry_point('bench==0.1', 'console_scripts', 'bench')()
  File "/home/erpnext/bench-repo/bench/cli.py", line 35, in cli
    return bench()
  File "/usr/local/lib/python2.7/dist-packages/click/core.py", line 610, in __call__
    return self.main(*args, **kwargs)
  File "/usr/local/lib/python2.7/dist-packages/click/core.py", line 590, in main
    rv = self.invoke(ctx)
  File "/usr/local/lib/python2.7/dist-packages/click/core.py", line 936, in invoke
    return _process_result(sub_ctx.command.invoke(sub_ctx))
  File "/usr/local/lib/python2.7/dist-packages/click/core.py", line 782, in invoke
    return ctx.invoke(self.callback, **ctx.params)
  File "/usr/local/lib/python2.7/dist-packages/click/core.py", line 416, in invoke
    return callback(*args, **kwargs)
  File "/home/erpnext/bench-repo/bench/cli.py", line 198, in migrate_3to4
    site=path))
  File "/home/erpnext/bench-repo/bench/utils.py", line 61, in exec_cmd
    subprocess.check_call(cmd, cwd=cwd, shell=True)
  File "/usr/lib/python2.7/subprocess.py", line 511, in check_call
    raise CalledProcessError(retcode, cmd)
subprocess.CalledProcessError: Command 'env/bin/python /home/erpnext/bench-repo/bench/migrate3to4.py /home/erpnext/erpnext' returned non-zero exit status 1
erpnext@Test101:~/frappe-bench$