coding_style_python.rst (2224B)
1 =================== 2 Python Coding style 3 =================== 4 5 Coding style 6 ~~~~~~~~~~~~ 7 8 :ref:`black` is the tool used to reformat the Python code. 9 10 Linting 11 ~~~~~~~ 12 13 The Python linting is done by :ref:`Flake8` and :ref:`pylint` 14 They are executed by mozlint both at review phase and in the CI. 15 16 Indentation 17 ~~~~~~~~~~~ 18 19 Four spaces in Python code. 20 21 22 Makefile/moz.build practices 23 ---------------------------- 24 25 - Changes to makefile and moz.build variables do not require 26 build-config peer review. Any other build system changes, such as 27 adding new scripts or rules, require review from the build-config 28 team. 29 - Suffix long ``if``/``endif`` conditionals with #{ & #}, so editors 30 can display matched tokens enclosing a block of statements. 31 32 :: 33 34 ifdef CHECK_TYPE #{ 35 ifneq ($(flavor var_type),recursive) #{ 36 $(warning var should be expandable but detected var_type=$(flavor var_type)) 37 endif #} 38 endif #} 39 40 - moz.build are python and follow normal Python style. 41 - List assignments should be written with one element per line. Align 42 closing square brace with start of variable assignment. If ordering 43 is not important, variables should be in alphabetical order. 44 45 .. code-block:: python 46 47 var += [ 48 'foo', 49 'bar' 50 ] 51 52 - Use ``CONFIG['TARGET_CPU'] {=arm}`` to test for generic classes of 53 architecture rather than ``CONFIG['OS_TEST'] {=armv7}`` (re: bug 886689). 54 55 56 Other advice 57 ~~~~~~~~~~~~ 58 59 - Install the 60 `mozext <https://hg.mozilla.org/hgcustom/version-control-tools/file/default/hgext/mozext>`__ 61 Mercurial extension, and address every issue reported on commit 62 or the output of ``hg critic``. 63 - Follow `PEP 8 <https://www.python.org/dev/peps/pep-0008/>`__. Please run :ref:`black` for this. 64 - Do not place statements on the same line as ``if/elif/else`` 65 conditionals to form a one-liner. 66 - Global vars, please avoid them at all cost. 67 - Exclude outer parenthesis from conditionals.Use 68 ``if x > 5:,``\ rather than ``if (x > 5):`` 69 - Use string formatters, rather than var + str(val). 70 ``var = 'Type %s value is %d'% ('int', 5).`` 71 - Testing/Unit tests, please write them and make sure that they are executed in the CI.