Branch: refs/heads/yves/curlyx_curlym
  Home:   https://github.com/Perl/perl5
  Commit: 32c009ba5d904b97fa291aa857234dd663694b2c
      
https://github.com/Perl/perl5/commit/32c009ba5d904b97fa291aa857234dd663694b2c
  Author: Yves Orton <demer...@gmail.com>
  Date:   2023-01-12 (Thu, 12 Jan 2023)

  Changed paths:
    M t/re/re_tests

  Log Message:
  -----------
  t/re/re_rests - extend test to show more buffers

This is a tricky test, showing more buffers makes it a bit easier
to understand if you break it. (Guess what I did?)


  Commit: a560ea0be847f8d00ecae70b4894fd3fe7165737
      
https://github.com/Perl/perl5/commit/a560ea0be847f8d00ecae70b4894fd3fe7165737
  Author: Yves Orton <demer...@gmail.com>
  Date:   2023-01-12 (Thu, 12 Jan 2023)

  Changed paths:
    M regcomp.c
    M regcomp.h
    M regcomp_internal.h
    M t/re/pat.t
    M t/re/reg_mesg.t

  Log Message:
  -----------
  regcomp.c - increase size of CURLY nodes so the min/max is a I32

This allows us to resolve a test inconsistency between CURLYX and CURLY
and CURLYM. We use I32 because the existing count logic uses -1 and
this keeps everything unsigned compatible.


  Commit: cd38d640c233998e5a998a6f53ff668369fd3168
      
https://github.com/Perl/perl5/commit/cd38d640c233998e5a998a6f53ff668369fd3168
  Author: Yves Orton <demer...@gmail.com>
  Date:   2023-01-12 (Thu, 12 Jan 2023)

  Changed paths:
    M regcomp_internal.h
    M regcomp_study.c

  Log Message:
  -----------
  regcomp_study.c - Add a way to disable CURLYX optimisations

Also break up the condition so there is one condition per line so
it is more readable, and fold repeated binary tests together. This
makes it more obvious what the expression is doing.


  Commit: 76e1f20f1d80d8d1bca7e1a4b7410dfe21354764
      
https://github.com/Perl/perl5/commit/76e1f20f1d80d8d1bca7e1a4b7410dfe21354764
  Author: Yves Orton <demer...@gmail.com>
  Date:   2023-01-12 (Thu, 12 Jan 2023)

  Changed paths:
    M regcomp_debug.c
    M regcomp_study.c
    M t/re/pat_re_eval.t

  Log Message:
  -----------
  regcomp_study.c - disable CURLYX optimizations when EVAL has been seen 
anywhere

Historically we disabled CURLYX optimizations when they
*contained* an EVAL, on the assumption that the optimization might
affect how many times, etc, the eval was called. However, this is
also true for CURLYX with evals *afterwards*. If the CURLYN or CURLYM
optimization can prune off the search space, then an eval afterwards
will be affected. An when you take into account GOSUB, it means that
an eval in front might be affected by an optimization after it.

So for now we disable CURLYN and CURLYM in any pattern with an EVAL.


  Commit: 995106349af81a044b298cf9c93b5903acf4670c
      
https://github.com/Perl/perl5/commit/995106349af81a044b298cf9c93b5903acf4670c
  Author: Yves Orton <demer...@gmail.com>
  Date:   2023-01-12 (Thu, 12 Jan 2023)

  Changed paths:
    M regexec.c

  Log Message:
  -----------
  regexec.c - rework CLOSE_CAPTURE() macro to take a rex argument

This allows it to be used in contexts where rex isn't set up under
this name.


  Commit: d8f65a38e2cd399eb371be91874931737919938b
      
https://github.com/Perl/perl5/commit/d8f65a38e2cd399eb371be91874931737919938b
  Author: Yves Orton <demer...@gmail.com>
  Date:   2023-01-12 (Thu, 12 Jan 2023)

  Changed paths:
    M regcomp.c
    M regcomp.h

  Log Message:
  -----------
  regcomp.h - get rid of EXTRA_STEP defines

They are unused these days.


  Commit: 568942115c3335bae354da4a9a9e7d8f89eeeaee
      
https://github.com/Perl/perl5/commit/568942115c3335bae354da4a9a9e7d8f89eeeaee
  Author: Yves Orton <demer...@gmail.com>
  Date:   2023-01-12 (Thu, 12 Jan 2023)

  Changed paths:
    M regcomp.c

  Log Message:
  -----------
  regcomp.c - add whitespace to binary operation

The tight & is hard to read.


