qapi: add pylintrc

Using `pylint --generate-rcfile > pylintrc`, generate a skeleton
pylintrc file. Sections that are not presently relevant (by the end of
this series) are removed leaving just the empty section as a search
engine / documentation hint to future authors.

I am targeting pylint 2.6.0. In the future (and hopefully before 5.2 is
released), I aim to have gitlab CI running the specific targeted
versions of pylint, mypy, flake8, etc in a job.

2.5.x will work if you additionally pass --disable=bad-whitespace.
This warning was removed from 2.6.x, for lack of consistent support.

Right now, quite a few modules are ignored as they are known to fail as
of this commit. modules will be removed from the known-bad list
throughout this and following series as they are repaired.

Note: Normally, pylintrc would go in the folder above the module, but as
that folder is shared by many things, it is going inside the module
folder (for now). Due to a bug in pylint 2.5+, pylint does not
correctly recognize when it is being run from "inside" a package, and
must be run *outside* of the package.

Therefore, to run it, you must:

 > pylint scripts/qapi/ --rcfile=scripts/qapi/pylintrc

Signed-off-by: John Snow <jsnow@redhat.com>
Tested-by: Eduardo Habkost <ehabkost@redhat.com>
Reviewed-by: Cleber Rosa <crosa@redhat.com>
Tested-by: Cleber Rosa <crosa@redhat.com>
Message-Id: <20201009161558.107041-10-jsnow@redhat.com>
Reviewed-by: Markus Armbruster <armbru@redhat.com>
Signed-off-by: Markus Armbruster <armbru@redhat.com>

scripts/qapi/pylintrc

@@ -0,0 +1,73 @@
+[MASTER]
+
+# Add files or directories matching the regex patterns to the ignore list.
+# The regex matches against base names, not paths.
+ignore-patterns=common.py,
+                error.py,
+                expr.py,
+                gen.py,
+                parser.py,
+                schema.py,
+                source.py,
+                types.py,
+                visit.py,
+
+
+[MESSAGES CONTROL]
+
+# Disable the message, report, category or checker with the given id(s). You
+# can either give multiple identifiers separated by comma (,) or put this
+# option multiple times (only on the command line, not in the configuration
+# file where it should appear only once). You can also use "--disable=all" to
+# disable everything first and then reenable specific checks. For example, if
+# you want to run only the similarities checker, you can use "--disable=all
+# --enable=similarities". If you want to run only the classes checker, but have
+# no Warning level messages displayed, use "--disable=all --enable=classes
+# --disable=W".
+disable=fixme,
+        missing-docstring,
+        too-many-arguments,
+        too-many-branches,
+        too-many-statements,
+        too-many-instance-attributes,
+
+[REPORTS]
+
+[REFACTORING]
+
+[MISCELLANEOUS]
+
+[LOGGING]
+
+[BASIC]
+
+# Good variable names which should always be accepted, separated by a comma.
+good-names=i,
+           j,
+           k,
+           ex,
+           Run,
+           _
+
+[VARIABLES]
+
+[STRING]
+
+[SPELLING]
+
+[FORMAT]
+
+[SIMILARITIES]
+
+# Ignore import statements themselves when computing similarities.
+ignore-imports=yes
+
+[TYPECHECK]
+
+[CLASSES]
+
+[IMPORTS]
+
+[DESIGN]
+
+[EXCEPTIONS]