From 03bee42a7e28b1bbd6bb8df03b9e9bdd54f44837 Mon Sep 17 00:00:00 2001
From: oliver <myungsekyo@gmail.com>
Date: Sat, 30 Mar 2019 23:14:07 +0900
Subject: [PATCH] Made startapp/project's overlaying error message use 'app' or
 'project'.

---
 django/core/management/templates.py | 26 ++++++++++++++------------
 tests/admin_scripts/tests.py        | 15 ++++++++++++++-
 2 files changed, 28 insertions(+), 13 deletions(-)

diff --git a/django/core/management/templates.py b/django/core/management/templates.py
index 299b36b6df..0e9adfeb09 100644
--- a/django/core/management/templates.py
+++ b/django/core/management/templates.py
@@ -58,10 +58,11 @@ class TemplateCommand(BaseCommand):
 
     def handle(self, app_or_project, name, target=None, **options):
         self.app_or_project = app_or_project
+        self.a_or_an = 'an' if app_or_project == 'app' else 'a'
         self.paths_to_remove = []
         self.verbosity = options['verbosity']
 
-        self.validate_name(name, app_or_project)
+        self.validate_name(name)
 
         # if some directory is given, make sure it's nicely expanded
         if target is None:
@@ -139,10 +140,12 @@ class TemplateCommand(BaseCommand):
                         break  # Only rewrite once
 
                 if path.exists(new_path):
-                    raise CommandError("%s already exists, overlaying a "
-                                       "project or app into an existing "
-                                       "directory won't replace conflicting "
-                                       "files" % new_path)
+                    raise CommandError(
+                        "%s already exists. Overlaying %s %s into an existing "
+                        "directory won't replace conflicting files." % (
+                            new_path, self.a_or_an, app_or_project,
+                        )
+                    )
 
                 # Only render the Python files, as we don't want to
                 # accidentally render Django templates files
@@ -202,12 +205,11 @@ class TemplateCommand(BaseCommand):
         raise CommandError("couldn't handle %s template %s." %
                            (self.app_or_project, template))
 
-    def validate_name(self, name, app_or_project):
-        a_or_an = 'an' if app_or_project == 'app' else 'a'
+    def validate_name(self, name):
         if name is None:
             raise CommandError('you must provide {an} {app} name'.format(
-                an=a_or_an,
-                app=app_or_project,
+                an=self.a_or_an,
+                app=self.app_or_project,
             ))
         # Check it's a valid directory name.
         if not name.isidentifier():
@@ -215,7 +217,7 @@ class TemplateCommand(BaseCommand):
                 "'{name}' is not a valid {app} name. Please make sure the "
                 "name is a valid identifier.".format(
                     name=name,
-                    app=app_or_project,
+                    app=self.app_or_project,
                 )
             )
         # Check it cannot be imported.
@@ -229,8 +231,8 @@ class TemplateCommand(BaseCommand):
                 "module and cannot be used as {an} {app} name. Please try "
                 "another name.".format(
                     name=name,
-                    an=a_or_an,
-                    app=app_or_project,
+                    an=self.a_or_an,
+                    app=self.app_or_project,
                 )
             )
 
diff --git a/tests/admin_scripts/tests.py b/tests/admin_scripts/tests.py
index 32233cf258..f6fb42b1aa 100644
--- a/tests/admin_scripts/tests.py
+++ b/tests/admin_scripts/tests.py
@@ -1938,7 +1938,11 @@ class StartProject(LiveServerTestCase, AdminScriptTestCase):
         # running again..
         out, err = self.run_django_admin(args)
         self.assertNoOutput(out)
-        self.assertOutput(err, "already exists")
+        self.assertOutput(
+            err,
+            "already exists. Overlaying a project into an existing directory "
+            "won't replace conflicting files."
+        )
 
     def test_custom_project_template(self):
         "Make sure the startproject management command is able to use a different project template"
@@ -2128,6 +2132,15 @@ class StartApp(AdminScriptTestCase):
         )
         self.assertFalse(os.path.exists(testproject_dir))
 
+    def test_overlaying_app(self):
+        self.run_django_admin(['startapp', 'app1'])
+        out, err = self.run_django_admin(['startapp', 'app2', 'app1'])
+        self.assertOutput(
+            err,
+            "already exists. Overlaying an app into an existing directory "
+            "won't replace conflicting files."
+        )
+
 
 class DiffSettings(AdminScriptTestCase):
     """Tests for diffsettings management command."""