  Commit: 9998e79469c31c02a4a7fb5b394df5c57d6a299e
      
https://github.com/Perl/perl5/commit/9998e79469c31c02a4a7fb5b394df5c57d6a299e
  Author: Yves Orton <demer...@gmail.com>
  Date:   2023-01-12 (Thu, 12 Jan 2023)

  Changed paths:
    M regcomp_trie.c

  Log Message:
  -----------
  regcomp_trie.c - use the indirect types so we are safe to changes

We shouldnt assume that a TRIEC is a regcomp_charclass. We have a per
opcode type exactly for this type of use, so lets use it.


  Commit: b223d00a98b4a766af19d523037f9b6a8789f43c
      
https://github.com/Perl/perl5/commit/b223d00a98b4a766af19d523037f9b6a8789f43c
  Author: Yves Orton <demer...@gmail.com>
  Date:   2023-01-12 (Thu, 12 Jan 2023)

  Changed paths:
    M pod/perldebguts.pod
    M pp_ctl.c
    M regcomp.c
    M regcomp.h
    M regcomp.sym
    M regcomp_debug.c
    M regexec.c
    M regexp.h
    M regnodes.h
    M t/re/pat.t
    M t/re/pat_rt_report.t
    M t/re/re_tests

  Log Message:
  -----------
  regcomp.c - Resolve issues clearing buffers in CURLYX (MAJOR-CHANGE)

CURLYX doesn't reset capture buffers properly. It is possible
for multiple buffers to be defined at once with values from
different iterations of the loop, which doesn't make sense really.

An example is this:

  "foobarfoo"=~/((foo)|(bar))+/

after this matches $1 should equal $2 and $3 should be undefined,
or $1 should equal $3 and $2 should be undefined. Prior to this
patch this would not be the case.

The solution that this patches uses is to introduce a form of
"layered transactional storage" for paren data. The existing
pair of start/end data for capture data is extended with a
start_new/end_new pair. When the vast majority of our code wants
to check if a given capture buffer is defined they first check
"start_new/end_new", if either is -1 then they fall back to
whatever is in start/end.

When a capture buffer is CLOSEd the data is written into the
start_new/end_new pair instead of the start/end pair. When a CURLYX
loop is executing and has matched something (at least one "A" in
/A*B/ -- thus actually in WHILEM) it "commits" the start_new/end_new
data by writing it into start/end. When we begin a new iteration of
the loop we clear the start_new/end_new pairs that are contained by
the loop, by setting them to -1. If the loop fails then we roll back
as we used to. If the loop succeeds we continue. When we hit an END
block we commit everything.

Consider the example above. We start off with everything set to -1.

 $1 = (-1,-1):(-1,-1)
 $2 = (-1,-1):(-1,-1)
 $3 = (-1,-1):(-1,-1)

In the first iteration we have matched "foo" and end up with this:

 $1 = (-1,-1):( 0, 3)
 $2 = (-1,-1):( 0, 3)
 $3 = (-1,-1):(-1,-1)

We commit the results of $2 and $3, and then clear the new data in
the beginning of the next loop:

 $1 = (-1,-1):( 0, 3)
 $2 = ( 0, 3):(-1,-1)
 $3 = (-1,-1):(-1,-1)

We then match "bar":

 $1 = (-1,-1):( 0, 3)
 $2 = ( 0, 3):(-1,-1)
 $3 = (-1,-1):( 3, 7)

and then commit the result and clear the new data:

 $1 = (-1,-1):( 0, 3)
 $2 = (-1,-1):(-1,-1)
 $3 = ( 3, 7):(-1,-1)

and then we match "foo" again:

 $1 = (-1,-1):( 0, 3)
 $2 = (-1,-1):( 7,10)
 $3 = ( 3, 7):(-1,-1)

And we then commit. We do a regcppush here as normal.

 $1 = (-1,-1):( 0, 3)
 $2 = ( 7,10):( 7,10)
 $3 = (-1,-1):(-1,-1)

We then clear it again, but since we don't match when we regcppop
we store the buffers back to the above layout. When we finally
hit the END buffer we also do a commit as well on all buffers, including
the 0th (for the full match).

Fixes GH Issue #18865, and adds tests for it and other things.


  Commit: 2e24dc304c7a02911e93910c92ba8482d1d028eb
      
https://github.com/Perl/perl5/commit/2e24dc304c7a02911e93910c92ba8482d1d028eb
  Author: Yves Orton <demer...@gmail.com>
  Date:   2023-01-12 (Thu, 12 Jan 2023)

  Changed paths:
    M regexec.c

  Log Message:
  -----------
  fixup for branch reset


  Commit: 07aeb06d7eec57efe5866062fc9eee778630d5e9
      
https://github.com/Perl/perl5/commit/07aeb06d7eec57efe5866062fc9eee778630d5e9
  Author: Yves Orton <demer...@gmail.com>
  Date:   2023-01-12 (Thu, 12 Jan 2023)

  Changed paths:
    M MANIFEST
    M t/re/regexp.t
    A t/re/regexp_normal.t

  Log Message:
  -----------
  t/re/regexp_normal.t - test "normalized" forms of patterns

This looks for discrepancies between different ways of writing
a pattern.


