Re: Conflict between FPAT and empty RS

[arnold]

You're welcome. Enjoy.

luciole75w <address@hidden> wrote:

> Cool, I have pulled the latest changes. Thanks Arnold for the quick fix !
>
> luciole
>
>
> On 4/10/20 1:21 PM, address@hidden wrote:
> > luciole75w <address@hidden> wrote:
> > 
> >> Hello,
> >>
> >> I'm having an odd behavior with GNU awk when using FPAT and RS together.
> >> Here is the code.
> >>
> >> $ awk '{ print ; $2 = "-" ; print }' RS='' FPAT='\\w+' <<<'a b c d'
> >> a b c d
> >> a -
> >>
> >> $ ... | xxd -g1 -c8
> >> 00000000: 61 20 62 20 63 20 64 0a  a b c d.
> >> 00000008: 61 20 2d 20 20 20 20 0a  a -    .
> >>
> >> I'd expect the 2nd print to output "a - c d" but as you can see,
> >> modifying the field 2 replaces fields 3 and 4 with spaces in $0. When RS
> >> is set to something other than the empty string (or just not set), the
> >> output is correct.
> > 
> > This was an interesting one to track down. Thanks for the clear
> > reproducer. The fix is below. I will push it to git shortly.
> > 
> > Arnold
> > ------------------------------------------------
> > diff --git a/field.c b/field.c
> > index 80495862..45ab9f5f 100644
> > --- a/field.c
> > +++ b/field.c
> > @@ -74,6 +74,9 @@ static bool resave_fs;
> >   static NODE *save_FS;             /* save current value of FS when line 
> > is read,
> >                              * to be used in deferred parsing
> >                              */
> > +static NODE *save_FPAT;            /* save current value of FPAT when line 
> > is read,
> > +                            * to be used in deferred parsing
> > +                            */
> >   static awk_fieldwidth_info_t *FIELDWIDTHS = NULL;
> >   
> >   NODE **fields_arr;                /* array of pointers to the field nodes 
> > */
> > @@ -842,6 +845,8 @@ get_field(long requested, Func_ptr *assign)
> >     bool in_middle = false;
> >     static bool warned = false;
> >     extern int currule;
> > +   NODE *saved_fs;
> > +   Regexp *fs_regexp;
> >   
> >     if (do_lint && currule == END && ! warned) {
> >             warned = true;
> > @@ -857,10 +862,17 @@ get_field(long requested, Func_ptr *assign)
> >                     /* first, parse remainder of input record */
> >                     if (NF == -1) {
> >                             in_middle = (parse_high_water != 0);
> > +                           if (current_field_sep() == Using_FPAT) {
> > +                                   saved_fs = save_FPAT;
> > +                                   fs_regexp = FPAT_regexp;
> > +                           } else {
> > +                                   saved_fs = save_FS;
> > +                                   fs_regexp = FS_regexp;
> > +                           }
> >                             NF = (*parse_field)(UNLIMITED - 1, 
> > &parse_extent,
> >                                     fields_arr[0]->stlen -
> >                                     (parse_extent - fields_arr[0]->stptr),
> > -                                   save_FS, FS_regexp, set_field,
> > +                                   saved_fs, fs_regexp, set_field,
> >                                     (NODE *) NULL,
> >                                     (NODE *) NULL,
> >                                     in_middle);
> > @@ -1424,7 +1436,6 @@ void
> >   set_FPAT()
> >   {
> >     static bool warned = false;
> > -   static NODE *save_fpat = NULL;
> >     bool remake_re = true;
> >     NODE *fpat;
> >   
> > @@ -1447,9 +1458,9 @@ set_FPAT()
> >      * This comparison can't use cmp_nodes(), which pays attention
> >      * to IGNORECASE, and that's not what we want.
> >      */
> > -   if (save_fpat
> > -           && FPAT_node->var_value->stlen == save_fpat->stlen
> > -           && memcmp(FPAT_node->var_value->stptr, save_fpat->stptr, 
> > save_fpat->stlen) == 0) {
> > +   if (save_FPAT
> > +           && FPAT_node->var_value->stlen == save_FPAT->stlen
> > +           && memcmp(FPAT_node->var_value->stptr, save_FPAT->stptr, 
> > save_FPAT->stlen) == 0) {
> >             if (FPAT_regexp != NULL)
> >                     FPAT_regexp = (IGNORECASE ? FPAT_re_no_case : 
> > FPAT_re_yes_case);
> >   
> > @@ -1462,8 +1473,8 @@ set_FPAT()
> >             }
> >     }
> >   
> > -   unref(save_fpat);
> > -   save_fpat = dupnode(FPAT_node->var_value);
> > +   unref(save_FPAT);
> > +   save_FPAT = dupnode(FPAT_node->var_value);
> >     refree(FPAT_re_yes_case);
> >     refree(FPAT_re_no_case);
> >     FPAT_re_yes_case = FPAT_re_no_case = FPAT_regexp = NULL;
> >