--to-exclusive (#370)

Co-authored-by: Greg Rychlewski <grychle@Gregs-MacBook-Pro.local>

Author: greg-rychlewski

lib/ecto/migrator.ex

@@ -376,7 +376,7 @@ defmodule Ecto.Migrator do
 
       Ecto.Migrator.run(Repo, [{0, MyApp.Migration1}, {1, MyApp.Migration2}, ...], :up, opts)
 
-  A strategy (which is one of `:all`, `:step` or `:to`) must be given as
+  A strategy (which is one of `:all`, `:step`, `:to`, or `:to_exclusive`) must be given as
   an option.
 
   ## Execution model
@@ -401,6 +401,9 @@ defmodule Ecto.Migrator do
     * `:to` - runs all until the supplied version is reached
       (including the version given in `:to`)
 
+    * `:to_exclusive` - runs all until the supplied version is reached
+      (excluding the version given in `:to_exclusive`)
+
   Plus all other options described in `up/4`.
   """
   @spec run(Ecto.Repo.t, String.t | [String.t] | [{integer, module}], atom, Keyword.t) :: [integer]
@@ -422,10 +425,12 @@ defmodule Ecto.Migrator do
             pending_all(versions, migration_source, direction)
           to = opts[:to] ->
             pending_to(versions, migration_source, direction, to)
+          to_exclusive = opts[:to_exclusive] ->
+            pending_to_exclusive(versions, migration_source, direction, to_exclusive)
           step = opts[:step] ->
             pending_step(versions, migration_source, direction, step)
           true ->
-            {:error, ArgumentError.exception("expected one of :all, :to, or :step strategies")}
+            {:error, ArgumentError.exception("expected one of :all, :to, :to_exclusive, or :step strategies")}
         end
       end
 
@@ -562,6 +567,18 @@ defmodule Ecto.Migrator do
     |> Enum.take_while(&(within_target_version?.(&1, target, direction)))
   end
 
+  defp pending_to_exclusive(versions, migration_source, direction, target) do
+    within_target_version? = fn
+      {version, _, _}, target, :up ->
+        version < target
+      {version, _, _}, target, :down ->
+        version > target
+    end
+
+    pending_in_direction(versions, migration_source, direction)
+    |> Enum.take_while(&(within_target_version?.(&1, target, direction)))
+  end
+
   defp pending_step(versions, migration_source, direction, count) do
     pending_in_direction(versions, migration_source, direction)
     |> Enum.take(count)

lib/mix/tasks/ecto.migrate.ex

@@ -14,6 +14,7 @@ defmodule Mix.Tasks.Ecto.Migrate do
     all: :boolean,
     step: :integer,
     to: :integer,
+    to_exclusive: :integer,
     quiet: :boolean,
     prefix: :string,
     pool_size: :integer,
@@ -102,6 +103,8 @@ defmodule Mix.Tasks.Ecto.Migrate do
 
     * `--to` - run all migrations up to and including version
 
+    * `--to-exclusive` - revert all migrations down to and excluding version
+
   """
 
   @impl true
@@ -110,7 +113,7 @@ defmodule Mix.Tasks.Ecto.Migrate do
     {opts, _} = OptionParser.parse! args, strict: @switches, aliases: @aliases
 
     opts =
-      if opts[:to] || opts[:step] || opts[:all],
+      if opts[:to] || opts[:to_exclusive] || opts[:step] || opts[:all],
         do: opts,
         else: Keyword.put(opts, :all, true)
 

lib/mix/tasks/ecto.rollback.ex

@@ -14,6 +14,7 @@ defmodule Mix.Tasks.Ecto.Rollback do
     all: :boolean,
     step: :integer,
     to: :integer,
+    to_exclusive: :integer,
     quiet: :boolean,
     prefix: :string,
     pool_size: :integer,
@@ -98,6 +99,8 @@ defmodule Mix.Tasks.Ecto.Rollback do
 
     * `--to` - revert all migrations down to and including version
 
+    * `--to-exclusive` - revert all migrations down to and excluding version
+
   """
 
   @impl true
@@ -106,7 +109,7 @@ defmodule Mix.Tasks.Ecto.Rollback do
     {opts, _} = OptionParser.parse!(args, strict: @switches, aliases: @aliases)
 
     opts =
-      if opts[:to] || opts[:step] || opts[:all],
+      if opts[:to] || opts[:to_exclusive] || opts[:step] || opts[:all],
         do: opts,
         else: Keyword.put(opts, :step, 1)
 

test/mix/tasks/ecto.migrate_test.exs

@@ -135,4 +135,15 @@ defmodule Mix.Tasks.Ecto.MigrateTest do
     run ["-r", to_string(Repo), "--migrations-path", path1, "--migrations-path", path2],
         fn Repo, [^path1, ^path2], _, _ -> [] end
   end
+
+  test "runs the migrator with --to_exclusive" do
+    run ["-r", to_string(Repo), "--to-exclusive", "12345"], fn repo, [path], direction, opts ->
+      assert repo == Repo
+      refute path =~ ~r/_build/
+      assert direction == :up
+      assert opts == [repo: "Elixir.Mix.Tasks.Ecto.MigrateTest.Repo", to_exclusive: 12345]
+      []
+    end
+    assert Process.get(:started)
+  end
 end

test/mix/tasks/ecto.rollback_test.exs

@@ -99,4 +99,15 @@ defmodule Mix.Tasks.Ecto.RollbackTest do
     run ["-r", to_string(Repo), "--migrations-path", path1, "--migrations-path", path2],
         fn Repo, [^path1, ^path2], _, _ -> [] end
   end
+
+  test "runs the migrator with --to_exclusive" do
+    run ["-r", to_string(Repo), "--to-exclusive", "12345"], fn repo, [path], direction, opts ->
+      assert repo == Repo
+      refute path =~ ~r/_build/
+      assert direction == :down
+      assert opts == [repo: "Elixir.Mix.Tasks.Ecto.RollbackTest.Repo", to_exclusive: 12345]
+      []
+    end
+    assert Process.get(:started)
+  end
 end