Re: [Django] #33192: It is not possible to use a custom lookup/transorm in a CheckConstraint

[Django]

#33192: It is not possible to use a custom lookup/transorm in a CheckConstraint
-+-
 Reporter:  Fabien MICHEL|Owner:  nobody
 Type:  Bug  |   Status:  closed
Component:  Database layer   |  Version:  3.1
  (models, ORM)  |   Resolution:
 Severity:  Normal   |  worksforme
 Keywords:  lookup, transform,   | Triage Stage:
  CheckContraint, migrate|  Unreviewed
Has patch:  0|  Needs documentation:  0
  Needs tests:  0|  Patch needs improvement:  0
Easy pickings:  0|UI/UX:  0
-+-

Comment (by Fabien MICHEL):

 It is all clear for me, thanks you. Shouldn't we add a warning about this
 in CheckConstraint documentation ?
 Here is a proposal:
 {{{
 .. note::

 If you use a :doc:`custom lookup ` in
 CheckContraint
 expression you will have to ensure the expected custom lookup is
 registered
 before the migration run. Therefore, the migration framework doesn't
 detect
 change at the resulting SQL of the expression. It is up to you to keep
 referenced lookup coherent with migration state.
 }}}

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Re: [Django] #33192: It is not possible to use a custom lookup/transorm in a CheckConstraint

[Django]

#33192: It is not possible to use a custom lookup/transorm in a CheckConstraint
-+-
 Reporter:  Fabien MICHEL|Owner:  nobody
 Type:  Bug  |   Status:  closed
Component:  Database layer   |  Version:  3.1
  (models, ORM)  |   Resolution:
 Severity:  Normal   |  worksforme
 Keywords:  lookup, transform,   | Triage Stage:
  CheckContraint, migrate|  Unreviewed
Has patch:  0|  Needs documentation:  0
  Needs tests:  0|  Patch needs improvement:  0
Easy pickings:  0|UI/UX:  0
-+-

Comment (by Simon Charette):

 > In this case, won't I expose my migration to use code that could be
 ananchronic if the code of the custom lookup changes after the migration
 has been created? Is it not better to embed the custom lookup on the
 migration which create the constraint in database ?

 The migration framework doesn't detect change at the resulting SQL level
 so if you were to change your lookup logic you'd have to manually create a
 migration that removes and adds back the new constraint. Nothing prevents
 you from defining the lookup in two locations though (`ready()`) and in
 the migration itself so it's already there and only overrides the project
 specific lookup when the migration file is loaded. Just keep in mind that
 Django won't be hand holding you if you change the SQL generated by the
 lookup.

 In a sense this is similar to how Django allows you to add and remove
 managers to your model definition without 'baking' the manage definition
 in the migration file; since the migration framework holds 'references' of
 managers and lookups it's your responsibility to keep 'referenced values'
 coherent with migration states.

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Re: [Django] #33192: It is not possible to use a custom lookup/transorm in a CheckConstraint

[Django]

#33192: It is not possible to use a custom lookup/transorm in a CheckConstraint
-+-
 Reporter:  Fabien MICHEL|Owner:  nobody
 Type:  Bug  |   Status:  closed
Component:  Database layer   |  Version:  3.1
  (models, ORM)  |   Resolution:
 Severity:  Normal   |  worksforme
 Keywords:  lookup, transform,   | Triage Stage:
  CheckContraint, migrate|  Unreviewed
Has patch:  0|  Needs documentation:  0
  Needs tests:  0|  Patch needs improvement:  0
Easy pickings:  0|UI/UX:  0
-+-

Comment (by Fabien MICHEL):

 In this case, won't I expose my migration to use code that could be
 ananchronic if the code of the custom lookup changes after the migration
 has been created ?
 Is it not better to embed the custom lookup on the migration which insert
 the constraint in database ?

-- 
Ticket URL: 
Django 
The Web framework for perfectionists with deadlines.

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Re: [Django] #33192: It is not possible to use a custom lookup/transorm in a CheckConstraint

[Django]

#33192: It is not possible to use a custom lookup/transorm in a CheckConstraint
-+-
 Reporter:  Fabien MICHEL|Owner:  nobody
 Type:  Bug  |   Status:  closed
Component:  Database layer   |  Version:  3.1
  (models, ORM)  |   Resolution:
 Severity:  Normal   |  worksforme
 Keywords:  lookup, transform,   | Triage Stage:
  CheckContraint, migrate|  Unreviewed
Has patch:  0|  Needs documentation:  0
  Needs tests:  0|  Patch needs improvement:  0
Easy pickings:  0|UI/UX:  0
-+-

Comment (by Mariusz Felisiak):

 Replying to [comment:5 Fabien MICHEL]:

 > If I understand, I should copy the custom lookup into the migration file
 to have it available during migration process ?

