Error in Switching to master branch

Install / Update Setup
1

Hello,

I have installed the ERPNext in ubuntu 16.04 with easy installation script.

The version it got installed is develop v12.

As suggested earlier I have also edited the git config file to downgrade it to v11.

I tried to downgrade to version 11 using this command: bench switch-to-branch master frappe erpnext --upgrade.

After using that command it showed successfully switched branch to master for erpnext & frappe.

But when I tried to run bench update --patch it is showing some error as mentioned below.

Successfully switched branches for:
frappe
erpnext
Switched to master
Please run `bench update --patch` to be safe from any differences in database schema
root@ubuntu:/home/frappe/frappe-bench# bench update --patch
Backing up sites...
Patching sites...
Migrating site1.local
Executing execute:frappe.db.sql("""update tabComment set comment = substr(comment, 6, locate(":", comment)-6) where comment_type in ("Assigned", "Assignment Completed")""") in site1.local (_1bd3e0294da19198)
Traceback (most recent call last):
  File "/usr/lib/python3.5/runpy.py", line 184, in _run_module_as_main
    "__main__", mod_spec)
  File "/usr/lib/python3.5/runpy.py", line 85, in _run_code
    exec(code, run_globals)
  File "/home/frappe/frappe-bench/apps/frappe/frappe/utils/bench_helper.py", line 97, in <module>
    main()
  File "/home/frappe/frappe-bench/apps/frappe/frappe/utils/bench_helper.py", line 18, in main
    click.Group(commands=commands)(prog_name='bench')
  File "/home/frappe/frappe-bench/env/lib/python3.5/site-packages/click/core.py", line 764, in __call__
    return self.main(*args, **kwargs)
  File "/home/frappe/frappe-bench/env/lib/python3.5/site-packages/click/core.py", line 717, in main
    rv = self.invoke(ctx)
  File "/home/frappe/frappe-bench/env/lib/python3.5/site-packages/click/core.py", line 1137, in invoke
    return _process_result(sub_ctx.command.invoke(sub_ctx))
  File "/home/frappe/frappe-bench/env/lib/python3.5/site-packages/click/core.py", line 1137, in invoke
    return _process_result(sub_ctx.command.invoke(sub_ctx))
  File "/home/frappe/frappe-bench/env/lib/python3.5/site-packages/click/core.py", line 956, in invoke
    return ctx.invoke(self.callback, **ctx.params)
  File "/home/frappe/frappe-bench/env/lib/python3.5/site-packages/click/core.py", line 555, in invoke
    return callback(*args, **kwargs)
  File "/home/frappe/frappe-bench/env/lib/python3.5/site-packages/click/decorators.py", line 17, in new_func
    return f(get_current_context(), *args, **kwargs)
  File "/home/frappe/frappe-bench/apps/frappe/frappe/commands/__init__.py", line 25, in _func
    ret = f(frappe._dict(ctx.obj), *args, **kwargs)
  File "/home/frappe/frappe-bench/apps/frappe/frappe/commands/site.py", line 227, in migrate
    migrate(context.verbose, rebuild_website=rebuild_website)
  File "/home/frappe/frappe-bench/apps/frappe/frappe/migrate.py", line 38, in migrate
    frappe.modules.patch_handler.run_all()
  File "/home/frappe/frappe-bench/apps/frappe/frappe/modules/patch_handler.py", line 29, in run_all
    if not run_single(patchmodule = patch):
  File "/home/frappe/frappe-bench/apps/frappe/frappe/modules/patch_handler.py", line 63, in run_single
    return execute_patch(patchmodule, method, methodargs)
  File "/home/frappe/frappe-bench/apps/frappe/frappe/modules/patch_handler.py", line 81, in execute_patch
    exec(patchmodule.split("execute:")[1],globals())
  File "<string>", line 1, in <module>
  File "/home/frappe/frappe-bench/apps/frappe/frappe/database.py", line 210, in sql
    self._cursor.execute(query)
  File "/home/frappe/frappe-bench/env/lib/python3.5/site-packages/pymysql/cursors.py", line 170, in execute
    result = self._query(query)
  File "/home/frappe/frappe-bench/env/lib/python3.5/site-packages/pymysql/cursors.py", line 328, in _query
    conn.query(q)
  File "/home/frappe/frappe-bench/env/lib/python3.5/site-packages/pymysql/connections.py", line 517, in query
    self._affected_rows = self._read_query_result(unbuffered=unbuffered)
  File "/home/frappe/frappe-bench/env/lib/python3.5/site-packages/pymysql/connections.py", line 732, in _read_query_result
    result.read()
  File "/home/frappe/frappe-bench/env/lib/python3.5/site-packages/pymysql/connections.py", line 1075, in read
    first_packet = self.connection._read_packet()
  File "/home/frappe/frappe-bench/env/lib/python3.5/site-packages/pymysql/connections.py", line 684, in _read_packet
    packet.check_error()
  File "/home/frappe/frappe-bench/env/lib/python3.5/site-packages/pymysql/protocol.py", line 220, in check_error
    err.raise_mysql_exception(self._data)
  File "/home/frappe/frappe-bench/env/lib/python3.5/site-packages/pymysql/err.py", line 109, in raise_mysql_exception
    raise errorclass(errno, errval)
pymysql.err.InternalError: (1054, "Unknown column 'comment' in 'field list'")
root@ubuntu:/home/frappe/frappe-bench#

Can anyone help me in solving this issue? Earlier these commands used to work me.

Thanks & Regards,
Sujay

2

Since this is a fresh installation , if you have the time start with a clean slate using this method:

This will avoid the hassle of bench switch-to-master. You get a new instance with master branch for both frappe and erpnext.

3

I don’t know whether this is related but … I believe that python3.6 is the support or at least recommended python3 version for frappe/erpnext, not 3.5

4

When I run apt-get install python-minimal it will install python 2.7 version.

How can we install python 3.6 version?

5

I’m having the same problem switching to master branch. Sir @vrms, how can we install python 3.6? Thank you in advance.

6

I think that depends on the distribution of your server. I’d google

[distribution] install python 3.6

to find that out in particular