From a7c706f401ebea3f25120cc155c7ab518c23df53 Mon Sep 17 00:00:00 2001
From: Bruno Rocha <rochacbruno@users.noreply.github.com>
Date: Wed, 21 Sep 2022 17:38:19 +0100
Subject: [PATCH] Allow merge_unique on lists when merge_enabled=True (#810)

Fix #726
---
 dynaconf/utils/__init__.py                       |  6 ++++++
 .../issues/726_unique_nested_list/app.py         | 16 ++++++++++++++++
 .../726_unique_nested_list/configuration.yaml    |  6 ++++++
 .../issues/726_unique_nested_list/defaults.yaml  |  4 ++++
 4 files changed, 32 insertions(+)
 create mode 100644 tests_functional/issues/726_unique_nested_list/app.py
 create mode 100644 tests_functional/issues/726_unique_nested_list/configuration.yaml
 create mode 100644 tests_functional/issues/726_unique_nested_list/defaults.yaml

diff --git a/dynaconf/utils/__init__.py b/dynaconf/utils/__init__.py
index 8515fee14..146062017 100644
--- a/dynaconf/utils/__init__.py
+++ b/dynaconf/utils/__init__.py
@@ -46,6 +46,12 @@ def object_merge(
         return new
 
     if isinstance(old, list) and isinstance(new, list):
+
+        # 726: allow local_merge to override global merge on lists
+        if "dynaconf_merge_unique" in new:
+            new.remove("dynaconf_merge_unique")
+            unique = True
+
         for item in old[::-1]:
             if unique and item in new:
                 continue
diff --git a/tests_functional/issues/726_unique_nested_list/app.py b/tests_functional/issues/726_unique_nested_list/app.py
new file mode 100644
index 000000000..f68ad9fba
--- /dev/null
+++ b/tests_functional/issues/726_unique_nested_list/app.py
@@ -0,0 +1,16 @@
+from __future__ import annotations
+
+from dynaconf import Dynaconf
+
+settings = Dynaconf(
+    envvar_prefix="ISSUE726",
+    settings_files=["defaults.yaml", "configuration.yaml"],
+    merge_enabled=True,
+)
+
+
+assert settings.config_key.nested_list == [
+    "item_a",
+    "item_b",
+    "item_c",
+], settings.config_key.nested_list
diff --git a/tests_functional/issues/726_unique_nested_list/configuration.yaml b/tests_functional/issues/726_unique_nested_list/configuration.yaml
new file mode 100644
index 000000000..4c55a3603
--- /dev/null
+++ b/tests_functional/issues/726_unique_nested_list/configuration.yaml
@@ -0,0 +1,6 @@
+config_key:
+  nested_list:
+    - dynaconf_merge_unique
+    - item_a
+    - item_b
+    - item_c
diff --git a/tests_functional/issues/726_unique_nested_list/defaults.yaml b/tests_functional/issues/726_unique_nested_list/defaults.yaml
new file mode 100644
index 000000000..22ff7907c
--- /dev/null
+++ b/tests_functional/issues/726_unique_nested_list/defaults.yaml
@@ -0,0 +1,4 @@
+config_key:
+  nested_list:
+    - item_a
+    - item_b