Re: gawk 5.1.1 internal error from line 1349 in eval.c

[arnold]

I think that's mentioned in the manual (not the man page!). I will look at
clarifying it some more.

Arnold

Ed Morton <mortoneccc@comcast.net> wrote:

> I didn't realise quicksort was being used behind the scenes. That makes 
> sense and I can see how it could be difficult and not particularly 
> worthwhile to implement code that'd guard against this particular error.
>
> Thanks,
>
>      Ed.
>
> On 2/26/2022 2:16 PM, arnold@skeeve.com wrote:
> > Hi Ed,
> >
> > David hit the nail on the head; you need to add the local variables
> > to str_num_cmp and then it works.
> >
> > Remember that qsort works recursively; the a1 and a2 variables
> > are global and they end up getting clobbered by the recursive
> > calls.
> >
> > I have attached a modified version of the program that lets you see
> > what's going on.
> >
> > Arnold
> >
> > david kerns<david.t.kerns@gmail.com>  wrote:
> >
> >> I reproduced this in
> >> GNU Awk 4.2.0, API: 2.0
> >>
> >> However, I also "fixed" it by forcing more *local* vars: (you should be
> >> able to delete my extra debug printing)
> >>
> >>      function str_num_to_a(i, a*, x*) {
> >>           print ">", i, typeof(i)
> >>           print match(i, /"([^0-9]*)([0-9]+)"/, a)
> >>           for (x in a) {
> >>                print ">>", a[x], typeof(a[x])
> >>           }
> >>      }
> >>
> >>      function str_num_cmp(i1, v1, i2, v2*, a1, a2*) {
> >>           str_num_to_a(i1, a1)
> >>           str_num_to_a(i2, a2)
> >>           if(a1[1] < a2[1])
> >>               return -1
> >>           if(a1[1] == a2[1]) {
> >>               if(a1[2] < a2[2])
> >>                   return -1
> >>               if(a1[2] == a2[2])
> >>                   return 0
> >>           }
> >>           return 1
> >>      }
> >>
> >>      BEGIN {
> >>           keys["foo6"]
> >>           keys["foo10"]
> >>           keys["\"foo6\""]
> >>           keys["\"foo10\""]
> >>           PROCINFO["sorted_in"] = "str_num_cmp"
> >>           for (k in keys) {
> >>               print k, keys[k]
> >>           }
> >>      }
> >>
> >>
> >>
> >>
> >> On Fri, Feb 25, 2022 at 7:37 AM Ed Morton<mortoneccc@comcast.net>  wrote:
> >>
> >>> Running on cygwin with:
> >>>
> >>>      $ $SHELL --version
> >>>      GNU bash, version 4.4.12(3)-release (x86_64-unknown-cygwin)
> >>>
> >>>      $ awk --version
> >>>      GNU Awk 5.1.1, API: 3.1 (GNU MPFR 4.1.0, GNU MP 6.2.1)
> >>>
> >>> I was reviewing someone else's code that has a user-provided comparison
> >>> function to sort alphanumeric strings like "foo123" alphabetically by
> >>> the alphabetic part and numerically by the numeric part so that "foo6"
> >>> would come before "foo10". I wasn't sure if the results of the match()
> >>> in their first function were strings or strnums so I added a loop in the
> >>> first function to dump each value in a[] and it's type after the match()::
> >>>
> >>>      $ cat tst.awk
> >>>      function str_num_to_a(i, a) {
> >>>           match(i, /"([^0-9]*)([0-9]+)"/, a)
> >>>           for (x in a) {
> >>>                print a[x], typeof(a[x])
> >>>           }
> >>>      }
> >>>
> >>>      function str_num_cmp(i1, v1, i2, v2) {
> >>>           str_num_to_a(i1, a1)
> >>>           str_num_to_a(i2, a2)
> >>>           if(a1[1] < a2[1])
> >>>               return -1
> >>>           if(a1[1] == a2[1]) {
> >>>               if(a1[2] < a2[2])
> >>>                   return -1
> >>>               if(a1[2] == a2[2])
> >>>                   return 0
> >>>           }
> >>>           return 1
> >>>      }
> >>>
> >>>      BEGIN {
> >>>           keys["foo6"]
> >>>           keys["foo10"]
> >>>           #keys["\"foo6\""]
> >>>           #keys["\"foo10\""]
> >>>           PROCINFO["sorted_in"] = "str_num_cmp"
> >>>           for (k in keys) {
> >>>               print k, keys[k]
> >>>           }
> >>>      }
> >>>
> >>> The above code works fine BUT then try uncommenting the 2 `#keys` lines
> >>> in the BEGIN section (doesn't matter if you comment out the other 2 keys
> >>> lines or not) and you'll get:
> >>>
> >>>      $ awk -f tst.awk
> >>>      awk: tst.awk:17: fatal: internal error line 1349, file:
> >>>      
> >>> /home/corinna/tmp/gawk-5.1.1/gawk-5.1.1-1.x86_64/src/gawk-5.1.1/eval.c
> >>>
> >>> Line 17 is the "return 0" in the middle function. Now comment out the
> >>> loop in the top function and the code will work again. I tried to reduce
> >>> this example further (it's already reduced from the original) but after
> >>> a lot of trial and error I surrendered.
> >>>
> >>>       Ed.