  Commit: 9936eb18bed72b3dbdd5c791da2833b8762ffb8a
      
https://github.com/Perl/perl5/commit/9936eb18bed72b3dbdd5c791da2833b8762ffb8a
  Author: Yves Orton <demer...@gmail.com>
  Date:   2023-01-12 (Thu, 12 Jan 2023)

  Changed paths:
    M pod/perldebguts.pod
    M regcomp.c
    M regcomp.h
    M regcomp.sym
    M regcomp_debug.c
    M regcomp_trie.c
    M regexec.c
    M regexp.h
    M regnodes.h
    M t/re/re_tests

  Log Message:
  -----------
  regexec.c - teach BRANCH and BRANCHJ nodes to reset capture buffers

In /((a)(b)|(a))+/ we should not end up with $2 and $4 being set at
the same time. When a branch fails it should reset any capture buffers
that might be touched by its branch.

We change BRANCH and BRANCHJ to store the number of parens before the
branch, and the number of parens after the branch was completed. When
a BRANCH operation fails, we clear the buffers it contains before we
continue on.

It is a bit more complex than it should be because we have BRANCHJ
and BRANCH. (One of these days we should merge them together.)

This is also made somewhat more complex because TRIE nodes are actually
branches, and may need to track capture buffers also, at two levels.
The overall TRIE op, and for jump tries especially where we emulate
the behavior of branches. So we have to do the same clearing logic if
a trie branch fails as well.


  Commit: c569fc6235dbd9effcafdd13864b5ef7b396efd3
      
https://github.com/Perl/perl5/commit/c569fc6235dbd9effcafdd13864b5ef7b396efd3
  Author: Yves Orton <demer...@gmail.com>
  Date:   2023-01-12 (Thu, 12 Jan 2023)

  Changed paths:
    M pod/perldelta.pod
    M pod/perlre.pod
    M regcomp.c
    M regcomp.h
    M regcomp_debug.c
    M regcomp_internal.h
    M regcomp_study.c
    M regexec.c
    M regnodes.h
    M t/re/pat_re_eval.t
    M t/re/pat_rt_report.t
    M toke.c

  Log Message:
  -----------
  regcomp.c - add optimistic eval

This adds (*{ ... }) and (**{ ... }) as equivalents to
(?{ ... }) and (??{ ... }). The only difference being that
the star variants are "optimisitic" and are defined to never
disable optimisations.  This is especially relevant now that
use of (?{ ... }) prevents important optimisations anywhere
in the pattern, instead of the older and inconsistent rules
where it only affected the parts that contained the EVAL.

It is also very useful for injecting debugging style expressions
to the pattern to understand what the regex engine is actually
doing. The older style (?{ ... }) variants would change the
regex engines behavior, meaning this was not as effective a
tool as it could have been.


  Commit: 7351c48f24377d6681942ff8f6bcb0776dab68b4
      
https://github.com/Perl/perl5/commit/7351c48f24377d6681942ff8f6bcb0776dab68b4
  Author: Yves Orton <demer...@gmail.com>
  Date:   2023-01-12 (Thu, 12 Jan 2023)

  Changed paths:
    M regexec.c
    M t/re/pat_re_eval.t
    M t/re/regexp.t

  Log Message:
  -----------
  regexec.c - fix accept in CURLYX/WHILEM construct.

The ACCEPT logic didnt know how to handle WHILEM, which for
some reason does not have a next_off defined. I am not sure why.

This was revealed by forcing CURLYX optimisations off. This includes
a patch to test what happens if we embed an eval group in the tests
run by regexp.t when run via regexp_normal.t, which disabled CURLYX ->
CURLYN and CURLYM optimisations and revealed this issue.


  Commit: 6513f007a25a2d370de568871b4fc07b4a8094dd
      
https://github.com/Perl/perl5/commit/6513f007a25a2d370de568871b4fc07b4a8094dd
  Author: Yves Orton <demer...@gmail.com>
  Date:   2023-01-12 (Thu, 12 Jan 2023)

  Changed paths:
    M pod/perldelta.pod

  Log Message:
  -----------
  perldelta - add note about regex engine changes

capture buffer semantics should now be consistent.


Compare: https://github.com/Perl/perl5/compare/ab4ad8dbfee3...6513f007a25a

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