Debugging ksh, trying to find printf %T bug and also supported format

[kshji]

Source code include message function calls, how I can setup show that I get message() output? And also debug() output?
I have compiled ksh using to get debug version of ksh
bin/package make CCFLAGS="-O -g" debug=1

I'm just looking libast/tm/tmxdate.c to find bug. the message output helps to read parser.
I have not found full manual with some examples when using excellent printf '%T'.

There is bug

• printf '%(%a)T\n' 'final day june 2001' works fine, result is correct
• printf '%(%Y-%m-%d)T\n' 'last month'
• printf "%(%Y-%m-%d)T\n" "final last 10 month" - result correct
• printf '%T\n' '10 month ago' works fine, result is correct
• printf '%T\n' '20 month ago' give wrong answer
• printf "%(%Y-%m-%d)T\n" "final last 20 month" - give wrong answer
  ** if you split: take 10 and 10 and 5 months, you got correct answer
• printf '%(%Y-%m-%d)T\n' '3rd wednesday july 2022' - give correct answer
• printf '%(%Y-%m-%d %H:%M)T\n' 'last workday' - give correct answer (Mon-Fri are workdays)
  I have tested cron format, nice:
• printf '%(%Y-%m-%d %H:%M)T\n' '5 6 1,15 * 1' - result is 2022-08-01 06:05

All reserved words (supported) in file libast/tm/tmdata.c

I found from source that you can use also sort format like 2M , 10H, ... 2Y, 2h and so on works also. Result is not same as "2 month".

• today is 2022-07-06
• printf '%(%Y-%m-%d)T\n' '10 month ago' - give correct result 2021-09-01
• printf '%(%Y-%m-%d)T\n' 2M - give correct result 2022-09-06 - exactly 2 month
• printf '%(%Y-%m-%d)T\n' '2 month' - give correct result 2022-09-01 = first day of 2 month forward
• printf "%(%Y-%m-%d %H:%M)T\n" "M-2" - give result 2022-02-06 17:29 = 2nd month, not -2 months
• But how I can use '2M' with some ??? but ago = result have to be currentdate - 2 months = 2022-05-06
  ** I have tried -, ago,past ... but always I got 2022-09-06 , not 2022-05-06

[McDutchie]

First of all, tervetuola/welcome! I'm glad someone is trying to work on this as no one has had time or motivation so far. See also #182 for more breakage; that issue would be a good place to discuss and test possible fixes.

You asked how to get those message() calls to show. That debug macro is defined in ast.h, here:

ksh/src/lib/libast/include/debug.h

Lines 38 to 41 in 9c037b0

	#if DEBUG || _BLD_DEBUG
	#define debug(x) x
	#define message(x) do if (error_info.trace < 0) { error x; } while (0)

So it is conditional upon either DEBUG or _BLD_DEBUG being defined. So you need to add either -DDEBUG or -D_BLD_DEBUG to CCFLAGS.

Then, whether it shows a message is also dependent on error_info.trace, as you can see above. The error.3 manual page documents how to make that happen:

EXTENDED DESCRIPTION
       <debug.h> provides debugging message macros when DEBUG or  _TRACE_  are
       defined  (_TRACE_  is  defined  by makerules when CCFLAGS contains -g).
       All of the macros expand to nothing when both DEBUG and _TRACE_ are not
       defined.   Otherwise  debug  expands its arg and libmessage and message
       call liberror and error  respectively  if  error_info.trace<0.   Notice
       that  libmessage and message are macro hacks that require double paren-
       theses ((...)) around the arguments.

EXAMPLE
       To enable debugging message level  -3,  library  messages,  and  system
       errno text for all commands:

              export ERROR_OPTIONS="trace=3 library system"

Actually, I think there's a mistake in that: _TRACE_ does not exist anywhere. I think they mean _BLD_DEBUG. Sure enough, a quick search in ksh93-history shows that _TRACE_ was changed to _BLD_DEBUG in debug.h on or before 2000-10-31 ksh93k; they forgot to update the manual. That fix will go into the next round of minor cleanups. The build system also no longer automatically adds either of these flags (probably due to nmake being removed); I should either find a way to fix that or update the documentation.

Anyhow, in summary: compiling with either -DDEBUG or -D_BLD_DEBUG and then doing export ERROR_OPTIONS="trace=3 library system" will get those message() calls to show.

[McDutchie]

Well, would you look at that... passing debug=1 to bin/package will actually get the system to define _BLD_DEBUG but only if you don't have your own CCFLAGS defined! If you do, they will override that flag and you have to add it manually. That's because the Mamfiles only define the debug flags as the default value for CCFLAGS which is simply overwritten if you pass your own:

ksh/src/lib/libast/Mamfile

Line 14 in 9c037b0

setv CCFLAGS ${-debug-symbols?1?${mam_cc_DEBUG} -D_BLD_DEBUG?${mam_cc_OPTIMIZE}?}

(note that the -debug-symbols MAM variable is set by mamake if the -G/--debug-symbols option was passed to it).

Anyway, the following will work to debug tmxdate.c:

$ unset CCFLAGS
$ bin/package make debug=1
$ export ERROR_OPTIONS="trace=1"
$ arch/*/bin/ksh -c 'printf %T\\n "4 years ago"'
printf: debug: AHA tmxdate 2009-03-06
printf: debug: AHA#233 state=| set=| '4 years ago'
printf: debug: AHA#712 n=4 w=1 u=' ' f=-1 t=" years ago"
printf: debug: AHA#841 n=4 u="years ago"
printf: debug: AHA#1090 s="years ago"
printf: debug: AHA#1108 n=4 q='y'
printf: debug: AHA#1335 n=4 j=61 f=-1 state=|LAST|NEXT|
printf: debug: AHA#1357 disambiguate LAST s=''
printf: debug: AHA#1372 disambiguate LAST k=-1
printf: debug: AHA#1378 f=-1 n=-4 i=1 j=61 k=-1 l=0 m=-4 state=|LAST|NEXT|
printf: debug: AHA#1693 DAY
printf: debug: AHA#233 state=| set=|LAST| ''
Mon Jan  1 00:00:00 CET 2018

[kshji]

Thank you. I hope that this answer helps all others who are interested to look ksh93, debug ksh93.
I'm just retired, so some raining day I start to look more why the ex. 25 month ago give wrong answer.

[phidebian]

I was asking for debug technic in my first post, and there are good start here :)

[phidebian]

@kshji I guess we can ignore things like M-2 etc as I can't find any docco about it, and gnudate is bogus on that anyway, so I guess this M+xyz M-xyz are kind of HP-41C secret opcode?

I got this with date(1)

TC$ date --date="now" +"%Y-%m-%d %H:%M:%S"                
2022-10-14 11:53:03

TC$ date --date="M-2" +"%Y-%m-%d %H:%M:%S"      
2022-10-13 16:00:00

TC$ date --date="M-1" +"%Y-%m-%d %H:%M:%S"
2022-10-13 15:00:00

TC$ date --date="M-2" +"%Y-%m-%d %H:%M:%S"
2022-10-13 16:00:00

TC$ date --date="M-3" +"%Y-%m-%d %H:%M:%S"
2022-10-13 17:00:00

M-xyz sometime touch the Month, sometime the Hours, look buggy to me.