 No, you ''"need to ensure that this registration happens before you
 try to create any querysets using it."'', so you can call
 `register_lookup()` in your `models.py` or `AppConfig.ready()`.

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Re: [Django] #33192: It is not possible to use a custom lookup/transorm in a CheckConstraint

[Django]

#33192: It is not possible to use a custom lookup/transorm in a CheckConstraint
-+-
 Reporter:  Fabien MICHEL|Owner:  nobody
 Type:  Bug  |   Status:  closed
Component:  Database layer   |  Version:  3.1
  (models, ORM)  |   Resolution:
 Severity:  Normal   |  worksforme
 Keywords:  lookup, transform,   | Triage Stage:
  CheckContraint, migrate|  Unreviewed
Has patch:  0|  Needs documentation:  0
  Needs tests:  0|  Patch needs improvement:  0
Easy pickings:  0|UI/UX:  0
-+-

Comment (by Fabien MICHEL):

 Thanks for your answer.

 If I understand, I should copy the custom lookup into the migration file
 to have it available during migration process ?

-- 
Ticket URL: 
Django 
The Web framework for perfectionists with deadlines.

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Re: [Django] #33192: It is not possible to use a custom lookup/transorm in a CheckConstraint

[Django]

#33192: It is not possible to use a custom lookup/transorm in a CheckConstraint
-+-
 Reporter:  Fabien MICHEL|Owner:  nobody
 Type:  Bug  |   Status:  closed
Component:  Database layer   |  Version:  3.1
  (models, ORM)  |   Resolution:
 Severity:  Normal   |  worksforme
 Keywords:  lookup, transform,   | Triage Stage:
  CheckContraint, migrate|  Unreviewed
Has patch:  0|  Needs documentation:  0
  Needs tests:  0|  Patch needs improvement:  0
Easy pickings:  0|UI/UX:  0
-+-
Changes (by Mariusz Felisiak):

 * status:  new => closed
 * resolution:   => worksforme


Comment:

 It works for me when you register a custom lookup as
 [https://docs.djangoproject.com/en/stable/howto/custom-lookups/#a-lookup-
 example documented]:

 ''"You will need to ensure that this registration happens before you try
 to create any querysets using it. You could place the implementation in a
 `models.py` file, or register the lookup in the `ready()` method of an
 `AppConfig`"''

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Re: [Django] #33192: It is not possible to use a custom lookup/transorm in a CheckConstraint

[Django]

#33192: It is not possible to use a custom lookup/transorm in a CheckConstraint
-+-
 Reporter:  Fabien MICHEL|Owner:  nobody
 Type:  Bug  |   Status:  new
Component:  Database layer   |  Version:  3.1
  (models, ORM)  |
 Severity:  Normal   |   Resolution:
 Keywords:  lookup, transform,   | Triage Stage:
  CheckContraint, migrate|  Unreviewed
Has patch:  0|  Needs documentation:  0
  Needs tests:  0|  Patch needs improvement:  0
Easy pickings:  0|UI/UX:  0
-+-
Description changed by Fabien MICHEL:

Old description:

> Using a custom lookup or transform in a **CheckContraint** make migrate
> command fail.
>

> {{{
>
> class MonthLastDay(Transform):
> lookup_name = "month_last_day"
> output_field = DateField()
> template = "(DATE_TRUNC('month', %(expressions)s) + (interval '1
> month - 1 day'))::date"
>
> DateField.register_lookup(MonthLastDay)
>
> class MyModel(models.Model):
> class Meta:
> constraints = [
> CheckConstraint(check=Q(date__month_last_day__gte=F("period_start")),
> name="date_month_end_after_period_start"),
> ]
>
>date = models.DateField()
>period_start = models.DateField()
> }}}
>
> django **makemigrations command** does not indicate any issue with this
> and make use of `month_last_day` lookup as if it know about it.
>
> Migration command for this contraint:
> {{{
> migrations.AddConstraint(
> model_name='mymodel',
> constraint=models.CheckConstraint(
> check=models.Q(
> ('date__month_last_day__gte',
> django.db.models.expressions.F('period_start'))
> ),
> name='project_period_charge_type_task_month_budget_month_in_period'),
> ),
> }}}
>
> django **migrate command** fail indicating that `date__month_last_day`
> join is not possible
>
> {{{django.core.exceptions.FieldError: Joined field references are not
> permitted in this query}}}
>
> I'm not sure what could be done. May be the documentation should warn to
> not use custom lookup/transform in CheckContraint.

