test for start as a var

pylint-dev · Oct 31, 2022 · 2a97187 · 2a97187
1 parent d6d72e2
commit 2a97187
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Showing 3 changed files with 25 additions and 12 deletions.
diff --git a/pylint/checkers/refactoring/refactoring_checker.py b/pylint/checkers/refactoring/refactoring_checker.py
@@ -2221,22 +2221,26 @@ def _enumerate_with_start(self, node: nodes.For | nodes.Comprehension) -> bool:
             # It's a reasonable assumption for now as it's the only possible argument:
             # https://docs.python.org/3/library/functions.html#enumerate
             start_arg = node.iter.args[1]
-
-            start_val = (
-                start_arg.operand.value
-                if isinstance(start_arg, nodes.UnaryOp)
-                else start_arg.value
-            )
+            start_val = self._get_start_value(start_arg)
+            if start_val is None:
+                return False
             return not start_val == 0
 
         for keyword in node.iter.keywords:
             if keyword.arg == "start":
-                start_val = (
-                    keyword.value.operand.value
-                    if isinstance(keyword.value, nodes.UnaryOp)
-                    else keyword.value.value
-                )
-
+                start_val = self._get_start_value(keyword.value)
+                if start_val is None:
+                    return False
                 return not start_val == 0
 
         return False
+
+    def _get_start_value(self, node: nodes.NodeNG) -> Any:
+        if isinstance(node, nodes.Name):
+            inferred = utils.safe_infer(node)
+            start_val = inferred.value if inferred else None
+        elif isinstance(node, nodes.UnaryOp):
+            start_val = node.operand.value
+        else:
+            start_val = node.value
+        return start_val
diff --git a/tests/functional/u/unnecessary/unnecessary_list_index_lookup.py b/tests/functional/u/unnecessary/unnecessary_list_index_lookup.py
@@ -113,3 +113,10 @@ def process_list_again(data):
 
 for idx, val in enumerate(series, 0):
     print(series[idx])  # [unnecessary-list-index-lookup]
+
+START = 0
+for idx, val in enumerate(series, start=START):
+    print(series[idx])  # [unnecessary-list-index-lookup]
+
+for idx, val in enumerate(series, START):
+    print(series[idx])  # [unnecessary-list-index-lookup]
diff --git a/tests/functional/u/unnecessary/unnecessary_list_index_lookup.txt b/tests/functional/u/unnecessary/unnecessary_list_index_lookup.txt
@@ -4,3 +4,5 @@ unnecessary-list-index-lookup:46:10:46:22::Unnecessary list index lookup, use 'v
 unnecessary-list-index-lookup:74:10:74:27::Unnecessary list index lookup, use 'val' instead:HIGH
 unnecessary-list-index-lookup:112:10:112:21::Unnecessary list index lookup, use 'val' instead:HIGH
 unnecessary-list-index-lookup:115:10:115:21::Unnecessary list index lookup, use 'val' instead:HIGH
+unnecessary-list-index-lookup:119:10:119:21::Unnecessary list index lookup, use 'val' instead:HIGH
+unnecessary-list-index-lookup:122:10:122:21::Unnecessary list index lookup, use 'val' instead:HIGH