From b7c2bacbd21007a06bbfb79a2937c41ea68265d6 Mon Sep 17 00:00:00 2001
From: Dave Halter <davidhalter88@gmail.com>
Date: Mon, 5 Aug 2019 10:11:36 +0200
Subject: [PATCH] Fix string additions when used in certain ways

---
 jedi/api/file_name.py            | 17 ++++++++++-------
 test/test_api/test_completion.py |  6 ++++++
 2 files changed, 16 insertions(+), 7 deletions(-)

diff --git a/jedi/api/file_name.py b/jedi/api/file_name.py
index cf0663c6..6dfaf7ea 100644
--- a/jedi/api/file_name.py
+++ b/jedi/api/file_name.py
@@ -7,27 +7,32 @@ 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 = base_name + like_name
-    string = os.path.dirname(string)
+    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
+    # `'foo' + 'bar`, it should complete to `foobar/`.
+    must_start_with = os.path.basename(string) + like_name
+    string = os.path.dirname(string)
+
     base_path = os.path.join(evaluator.project._path, string)
     try:
         listed = os.listdir(base_path)
     except FileNotFoundError:
         return
     for name in listed:
-        if name.startswith(like_name):
+        if name.startswith(must_start_with):
             path_for_name = os.path.join(base_path, name)
             if os.path.isdir(path_for_name):
                 name += os.path.sep
 
             yield classes.Completion(
                 evaluator,
-                FileName(evaluator, name),
+                FileName(evaluator, name[len(must_start_with) - like_name_length:]),
                 stack=None,
-                like_name_length=len(like_name),
+                like_name_length=like_name_length
             )
 
 
@@ -55,8 +60,6 @@ def _get_string_additions(module_context, start_leaf):
         if child_node != '+':
             break
         was_addition = True
-        child_node
-    module_context
     return string
 
 
diff --git a/test/test_api/test_completion.py b/test/test_api/test_completion.py
index 1d333996..286e969e 100644
--- a/test/test_api/test_completion.py
+++ b/test/test_api/test_completion.py
@@ -190,6 +190,12 @@ def test_keyword_completion(Script, code, has_keywords):
         ('example.py', '"test" + "%stest_cac' % s, None, ['he.py']),
         ('example.py', '"test" + "%s" + "test_cac' % s, None, ['he.py']),
         ('example.py', 'x = 1 + "test', None, [s]),
+        ('example.py', 'x = f("te" + "st)', 16, [s]),
+        ('example.py', 'x = f("te" + "st', 16, [s]),
+        ('example.py', 'x = f("te" + "st"', 16, [s]),
+        ('example.py', 'x = f("te" + "st")', 16, [s]),
+        ('example.py', 'x = f("t" + "est")', 16, [s]),
+        ('example.py', '"test" + "', None, [s]),
     ]
 )
 def test_file_path_completions(Script, file, code, column, expected):