Fix incorrect suggestion for unnecessary-comprehension (#9172) (#9242)

(cherry picked from commit 6f83d5a)

Co-authored-by: Sayyed Faisal Ali <[email protected]>

Author: github-actions[bot]

doc/whatsnew/fragments/9172.false_positive

@@ -0,0 +1,12 @@
+Fixed incorrect suggestion for shallow copy in unnecessary-comprehension
+
+Example of the suggestion:
+#pylint: disable=missing-module-docstring
+a = [1, 2, 3]
+b = [x for x in a]
+b[0] = 0
+print(a) # [1, 2, 3]
+
+After changing b = [x for x in a] to b = a based on the suggestion, the script now prints [0, 2, 3]. The correct suggestion should be use list(a) to preserve the original behavior.
+
+Closes #9172

pylint/checkers/refactoring/refactoring_checker.py

@@ -1779,15 +1779,15 @@ def _check_unnecessary_comprehension(self, node: nodes.Comprehension) -> None:
             if isinstance(node.parent, nodes.DictComp) and isinstance(
                 inferred, astroid.objects.DictItems
             ):
-                args = (f"{node.iter.func.expr.as_string()}",)
-            elif (
-                isinstance(node.parent, nodes.ListComp)
-                and isinstance(inferred, nodes.List)
-            ) or (
-                isinstance(node.parent, nodes.SetComp)
-                and isinstance(inferred, nodes.Set)
+                args = (f"dict({node.iter.func.expr.as_string()})",)
+            elif isinstance(node.parent, nodes.ListComp) and isinstance(
+                inferred, nodes.List
             ):
-                args = (f"{node.iter.as_string()}",)
+                args = (f"list({node.iter.as_string()})",)
+            elif isinstance(node.parent, nodes.SetComp) and isinstance(
+                inferred, nodes.Set
+            ):
+                args = (f"set({node.iter.as_string()})",)
             if args:
                 self.add_message(
                     "unnecessary-comprehension", node=node.parent, args=args

tests/functional/u/unnecessary/unnecessary_comprehension.py

@@ -4,7 +4,9 @@
 # List comprehensions
 [x for x in iterable]  # [unnecessary-comprehension]
 [y for x in iterable]  # expression != target_list
+[x for x in iterable] # [unnecessary-comprehension] use list(iterable)
 [x for x,y,z in iterable]  # expression != target_list
+[(x, y) for x, y in iterable]  # [unnecessary-comprehension]
 [(x,y,z) for x,y,z in iterable]  # [unnecessary-comprehension]
 [(x,y,z) for (x,y,z) in iterable]  # [unnecessary-comprehension]
 [x for x, *y in iterable]  # expression != target_list

tests/functional/u/unnecessary/unnecessary_comprehension.txt

@@ -1,13 +1,15 @@
 unnecessary-comprehension:5:0:5:21::Unnecessary use of a comprehension, use list(iterable) instead.:UNDEFINED
-unnecessary-comprehension:8:0:8:31::Unnecessary use of a comprehension, use list(iterable) instead.:UNDEFINED
-unnecessary-comprehension:9:0:9:33::Unnecessary use of a comprehension, use list(iterable) instead.:UNDEFINED
-unnecessary-comprehension:17:7:17:42::Unnecessary use of a comprehension, use list(a_dict.items()) instead.:UNDEFINED
-unnecessary-comprehension:20:0:20:21::Unnecessary use of a comprehension, use set(iterable) instead.:UNDEFINED
-unnecessary-comprehension:23:0:23:31::Unnecessary use of a comprehension, use set(iterable) instead.:UNDEFINED
-unnecessary-comprehension:24:7:24:42::Unnecessary use of a comprehension, use set(iterable) instead.:UNDEFINED
-unnecessary-comprehension:32:0:32:27::Unnecessary use of a comprehension, use dict(iterable) instead.:UNDEFINED
-unnecessary-comprehension:34:0:34:29::Unnecessary use of a comprehension, use dict(iterable) instead.:UNDEFINED
-unnecessary-comprehension:46:0:46:26::Unnecessary use of a comprehension, use my_list instead.:UNDEFINED
-unnecessary-comprehension:47:8:47:42::Unnecessary use of a comprehension, use my_dict instead.:UNDEFINED
-consider-using-dict-items:48:0:None:None::Consider iterating with .items():UNDEFINED
-unnecessary-comprehension:49:0:49:25::Unnecessary use of a comprehension, use my_set instead.:UNDEFINED
+unnecessary-comprehension:7:0:7:21::Unnecessary use of a comprehension, use list(iterable) instead.:UNDEFINED
+unnecessary-comprehension:9:0:9:29::Unnecessary use of a comprehension, use list(iterable) instead.:UNDEFINED
+unnecessary-comprehension:10:0:10:31::Unnecessary use of a comprehension, use list(iterable) instead.:UNDEFINED
+unnecessary-comprehension:11:0:11:33::Unnecessary use of a comprehension, use list(iterable) instead.:UNDEFINED
+unnecessary-comprehension:19:7:19:42::Unnecessary use of a comprehension, use list(a_dict.items()) instead.:UNDEFINED
+unnecessary-comprehension:22:0:22:21::Unnecessary use of a comprehension, use set(iterable) instead.:UNDEFINED
+unnecessary-comprehension:25:0:25:31::Unnecessary use of a comprehension, use set(iterable) instead.:UNDEFINED
+unnecessary-comprehension:26:7:26:42::Unnecessary use of a comprehension, use set(iterable) instead.:UNDEFINED
+unnecessary-comprehension:34:0:34:27::Unnecessary use of a comprehension, use dict(iterable) instead.:UNDEFINED
+unnecessary-comprehension:36:0:36:29::Unnecessary use of a comprehension, use dict(iterable) instead.:UNDEFINED
+unnecessary-comprehension:48:0:48:26::Unnecessary use of a comprehension, use list(my_list) instead.:UNDEFINED
+unnecessary-comprehension:49:8:49:42::Unnecessary use of a comprehension, use dict(my_dict) instead.:UNDEFINED
+consider-using-dict-items:50:0:None:None::Consider iterating with .items():UNDEFINED
+unnecessary-comprehension:51:0:51:25::Unnecessary use of a comprehension, use set(my_set) instead.:UNDEFINED