Refs #36559 -- Ran template partial source tests in debug mode only.

Added a warning for accessing PartialTemplate.source when debugging is disabled.
Thanks Sarah Boyce for the idea.

3 files changed, 153 insertions, 65 deletions

diff --git a/django/template/base.py b/django/template/base.py
index 74b3987410..d7bc59d668 100644
--- a/django/template/base.py
+++ b/django/template/base.py
@@ -53,6 +53,7 @@ times with multiple contexts)
 import inspect
 import logging
 import re
+import warnings
 from enum import Enum
 
 from django.template.context import BaseContext
@@ -329,6 +330,13 @@ class PartialTemplate:
     @property
     def source(self):
         template = self.origin.loader.get_template(self.origin.template_name)
+        if not template.engine.debug:
+            warnings.warn(
+                "PartialTemplate.source is only available when template "
+                "debugging is enabled.",
+                RuntimeWarning,
+                stacklevel=2,
+            )
         return self.find_partial_source(template.source, self.name)
 
     def _render(self, context):
diff --git a/tests/template_tests/test_partials.py b/tests/template_tests/test_partials.py
index 8f1a74b2ec..cc3ef7fb25 100644
--- a/tests/template_tests/test_partials.py
+++ b/tests/template_tests/test_partials.py
@@ -4,7 +4,9 @@ from unittest import mock
 from django.http import HttpResponse
 from django.template import (
     Context,
+    NodeList,
     Origin,
+    PartialTemplate,
     Template,
     TemplateDoesNotExist,
     TemplateSyntaxError,
@@ -15,6 +17,8 @@ from django.template.loader import render_to_string
 from django.test import TestCase, override_settings
 from django.urls import path, reverse
 
+from .utils import setup
+
 engine = engines["django"]
 
 
@@ -30,18 +34,30 @@ class PartialTagsTests(TestCase):
 
     def test_template_source_is_correct(self):
         partial = engine.get_template("partial_examples.html#test-partial")
-        self.assertEqual(
-            partial.template.source,
-            "{% partialdef test-partial %}\nTEST-PARTIAL-CONTENT\n{% endpartialdef %}",
+        msg = (
+            "PartialTemplate.source is only available when "
+            "template debugging is enabled."
         )
+        with self.assertRaisesMessage(RuntimeWarning, msg):
+            self.assertEqual(
+                partial.template.source,
+                "{% partialdef test-partial %}\n"
+                "TEST-PARTIAL-CONTENT\n"
+                "{% endpartialdef %}",
+            )
 
     def test_template_source_inline_is_correct(self):
         partial = engine.get_template("partial_examples.html#inline-partial")
-        self.assertEqual(
-            partial.template.source,
-            "{% partialdef inline-partial inline %}\nINLINE-CONTENT\n"
-            "{% endpartialdef %}",
+        msg = (
+            "PartialTemplate.source is only available when "
+            "template debugging is enabled."
         )
+        with self.assertRaisesMessage(RuntimeWarning, msg):
+            self.assertEqual(
+                partial.template.source,
+                "{% partialdef inline-partial inline %}\nINLINE-CONTENT\n"
+                "{% endpartialdef %}",
+            )
 
     def test_full_template_from_loader(self):
         template = engine.get_template("partial_examples.html")
@@ -149,6 +165,20 @@ class PartialTagsTests(TestCase):
         rendered_content = template_with_partial.render({})
         self.assertEqual("TEST-PARTIAL-CONTENT", rendered_content.strip())
 
+    def test_template_source_warning(self):
+        partial = engine.get_template("partial_examples.html#test-partial")
+        with self.assertWarnsMessage(
+            RuntimeWarning,
+            "PartialTemplate.source is only available when template "
+            "debugging is enabled.",
+        ):
+            self.assertEqual(
+                partial.template.source,
+                "{% partialdef test-partial %}\n"
+                "TEST-PARTIAL-CONTENT\n"
+                "{% endpartialdef %}",
+            )
+
 
 class RobustPartialHandlingTests(TestCase):
 
@@ -219,8 +249,18 @@ class RobustPartialHandlingTests(TestCase):
 
 class FindPartialSourceTests(TestCase):
 
+    @setup(
+        {
+            "partial_source_success_template": (
+                "{% partialdef test-partial %}\n"
+                "TEST-PARTIAL-CONTENT\n"
+                "{% endpartialdef %}\n"
+            ),
+        },
+        debug_only=True,
+    )
     def test_find_partial_source_success(self):
-        template = engine.get_template("partial_examples.html").template
+        template = self.engine.get_template("partial_source_success_template")
         partial_proxy = template.extra_data["partials"]["test-partial"]
 
         expected = """{% partialdef test-partial %}
@@ -228,8 +268,18 @@ TEST-PARTIAL-CONTENT
 {% endpartialdef %}"""
         self.assertEqual(partial_proxy.source.strip(), expected.strip())
 
