Resolve false negative for implicit str concat inside calls

Closes pylint-dev#6441

ChangeLog

@@ -73,6 +73,10 @@ Release date: TBA
 
   Ref #5392
 
+* ``implicit-str-concat`` will now be raised on calls like ``open("myfile.txt" "a+b")`` too.
+
+  Closes #6441
+
 * The ``config`` attribute of ``PyLinter`` is now of the ``argparse.Namespace`` type instead of
   ``optparse.Values``.
 

doc/whatsnew/2.14.rst

@@ -91,6 +91,10 @@ Other Changes
 
   Closes #6101
 
+* ``implicit-str-concat`` will now be raised on calls like ``open("myfile.txt" "a+b")`` too.
+
+  Closes #6441
+
 * Fix a failure to respect inline disables for ``fixme`` occurring on the last line
   of a module when pylint is launched with ``--enable=fixme``.
 

pylint/checkers/strings.py

@@ -723,6 +723,10 @@ def process_tokens(self, tokens: list[tokenize.TokenInfo]) -> None:
         if self.linter.config.check_quote_consistency:
             self.check_for_consistent_string_delimiters(tokens)
 
+    @only_required_for_messages("implicit-str-concat")
+    def visit_call(self, node: nodes.Call) -> None:
+        self.check_for_concatenated_strings(node.args, "call")
+
     @only_required_for_messages("implicit-str-concat")
     def visit_list(self, node: nodes.List) -> None:
         self.check_for_concatenated_strings(node.elts, "list")

tests/functional/i/implicit/implicit_str_concat.py

@@ -1,4 +1,4 @@
-#pylint: disable=invalid-name,missing-docstring,redundant-u-string-prefix
+# pylint: disable=invalid-name, missing-docstring, redundant-u-string-prefix, line-too-long
 
 # Basic test with a list
 TEST_LIST1 = ['a' 'b']  # [implicit-str-concat]
@@ -10,8 +10,8 @@
 # in the middle of a list
 TEST_LIST4 = ["""a""", """b""" """c""", """d"""]  # [implicit-str-concat]
 
-# The following shouldn't raise a warning because it is a function call
-print('a', 'bbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbb' 'ccc')
+print("Lorem ipsum " "dolor sit amet")  # [implicit-str-concat]
+print('a', 'bbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbb' 'ccc')  # [implicit-str-concat]
 
 # The following shouldn't raise a warning because string literals are
 # on different lines
@@ -29,3 +29,13 @@
 
 # No warning for bytes
 TEST_LIST8 = [b'A' b'B']
+
+print(
+    "Lorem ipsum dolor sit amet, consectetur adipiscing elit,"
+    " sed do eiusmod tempor incididunt ut labore et dolore "
+    "magna aliqua. Ut enim ad minim veniam, quis nostrud "
+    "exercitation ullamco laboris nisi ut aliquip ex ea "
+)
+
+with open("myfile.txt" "a+b", encoding="utf8") as f:  # [implicit-str-concat]
+    content = f.read()

tests/functional/i/implicit/implicit_str_concat.txt

@@ -2,4 +2,7 @@ implicit-str-concat:4:0:None:None::Implicit string concatenation found in list:U
 implicit-str-concat:6:0:None:None::Implicit string concatenation found in tuple:UNDEFINED
 implicit-str-concat:8:0:None:None::Implicit string concatenation found in set:UNDEFINED
 implicit-str-concat:11:0:None:None::Implicit string concatenation found in list:UNDEFINED
+implicit-str-concat:13:0:None:None::Implicit string concatenation found in call:UNDEFINED
+implicit-str-concat:14:0:None:None::Implicit string concatenation found in call:UNDEFINED
 implicit-str-concat:27:0:None:None::Implicit string concatenation found in assignment:UNDEFINED
+implicit-str-concat:40:0:None:None::Implicit string concatenation found in call:UNDEFINED

tests/functional/i/implicit/implicit_str_concat_multiline.py

@@ -2,3 +2,10 @@
 
 TEST_TUPLE = ('a', 'b'  # [implicit-str-concat]
               'c')
+
+print(
+    "Lorem ipsum dolor sit amet, consectetur adipiscing elit," # [implicit-str-concat]
+    " sed do eiusmod tempor incididunt ut labore et dolore "
+    "magna aliqua. Ut enim ad minim veniam, quis nostrud "
+    "exercitation ullamco laboris nisi ut aliquip ex ea "
+)

tests/functional/i/implicit/implicit_str_concat_multiline.txt

@@ -1 +1,2 @@
 implicit-str-concat:3:0:None:None::Implicit string concatenation found in tuple:UNDEFINED
+implicit-str-concat:7:0:None:None::Implicit string concatenation found in call:UNDEFINED