Ecto: Drop Constraint Not Working in Migration

[maxsalven]

Precheck

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Environment

• Elixir version (elixir -v): 1.3.1
• Database and version (PostgreSQL 9.4, MongoDB 3.2, etc.): 9.5.4
• Ecto version (mix dips): 2.1.2
• Database adapter and version (mix dips): postgrex 0.13.0
• Operating system: OS X 10.11.6

Current behavior

def down do
    drop constraint(:users, "must_belong_to_company_or_organization")
    Repo.update_all(User, set: [company_id: nil, organization_id: nil])
 end

** (Postgrex.Error) ERROR 23514 (check_violation): new row for relation "users" violates check constraint "must_belong_to_company_or_organization"

    table: users
    constraint: must_belong_to_company_or_organization

Expected behaviour

I expect the constraint to be dropped before the update is executed.

[josevalim]

Migration instructions are accumulated. If you want to execute them before the end of the migration, you need to call flush().