+    @setup(
+        {
+            "partial_source_with_inline_template": (
+                "{% partialdef inline-partial inline %}\n"
+                "INLINE-CONTENT\n"
+                "{% endpartialdef %}\n"
+            ),
+        },
+        debug_only=True,
+    )
     def test_find_partial_source_with_inline(self):
-        template = engine.get_template("partial_examples.html").template
+        template = self.engine.get_template("partial_source_with_inline_template")
         partial_proxy = template.extra_data["partials"]["inline-partial"]
 
         expected = """{% partialdef inline-partial inline %}
@@ -237,38 +287,38 @@ INLINE-CONTENT
 {% endpartialdef %}"""
         self.assertEqual(partial_proxy.source.strip(), expected.strip())
 
-    def test_find_partial_source_nonexistent_partial(self):
-        template = engine.get_template("partial_examples.html").template
-        partial_proxy = template.extra_data["partials"]["test-partial"]
-
-        result = partial_proxy.find_partial_source(
-            template.source, "nonexistent-partial"
-        )
-        self.assertEqual(result, "")
-
+    @setup(
+        {
+            "empty_partial_template": ("{% partialdef empty %}{% endpartialdef %}"),
+        },
+        debug_only=True,
+    )
     def test_find_partial_source_empty_partial(self):
-        template_source = "{% partialdef empty %}{% endpartialdef %}"
-        template = Template(template_source)
+        template = self.engine.get_template("empty_partial_template")
         partial_proxy = template.extra_data["partials"]["empty"]
 
-        result = partial_proxy.find_partial_source(template_source, "empty")
+        result = partial_proxy.find_partial_source(template.source, "empty")
         self.assertEqual(result, "{% partialdef empty %}{% endpartialdef %}")
 
+    @setup(
+        {
+            "consecutive_partials_template": (
+                "{% partialdef empty %}{% endpartialdef %}"
+                "{% partialdef other %}...{% endpartialdef %}"
+            ),
+        },
+        debug_only=True,
+    )
     def test_find_partial_source_multiple_consecutive_partials(self):
-
-        template_source = (
-            "{% partialdef empty %}{% endpartialdef %}"
-            "{% partialdef other %}...{% endpartialdef %}"
-        )
-        template = Template(template_source)
+        template = self.engine.get_template("consecutive_partials_template")
 
         empty_proxy = template.extra_data["partials"]["empty"]
         other_proxy = template.extra_data["partials"]["other"]
 
-        empty_result = empty_proxy.find_partial_source(template_source, "empty")
+        empty_result = empty_proxy.find_partial_source(template.source, "empty")
         self.assertEqual(empty_result, "{% partialdef empty %}{% endpartialdef %}")
 
-        other_result = other_proxy.find_partial_source(template_source, "other")
+        other_result = other_proxy.find_partial_source(template.source, "other")
         self.assertEqual(other_result, "{% partialdef other %}...{% endpartialdef %}")
 
     def test_partials_with_duplicate_names(self):
@@ -306,28 +356,40 @@ INLINE-CONTENT
                 ):
                     Template(template_source, origin=Origin(name="template.html"))
 
+    @setup(
+        {
+            "named_end_tag_template": (
+                "{% partialdef thing %}CONTENT{% endpartialdef thing %}"
+            ),
+        },
+        debug_only=True,
+    )
     def test_find_partial_source_supports_named_end_tag(self):
-        template_source = "{% partialdef thing %}CONTENT{% endpartialdef thing %}"
-        template = Template(template_source)
+        template = self.engine.get_template("named_end_tag_template")
         partial_proxy = template.extra_data["partials"]["thing"]
 
-        result = partial_proxy.find_partial_source(template_source, "thing")
+        result = partial_proxy.find_partial_source(template.source, "thing")
         self.assertEqual(
             result, "{% partialdef thing %}CONTENT{% endpartialdef thing %}"
         )
 
+    @setup(
+        {
+            "nested_partials_basic_template": (
+                "{% partialdef outer %}"
+                "{% partialdef inner %}...{% endpartialdef %}"
+                "{% endpartialdef %}"
+            ),
+        },
+        debug_only=True,
+    )
     def test_find_partial_source_supports_nested_partials(self):
-        template_source = (
-            "{% partialdef outer %}"
-            "{% partialdef inner %}...{% endpartialdef %}"
-            "{% endpartialdef %}"
-        )
-        template = Template(template_source)
+        template = self.engine.get_template("nested_partials_basic_template")
 
         empty_proxy = template.extra_data["partials"]["outer"]
         other_proxy = template.extra_data["partials"]["inner"]
 
-        outer_result = empty_proxy.find_partial_source(template_source, "outer")
+        outer_result = empty_proxy.find_partial_source(template.source, "outer")
         self.assertEqual(
             outer_result,
             (
@@ -336,21 +398,26 @@ INLINE-CONTENT
             ),
         )
 
-        inner_result = other_proxy.find_partial_source(template_source, "inner")
+        inner_result = other_proxy.find_partial_source(template.source, "inner")
         self.assertEqual(inner_result, "{% partialdef inner %}...{% endpartialdef %}")
 
