Fix string name completion for stuff like dirname and abspath

jedi/api/file_name.py

@@ -8,8 +8,7 @@ from jedi.evaluate.helpers import get_str_or_none
 
 def file_name_completions(evaluator, module_context, start_leaf, string, like_name):
     # First we want to find out what can actually be changed as a name.
-    base_name = os.path.basename(string)
+    like_name_length = len(os.path.basename(string) + like_name)
-    like_name_length = len(base_name + like_name)
 
     string = _get_string_additions(module_context, start_leaf) + string
     # Here we use basename again, because if strings are added like

jedi/evaluate/filters.py

@@ -386,7 +386,7 @@ def get_global_filters(evaluator, context, until_position, origin_scope):
     >>> list(filters[1].values())  # package modules -> Also empty.
     []
     >>> sorted(name.string_name for name in filters[2].values())  # Module attributes
-    ['__doc__', '__file__', '__name__', '__package__']
+    ['__doc__', '__name__', '__package__']
 
     Finally, it yields the builtin filter, if `include_builtin` is
     true (default).

jedi/plugins/stdlib.py

@@ -10,6 +10,7 @@ the standard library. The usual way to understand the standard library is the
 compiled module that returns the types for C-builtins.
 """
 import parso
+import os
 
 from jedi._compatibility import force_unicode, Parameter
 from jedi import debug
@@ -678,6 +679,22 @@ def _operator_itemgetter(args_context_set, obj, arguments):
     ])
 
 
+def _create_string_input_function(func):
+    @argument_clinic('string, /', want_obj=True, want_arguments=True)
+    def wrapper(strings, obj, arguments):
+        def iterate():
+            for context in strings:
+                s = get_str_or_none(context)
+                if s is not None:
+                    s = func(s)
+                    yield compiled.create_simple_object(context.evaluator, s)
+        contexts = ContextSet(iterate())
+        if contexts:
+            return contexts
+        return obj.py__call__(arguments)
+    return wrapper
+
+
 _implemented = {
     'builtins': {
         'getattr': builtins_getattr,
@@ -729,6 +746,11 @@ _implemented = {
         # For now this works at least better than Jedi trying to understand it.
         'dataclass': _dataclass
     },
+    'os.path': {
+        'dirname': _create_string_input_function(os.path.dirname),
+        'abspath': _create_string_input_function(os.path.abspath),
+        'relpath': _create_string_input_function(os.path.relpath),
+    }
 }
 
 

test/test_api/test_completion.py

@@ -159,6 +159,10 @@ def test_keyword_completion(Script, code, has_keywords):
     assert has_keywords == any(x.is_keyword for x in Script(code).completions())
 
 
+f1 = join(root_dir, 'example.py')
+f2 = join(root_dir, 'test', 'example.py')
+
+
 @pytest.mark.parametrize(
     'file, code, column, expected', [
         # General tests / relative paths
@@ -199,6 +203,12 @@ def test_keyword_completion(Script, code, has_keywords):
         # Python 2.
         ('example.py', 'x = f(b"t" + "est")', 17, [s]),
         ('example.py', '"test" + "', None, [s]),
+
+        # __file__
+        (f1, 'from os.path import *\ndirname(__file__) + "%stest' % s, None, [s]),
+        (f2, 'from os.path import *\ndirname(__file__) + "%stest_ca' % s, None, ['che.py']),
+        (f2, 'from os.path import *\ndirname(abspath(__file__)) + "%stest_ca' % s,
+         None, ['che.py']),
     ]
 )
 def test_file_path_completions(Script, file, code, column, expected):