id	summary	reporter	owner	description	type	status	component	version	severity	resolution	keywords	cc	stage	has_patch	needs_docs	needs_tests	needs_better_patch	easy	ui_ux
35882	Loop on all errors in `InteractiveMigrationQuestioner._ask_default()`	Adam Johnson	Adam Johnson	"When changing some fields, the migration questioner can ask for new field default values entered through a Python prompt.

Yesterday, I made a typo which made the makemigrations process exit. This was a little frustrating as there were several fields to fix, and my work answering for the first fields was lost.

Currently, the questioner loops on `SyntaxError` and `NameError` ([https://github.com/django/django/blob/1feedc8ef8a34484cb5afe33f5c45b543b860210/django/db/migrations/questioner.py#L163 source]).  My mistake lead to an `AttributeError`, hence the crash and lost work. I propose we extend this clause to `Exception` - there's little harm in displaying the error and looping.

Here's a reproducing example. Say you drop `null=True`  from two model fields:

{{{#!diff
diff --git example/models.py example/models.py
index 816fe37..9743877 100644
--- example/models.py
+++ example/models.py
@@ -2,5 +2,5 @@
 
 
 class Book(models.Model):
-    title = models.CharField(max_length=100, null=True)
-    published_date = models.DateField(null=True)
+    title = models.CharField(max_length=100)
+    published_date = models.DateField()
}}}

`makemigrations` asks you about the first one:

{{{
$ ./manage.py makemigrations example
It is impossible to change a nullable field 'title' on book to non-nullable without providing a default. This is because the database needs something to populate existing rows.
Please select a fix:
 1) Provide a one-off default now (will be set on all existing rows with a null value for this column)
 2) Ignore for now. Existing rows that contain NULL values will have to be handled manually, for example with a RunPython or RunSQL operation.
 3) Quit and manually define a default value in models.py.
Select an option: 1
Please enter the default value as valid Python.
The datetime and django.utils.timezone modules are available, so it is possible to provide e.g. timezone.now as a value.
Type 'exit' to exit this prompt
>>> ""Unknown book""
}}}

Immediately after this, it asks about the second field. Making a typo like `.dat()` instead of `.date()` crashes the process:

{{{
It is impossible to change a nullable field 'published_date' on book to non-nullable without providing a default. This is because the database needs something to populate existing rows.
Please select a fix:
 1) Provide a one-off default now (will be set on all existing rows with a null value for this column)
 2) Ignore for now. Existing rows that contain NULL values will have to be handled manually, for example with a RunPython or RunSQL operation.
 3) Quit and manually define a default value in models.py.
Select an option: 1
Please enter the default value as valid Python.
The datetime and django.utils.timezone modules are available, so it is possible to provide e.g. timezone.now as a value.
Type 'exit' to exit this prompt
>>> datetime.dat(1970, 1, 1)
Traceback (most recent call last):
  File ""/..././manage.py"", line 21, in <module>
    main()
  ...
  File ""/.../.venv/.../django/db/migrations/questioner.py"", line 162, in _ask_default
    return eval(code, {}, {""datetime"": datetime, ""timezone"": timezone})
           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File ""<string>"", line 1, in <module>
AttributeError: module 'datetime' has no attribute 'dat'. Did you mean: 'date'?
}}}

But if you instead made a typo in the `datetime` name, it would loop:

{{{
>>> datetme.date(1970,1,1)
Invalid input: name 'datetme' is not defined
>>>
}}}"	Cleanup/optimization	closed	Migrations	dev	Normal	fixed			Ready for checkin	1	0	0	0	0	0