Fix list formatting forcing a split before short function-call elements

CHANGELOG.md

@@ -75,6 +75,9 @@
   by taking precedence over SPLIT_BEFORE_NAMED_ASSIGNS.
 - Fix SPLIT_ALL_COMMA_SEPARATED_VALUES and SPLIT_ALL_TOP_LEVEL_COMMA_SEPARATED_VALUES
   being too agressive for lambdas and unpacking.
+- Fix a short, no-argument function call in a list being forced onto its own
+  line just because the list as a whole didn't fit on one line, producing
+  inconsistent formatting between call and non-call elements.
 
 ## [0.40.2] 2023-09-22
 ### Changes

yapf/yapflib/format_decision_state.py

@@ -317,11 +317,18 @@ def SurroundedByParens(token):
       if func_call_or_string_format:
         open_bracket = logical_line.IsSurroundedByBrackets(current)
         if open_bracket:
-          if open_bracket.value in '[{':
+          if open_bracket.value in '[{' and tok.value != '(':
             if not self._FitsOnLine(open_bracket,
                                     open_bracket.matching_bracket):
               return True
           elif tok.value == '(':
+            # Only force a split before this function-call element if the
+            # call itself doesn't fit on the line. Checking whether the
+            # *whole* surrounding list/dict fits (as above) forces a split
+            # before every function-call element whenever the container is
+            # too long overall, even for short calls like `f()`, producing
+            # inconsistent formatting between call and non-call elements.
+            # See https://github.com/google/yapf/issues/422.
             if not self._FitsOnLine(current, tok.matching_bracket):
               return True
 

yapftests/reformatter_basic_test.py

@@ -2816,6 +2816,22 @@ def foo():
     llines = yapf_test_helper.ParseAndUnwrap(unformatted_code)
     self.assertCodeEqual(expected_code, reformatter.Reformat(llines))
 
+  def testListWithShortFunctionCallsAmongPlainElements(self):
+    # A short, no-argument function call in a list shouldn't be forced onto
+    # its own line just because the list as a whole doesn't fit: only calls
+    # that don't themselves fit on the line should be split like that.
+    # See https://github.com/google/yapf/issues/422.
+    unformatted_code = textwrap.dedent("""\
+        array = [first, make_second(), third, fourth, fifth, make_sixth(), seventh, eighth]
+    """)
+    expected_code = textwrap.dedent("""\
+        array = [
+            first, make_second(), third, fourth, fifth, make_sixth(), seventh, eighth
+        ]
+    """)
+    llines = yapf_test_helper.ParseAndUnwrap(unformatted_code)
+    self.assertCodeEqual(expected_code, reformatter.Reformat(llines))
+
   def testEllipses(self):
     unformatted_code = textwrap.dedent("""\
         X=...