#33295: Django throws an error when a list is passed into self.stdout.write for
writing message into the terminal
-------------------------------------+-------------------------------------
Reporter: Vishal | Owner: nobody
Pandey |
Type: Bug | Status: assigned
Component: Core | Version: 3.2
(Management commands) |
Severity: Normal | Keywords:
Triage Stage: | Has patch: 0
Unreviewed |
Needs documentation: 0 | Needs tests: 0
Patch needs improvement: 0 | Easy pickings: 1
UI/UX: 0 |
-------------------------------------+-------------------------------------
{{{
class Command(BaseCommand):
def handle(self, *args, **kwargs):
self.stdout.write([1,2,3])
}}}
The following piece of code throws an Attribute error stating that list'
object has no attribute 'endswith', it is because the datatype of msg is
not checked in handle function while writing the source code.
Here is the full traceback of the error
{{{
Traceback (most recent call last):
File "manage.py", line 22, in <module>
main()
File "manage.py", line 18, in main
execute_from_command_line(sys.argv)
File "/home/vishal/.local/lib/python3.8/site-
packages/django/core/management/__init__.py", line 401, in
execute_from_command_line
utility.execute()
File "/home/vishal/.local/lib/python3.8/site-
packages/django/core/management/__init__.py", line 395, in execute
self.fetch_command(subcommand).run_from_argv(self.argv)
File "/home/vishal/.local/lib/python3.8/site-
packages/django/core/management/base.py", line 330, in run_from_argv
self.execute(*args, **cmd_options)
File "/home/vishal/.local/lib/python3.8/site-
packages/django/core/management/base.py", line 371, in execute
output = self.handle(*args, **options)
File
"/home/vishal/Desktop/open_source/leetcode_companywise/questions/management/commands/addcompanies.py",
line 18, in handle
self.stdout.write([1,2,3])
File "/home/vishal/.local/lib/python3.8/site-
packages/django/core/management/base.py", line 144, in write
if ending and not msg.endswith(ending):
AttributeError: 'list' object has no attribute 'endswith'
}}}
It can be fixed if we just ensure the datatype of the msg is string and
handle it accordingly with
{{{
isinstance(msg, str)
}}}
in line 151 of /django/core/management/base.py.
After handling this error a proper error message(i.e. TypeError) will be
shown on the terminal of the user which is more appropriate in this
situation.
New traceback:
{{{
Traceback (most recent call last):
File "manage.py", line 22, in <module>
main()
File "manage.py", line 18, in main
execute_from_command_line(sys.argv)
File "/home/vishal/.local/lib/python3.8/site-
packages/django/core/management/__init__.py", line 401, in
execute_from_command_line
utility.execute()
File "/home/vishal/.local/lib/python3.8/site-
packages/django/core/management/__init__.py", line 395, in execute
self.fetch_command(subcommand).run_from_argv(self.argv)
File "/home/vishal/.local/lib/python3.8/site-
packages/django/core/management/base.py", line 330, in run_from_argv
self.execute(*args, **cmd_options)
File "/home/vishal/.local/lib/python3.8/site-
packages/django/core/management/base.py", line 371, in execute
output = self.handle(*args, **options)
File
"/home/vishal/Desktop/open_source/leetcode_companywise/questions/management/commands/addcompanies.py",
line 18, in handle
self.stdout.write([1,2,3])
File "/home/vishal/.local/lib/python3.8/site-
packages/django/core/management/base.py", line 147, in write
self._out.write(style_func(msg))
TypeError: write() argument must be str, not list
}}}
--
Ticket URL: <https://code.djangoproject.com/ticket/33295>
Django <https://code.djangoproject.com/>
The Web framework for perfectionists with deadlines.
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