CODING_STYLE - platform/external/autotest - Gitiles

 These rules are fairly standard and boring. People will bitch about something
 in here, no doubt. Get over it. Much of this was stolen from the Linux Kernel
 coding style, because most of it makes good sense. If you disagree, that's OK,
 but please stick to the rules anyway ;-)


 Language

 Please use Python where possible. It's not the ideal language for everything,
 but it's pretty good, and consistency goes a long way in making the project
 maintainable. (Obviously using C or whatever for writing tests is fine).


 Base coding style

 When writing python code, unless otherwise stated, stick to the python style
 guide (http://www.python.org/dev/peps/pep-0008/).


 Indentation & whitespace

 Format your code for an 80 character wide screen.

 Indentation is now 4 spaces, as opposed to hard tabs (which it used to be).
 This is the Python standard.

 Don't leave trailing whitespace, or put whitespace on blank lines.
 Leave TWO blank lines between functions - this is Python, there are no clear
 function end markers, and we need help.


 Variable names and UpPeR cAsE

 Use descriptive variable names where possible - it helps to make the code
 self documenting.

 Don't use CamelCaps style in most places - use underscores to separate parts
 of your variable_names please. I shall make a bedgrudging exception for class
 names I suppose, but I'll still whine about it a lot.


 Importing modules

 The order of imports should be as follows:

 Standard python modules
 Non-standard python modules
 Autotest modules

 Within one of these three sections, all module imports using the from
 keyword should appear after regular imports.
 Modules should be lumped together on the same line.
 Wildcard imports (from x import *) should be avoided if possible.
 Classes should not be imported from modules, but modules may be imported
  from packages, i.e.:
 from common_lib import error
 and not
 from common_lib.error import AutoservError

 For example:
 import os, pickle, random, re, select, shutil, signal, StringIO, subprocess
 import sys, time, urllib, urlparse
 import MySQLdb
 from common_lib import error

 Testing None

 Use "is None" rather than "== None" and "is not None" rather than "!= None".
 This way you'll never run into a case where someone's __eq__ or __ne__
 method do the wrong thing


 Comments

 Generally, you want your comments to tell WHAT your code does, not HOW.
 We can figure out how from the code itself (or if not, your code needs fixing).

 Try to describle the intent of a function and what it does in a triple-quoted
 (multiline) string just after the def line. We've tried to do that in most
 places, though undoubtedly we're not perfect. A high level overview is
 incredibly helpful in understanding code.


 Simple code

 Keep it simple; this is not the right place to show how smart you are. We
 have plenty of system failures to deal with without having to spend ages
 figuring out your code, thanks ;-) Readbility, readability, readability.
 I really don't care if other things are more compact.

 "Debugging is twice as hard as writing the code in the first place. Therefore,
 if you write the code as cleverly as possible, you are, by definition, not
 smart enough to debug it."  Brian Kernighan


 Function length

 Please keep functions short, under 30 lines or so if possible. Even though
 you are amazingly clever, and can cope with it, the rest of us are all stupid,
 so be nice and help us out. To quote the Linux Kernel coding style:

 Functions should be short and sweet, and do just one thing.  They should
 fit on one or two screenfuls of text (the ISO/ANSI screen size is 80x24,
 as we all know), and do one thing and do that well.


 Exceptions

 When raising exceptions, the preferred syntax for it is:

 raise FooException('Exception Message')

 Please don't raise string exceptions, as they're deprecated and will be removed
 from future versions of python. If you're in doubt about what type of exception
 you will raise, please look at http://docs.python.org/lib/module-exceptions.html
 and client/common_lib/error.py, the former is a list of python built in
 exceptions and the later is a list of autotest/autoserv internal exceptions. Of
 course, if you really need to, you can extend the exception definitions on
 client/common_lib/error.py.


 Submitting patches

 Generate universal diffs. Email them to autotest@test.kernel.org.
 Most mailers now break lines and/or changes tabs to spaces. If you know how
 to avoid that - great, put your patches inline. If you're not sure, just
 attatch them, I don't care much. Please base them off the current version.