+    @setup(
+        {
+            "nested_partials_named_end_template": (
+                "{% partialdef outer %}"
+                "{% partialdef inner %}...{% endpartialdef inner %}"
+                "{% endpartialdef outer %}"
+            ),
+        },
+        debug_only=True,
+    )
     def test_find_partial_source_supports_nested_partials_and_named_end_tags(self):
-        template_source = (
-            "{% partialdef outer %}"
-            "{% partialdef inner %}...{% endpartialdef inner %}"
-            "{% endpartialdef outer %}"
-        )
-        template = Template(template_source)
+        template = self.engine.get_template("nested_partials_named_end_template")
 
         empty_proxy = template.extra_data["partials"]["outer"]
         other_proxy = template.extra_data["partials"]["inner"]
 
-        outer_result = empty_proxy.find_partial_source(template_source, "outer")
+        outer_result = empty_proxy.find_partial_source(template.source, "outer")
         self.assertEqual(
             outer_result,
             (
@@ -359,23 +426,28 @@ INLINE-CONTENT
             ),
         )
 
-        inner_result = other_proxy.find_partial_source(template_source, "inner")
+        inner_result = other_proxy.find_partial_source(template.source, "inner")
         self.assertEqual(
             inner_result, "{% partialdef inner %}...{% endpartialdef inner %}"
         )
 
+    @setup(
+        {
+            "nested_partials_mixed_end_1_template": (
+                "{% partialdef outer %}"
+                "{% partialdef inner %}...{% endpartialdef %}"
+                "{% endpartialdef outer %}"
+            ),
+        },
+        debug_only=True,
+    )
     def test_find_partial_source_supports_nested_partials_and_mixed_end_tags_1(self):
-        template_source = (
-            "{% partialdef outer %}"
-            "{% partialdef inner %}...{% endpartialdef %}"
-            "{% endpartialdef outer %}"
-        )
-        template = Template(template_source)
+        template = self.engine.get_template("nested_partials_mixed_end_1_template")
 
         empty_proxy = template.extra_data["partials"]["outer"]
         other_proxy = template.extra_data["partials"]["inner"]
 
-        outer_result = empty_proxy.find_partial_source(template_source, "outer")
+        outer_result = empty_proxy.find_partial_source(template.source, "outer")
         self.assertEqual(
             outer_result,
             (
@@ -384,21 +456,26 @@ INLINE-CONTENT
             ),
         )
 
-        inner_result = other_proxy.find_partial_source(template_source, "inner")
+        inner_result = other_proxy.find_partial_source(template.source, "inner")
         self.assertEqual(inner_result, "{% partialdef inner %}...{% endpartialdef %}")
 
+    @setup(
+        {
+            "nested_partials_mixed_end_2_template": (
+                "{% partialdef outer %}"
+                "{% partialdef inner %}...{% endpartialdef inner %}"
+                "{% endpartialdef %}"
+            ),
+        },
+        debug_only=True,
+    )
     def test_find_partial_source_supports_nested_partials_and_mixed_end_tags_2(self):
-        template_source = (
-            "{% partialdef outer %}"
-            "{% partialdef inner %}...{% endpartialdef inner %}"
-            "{% endpartialdef %}"
-        )
-        template = Template(template_source)
+        template = self.engine.get_template("nested_partials_mixed_end_2_template")
 
         empty_proxy = template.extra_data["partials"]["outer"]
         other_proxy = template.extra_data["partials"]["inner"]
 
-        outer_result = empty_proxy.find_partial_source(template_source, "outer")
+        outer_result = empty_proxy.find_partial_source(template.source, "outer")
         self.assertEqual(
             outer_result,
             (
@@ -407,7 +484,7 @@ INLINE-CONTENT
             ),
         )
 
-        inner_result = other_proxy.find_partial_source(template_source, "inner")
+        inner_result = other_proxy.find_partial_source(template.source, "inner")
         self.assertEqual(
             inner_result, "{% partialdef inner %}...{% endpartialdef inner %}"
         )
diff --git a/tests/template_tests/utils.py b/tests/template_tests/utils.py
index 9bab583e79..da5da123f1 100644
--- a/tests/template_tests/utils.py
+++ b/tests/template_tests/utils.py
@@ -9,7 +9,7 @@ ROOT = os.path.dirname(os.path.abspath(__file__))
 TEMPLATE_DIR = os.path.join(ROOT, "templates")
 
 
-def setup(templates, *args, test_once=False):
+def setup(templates, *args, test_once=False, debug_only=False):
     """
     Runs test method multiple times in the following order:
 
@@ -54,11 +54,14 @@ def setup(templates, *args, test_once=False):
             self.engine = Engine(
                 libraries=libraries,
                 loaders=loaders,
+                debug=debug_only,
             )
             func(self)
             if test_once:
                 return
             func(self)
+            if debug_only:
+                return
 
             self.engine = Engine(
                 libraries=libraries,