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*MARK names in atomic groups #16634

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p5pRT opened this issue Jul 16, 2018 · 1 comment
Open

*MARK names in atomic groups #16634

p5pRT opened this issue Jul 16, 2018 · 1 comment
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type-core type-regex type-regex-verb

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@p5pRT
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p5pRT commented Jul 16, 2018

Migrated from rt.perl.org#133381 (status was 'new')

Searchable as RT133381$
@p5pRT
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p5pRT commented Jul 16, 2018

From ph10@hermes.cam.ac.uk

Created by ph10@cam.ac.uk

The perlre man page says this​:

  When a match is successful, the $REGMARK variable will be set to the name of
  the most recently executed "(*MARK​:NAME)" that was involved in the match.

To me "most recently executed" implies that it's part of the successful path
through the pattern. However, consider these examples​:

$ perl -e 'if (ax =~ /\A(?>(*​:A)a)((*​:B)x|)/) { print "yes >$REGMARK<\n"; } else { print "no \n"; }'
yes >B<

That's exactly what I would expect.

$ perl -e 'if (ab =~ /\A(?>(*​:A)a)((*​:B)x|)/) { print "yes >$REGMARK<\n"; } else { print "no \n"; }'
yes >1<

...but that is not​: I was expecting $REGMARK to be "A" since that is the last
*MARK on the matching path. Incidentally, it's the same when the pattern is
prefixed with (??{""}) to turn off optimization. If the (*​:A) setting is not in
an atomic group, then indeed the answer *is* "A".

So, is this a documentation bug ("(*MARK) inside an atomic group doesn't
propagate outside it"), or is it a code bug? PCRE does give "A" with the
atomic group, because I considered the (*MARK) inside to be "involved in the
match".

Philip Hazel

Perl Info 

Flags:
    category=core
    severity=low

Site configuration information for perl 5.26.2:

Configured by builduser at Wed Apr 18 22:20:25 CEST 2018.

Summary of my perl5 (revision 5 version 26 subversion 2) configuration:
   
  Platform:
    osname=linux
    osvers=4.15.15-1-arch
    archname=x86_64-linux-thread-multi
    uname='linux flo-64 4.15.15-1-arch #1 smp preempt sat mar 31 23:59:25 utc 2018 x86_64 gnulinux '
    config_args='-des -Dusethreads -Duseshrplib -Doptimize=-march=x86-64 -mtune=generic -O2 -pipe -fstack-protector-strong -fno-plt -Dprefix=/usr -Dvendorprefix=/usr -Dprivlib=/usr/share/perl5/core_perl -Darchlib=/usr/lib/perl5/5.26/core_perl -Dsitelib=/usr/share/perl5/site_perl -Dsitearch=/usr/lib/perl5/5.26/site_perl -Dvendorlib=/usr/share/perl5/vendor_perl -Dvendorarch=/usr/lib/perl5/5.26/vendor_perl -Dscriptdir=/usr/bin/core_perl -Dsitescript=/usr/bin/site_perl -Dvendorscript=/usr/bin/vendor_perl -Dinc_version_list=none -Dman1ext=1perl -Dman3ext=3perl -Dcccdlflags='-fPIC' -Dlddlflags=-shared -Wl,-O1,--sort-common,--as-needed,-z,relro,-z,now -Dldflags=-Wl,-O1,--sort-common,--as-needed,-z,relro,-z,now'
    hint=recommended
    useposix=true
    d_sigaction=define
    useithreads=define
    usemultiplicity=define
    use64bitint=define
    use64bitall=define
    uselongdouble=undef
    usemymalloc=n
    default_inc_excludes_dot=define
    bincompat5005=undef
  Compiler:
    cc='cc'
    ccflags ='-D_REENTRANT -D_GNU_SOURCE -fwrapv -fno-strict-aliasing -pipe -fstack-protector-strong -I/usr/local/include -D_LARGEFILE_SOURCE -D_FILE_OFFSET_BITS=64 -D_FORTIFY_SOURCE=2'
    optimize='-march=x86-64 -mtune=generic -O2 -pipe -fstack-protector-strong -fno-plt'
    cppflags='-D_REENTRANT -D_GNU_SOURCE -fwrapv -fno-strict-aliasing -pipe -fstack-protector-strong -I/usr/local/include'
    ccversion=''
    gccversion='7.3.1 20180312'
    gccosandvers=''
    intsize=4
    longsize=8
    ptrsize=8
    doublesize=8
    byteorder=12345678
    doublekind=3
    d_longlong=define
    longlongsize=8
    d_longdbl=define
    longdblsize=16
    longdblkind=3
    ivtype='long'
    ivsize=8
    nvtype='double'
    nvsize=8
    Off_t='off_t'
    lseeksize=8
    alignbytes=8
    prototype=define
  Linker and Libraries:
    ld='cc'
    ldflags ='-Wl,-O1,--sort-common,--as-needed,-z,relro,-z,now -fstack-protector-strong -L/usr/local/lib'
    libpth=/usr/local/lib /usr/lib/gcc/x86_64-pc-linux-gnu/7.3.1/include-fixed /usr/lib /lib/../lib /usr/lib/../lib /lib /lib64 /usr/lib64
    libs=-lpthread -lnsl -lgdbm -ldb -ldl -lm -lcrypt -lutil -lc -lgdbm_compat
    perllibs=-lpthread -lnsl -ldl -lm -lcrypt -lutil -lc
    libc=libc-2.26.so
    so=so
    useshrplib=true
    libperl=libperl.so
    gnulibc_version='2.26'
  Dynamic Linking:
    dlsrc=dl_dlopen.xs
    dlext=so
    d_dlsymun=undef
    ccdlflags='-Wl,-E -Wl,-rpath,/usr/lib/perl5/5.26/core_perl/CORE'
    cccdlflags='-fPIC'
    lddlflags='-shared -Wl,-O1,--sort-common,--as-needed,-z,relro,-z,now -L/usr/local/lib -fstack-protector-strong'



@INC for perl 5.26.2:
    /usr/lib/perl5/5.26/site_perl
    /usr/share/perl5/site_perl
    /usr/lib/perl5/5.26/vendor_perl
    /usr/share/perl5/vendor_perl
    /usr/lib/perl5/5.26/core_perl
    /usr/share/perl5/core_perl


Environment for perl 5.26.2:
    HOME=/home/ph10
    LANG=en_GB.utf8
    LANGUAGE=en_GB.utf8
    LC_ALL=C
    LC_COLLATE=C
    LD_LIBRARY_PATH (unset)
    LOGDIR (unset)
    PATH=/home/ph10/bin:/usr/local/sbin:/usr/local/bin:/usr/bin:/opt/android-sdk/platform-tools:/opt/android-sdk/tools:/usr/lib/jvm/default/bin:/usr/bin/site_perl:/usr/bin/vendor_perl:/usr/bin/core_perl:/usr/sbin:.:/opt/android-sdk/platform-tools:/opt/android-sdk/tools:/usr/lib/jvm/default/bin:/usr/bin/site_perl:/usr/bin/vendor_perl:/usr/bin/core_perl
    PERL_BADLANG (unset)
    SHELL=/bin/bash

@xenu xenu removed the affects-5.26 label Nov 19, 2021
@xenu xenu removed the Severity Low label Dec 29, 2021
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@khwilliamson @xenu @p5pRT