
WHAT IS IT?
-----------------------------

Namcap is a tool for pacman checking binary packages and source PKGBUILDs for 
common packaging errors.


HOW CAN I HELP?
-----------------------------

There are several ways that you can contribute and help namcap's development. 
You can contribute with code, patches, tests, bugs and feature requests.

To report a bug or a feature request for namcap, file a bug in the 
Packages:Extra section of the Arch Linux bugtracker and the set the importance 
accordingly. If you're reporting a bug, please give concrete examples of 
packages where the problem occurs.

Minimal examples (very simple packages forged to exhibit unexpected
behaviour from namcap) are also welcome to extend namcap's test suite.

If you've a patch (fixing a bug or a new namcap module), then you can send it 
to the arch-general mailing list. Namcap development is managed with git, so 
git-formatted patches are preferred. 

Namcap's source is available on:

http://projects.archlinux.org/?p=namcap.git;a=summary


HOW TO USE
-----------------------------

To run namcap on a PKGBUILD or a binary pkg.tar.xz:

$ namcap FILENAME

If you want to see extra informational messages, then invoke namcap with 
the -i flag:

$ namcap -i FILENAME

You can also see the namcap(1) manual by typing man namcap at the command line 
or see the usage help:

$ namcap -h 


UNDERSTANDING THE OUTPUT
-----------------------------

Namcap uses a system of tags to classify the output. Currently, tags are of 
three types, errors (denoted by E), warnings (denoted by W) and informational 
(denoted by I). 

An error is important and should be fixed immediately; mostly they relate to 
insufficient security, missing licenses or permission problems.

Normally namcap prints a human-readable explanation (sometimes with suggestions 
on how to fix the problem). If you want output which can be easily parsed by a 
program, then pass the -m (machine-readable) flag to namcap. 


HOW IT WORKS
-----------------------------

Namcap takes the package name (or a PKGBUILD) as an argument that runs through 
all the rules defined in Namcap.rules submodules and tests them against the argument 
looking for flaws.


HOW TO CREATE A MODULE
-----------------------------

This section documents the innards of namcap and specifies how to create a new 
namcap rule.

The main namcap program namcap.py takes as parameters the filename of a package 
or a PKGBUILD and makes a pkginfo object, which it passes to a list of rules 
defined in Namcap.rules.all_rules :

	* a rule is a subclass of AbstractRule (defined in Namcap.ruleclass)
	* PkgInfoRule classes process any pkginfo object
	* PkgbuildRule classes process only PKGBUILDs
	* TarballRule classes process binary packages
	* PkgdirRule classes (unused) process uncompressed binary packages

Put the new rule in a module and make sure it is imported in
Namcap/rules/__init__.py

A very simple rule is the "url" rule (Namcap/rules/pkginfo.py):

from Namcap.ruleclass import PkgInfoRule

class UrlRule(PkgInfoRule):
	name = "url"
	description = "Verifies the package comes with an URL"
	def analyze(self, pkginfo, tar):
		if 'url' not in pkginfo:
			self.errors.append(("missing-url", ()))

Mostly, the code is self-explanatory. The following are the list of
attributes that each namcap rule must have:

	* base class
	Either PkgInfoRull, PkgbuildRule, TarballRule.
	
	* name
	Contains a string containing a short name of the module. Usually, this
	is the same as the basename of the module file.
	
	* description
	A string containing a concise description of the module. This 
	description is used when listing all the rules using namcap -r list.
	
	* analyze(self, pkginfo, tar) 
	Should fill three lists self.errors, self.warnings and self.infos
	with error tags, warning tags and information tags respectively. 
	Each member of these tag lists should be a tuple consisting of two 
	components: the short, hyphenated form of the tag with the appropriate 
	format specifiers (%s, etc.) The first word of this string must be the tag 
	name. The human readable form of the tag should be put in the namcap-tags
	file. The format of the tags file is described below; and the parameters
	which should replace the format specifier tokens in the final output. 
	

The namcap-tags file consists of lines specifying the human readable form of
the hyphenated tags used in the namcap code. A line beginning with a '#' is
treated as a comment. Otherwise the format of the file is:

	machine-parseable-tag %s :: This is machine parseable tag %s

Note that a double colon (::) is used to separate the hyphenated tag from the 
human readable description.

HOW TO TEST A RULE
-----------------------------

Namcap comes with a test suite covering the classical mistakes or
warnings we are expecting from the rules. The test suite
is in Namcap/tests. The makepkg and pkgbuild_test submodules
provide easy generic methods to test a rule.

Here is an example testing the rule "pkgnameindesc"

from Namcap.tests.pkgbuild_test import PkgbuildTest
import Namcap.rules.pkgnameindesc

class NamcapPkgnameInDescTest(PkgbuildTest):
	pkgbuild1 = "...some bogus pkgbuild..."
	def preSetUp(self):
		self.rule = Namcap.rules.pkgnameindesc.package

	def test_example1(self):
		r = self.run_on_pkg(self.pkgbuild1)
		self.assertEqual(r.errors, [])
		self.assertEqual(set(r.warnings), set(
			[("pkgname-in-description", ())] ))
		self.assertEqual(r.infos, [])

* the preSetUp() method sets the rule to be used in the test

* the test_example1() method runs the rule on the given PKGBUILD and
  tests whether the results are as expected

* the PkgbuildTest also automatically tests the rule against a set
  of known valid PKGBUILDs.

MORE INFORMATION
-----------------------------

You can find more information about namcap on namcap's wiki page:

http://wiki.archlinux.org/index.php/Namcap

