in reply to Bug with finding all regexp matches

Is it a bug?

If you enable re 'debug', then you'll get to see what's going on in detail. The compiled regexes differ in much the way you'd expect:

Final program:                               Final program:
   1: BOL (2)                                   1: BOL (2)
   2: OPEN1 (4)                                 2: OPEN1 (4)
   4:   PLUS (6)                                4:   PLUS (6)
   5:     REG_ANY (0)                           5:     REG_ANY (0)
   6: CLOSE1 (8)                                6: CLOSE1 (8)
   8: OPEN2 (10)                                8: OPEN2 (10)
  10:   PLUS (12)                              10:   PLUS (12)
  11:     REG_ANY (0)                          11:     REG_ANY (0)
  12: CLOSE2 (14)                              12: CLOSE2 (14)
  14: OPEN3 (16)                               14: OPEN3 (16)
  16:   PLUS (18)                              16:   CURLYX[2] {1,3276
+7} (24)
  17:     REG_ANY (0)                          18:     REG_ANY (19)
                                               19:     CURLY {0,1} (23
+)
                                               21:       EXACT <z> (0)
                                               23:   WHILEM[1/1] (0)
                                               24:   NOTHING (25)
  18: CLOSE3 (20)                              25: CLOSE3 (27)
  20: EOL (21)                                 27: EOL (28)
  21: EVAL (23)                                28: EVAL (30)
  23: OPFAIL (24)                              30: OPFAIL (31)
  24: END (0)                                  31: END (0)

[download]

Comparing the traces is harder.

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Re^2: Bug with finding all regexp matches
by Anonymous Monk on Oct 15, 2016 at 18:12 UTC
    For 
    perl -e 'use re "debug"; "01234" =~ /^(.+)(.+)((?:.z?)+)$(?{ print "$1
+ $2 $3\n" })(*FAIL)/' 2>&1 | less

    [download]
    for the missing "0 1 234" the trace has 
    whilem: (cache) already tried at this position...
failed...

    [download]
    and my wild guess is that it cached the effect of (*FAIL) and not the real failure of a regexp, hence EVAL is skipped and last result is missed. I didn't find the way to disable the cache with "use re".
[reply]
[d/l]
[select]
      To add to the previous post: For 
      perl -e 'use re "debug"; "01234" =~ /^(.+?)(.+)((?:.z?)+)$(?{ print "$
+1 $2 $3\n" })(*FAIL)/' 2>&1 | less

      [download]
      two results are missing and there are two entries 
      whilem: (cache) already tried at this position...
failed...

      [download]
      It figures.
[reply]
[d/l]
[select]
        I opened a bug on this, https://rt.perl.org/Ticket/Display.html?id=129886 .
[reply]

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