yapf formatting differs based on Python 3 version

[imphil]

I have the following code:

class A:
    def __init__(self, *extras):
        super().__init__(
            *chain((AbcdEfghij, AbcDef, AbcdEfghiJklmnopqr), extras))

Running yapf master e43ad9d/0.26.0/0.25.0 on Python 3.7.2 gives the following output:

$ yapf --style=pep8 -d testfile.py
--- testfile.py (original)
+++ testfile.py (reformatted)
@@ -1,4 +1,4 @@
 class A:
     def __init__(self, *extras):
-        super().__init__(
-            *chain((AbcdEfghij, AbcDef, AbcdEfghiJklmnopqr), extras))
+        super().__init__(*chain((AbcdEfghij, AbcDef,
+                                 AbcdEfghiJklmnopqr), extras))

Running yapf master e43ad9d/0.26.0/0.25.0 on Python 3.5.2 (Ubuntu 16.04 default) gives the following output:

$ yapf --style=pep8 -d testfile.py
$ echo $?
0

We expect users to run yapf locally and we run it in CI. Having different formatting requirements between a local runs and CI is very unfortunate for us.

Notes:

• I know that yapf 0.26.0 doesn't support Python 3.5 any more. Still the same bug is present in the previous version 0.25.0 which did support Python 3.5. (We still need to use it for Ubuntu 16.04 users.)
• The same bug can be observed when using the google instead of the pep8 style.
• I didn't bisect which Python version is the tipping point for this behavior, and I didn't exclude other factors beyond the Python version which might also play a role.

[bwendling]

Interesting. It of course shouldn't make a difference. I'll see what's up.

[rory-ye-nv]

I have the same problem, for yapf in python 3 and python 2, both with google style.

15:56:14 find . -name '*.py' -print0 | xargs -0 yapf --diff
15:56:40 --- ./aws/emr/s3/steps/download-artifact-new.py    (original)
15:56:40 +++ ./aws/emr/s3/steps/download-artifact-new.py    (reformatted)
15:56:40 @@ -33,8 +33,8 @@
15:56:40          # the path is allowed to contain variables like:
15:56:40          # {artifact_name}, {artifact_version}, etc.
15:56:40          # e.g. /{artifact_name}/{artifact_version}
15:56:40 -        self.artifact_path = args.artifact_path.format(
15:56:40 -            **args.__dict__).strip('/')
15:56:40 +        self.artifact_path = args.artifact_path.format(**args.__dict__).strip(
15:56:40 +            '/')
15:56:40          self.artifact_name = args.artifact_name
15:56:40          self.package_type = args.package_type
15:56:40          self.artifact_version = args.artifact_version
15:56:40 --- ./aws/emr/s3/steps/download-artifact.py    (original)
15:56:40 +++ ./aws/emr/s3/steps/download-artifact.py    (reformatted)
15:56:40 @@ -32,8 +32,8 @@
15:56:40          # the path is allowed to contain variables like:
15:56:40          # {artifact_name}, {artifact_version}, etc.
15:56:40          # e.g. /{artifact_name}/{artifact_version}
15:56:40 -        self.artifact_path = args.artifact_path.format(
15:56:40 -            **args.__dict__).strip('/')
15:56:40 +        self.artifact_path = args.artifact_path.format(**args.__dict__).strip(
15:56:40 +            '/')
15:56:40          self.artifact_name = args.artifact_name
15:56:40          self.package_type = args.package_type
15:56:40          self.artifact_version = args.artifact_version