New description:

 Using a custom lookup or transform in a **CheckContraint** make migrate
 command fail.


 {{{

 class MonthLastDay(Transform):
 lookup_name = "month_last_day"
 output_field = DateField()
 template = "(DATE_TRUNC('month', %(expressions)s) + (interval '1 month
 - 1 day'))::date"

 DateField.register_lookup(MonthLastDay)

 class MyModel(models.Model):
 class Meta:
 constraints = [
 CheckConstraint(check=Q(date__month_last_day__gte=F("period_start")),
 name="date_month_end_after_period_start"),
 ]

date = models.DateField()
period_start = models.DateField()
 }}}

 django **makemigrations command** does not indicate any issue with this
 and make use of `month_last_day` lookup as if it know about it.

 Migration command for this contraint:
 {{{
 migrations.AddConstraint(
 model_name='mymodel',
 constraint=models.CheckConstraint(
 check=models.Q(
 ('date__month_last_day__gte',
 django.db.models.expressions.F('period_start'))
 ),
 name='date_month_end_after_period_start'),
 ),
 }}}

 django **migrate command** fail indicating that `date__month_last_day`
 join is not possible

 {{{django.core.exceptions.FieldError: Joined field references are not
 permitted in this query}}}

 I'm not sure what could be done. May be the documentation should warn to
 not use custom lookup/transform in CheckContraint.

--

-- 
Ticket URL: 
Django 
The Web framework for perfectionists with deadlines.

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Re: [Django] #33192: It is not possible to use a custom lookup/transorm in a CheckConstraint

[Django]

#33192: It is not possible to use a custom lookup/transorm in a CheckConstraint
-+-
 Reporter:  Fabien MICHEL|Owner:  nobody
 Type:  Bug  |   Status:  new
Component:  Database layer   |  Version:  3.1
  (models, ORM)  |
 Severity:  Normal   |   Resolution:
 Keywords:  lookup, transform,   | Triage Stage:
  CheckContraint, migrate|  Unreviewed
Has patch:  0|  Needs documentation:  0
  Needs tests:  0|  Patch needs improvement:  0
Easy pickings:  0|UI/UX:  0
-+-
Description changed by Fabien MICHEL:

Old description:

> Using a custom lookup or transform in a **CheckContraint** make migrate
> command fail.
>

> {{{
>
> class MonthLastDay(Transform):
> lookup_name = "month_last_day"
> output_field = DateField()
> template = "(DATE_TRUNC('month', %(expressions)s) + (interval '1
> month - 1 day'))::date"
>
> DateField.register_lookup(MonthLastDay)
>
> class MyModel(models.Model):
> class Meta:
> constraints = [
> CheckConstraint(check=Q(date__month_last_day__gte=F("period_start")),
> name="date_month_end_after_period_start"),
> ]
>
>date = models.DateField()
>period_start = models.DateField()
> }}}
>
> django **makemigrations command** does not indicate any issue with this
> and make use of `month_last_day` lookup as if it know about it.
>
> Migration command for this contraint:
> {{{
> migrations.AddConstraint(
> model_name='projectperiodchargetypetaskmonthbudget',
> constraint=models.CheckConstraint(
> check=models.Q(
> ('date__month_last_day__gte',
> django.db.models.expressions.F('period_start'))
> ),
> name='project_period_charge_type_task_month_budget_month_in_period'),
> ),
> }}}
>
> django **migrate command** fail indicating that `date__month_last_day`
> join is not possible
>
> {{{django.core.exceptions.FieldError: Joined field references are not
> permitted in this query}}}
>
> I'm not sure what could be done. May be the documentation should warn to
> not use custom lookup/transform in CheckContraint.

New description:

 Using a custom lookup or transform in a **CheckContraint** make migrate
 command fail.


 {{{

 class MonthLastDay(Transform):
 lookup_name = "month_last_day"
 output_field = DateField()
 template = "(DATE_TRUNC('month', %(expressions)s) + (interval '1 month
 - 1 day'))::date"

 DateField.register_lookup(MonthLastDay)

 class MyModel(models.Model):
 class Meta:
 constraints = [
 CheckConstraint(check=Q(date__month_last_day__gte=F("period_start")),
 name="date_month_end_after_period_start"),
 ]

date = models.DateField()
period_start = models.DateField()
 }}}

 django **makemigrations command** does not indicate any issue with this
 and make use of `month_last_day` lookup as if it know about it.

