add a .coafile for coala (#2592)

add support for using coala, fixes #1366

ignores / disable are set up so that there are not many faults.
we can improve that iteratively.

.coafile

@@ -0,0 +1,38 @@
+[all]
+# note: put developer specific settings into ~/.coarc (e.g. editor = ...)
+max_line_length = 255
+use_spaces = True
+
+[all.general]
+files = src/borg/**/*.(py|pyx|c)
+ignore = src/borg/(compress.c|hashindex.c|item.c),
+         src/borg/algorithms/(chunker.c|checksums.c|crc32.c),
+         src/borg/algorithms/blake2/*,
+         src/borg/algorithms/xxh64/*,
+         src/borg/crypto/low_level.c,
+         src/borg/platform/*.c
+bears = SpaceConsistencyBear, FilenameBear, InvalidLinkBear, LineLengthBear
+file_naming_convention = snake
+
+
+[all.python]
+files = src/borg/**/*.py
+bears = PEP8Bear, PyDocStyleBear, PyLintBear
+pep_ignore = E122,E123,E125,E126,E127,E128,E226,E301,E309,E402,F401,F405,F811,W690
+pylint_disable = C0103, C0111, C0112, C0301, C0302, C0325, C0330, C0411, C0412, C0413,
+                 W0102, W0104, W0106, W0108, W0120, W0201, W0212, W0221, W0231, W0401, W0404,
+                 W0511, W0603, W0611, W0612, W0613, W0614, W0621, W0622, W0702, W0703,
+                 W1201, W1202, W1401, W1503, W1505,
+                 R0101, R0201, R0204, R0902, R0903, R0904, R0911, R0912, R0913, R0914, R0915, R0916,
+                 E0102, E0202, E0211, E0401, E0611, E0702, E1101, E1102, E1120, E1133
+pydocstyle_ignore = D100, D101, D102, D103, D104, D105, D200, D201, D202, D203, D204, D205, D209, D210,
+                    D212, D213, D300, D301, D400, D401, D402, D403, D404
+
+[all.c]
+files = src/borg/**/*.c
+bears = CPPCheckBear
+
+[all.html]
+files = src/borg/**/*.html
+bears = HTMLLintBear
+htmllint_ignore = *

docs/development.rst

@@ -195,6 +195,21 @@ Important notes:
 - When using ``--`` to give options to py.test, you MUST also give ``borg.testsuite[.module]``.
 
 
+Running more checks using coala
+-------------------------------
+
+First install coala and some checkers ("bears"):
+
+  pip install -r requirements.d/coala.txt
+
+You can now run coala from the toplevel directory; it will read its settings
+from ``.coafile`` there:
+
+  coala
+
+Some bears have additional requirements and they usually tell you about
+them in case they are missing.
+
 Documentation
 -------------
 

requirements.d/coala.txt

@@ -0,0 +1,4 @@
+# style and other checks for many languages.
+# some bears (checkers) have additional requirements.
+coala coala-bears
+