[#3213] Partially addressed code review points.

migration rollback task changes, hashtags-related config handling tweaks, `hashtags.data` deletion (unused).

lib/mix/tasks/pleroma/database.ex

@@ -20,30 +20,6 @@ defmodule Mix.Tasks.Pleroma.Database do
   @shortdoc "A collection of database related tasks"
   @moduledoc File.read!("docs/administration/CLI_tasks/database.md")
 
-  # Rolls back a specific migration (leaving subsequent migrations applied)
-  # Based on https://stackoverflow.com/a/53825840
-  def run(["rollback", version]) do
-    start_pleroma()
-
-    version = String.to_integer(version)
-    re = ~r/^#{version}_.*\.exs/
-    path = Application.app_dir(:pleroma, Path.join(["priv", "repo", "migrations"]))
-
-    result =
-      with {:find, "" <> file} <- {:find, Enum.find(File.ls!(path), &String.match?(&1, re))},
-           {:compile, [{mod, _} | _]} <- {:compile, Code.compile_file(Path.join(path, file))},
-           {:rollback, :ok} <- {:rollback, Ecto.Migrator.down(Repo, version, mod)} do
-        {:ok, "Reversed migration: #{file}"}
-      else
-        {:find, _} -> {:error, "No migration found with version prefix: #{version}"}
-        {:compile, e} -> {:error, "Problem compiling migration module: #{inspect(e)}"}
-        {:rollback, e} -> {:error, "Problem reversing migration: #{inspect(e)}"}
-        e -> {:error, "Something unexpected happened: #{inspect(e)}"}
-      end
-
-    IO.inspect(result)
-  end
-
   def run(["remove_embedded_objects" | args]) do
     {options, [], []} =
       OptionParser.parse(
@@ -194,4 +170,33 @@ defmodule Mix.Tasks.Pleroma.Database do
     end)
     |> Stream.run()
   end
+
+  # Rolls back a specific migration (leaving subsequent migrations applied).
+  # WARNING: imposes a risk of unrecoverable data loss — proceed at your own responsibility.
+  # Based on https://stackoverflow.com/a/53825840
+  def run(["rollback", version]) do
+    prompt = "SEVERE WARNING: this operation may result in unrecoverable data loss. Continue?"
+
+    if shell_prompt(prompt, "n") in ~w(Yn Y y) do
+      {_, result, _} =
+        Ecto.Migrator.with_repo(Pleroma.Repo, fn repo ->
+          version = String.to_integer(version)
+          re = ~r/^#{version}_.*\.exs/
+          path = Ecto.Migrator.migrations_path(repo)
+
+          with {:find, "" <> file} <- {:find, Enum.find(File.ls!(path), &String.match?(&1, re))},
+               {:compile, [{mod, _} | _]} <- {:compile, Code.compile_file(Path.join(path, file))},
+               {:rollback, :ok} <- {:rollback, Ecto.Migrator.down(repo, version, mod)} do
+            {:ok, "Reversed migration: #{file}"}
+          else
+            {:find, _} -> {:error, "No migration found with version prefix: #{version}"}
+            {:compile, e} -> {:error, "Problem compiling migration module: #{inspect(e)}"}
+            {:rollback, e} -> {:error, "Problem reversing migration: #{inspect(e)}"}
+            e -> {:error, "Something unexpected happened: #{inspect(e)}"}
+          end
+        end)
+
+      IO.inspect(result)
+    end
+  end
 end