`insert_all` with queries ignore field mapping and writability

[lukaszsamson]

Elixir version

any

Database and Version

any

Ecto Versions

3.14

Database Adapter and Versions (postgrex, myxql, etc)

any

Current behavior

When Repo.insert_all/3 receives a source query using select: r, it builds the insert column list from the source schema instead of destination. This results in incorrect SQL in case of mapping and ignoring writable: false

Repro:
With those schemas

  defmodule InsertSelectSource do
    use Ecto.Schema

    @primary_key false
    schema "insert_select_source" do
      field :name, :string
    end
  end

  defmodule InsertSelectRenamed do
    use Ecto.Schema

    @primary_key false
    schema "insert_select_renamed" do
      field :name, :string, source: :renamed_name
    end
  end

  defmodule InsertSelectReadOnly do
    use Ecto.Schema

    @primary_key false
    schema "insert_select_read_only" do
      field :name, :string, writable: :never
    end
  end

      query = from s in InsertSelectSource, select: s
      TestRepo.insert_all(InsertSelectRenamed, query)

Errors with 42703 undefined_column on postgres

query = from s in InsertSelectSource, select: s
TestRepo.insert_all(InsertSelectReadOnly, query)

writes into filed marked as not writable

Expected behavior

destination schema respected

[josevalim]

We need to fix the select but I think the writable being bypassed is documented? So if you are sending PRs, can you please break it in two while I investigate? Thank you! ❤️

[josevalim]

I can confirm that both bugs are correct. We should respect writable here too (whenever there is a schema).

[lukaszsamson]

I have a branch with tests and a candidate fix but it’s not ready for a PR yet https://github.com/elixir-ecto/ecto/compare/master...lukaszsamson:ecto:ls-insert-all-writability?expand=1