fix: don't use symlinked app dir for migration's path

fixes #452

lib/data_layer.ex

@@ -1963,7 +1963,7 @@ defmodule AshPostgres.DataLayer do
 
     fields_to_upsert =
       upsert_fields --
-        Keyword.keys(Enum.at(changesets, 0).atomics) -- keys
+        (Keyword.keys(Enum.at(changesets, 0).atomics) -- keys)
 
     fields_to_upsert =
       case fields_to_upsert do

lib/migration_generator/migration_generator.ex

@@ -157,11 +157,7 @@ defmodule AshPostgres.MigrationGenerator do
       snapshot_path
     else
       app = Keyword.fetch!(config, :otp_app)
-
-      Application.app_dir(
-        app,
-        ["priv", "resource_snapshots"]
-      )
+      Path.join(Mix.Project.deps_paths()[app] || File.cwd!(), "priv/resource_snapshots")
     end
   end
 
@@ -889,25 +885,24 @@ defmodule AshPostgres.MigrationGenerator do
   defp migration_path(opts, repo, tenant? \\ false) do
     # Copied from ecto's mix task, thanks Ecto ❤️
     config = repo.config()
-    app = Keyword.fetch!(config, :otp_app)
 
     if tenant? do
       if path = opts.tenant_migration_path || config[:tenant_migrations_path] do
         path
       else
         priv =
-          config[:priv] || "priv/#{repo |> Module.split() |> List.last() |> Macro.underscore()}"
+          AshPostgres.Mix.Helpers.source_repo_priv(repo)
 
-        Application.app_dir(app, Path.join(priv, "tenant_migrations"))
+        Path.join(priv, "tenant_migrations")
       end
     else
       if path = opts.migration_path || config[:tenant_migrations_path] do
         path
       else
         priv =
-          config[:priv] || "priv/#{repo |> Module.split() |> List.last() |> Macro.underscore()}"
+          AshPostgres.Mix.Helpers.source_repo_priv(repo)
 
-        Application.app_dir(app, Path.join(priv, "migrations"))
+        Path.join(priv, "migrations")
       end
     end
   end

lib/mix/helpers.ex

@@ -170,16 +170,19 @@ defmodule AshPostgres.Mix.Helpers do
   end
 
   def derive_migrations_path(repo) do
-    config = repo.config()
-    priv = config[:priv] || "priv/#{repo |> Module.split() |> List.last() |> Macro.underscore()}"
-    app = Keyword.fetch!(config, :otp_app)
-    Application.app_dir(app, Path.join(priv, "migrations"))
+    priv = source_repo_priv(repo)
+    Path.join(priv, "migrations")
   end
 
   def derive_tenant_migrations_path(repo) do
+    priv = source_repo_priv(repo)
+    Path.join(priv, "tenant_migrations")
+  end
+
+  def source_repo_priv(repo) do
     config = repo.config()
     priv = config[:priv] || "priv/#{repo |> Module.split() |> List.last() |> Macro.underscore()}"
     app = Keyword.fetch!(config, :otp_app)
-    Application.app_dir(app, Path.join(priv, "tenant_migrations"))
+    Path.join(Mix.Project.deps_paths()[app] || File.cwd!(), priv)
   end
 end