feat(admin): deep-link email search to user change page with prefilled login-as reason

posthog/admin/admins/user_admin.py

@@ -1,5 +1,9 @@
+from urllib.parse import urlencode
+
 from django.contrib.auth.admin import UserAdmin as DjangoUserAdmin
 from django.contrib.auth.forms import UserChangeForm as DjangoUserChangeForm
+from django.shortcuts import redirect
+from django.urls import reverse
 from django.utils.html import format_html
 from django.utils.translation import gettext_lazy as _
 
@@ -30,7 +34,8 @@ class UserAdmin(DjangoUserAdmin):
 
     form = UserChangeForm
     change_password_form = None  # This view is not exposed in our subclass of UserChangeForm
-    change_form_template = "loginas/change_form.html"
+    # Extends loginas/change_form.html to also pre-fill the "Log in as" reason from a ?reason= param.
+    change_form_template = "admin/posthog/user/change_form.html"
 
     inlines = [OrganizationMemberInline, TOTPDeviceInline]
     fieldsets = (
@@ -70,6 +75,23 @@ class UserAdmin(DjangoUserAdmin):
     readonly_fields = ["id", "current_team", "current_organization"]
     ordering = ("email",)
 
+    def changelist_view(self, request, extra_context=None):
+        # Deep-link straight to a single user's change page — where the loginas "Log in as"
+        # button and its reason field live — from tools that only know the customer's email,
+        # not their user ID (e.g. our support desk). When an impersonation `reason` is passed
+        # alongside a search `q` that resolves to exactly one user by email, redirect to that
+        # user and carry the reason through so it can be pre-filled on the change page.
+        # `email` is unique, so an exact match identifies the user unambiguously. Without a
+        # `reason`, the normal changelist (search results) is shown as before.
+        reason = request.GET.get("reason")
+        query = request.GET.get("q")
+        if reason and query and self.has_view_or_change_permission(request):
+            match = User.objects.filter(email__iexact=query.strip()).first()
+            if match is not None:
+                change_url = reverse("admin:posthog_user_change", args=[match.pk])
+                return redirect(f"{change_url}?{urlencode({'reason': reason})}")
+        return super().changelist_view(request, extra_context=extra_context)
+
     def current_team_link(self, user: User):
         if not user.team:
             return "–"

posthog/admin/test/test_user_admin.py

@@ -0,0 +1,56 @@
+from django.contrib import admin
+from django.test import Client, override_settings
+from django.urls import include, path
+
+from posthog.test.base import BaseTest
+
+# The admin URLs are only routed when ADMIN_PORTAL_ENABLED (DEBUG/DEMO), so give
+# these tests their own urlconf that always mounts the admin + loginas routes.
+urlpatterns = [
+    path("admin/", include("loginas.urls")),
+    path("admin/", admin.site.urls),
+]
+
+
+@override_settings(ROOT_URLCONF="posthog.admin.test.test_user_admin")
+class TestUserAdminImpersonationDeepLink(BaseTest):
+    def setUp(self):
+        super().setUp()
+        self.user.is_staff = True
+        self.user.is_superuser = True
+        self.user.save()
+        self.client = Client()
+        self.client.force_login(self.user)
+
+    def test_email_search_with_reason_redirects_to_user_change_page(self):
+        target = self._create_user("customer@example.com")
+
+        response = self.client.get(
+            "/admin/posthog/user/", {"q": "customer@example.com", "reason": "Support ticket #1234"}
+        )
+
+        assert response.status_code == 302
+        assert response.headers["Location"] == (
+            f"/admin/posthog/user/{target.pk}/change/?reason=Support+ticket+%231234"
+        )
+
+    def test_email_search_is_case_insensitive(self):
+        target = self._create_user("customer@example.com")
+
+        response = self.client.get("/admin/posthog/user/", {"q": "Customer@Example.com", "reason": "ticket #1"})
+
+        assert response.status_code == 302
+        assert response.headers["Location"].startswith(f"/admin/posthog/user/{target.pk}/change/")
+
+    def test_search_without_reason_shows_changelist(self):
+        self._create_user("customer@example.com")
+
+        response = self.client.get("/admin/posthog/user/", {"q": "customer@example.com"})
+
+        # No reason → normal changelist, no redirect to a specific user.
+        assert response.status_code == 200
+
+    def test_reason_without_matching_user_shows_changelist(self):
+        response = self.client.get("/admin/posthog/user/", {"q": "nobody@example.com", "reason": "ticket #1"})
+
+        assert response.status_code == 200

posthog/templates/admin/posthog/user/change_form.html

@@ -0,0 +1,26 @@
+{% extends "loginas/change_form.html" %}
+
+{% block footer %}
+    {{ block.super }}
+    {# Pre-fill the "Log in as" reason from a ?reason= query param, so support tools can
+       deep-link an agent straight into impersonation with the ticket reference already set.
+       loginas clears the textarea when the modal opens, so we re-apply on link click too —
+       this handler binds after loginas's, and the setTimeout guarantees it runs last. #}
+    <script>
+        django.jQuery(function () {
+            var $ = django.jQuery;
+            var params = new URLSearchParams(window.location.search);
+            var reason = params.get('reason');
+            if (!reason) {
+                return;
+            }
+            var applyReason = function () {
+                $('#loginas-reason').val(reason);
+            };
+            applyReason();
+            $('#loginas-link').on('click', function () {
+                setTimeout(applyReason, 0);
+            });
+        });
+    </script>
+{% endblock %}