Merge branch 'fix_install_fe_bug' into 'develop'

Fix frontend install mix task bug

See merge request pleroma/pleroma!2942

lib/mix/tasks/pleroma/frontend.ex

@@ -69,7 +69,7 @@ def run(["install", frontend | args]) do
 
     fe_label = "#{frontend} (#{ref})"
 
-    tmp_dir = Path.join(dest, "tmp")
+    tmp_dir = Path.join([instance_static_dir, "frontends", "tmp"])
 
     with {_, :ok} <-
            {:download_or_unzip, download_or_unzip(frontend_info, tmp_dir, options[:file])},
@@ -135,6 +135,7 @@ defp download_build(frontend_info, dest) do
 
   defp install_frontend(frontend_info, source, dest) do
     from = frontend_info["build_dir"] || "dist"
+    File.rm_rf!(dest)
     File.mkdir_p!(dest)
     File.cp_r!(Path.join([source, from]), dest)
     :ok

test/tasks/frontend_test.exs

@@ -48,11 +48,18 @@ test "it also works given a file" do
       }
     })
 
+    folder = Path.join([@dir, "frontends", "pleroma", "fantasy"])
+    previously_existing = Path.join([folder, "temp"])
+    File.mkdir_p!(folder)
+    File.write!(previously_existing, "yey")
+    assert File.exists?(previously_existing)
+
     capture_io(fn ->
       Frontend.run(["install", "pleroma", "--file", "test/fixtures/tesla_mock/frontend.zip"])
     end)
 
-    assert File.exists?(Path.join([@dir, "frontends", "pleroma", "fantasy", "test.txt"]))
+    assert File.exists?(Path.join([folder, "test.txt"]))
+    refute File.exists?(previously_existing)
   end
 
   test "it downloads and unzips unknown frontends" do