fix(inspect): Fixed an error that would raise when using get_history(…

…) with lazy values (#1184)

This fixes the error by avoiding the attempt to evaluate altogheter.

get_history() should provide the original representation, so the user
can reliably inspect its data. The evaluted value might be hard to track
and potentially confusing to inspect.

Closes #1180

docs/flask.md

@@ -23,7 +23,7 @@ FlaskDynaconf(app)
 
 Dynaconf transform nested data structures to a new DynaBox instance, this is an
 object that allows dot notation access such as `app.config.key.value.other`.
-However this feature is imcompatible with some Flask extensions, for example:
+However this feature is incompatible with some Flask extensions, for example:
 `Flask-Alembic`.
 
 So in case you see a `BoxKeyError` when running your app with you can run it on

dynaconf/utils/inspect.py

@@ -17,6 +17,7 @@
 from dynaconf.loaders.base import SourceMetadata
 from dynaconf.utils.boxing import DynaBox
 from dynaconf.utils.functional import empty
+from dynaconf.utils.parse_conf import Lazy
 from dynaconf.vendor.box.box_list import BoxList
 from dynaconf.vendor.ruamel.yaml import YAML
 
@@ -322,13 +323,19 @@ def _get_data_by_key(
     if sep in key_dotted_path:
         key_dotted_path = key_dotted_path.replace(sep, ".")
 
+    def handle_repr(value):
+        # lazy values shouldnt be evaluated for inspecting
+        if isinstance(value, Lazy):
+            return value._dynaconf_encode()
+        return value
+
     def traverse_data(data, path):
         # transform `a.b.c` in successive calls to `data['a']['b']['c']`
         path = path.split(".")
         root_key, nested_keys = path[0], path[1:]
-        result = data[root_key]
+        result = data._safe_get(root_key)
         for key in nested_keys:
-            result = result[key]
+            result = handle_repr(result._safe_get(key))
         return result
 
     try:

tests/test_inspect.py

@@ -559,6 +559,37 @@ def test_get_history_env_and_key_filter(tmp_path):
     assert history[1]["value"] == "from_prod_b"
 
 
+def tests_get_history_with_variable_interpolation():
+    """Variable interpolation is not evaluated.
+    https://github.com/dynaconf/dynaconf/issues/1180
+
+    The original issue was about an exception being raised when there was
+    variable interpolation involved. But in the end, the get_history shouldnt
+    evaluate the interpolations:
+
+    - History should accurately inform the order and content of what the user loaded.
+    - For a key with a interpolation value, the accurate representation is not the evaluated
+      value, but the original template string.
+    - The evaluated depends on other keys, so for
+      history inspecting it is more reliable to show what variables were used so the user
+      can verify if everything happened as expected.
+    """
+    data = {
+        "a": {
+            "b": "foo",
+            "c": "bar",
+            "d": "@format {this.a.b} {this.a.c}",
+        }
+    }
+
+    settings = Dynaconf(**data)
+
+    assert settings.a.d == "foo bar"
+    history = get_history(settings, "a.d")
+    # shows the not-evaluated (raw) value
+    assert history[0]["value"] == "@format {this.a.b} {this.a.c}"
+
+
 def test_caveat__get_history_env_true(tmp_path):
     """
     Given environments=True and sources=file