django 2.x is giving programming error while migrating "migrations.AlterUniqueTogether" part of migration

[Anvesh Agarwal]

problem is while migrating my migrations in django 2.x(previously using 1.11 and everything was working fine) , the query generated by the django is not correct for "migrations.AlterUniqueTogether" part of migrations.

It is missing 'double quotes' while generating the sql query for particularly "migrations.AlterUniqueTogether()" .
A small traceback is here:

  File "/lib/python3.7/site-packages/django/db/backends/utils.py", line 85, in _execute
    return self.cursor.execute(sql, params)
  File "//lib/python3.7/site-packages/django/db/utils.py", line 89, in __exit__
    raise dj_exc_value.with_traceback(traceback) from exc_value
  File "/lib/python3.7/site-packages/django/db/backends/utils.py", line 85, in _execute
    return self.cursor.execute(sql, params)
django.db.utils.ProgrammingError: syntax error at or near "."
LINE 1: ...eways.juspay_juspayrefund" ADD CONSTRAINT gateways.juspay_ju...

i have hundreds of migrations.AlterUniqueTogether() in migrations but it is showing error for only few.

so to confirm the sql query generated by the django from the migration files...

i used python manage.py sqlmigrate <app name> <migration file number> (in django 2.0)

so the result was

ALTER TABLE "gateways.juspay_juspayrefund" ADD CONSTRAINT gateways.juspay_juspayre_refund_type_id_refund_ob_c256672d_uniq UNIQUE ("refund_type_id", "refund_object_id");

ALTER TABLE "gateways.juspay_juspayorder" ADD CONSTRAINT "gateways.juspay_jusp_attempt_id_799d9fbb_fk_gateways_" FOREIGN KEY ("attempt_id") REFERENCES "gateways_attempt" ("id") DEFERRABLE INITIALLY DEFERRED;

here we have double quotes (" ") missing in ADD CONSTRAINT ...UNIQUE which is not letting me to migrate and hence i cant upgrade to django 2.x

while the result in django 1.11 is

ALTER TABLE "gateways.juspay_juspayrefund" ADD CONSTRAINT "gateways.juspay_juspayre_refund_type_id_refund_ob_c256672d_uniq" UNIQUE ("refund_type_id", "refund_object_id");

ALTER TABLE "gateways.juspay_juspayorder" ADD CONSTRAINT "gateways.juspay_jusp_attempt_id_799d9fbb_fk_gateways_" FOREIGN KEY ("attempt_id") REFERENCES "gateways_attempt" ("id") DEFERRABLE INITIALLY DEFERRED;

it is having proper double quotes (" ")

[Simon Charette]

Thank you for your report.

Just to make it easier to reproduce.

Which database backend are you using (this looks like PostgreSQL) and do you have a justpay.JustPayOrder.Meta.db_table override? Django doesn't generate table names like that by default, are you trying to use PostgreSQL schemas?

[Anvesh Agarwal]

yes i am using PostgreSQL. And neither am i using PostgreSQL schema and nor i am trying to override the justpay.JustPayOrder.Meta.db_table .

[Simon Charette]

Duplicate of #29778 which is fixed in Django 2.1+.