Show the impersonator in the admin header, not the impersonated user

plain-admin/plain/admin/README.md

@@ -480,6 +480,8 @@ The impersonate feature lets admin users log in as another user to debug issues
 
 To start impersonating, visit a user's detail page in the admin and click the "Impersonate" link. The admin toolbar will show who you're impersonating and provide a link to stop.
 
+Inside the admin itself, the account menu in the top right keeps showing *your* avatar while you impersonate — it acts on your account, not the impersonated user's — and it lists who you're impersonating with a "Stop impersonating" item.
+
 By default, users with `is_admin=True` can impersonate other users. Admin users cannot be impersonated (for security). You can customize who can impersonate by defining `IMPERSONATE_ALLOWED` in your settings:
 
 ```python

plain-admin/plain/admin/templates/admin/_header.html

@@ -55,11 +55,15 @@
                     aria-controls="user-menu-popover"
                     class="flex items-center cursor-pointer"
                 >
-                    {% set avatar_url = user.get_avatar_url() if user.get_avatar_url is defined else None %}
+                    {# While impersonating, this menu still acts on the real
+                       account (App Settings, Log out), so it shows the
+                       impersonator — not the user being impersonated. #}
+                    {% set account_user = impersonator or user %}
+                    {% set avatar_url = account_user.get_avatar_url() if account_user.get_avatar_url is defined else None %}
                     {% if avatar_url %}
                         <img
                             src="{{ avatar_url }}"
-                            alt="{{ user }}"
+                            alt="{{ account_user }}"
                             class="w-7 h-7 rounded-full"
                         />
                     {% else %}
@@ -90,6 +94,16 @@
                     <div role="separator"></div>
                     {% endif %}
                     <div role="menu">
+                        {% if impersonator %}
+                        <div class="px-2 py-1.5 text-xs text-admin-muted-foreground">
+                            Impersonating <span class="font-medium text-admin-foreground">{{ user }}</span>
+                        </div>
+                        <a role="menuitem" href="{{ url('admin:impersonate:stop') }}">
+                            <admin.Icon name="x-octagon" />
+                            Stop impersonating
+                        </a>
+                        <div role="separator"></div>
+                        {% endif %}
                         {% include "admin/user_menu_items.html" ignore missing %}
                         <a role="menuitem" href="{{ url('admin:settings') }}">
                             <admin.Icon name="gear" />

plain-admin/plain/admin/views/base.py

@@ -11,6 +11,7 @@
 from plain.urls import reverse
 from plain.utils import timezone
 
+from ..impersonate import get_request_impersonator
 from ..models import PinnedNavItem
 from .registry import registry, track_recent_nav
 from .types import Img
@@ -118,6 +119,9 @@ def get_template_context(self) -> dict[str, Any]:
             )
         )
         context["preflight_counts"] = get_check_counts()
+        # The real, logged-in user when impersonation is active (None otherwise).
+        # The header's account menu belongs to *them*, not the impersonated user.
+        context["impersonator"] = get_request_impersonator(self.request)
         context["admin_url"] = registry.get_url
 
         return context

plain-admin/tests/app/users/models.py

@@ -12,6 +12,10 @@ class User(postgres.Model):
 
     query: postgres.QuerySet[User] = postgres.QuerySet()
 
+    def get_avatar_url(self) -> str:
+        """The admin header renders this when the user model provides it."""
+        return f"https://avatars.example.com/{self.username}.png"
+
     @property
     def username_upper(self) -> str:
         """A computed (non-column) field, to exercise in-memory sorting."""

plain-admin/tests/public/test_impersonate.py

@@ -72,3 +72,24 @@ def test_admin_users_cannot_be_impersonated(db):
 
     # After the refusal the marker is cleared, so normal requests resume.
     assert client.get("/whoami").user.id == admin.id
+
+
+def test_admin_header_shows_the_impersonator_not_the_impersonated_user(db):
+    """The account menu acts on the real account, so it shows that avatar."""
+    admin = User.query.create(username="admin", is_admin=True)
+    target = User.query.create(username="target", is_admin=False)
+
+    client = Client()
+    client.force_login(admin)
+    client.get(f"/admin/impersonate/start/{target.id}")
+
+    # Land on a real admin page (the index redirects to the first list view).
+    admin_page = client.get(client.get("/admin").url)
+    assert admin_page.status_code == 200
+
+    content = admin_page.content.decode()
+    assert "https://avatars.example.com/admin.png" in content
+    assert "https://avatars.example.com/target.png" not in content
+
+    # ...and the menu says who is being impersonated, with a way out.
+    assert "Stop impersonating" in content