bring back `db:test:prepare`.

This reverts deprecations added in #13528.
The task is brought back for two reasons:
  1. Give plugins a way to hook into the test database initialization process
  2. Give the user a way to force a test database synchronization

While `test:prepare` is still a dependency of every test task, `db:test:prepare`
no longer hooks into it. This means that `test:prepare` runs before the schema
is synchronized. Plugins, which insert data can now hook into `db:test:prepare`.

The automatic schema maintenance can't detect when a migration is rolled-back,
modified and reapplied. In this case the user has to fall back to `db:test:prepare`
to force the synchronization to happen.

1 files changed, 15 insertions, 0 deletions

diff --git a/activerecord/CHANGELOG.md b/activerecord/CHANGELOG.md
index 9130cfbe9e..2140b1ea83 100644
--- a/activerecord/CHANGELOG.md
+++ b/activerecord/CHANGELOG.md
@@ -1,3 +1,18 @@
+*   Bring back `db:test:prepare` to synchronize the test database schema.
+
+    Manual synchronization using `bin/rake db:test:prepare` is required
+    when a migration is rolled-back, edited and reapplied.
+
+    `ActiveRecord::Base.maintain_test_schema` now uses `db:test:prepare`
+    to synchronize the schema. Plugins can use this task as a hook to
+    provide custom behavior after the schema has been loaded.
+
+    NOTE: `test:prepare` runs before the schema was synchronized.
+
+    Fixes #17171, #15787.
+
+    *Yves Senn*
+
 *   Change `reflections` public api to return the keys as String objects.
 
     Fixes #16928.