Do not always load applications during convergence, closes #12682

Author: josevalim

lib/mix/lib/mix/dep.ex

@@ -114,12 +114,12 @@ defmodule Mix.Dep do
         write_cached_deps(top, {env, target}, load_and_cache(config, top, bottom, env, target))
 
       _ ->
-        converge(env: env, target: target)
+        converge_and_load(env: env, target: target)
     end
   end
 
   defp load_and_cache(_config, top, top, env, target) do
-    converge(env: env, target: target)
+    converge_and_load(env: env, target: target)
   end
 
   defp load_and_cache(config, _top, bottom, _env, _target) do
@@ -152,6 +152,20 @@ defmodule Mix.Dep do
     end)
   end
 
+  defp converge_and_load(opts) do
+    for %{app: app, opts: opts} = dep <- Mix.Dep.Converger.converge(opts) do
+      case Keyword.pop(opts, :app_properties) do
+        {nil, _opts} ->
+          dep
+
+        {app_properties, opts} ->
+          # We don't raise because child dependencies may be missing if manually cleaned
+          :application.load({:application, app, app_properties})
+          %{dep | opts: opts}
+      end
+    end
+  end
+
   defp read_cached_deps(project, env_target) do
     case Mix.State.read_cache({:cached_deps, project}) do
       {^env_target, deps} -> deps
@@ -164,6 +178,13 @@ defmodule Mix.Dep do
     deps
   end
 
+  @doc """
+  Although private API, this is kept to avoid breaking code on patch releases.
+  """
+  def load_on_environment(opts) do
+    Mix.Dep.Converger.converge(opts)
+  end
+
   @doc """
   Clears loaded dependencies from the cache for the current environment.
   """
@@ -174,25 +195,6 @@ defmodule Mix.Dep do
     end
   end
 
-  @doc """
-  Returns loaded dependencies recursively on the given environment.
-
-  If no environment is passed, dependencies are loaded across all
-  environments. The result is not cached.
-
-  ## Exceptions
-
-  This function raises an exception if any of the dependencies
-  provided in the project are in the wrong format.
-  """
-  def load_on_environment(opts) do
-    converge(opts)
-  end
-
-  defp converge(opts) do
-    Mix.Dep.Converger.converge(nil, nil, opts, &{&1, &2, &3}) |> elem(0)
-  end
-
   @doc """
   Filters the given dependencies by name.
 

lib/mix/lib/mix/dep/converger.ex

@@ -60,6 +60,18 @@ defmodule Mix.Dep.Converger do
     )
   end
 
+  @doc """
+  Converge without lock and accumulator updates.
+
+  Note the dependencies returned from converge are not yet loaded.
+  The relevant app keys are found under `dep.opts[:app_properties]`.
+
+  See `Mix.Dep.Loader.children/1` for options.
+  """
+  def converge(opts \\ []) do
+    converge(nil, nil, opts, &{&1, &2, &3}) |> elem(0)
+  end
+
   @doc """
   Converges all dependencies from the current project,
   including nested dependencies.
@@ -68,35 +80,15 @@ defmodule Mix.Dep.Converger do
   must return an updated dependency in case some processing
   is done.
 
+  Note the dependencies returned from converge are not yet loaded.
+  The relevant app keys are found under `dep.opts[:app_properties]`.
+
   See `Mix.Dep.Loader.children/1` for options.
   """
   def converge(acc, lock, opts, callback) do
     {deps, acc, lock} = all(acc, lock, opts, callback)
     if remote = Mix.RemoteConverger.get(), do: remote.post_converge()
-
-    deps =
-      for %{app: app, opts: opts} = dep <- topological_sort(deps) do
-        case Keyword.pop(opts, :app_properties) do
-          {nil, _opts} ->
-            dep
-
-          {app_properties, opts} ->
-            case :application.load({:application, app, app_properties}) do
-              :ok ->
-                :ok
-
-              {:error, {:already_loaded, _}} ->
-                :ok
-
-              {:error, error} ->
-                Mix.raise("Could not load application #{inspect(app)}: #{inspect(error)}")
-            end
-
-            %{dep | opts: opts}
-        end
-      end
-
-    {deps, acc, lock}
+    {topological_sort(deps), acc, lock}
   end
 
   defp all(acc, lock, opts, callback) do

lib/mix/lib/mix/tasks/deps.clean.ex

@@ -41,7 +41,7 @@ defmodule Mix.Tasks.Deps.Clean do
           value = opts[switch],
           do: {key, :"#{value}"}
 
-    loaded_deps = Mix.Dep.load_on_environment(loaded_opts)
+    loaded_deps = Mix.Dep.Converger.converge(loaded_opts)
 
     apps_to_clean =
       cond do

lib/mix/lib/mix/tasks/deps.compile.ex

@@ -57,9 +57,6 @@ defmodule Mix.Tasks.Deps.Compile do
 
     case OptionParser.parse(args, switches: @switches) do
       {opts, [], _} ->
-        # Because this command may be invoked explicitly with
-        # deps.compile, we simply try to compile any available
-        # or local dependency.
         compile(filter_available_and_local_deps(deps), opts)
 
       {opts, tail, _} ->

lib/mix/lib/mix/tasks/deps.ex

@@ -1,7 +1,7 @@
 defmodule Mix.Tasks.Deps do
   use Mix.Task
 
-  import Mix.Dep, only: [load_on_environment: 1, format_dep: 1, format_status: 1, check_lock: 1]
+  import Mix.Dep, only: [format_dep: 1, format_status: 1, check_lock: 1]
 
   @shortdoc "Lists dependencies and their status"
 
@@ -167,7 +167,7 @@ defmodule Mix.Tasks.Deps do
 
     shell = Mix.shell()
 
-    load_on_environment(loaded_opts)
+    Mix.Dep.Converger.converge(loaded_opts)
     |> Enum.sort_by(& &1.app)
     |> Enum.each(fn dep ->
       %Mix.Dep{scm: scm, manager: manager} = dep

lib/mix/lib/mix/tasks/deps.tree.ex

@@ -44,7 +44,7 @@ defmodule Mix.Tasks.Deps.Tree do
           value = opts[switch],
           do: {key, :"#{value}"}
 
-    deps = Mix.Dep.load_on_environment(deps_opts)
+    deps = Mix.Dep.Converger.converge(deps_opts)
 
     root =
       case args do

lib/mix/lib/mix/tasks/deps.unlock.ex

@@ -83,7 +83,7 @@ defmodule Mix.Tasks.Deps.Unlock do
   end
 
   defp unused_apps(lock) do
-    apps = Mix.Dep.load_on_environment([]) |> Enum.map(& &1.app)
+    apps = Mix.Dep.Converger.converge([]) |> Enum.map(& &1.app)
 
     lock
     |> Map.drop(apps)