 Don't worry about submitting patches to a public list - everybody makes
 mistakes, especially me ... so get over it and don't worry about it.
 (though do give your changes a test first ;-))
	These rules are fairly standard and boring. People will bitch about something
	in here, no doubt. Get over it. Much of this was stolen from the Linux Kernel
	coding style, because most of it makes good sense. If you disagree, that's OK,
	but please stick to the rules anyway ;-)


	Language

	Please use Python where possible. It's not the ideal language for everything,
	but it's pretty good, and consistency goes a long way in making the project
	maintainable. (Obviously using C or whatever for writing tests is fine).


	Base coding style

	When writing python code, unless otherwise stated, stick to the python style
	guide (http://www.python.org/dev/peps/pep-0008/).


	Indentation & whitespace

	Format your code for an 80 character wide screen.

	Indentation is now 4 spaces, as opposed to hard tabs (which it used to be).
	This is the Python standard.

	Don't leave trailing whitespace, or put whitespace on blank lines.
	Leave TWO blank lines between functions - this is Python, there are no clear
	function end markers, and we need help.


	Variable names and UpPeR cAsE

	Use descriptive variable names where possible - it helps to make the code
	self documenting.

	Don't use CamelCaps style in most places - use underscores to separate parts
	of your variable_names please. I shall make a bedgrudging exception for class
	names I suppose, but I'll still whine about it a lot.


	Importing modules

	The order of imports should be as follows:

	Standard python modules
	Non-standard python modules
	Autotest modules

	Within one of these three sections, all module imports using the from
	keyword should appear after regular imports.
	Modules should be lumped together on the same line.
	Wildcard imports (from x import *) should be avoided if possible.
	Classes should not be imported from modules, but modules may be imported
	from packages, i.e.:
	from common_lib import error
	and not
	from common_lib.error import AutoservError

	For example:
	import os, pickle, random, re, select, shutil, signal, StringIO, subprocess
	import sys, time, urllib, urlparse
	import MySQLdb
	from common_lib import error

	Testing None

	Use "is None" rather than "== None" and "is not None" rather than "!= None".
	This way you'll never run into a case where someone's __eq__ or __ne__
	method do the wrong thing


	Comments

	Generally, you want your comments to tell WHAT your code does, not HOW.
	We can figure out how from the code itself (or if not, your code needs fixing).

	Try to describle the intent of a function and what it does in a triple-quoted
	(multiline) string just after the def line. We've tried to do that in most
	places, though undoubtedly we're not perfect. A high level overview is
	incredibly helpful in understanding code.


	Simple code

	Keep it simple; this is not the right place to show how smart you are. We
	have plenty of system failures to deal with without having to spend ages
	figuring out your code, thanks ;-) Readbility, readability, readability.
	I really don't care if other things are more compact.

	"Debugging is twice as hard as writing the code in the first place. Therefore,
	if you write the code as cleverly as possible, you are, by definition, not
	smart enough to debug it." Brian Kernighan


	Function length

	Please keep functions short, under 30 lines or so if possible. Even though
	you are amazingly clever, and can cope with it, the rest of us are all stupid,
	so be nice and help us out. To quote the Linux Kernel coding style:

	Functions should be short and sweet, and do just one thing. They should
	fit on one or two screenfuls of text (the ISO/ANSI screen size is 80x24,
	as we all know), and do one thing and do that well.


	Exceptions

	When raising exceptions, the preferred syntax for it is:

	raise FooException('Exception Message')

	Please don't raise string exceptions, as they're deprecated and will be removed
	from future versions of python. If you're in doubt about what type of exception
	you will raise, please look at http://docs.python.org/lib/module-exceptions.html
	and client/common_lib/error.py, the former is a list of python built in
	exceptions and the later is a list of autotest/autoserv internal exceptions. Of
	course, if you really need to, you can extend the exception definitions on
	client/common_lib/error.py.


	Submitting patches

	Generate universal diffs. Email them to autotest@test.kernel.org.
	Most mailers now break lines and/or changes tabs to spaces. If you know how
	to avoid that - great, put your patches inline. If you're not sure, just
	attatch them, I don't care much. Please base them off the current version.

	Don't worry about submitting patches to a public list - everybody makes
	mistakes, especially me ... so get over it and don't worry about it.
	(though do give your changes a test first ;-))