 Migration command for this contraint:
 {{{
 migrations.AddConstraint(
 model_name='mymodel',
 constraint=models.CheckConstraint(
 check=models.Q(
 ('date__month_last_day__gte',
 django.db.models.expressions.F('period_start'))
 ),
 name='project_period_charge_type_task_month_budget_month_in_period'),
 ),
 }}}

 django **migrate command** fail indicating that `date__month_last_day`
 join is not possible

 {{{django.core.exceptions.FieldError: Joined field references are not
 permitted in this query}}}

 I'm not sure what could be done. May be the documentation should warn to
 not use custom lookup/transform in CheckContraint.

--

-- 
Ticket URL: 
Django 
The Web framework for perfectionists with deadlines.

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Re: [Django] #33192: It is not possible to use a custom lookup/transorm in a CheckConstraint

[Django]

#33192: It is not possible to use a custom lookup/transorm in a CheckConstraint
-+-
 Reporter:  Fabien MICHEL|Owner:  nobody
 Type:  Bug  |   Status:  new
Component:  Database layer   |  Version:  3.1
  (models, ORM)  |
 Severity:  Normal   |   Resolution:
 Keywords:  lookup, transform,   | Triage Stage:
  CheckContraint, migrate|  Unreviewed
Has patch:  0|  Needs documentation:  0
  Needs tests:  0|  Patch needs improvement:  0
Easy pickings:  0|UI/UX:  0
-+-
Description changed by Fabien MICHEL:

Old description:

> Using a custom lookup or transform in a **CheckContraint** make migrate
> command fail.
>

> {{{
>
> class MonthLastDay(Transform):
> lookup_name = "month_last_day"
> output_field = DateField()
> template = "(DATE_TRUNC('month', %(expressions)s) + (interval '1
> month - 1 day'))::date"
>
> DateField.register_lookup(MonthLastDay)
>
> class MyModel(models.Model):
> class Meta:
> constraints = [
> CheckConstraint(check=Q(date__month_last_day__gte=F("period_start")),
> name="date_month_end_after_period_start"),
> ]
>
>date = models.DateField()
>period_start = models.DateField()
> }}}
>
> django **makemigrations command** does not indicate any issue with this
> and make use of `month_last_day` lookup as if it know about it.
>
> Migration command for this contraint:
> {{{
> migrations.AddConstraint(
> model_name='projectperiodchargetypetaskmonthbudget',
> constraint=models.CheckConstraint(
> check=models.Q(
> ('date__month_last_day__gte',
> django.db.models.expressions.F('period_start'))
> ),
> name='project_period_charge_type_task_month_budget_month_in_period'),
> ),
> }}}
>
> django **migrate command** fail indicating that `date__month_last_day`
> join is not possible
>
> {{{django.core.exceptions.FieldError: Joined field references are not
> permitted in this query}}}
>
> I'm not sure what could be done. May be the documentation should warn to
> using custom lookup/transform in CheckContraint.

New description:

 Using a custom lookup or transform in a **CheckContraint** make migrate
 command fail.


 {{{

 class MonthLastDay(Transform):
 lookup_name = "month_last_day"
 output_field = DateField()
 template = "(DATE_TRUNC('month', %(expressions)s) + (interval '1 month
 - 1 day'))::date"

 DateField.register_lookup(MonthLastDay)

 class MyModel(models.Model):
 class Meta:
 constraints = [
 CheckConstraint(check=Q(date__month_last_day__gte=F("period_start")),
 name="date_month_end_after_period_start"),
 ]

date = models.DateField()
period_start = models.DateField()
 }}}

 django **makemigrations command** does not indicate any issue with this
 and make use of `month_last_day` lookup as if it know about it.

 Migration command for this contraint:
 {{{
 migrations.AddConstraint(
 model_name='projectperiodchargetypetaskmonthbudget',
 constraint=models.CheckConstraint(
 check=models.Q(
 ('date__month_last_day__gte',
 django.db.models.expressions.F('period_start'))
 ),
 name='project_period_charge_type_task_month_budget_month_in_period'),
 ),
 }}}

 django **migrate command** fail indicating that `date__month_last_day`
 join is not possible

 {{{django.core.exceptions.FieldError: Joined field references are not
 permitted in this query}}}

 I'm not sure what could be done. May be the documentation should warn to
 not use custom lookup/transform in CheckContraint.

--

-- 
Ticket URL: 
Django 
The Web framework for perfectionists with deadlines.

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