Fixed #35493 -- Allowed template self-inclusion with relative paths.

Co-authored-by: Brock <bsmick97@gmail.com>

django/template/loader_tags.py

@@ -242,7 +242,11 @@ def do_block(parser, token):
     return BlockNode(block_name, nodelist)
 
 
-def construct_relative_path(current_template_name, relative_name):
+def construct_relative_path(
+    current_template_name,
+    relative_name,
+    allow_recursion=False,
+):
     """
     Convert a relative path (starting with './' or '../') to the full template
     name based on the current_template_name.
@@ -264,7 +268,7 @@ def construct_relative_path(current_template_name, relative_name):
             "The relative path '%s' points outside the file hierarchy that "
             "template '%s' is in." % (relative_name, current_template_name)
         )
-    if current_template_name.lstrip("/") == new_name:
+    if not allow_recursion and current_template_name.lstrip("/") == new_name:
         raise TemplateSyntaxError(
             "The relative path '%s' was translated to template name '%s', the "
             "same template in which the tag appears."
@@ -346,7 +350,11 @@ def do_include(parser, token):
         options[option] = value
     isolated_context = options.get("only", False)
     namemap = options.get("with", {})
-    bits[1] = construct_relative_path(parser.origin.template_name, bits[1])
+    bits[1] = construct_relative_path(
+        parser.origin.template_name,
+        bits[1],
+        allow_recursion=True,
+    )
     return IncludeNode(
         parser.compile_filter(bits[1]),
         extra_context=namemap,