DebugUndefined does not handle object.value replacements

[David Parker]

Description

when using object.value syntax, undefined.DebugUndefined breaks instead of returning the missing substitution. If the parent object is defined, it returns the python object access error. If the parent object is not defined, it throws an error (like with default undefined)

Code Replication

import jinja2
template = jinja2.Environment(undefined=jinja2.DebugUndefined).from_string("env.val is {{ env.val }}")
print(template.render({'env': {'val': 'something'}}))
print(template.render({'env': {}}))
print(template.render({'other': 'something'}))

Expected Results

env.val is something
env.val is {{ env.val }}
env.val is {{ env.val }}

Actual Results

env.val is something
env.val is {{ no such element: dict object['val'] }}
Traceback (most recent call last):
  File "/Users/taapadak/Work/opsgenie-kafka/jinjaissue.yml.py", line 5, in <module>
    print(template.render({'other': 'something'}))
  File "/Users/taapadak/Work/opsgenie-kafka/venv/lib/python3.9/site-packages/jinja2/environment.py", line 1301, in render
    self.environment.handle_exception()
  File "/Users/taapadak/Work/opsgenie-kafka/venv/lib/python3.9/site-packages/jinja2/environment.py", line 936, in handle_exception
    raise rewrite_traceback_stack(source=source)
  File "<template>", line 1, in top-level template code
  File "/Users/taapadak/Work/opsgenie-kafka/venv/lib/python3.9/site-packages/jinja2/environment.py", line 485, in getattr
    return getattr(obj, attribute)
jinja2.exceptions.UndefinedError: 'env' is undefined

Environment

• Python version: 3.9.6
• Jinja version: Jinja2==3.1.2