Always add description of migration operation to sqlmigrate output

[Markus Holtermann]

Especially when debugging the SQL code generated from migration files it can be hard to see where the code of one migration operation ends and where the next one starts. Instead of only including an operation's description when the operation ​cannot be reduced to SQL code I propose to always output the description:

BEGIN;
--
-- Create model Author
--
CREATE TABLE "testapp_author" ("id" serial NOT NULL PRIMARY KEY);
--
-- Create model Publisher
--
CREATE TABLE "testapp_publisher" ("id" serial NOT NULL PRIMARY KEY, "name" varchar(100) NOT NULL);
--
-- Add field publishers to author
--
CREATE TABLE "testapp_author_publishers" ("id" serial NOT NULL PRIMARY KEY, "author_id" integer NOT NULL, "publisher_id" integer NOT NULL);
ALTER TABLE "testapp_author_publishers" ADD CONSTRAINT "testapp_author_publishe_author_id_ab13cccc_fk_testapp_author_id" FOREIGN KEY ("author_id") REFERENCES "testapp_author" ("id") DEFERRABLE INITIALLY DEFERRED;
ALTER TABLE "testapp_author_publishers" ADD CONSTRAINT "testapp_author_pu_publisher_id_60b8aa93_fk_testapp_publisher_id" FOREIGN KEY ("publisher_id") REFERENCES "testapp_publisher" ("id") DEFERRABLE INITIALLY DEFERRED;
ALTER TABLE "testapp_author_publishers" ADD CONSTRAINT "testapp_author_publishers_author_id_6e6ec2f2_uniq" UNIQUE ("author_id", "publisher_id");
CREATE INDEX "testapp_author_publishers_4f331e2f" ON "testapp_author_publishers" ("author_id");
CREATE INDEX "testapp_author_publishers_2604cbea" ON "testapp_author_publishers" ("publisher_id");

COMMIT;

[Markus Holtermann]

PR: ​https://github.com/django/django/pull/4408

[Markus Holtermann <info@…>]

In c5cc332b:

Fixed #24550 -- Added migration operation description to sqlmigrate output

Thanks Tim Graham for the review.