Black does not respect line length in case of long attribute chaining

[adarshk7]

Describe the bug

In a case where there is code that chains a lot of attributes within a parentheses block (to avoid using backslashes) Black fails to respect the line length supplied to it.

To Reproduce

1. Take this file

class BlackTestingClass():
    def __getattr__(self):
        return self


def some_function():
    btc = BlackTestingClass()
    (
        btc
        .attribute1.something
        .attribute2.something
        .attribute3.something
        .attribute4.something
        .attribute5.something
    )

2. Run Black on it with these arguments : black . --diff -l 100
3. See error

@@ -1,16 +1,11 @@
-class BlackTestingClass():
+class BlackTestingClass:
     def __getattr__(self):
         return self


 def some_function():
     btc = BlackTestingClass()
     (
-        btc
-        .attribute1.something
-        .attribute2.something
-        .attribute3.something
-        .attribute4.something
-        .attribute5.something
+        btc.attribute1.something.attribute2.something.attribute3.something.attribute4.something.attribute5.something
     )

Expected behavior

The existing code in the block should be kept as it is (if it doesn't break any formatting rules otherwise) as it is probably a well thought out pattern by a developer or at least black should not put everything to the same line which exceeds the line-length (in this case the output line is 113 characters whereas the limit supplied to black is 100.)

Environment

• Version: 19.10b0
• OS and Python version: macOS 10.14.6/Python 3.7.4

Does this bug also happen on master?

Yes (Verified from the playground)

Additional context

As to where one might encounter this kind of block in real life, mocking and patching specific things in tests might get fairly nested (especially with unittests .return_value) or something like long ORM queries with SQLAlchemy.

[JelleZijlstra]

Duplicate of #510