Extend safe_infer's sense of ambiguity to arg names and defaults (#8668)

Co-authored-by: Mehdi Drissi <[email protected]>
Co-authored-by: Jacob Walls <[email protected]>

Author: 3 people

doc/whatsnew/fragments/3613.false_positive

@@ -0,0 +1,6 @@
+Extend concept of "function ambiguity" in ``safe_infer()`` from
+differing number of function arguments to differing set of argument names.
+
+Solves false positives in ``tensorflow``.
+
+Closes #3613

pylint/checkers/utils.py

@@ -1381,12 +1381,10 @@ def safe_infer(
                 return None
             if (
                 isinstance(inferred, nodes.FunctionDef)
-                and inferred.args.args is not None
                 and isinstance(value, nodes.FunctionDef)
-                and value.args.args is not None
-                and len(inferred.args.args) != len(value.args.args)
+                and function_arguments_are_ambiguous(inferred, value)
             ):
-                return None  # Different number of arguments indicates ambiguity
+                return None
     except astroid.InferenceError:
         return None  # There is some kind of ambiguity
     except StopIteration:
@@ -1408,6 +1406,33 @@ def infer_all(
         raise AstroidError from e
 
 
+def function_arguments_are_ambiguous(
+    func1: nodes.FunctionDef, func2: nodes.FunctionDef
+) -> bool:
+    if func1.argnames() != func2.argnames():
+        return True
+    # Check ambiguity among function default values
+    pairs_of_defaults = [
+        (func1.args.defaults, func2.args.defaults),
+        (func1.args.kw_defaults, func2.args.kw_defaults),
+    ]
+    for zippable_default in pairs_of_defaults:
+        if None in zippable_default:
+            continue
+        if len(zippable_default[0]) != len(zippable_default[1]):
+            return True
+        for default1, default2 in zip(*zippable_default):
+            if isinstance(default1, nodes.Const) and isinstance(default2, nodes.Const):
+                if default1.value != default2.value:
+                    return True
+            elif isinstance(default1, nodes.Name) and isinstance(default2, nodes.Name):
+                if default1.name != default2.name:
+                    return True
+            else:
+                return True
+    return False
+
+
 def has_known_bases(
     klass: nodes.ClassDef, context: InferenceContext | None = None
 ) -> bool:

tests/functional/u/unexpected_keyword_arg.py

@@ -116,3 +116,50 @@ def test_no_return():
 
 
 test_no_return(internal_arg=2)  # [unexpected-keyword-arg]
+
+
+def ambiguous_func1(arg1):
+    print(arg1)
+
+
+def ambiguous_func2(other_arg1):
+    print(other_arg1)
+
+
+func1 = ambiguous_func1 if unknown else ambiguous_func2
+func1(other_arg1=1)
+
+
+def ambiguous_func3(arg1=None):
+    print(arg1)
+
+
+func2 = ambiguous_func1 if unknown else ambiguous_func3
+func2()
+
+
+def ambiguous_func4(arg1=print):
+    print(arg1)
+
+
+def ambiguous_func5(arg1=input):
+    print(arg1)
+
+
+def ambiguous_func6(arg1=42):
+    print(arg1)
+
+
+# Two functions with same keyword argument but different defaults (names)
+func3 = ambiguous_func4 if unknown else ambiguous_func5
+func3()
+
+
+# Two functions with same keyword argument but different defaults (constants)
+func4 = ambiguous_func3 if unknown else ambiguous_func6
+func4()
+
+
+# Two functions with same keyword argument but mixed defaults (names, constant)
+func5 = ambiguous_func3 if unknown else ambiguous_func5
+func5()