Improve and extend checkpatch.pl Kconfig help text checks

Hello,

This patchset contains some improvements for the Kconfig help text check in scripts/checkconfig.pl:

- Commits 1 and 2 make the check more robust by checking menuconfig symbols and choices as well as symbols defined with 'config', and by making the detection of definition boundaries more reliable.

- Commit 3 adds a check for new '---help---'s being introduced. IMO, 'help' should be encouraged in new code.

All three commits can be applied independently.

The existing code is a bit weird in that it doesn't require symbols with "long" definitions (e.g., many selects) to have help texts. Fixing that is outside the scope of this patchset. I couldn't tell if it was deliberate.

I'm a Perl noob, so check for bad practices. :)

The changes were tested by running 'checkpatch.pl -f' on some large existing Kconfig files in the kernel and looking for false positives (e.g. arch/{x86,arm}/Kconfig).

This test file was also used, which contains some cases that confused the old code:

	config BAD_1
		bool "bad 1"
	
	config BAD_2
		bool 'bad 2'
	
	config BAD_3
		bool "bad 3"
		help
		  1
		  2
		  3
	
	menuconfig BAD_4
		bool "bad 4"
		help
		  1
		  2
		  3
	
	config BAD_5
		bool
		prompt "bad 5"
		help
		  1
		  2
		  3
	
	config BAD_6
		bool "bad 6"
		help
		  1
		  2
		  3
	
	if FOO
	
	config BAD_7
		bool "bad 7"
		help
		  1
		  2
		  3
	
	endif
	
	config BAD_8
		bool "bad 8"
		help
		  1
		  2
		  3
	
	source "foo"
	
	config BAD_9
		bool "bad 9"
		---help---
		  1
		  2
		  3
		  4
	
	choice
		bool "bad choice"
		help
		  1
		  2
		  3
	
	endchoice
	
	config OK_1
		bool
	
	config OK_2
		bool "ok 2"
		help
		  1
		  2
		  3
		  4
	
	config OK_3
		tristate "ok 3"
		help
		  1
		  2
		  3
		  4
	
	config OK_4
		tristate
		prompt "ok 4"
		help
		  1
		  2
		  3
		  4
	
	choice
		bool "ok choice"
		help
		  1
		  2
		  3
		  4
	
	endchoice

This now produces the following warnings:

WARNING: please write a paragraph that describes the config symbol fully #9: FILE: Kconfig.test_help_check:9:
+config BAD_1

WARNING: please write a paragraph that describes the config symbol fully #12: FILE: Kconfig.test_help_check:12:
+config BAD_2

WARNING: please write a paragraph that describes the config symbol fully #15: FILE: Kconfig.test_help_check:15:
+config BAD_3

WARNING: please write a paragraph that describes the config symbol fully #22: FILE: Kconfig.test_help_check:22:
+menuconfig BAD_4

WARNING: please write a paragraph that describes the config symbol fully #29: FILE: Kconfig.test_help_check:29:
+config BAD_5

WARNING: please write a paragraph that describes the config symbol fully #37: FILE: Kconfig.test_help_check:37:
+config BAD_6

WARNING: please write a paragraph that describes the config symbol fully #46: FILE: Kconfig.test_help_check:46:
+config BAD_7

WARNING: please write a paragraph that describes the config symbol fully #55: FILE: Kconfig.test_help_check:55:
+config BAD_8

WARNING: prefer 'help' over '---help---' for new help texts #64: FILE: Kconfig.test_help_check:64:
+config BAD_9

WARNING: please write a paragraph that describes the config symbol fully #72: FILE: Kconfig.test_help_check:72:
+choice

total: 0 errors, 10 warnings, 117 lines checked

NOTE: For some of the reported defects, checkpatch may be able to
mechanically convert to the typical style using --fix or --fix-inplace.

Kconfig.test_help_check has style problems, please review.

NOTE: If any of the errors are false positives, please report
them to the maintainer, see CHECKPATCH in MAINTAINERS.

Cheers,
Ulf

Ulf Magnusson (3):
checkpatch: kconfig: recognize more prompts when checking help texts
checkpatch: kconfig: check help texts for menuconfig and choice
checkpatch: kconfig: prefer 'help' over '---help---'

 scripts/checkpatch.pl | 21 +++++++++++++++++----
 1 file changed, 17 insertions(+), 4 deletions(-)

2.14.1