Make array encoding configurable

Author: a-nassim

lib/ecto/adapters/sqlite3.ex

@@ -54,6 +54,9 @@ defmodule Ecto.Adapters.SQLite3 do
     * `:map_type` - Defaults to `:string`. Determines the type of `:map` columns.
       Set to `:binary` to use the [JSONB](https://sqlite.org/draft/jsonb.html)
       storage format.
+    * `:array_type` - Defaults to `:string`. Determines the type of `:array` columns.
+      Arrays are serialized using JSON. Set to `:binary` to use the
+      [JSONB](https://sqlite.org/draft/jsonb.html) storage format.
     * `:datetime_type` - Defaults to `:iso8601`. Determines how datetime fields are
       stored in the database. The allowed values are `:iso8601` and `:text_datetime`.
       `:iso8601` corresponds to a string of the form `YYYY-MM-DDThh:mm:ss` and

lib/ecto/adapters/sqlite3/data_type.ex

@@ -17,8 +17,6 @@ defmodule Ecto.Adapters.SQLite3.DataType do
   def column_type(:string, _opts), do: "TEXT"
   def column_type(:float, _opts), do: "NUMERIC"
   def column_type(:binary, _opts), do: "BLOB"
-  def column_type(:array, _opts), do: "TEXT"
-  def column_type({:array, _}, _opts), do: "TEXT"
   def column_type(:date, _opts), do: "TEXT"
   def column_type(:utc_datetime, _opts), do: "TEXT"
   def column_type(:utc_datetime_usec, _opts), do: "TEXT"
@@ -41,6 +39,20 @@ defmodule Ecto.Adapters.SQLite3.DataType do
     end
   end
 
+  def column_type(:array, _opts) do
+    case Application.get_env(:ecto_sqlite3, :array_type, :string) do
+      :string -> "TEXT"
+      :binary -> "BLOB"
+    end
+  end
+
+  def column_type({:array, _}, _opts) do
+    case Application.get_env(:ecto_sqlite3, :array_type, :string) do
+      :string -> "TEXT"
+      :binary -> "BLOB"
+    end
+  end
+
   def column_type(:binary_id, _opts) do
     case Application.get_env(:ecto_sqlite3, :binary_id_type, :string) do
       :string -> "TEXT"

test/ecto/adapters/sqlite3/data_type_test.exs

@@ -4,11 +4,13 @@ defmodule Ecto.Adapters.SQLite3.DataTypeTest do
   alias Ecto.Adapters.SQLite3.DataType
 
   setup do
+    Application.put_env(:ecto_sqlite3, :array_type, :string)
     Application.put_env(:ecto_sqlite3, :binary_id_type, :string)
     Application.put_env(:ecto_sqlite3, :map_type, :string)
     Application.put_env(:ecto_sqlite3, :uuid_type, :string)
 
     on_exit(fn ->
+      Application.put_env(:ecto_sqlite3, :array_type, :string)
       Application.put_env(:ecto_sqlite3, :binary_id_type, :string)
       Application.put_env(:ecto_sqlite3, :map_type, :string)
       Application.put_env(:ecto_sqlite3, :uuid_type, :string)
@@ -64,12 +66,20 @@ defmodule Ecto.Adapters.SQLite3.DataTypeTest do
       assert DataType.column_type({:map, %{}}, nil) == "BLOB"
     end
 
-    test ":array is TEXT" do
+    test ":array is TEXT or BLOB" do
       assert DataType.column_type(:array, nil) == "TEXT"
+
+      Application.put_env(:ecto_sqlite3, :array_type, :binary)
+
+      assert DataType.column_type(:array, nil) == "BLOB"
     end
 
-    test "{:array, _} is TEXT" do
+    test "{:array, _} is TEXT or BLOB" do
       assert DataType.column_type({:array, []}, nil) == "TEXT"
+
+      Application.put_env(:ecto_sqlite3, :array_type, :binary)
+
+      assert DataType.column_type({:array, []}, nil) == "BLOB"
     end
 
     test ":float is NUMERIC" do