[GSoC 2021] Adapt Schema Editors to operate from model states instead of fake rendered models

Planning

May 22, 2021

I will complete the following checklist during the first milestone

Creating the proxy for all Operation subclasses' state_forwards and state_backwards methods in ProjectState.
Initialization of the Central Registry in ProjectState(like ProjectState.add_field() etc.).
Code the logic to populate the registry with ProjectState.add_model() and newly introduced ProjectState.add_field().
Fixing and Writing tests along with Documentaion.(if required)

Creating the proxy for all Operation subclasses' state_forwards and state_backwards methods in ProjectState.

May 24, 2021

Added Proxy for all Operations' state_forwards in ProjectState. Created the following function in ProjectState for their respective operations' state_forwards.

rename_model
alter_model_table
alter_together_option_operation
alter_order_with_respect_to
alter_model_options
alter_model_managers
add_index
remove_index
add_constraint
remove_constraint
add_field
remove_field
alter_field
rename_field
separate_database_and_state
run_sql

Tested all the changes and there were no broken tests.

Initialization of the Central Registry in ProjectState(like ProjectState.add_field() etc.).

May 25, 2021

Initialized the central repository in the ProjectState class constructor using the following line of code.
self.related_fields = related_fields or {} Also decided how to populate the registry and asked a question for a problem on Django Forum.(here)

Code the logic to populate the registry with ProjectState.add_model() and newly introduced ProjectState.add_field().(PR-14436)

May 26, 2021

Populated the central registry in ProjectState.add_model
Improvements in PR-14436
Read the code of CreateModel.databas_forwards
Made allow_migrate_model work with ModelStates by adding ModelStateOptions in ModelState

June 9, 2021

The pull request got reviewed.
Requested changes are mentioned here

June 10, 2021 - June 12, 2021

Added the Following changes and made a commit

Reverted the changes of using Operations references with self in ProjectState.
Added a single alter_model_options for all model option related functionalities.
Reverted the Special operations' state_forwards from ProjectState to special.py in Operations.
Passed old_name_lower and new_name_lower in state alteration functions.

June 12, 2021

Added the Following changes and made a commit

Reverted the changes of using Operations references with self in ProjectState.
Added a single alter_model_options for all model option related functionalities.
Reverted the Special operations' state_forwards from ProjectState to special.py in Operations.
Passed old_name_lower and new_name_lower in state alteration functions.

June 12, 2021

The new changes got reviewed.
Requested changes are mentioned here

June 13, 2021

Added the Following changes and made a commit

Merged django.db.migrations.operations.utils with django.db.migrations.utils.
Reverted the pushed knowledge of Operation to State.
Minor other changes

June 14, 2021

The new changes got reviewed.
Requested changes are mentioned here

June 22, 2021

The commits were force pushed to 7d71e36 and PR is rebased.
Requested changes are mentioned here

June 22, 2021 - June 28, 2021

Dicussion on the need to add furthur tests and documentation.
Discussion can be found here
Starting working on structure of central mapping.

June 29, 2021

Mariusz made the final edits.
PR got merged in 503ee41