[Bug gdb/15294] list with unlimited listsize broken

["cvs-commit at gcc dot gnu.org" <sourceware-bugzilla at sourceware dot org>]

http://sourceware.org/bugzilla/show_bug.cgi?id=15294

--- Comment #1 from cvs-commit at gcc dot gnu.org <cvs-commit at gcc dot gnu.org> 2013-03-28 11:50:01 UTC ---
CVSROOT:    /cvs/src
Module name:    src
Branch:     gdb_7_6-branch
Changes by:    palves@sourceware.org    2013-03-28 11:50:00

Modified files:
    gdb            : ChangeLog source.c 
    gdb/doc        : ChangeLog gdb.texinfo 
    gdb/testsuite  : ChangeLog 
    gdb/testsuite/gdb.base: list.exp 

Log message:
    Fix PR gdb/15294: list with unlimited listsize broken

    Currently, "set listsize -1" is supposed to mean "unlimited" source
    lines, but, alas, it doesn't actually work:

    (gdb) set listsize -1
    (gdb) show listsize
    Number of source lines gdb will list by default is unlimited.
    (gdb) list 1
    (gdb) list 1
    (gdb) list 1
    (gdb) set listsize 10
    (gdb) list 1
    1       /* Main function for CLI gdb.
    2          Copyright (C) 2002-2013 Free Software Foundation, Inc.
    3
    4          This file is part of GDB.
    5
    6          This program is free software; you can redistribute it and/or
modify
    7          it under the terms of the GNU General Public License as
published by
    8          the Free Software Foundation; either version 3 of the License,
or
    9          (at your option) any later version.
    10

    Before this patch:

    http://sourceware.org/ml/gdb-patches/2012-08/msg00367.html

    was applied, the "set listsize" command was a var_integer command, and
    "unlimited" was set with 0.  Internally, var_integer maps 0 to INT_MAX

    case var_integer:
    {
    ...
    if (val == 0 && c->var_type == var_integer)
    val = INT_MAX;

    The change in that patch to zuinteger_unlimited command, meant that -1
    is left as -1 in the command's control variable (lines_to_list), and
    the code in source.c isn't expecting that -- it only expects positive
    numbers.

    I previously suggested fixing the code and keeping the new behavior,
    but I found that "set listsize 0" is currently used in the wild, and
    we do have a bunch of other commands where "0" means unlimited, so I'm
    thinking that changing this command alone in isolation is not a good
    idea.

    So I now strongly prefer reverting back the behavior in 7.6 to the
    same behavior the command has had since 2006 (0==unlimited, -1=error).
    Before that, set listsize -1 would be accepted as unlimited as well.

    After 7.6 is out, in mainline, we can get back to reconsidering
    changing this command's behavior, if there's a real need for being
    able to suppress output.  For now, let's play it safe.

    The "list line 1 with unlimited listsize" test in list.exp was
    originally written years and years ago expecting 0 to mean "no
    output", but GDB never actually worked that way, even when the tests
    were written, so the tests had been xfailed then.  This patch now
    adjusts the test to the new behavior, so that the test actually
    passes, and the xfail is removed.

    gdb/
    2013-03-28  Pedro Alves  <palves@redhat.com>

    PR gdb/15294

    * source.c (_initialize_source): Change back "set listsize" to an
    integer command.

    gdb/testsuite/
    2013-03-28  Pedro Alves  <palves@redhat.com>

    PR gdb/15294

    * gdb.base/list.exp (set_listsize): Adjust to accept $arg == 0 to
    mean unlimited instead of $arg < 0.
    (test_listsize): Remove "listsize of 0 suppresses output" test.
    Test that "set listsize 0" ends up with an unlimited listsize.

    gdb/doc/
    2013-03-28  Pedro Alves  <palves@redhat.com>

    PR gdb/15294

    * gdb.texinfo (List) <set listsize>: Adjust to document that
    listsize 0 means no limit, and remove mention of -1.

Patches:
http://sourceware.org/cgi-bin/cvsweb.cgi/src/gdb/ChangeLog.diff?cvsroot=src&only_with_tag=gdb_7_6-branch&r1=1.15260.2.17&r2=1.15260.2.18
http://sourceware.org/cgi-bin/cvsweb.cgi/src/gdb/source.c.diff?cvsroot=src&only_with_tag=gdb_7_6-branch&r1=1.153.2.2&r2=1.153.2.3
http://sourceware.org/cgi-bin/cvsweb.cgi/src/gdb/doc/ChangeLog.diff?cvsroot=src&only_with_tag=gdb_7_6-branch&r1=1.1423&r2=1.1423.2.1
http://sourceware.org/cgi-bin/cvsweb.cgi/src/gdb/doc/gdb.texinfo.diff?cvsroot=src&only_with_tag=gdb_7_6-branch&r1=1.1060&r2=1.1060.2.1
http://sourceware.org/cgi-bin/cvsweb.cgi/src/gdb/testsuite/ChangeLog.diff?cvsroot=src&only_with_tag=gdb_7_6-branch&r1=1.3580.2.9&r2=1.3580.2.10
http://sourceware.org/cgi-bin/cvsweb.cgi/src/gdb/testsuite/gdb.base/list.exp.diff?cvsroot=src&only_with_tag=gdb_7_6-branch&r1=1.34.2.3&r2=1.34.2.4

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