Mark Glines
and 1 contributors

NAME

svn-bisect

SYNOPSIS

    $ svn-bisect start --min 25000 --max 26000
    $ svn-bisect bad
    $ svn-bisect bad
    $ svn-bisect good
    [etc etc]
    $ svn-bisect reset

DESCRIPTION

This tool's purpose is to help you determine which revision of a subversion repository contains a change. It does this by employing a binary search. It will manage the current revision of your checkout directory, and narrow in on the target revision, as you give it clues about the current revision such as "before" (this revision is before the one you want) or "after" (this revision is after the one you want).

Start a bisect session with the "start" command. Then, walk the binary tree by using the "before" and "after" commands. When you are done, the tool will tell you the target revision.

The most common usage scenario is finding out which rev a bug was introduced in. For this purpose, some command aliases have been added: if the current revision contains the bug, you can use the "bad" command (meaning, this revision is "after" the change you want to find), otherwise use the "good" command (meaning, this revision is "before" the change you want to find).

All commands should be run from within a subversion checkout directory. After a "svn-bisect start", all subsequent svn-bisect commands need to be run from that same directory.

SUBCOMMANDS

start

    svn-bisect start --min M --max N

Start a new bisect session. If --min isn't specified, rev 0 is used. If --max isn't specified, the biggest rev in the repository is used.

after

    svn-bisect after
    or: svn-bisect bad

Inform svn-bisect that the current revision is *after* the change we're looking for. If you are looking for the rev which introduced a bug, the alias "bad" might be easier to remember.

before

    svn-bisect before
    or: svn-bisect good

Inform svn-bisect that the current revision is *before* the change we're looking for. If you are looking for the rev which introduced a bug, the alias "good" might be easier to remember.

skip

    svn-bisect skip

Tell svn-bisect to skip the current revision. Do this if you can't determine whether the current revision is bad or good, if, for instance, some other change prevents it from compiling successfully.

reset

    svn-bisect reset

Clean up after a bisect, and return the repository to the revision it was at before you started.

help

    svn-bisect help
    svn-bisect help start

Gives you some useful descriptions and usage information.

EXAMPLE

...Because, you know, no software documentation is complete without a flashy screenshot, these days.

So, lets say you were wondering when the subversion project added the "Last Changed Rev:" line to the output of "svn info". Determining the existence of this change is a straightforward matter of searching for the text string... if a result was found, the current revision is "after", otherwise it was "before". So a bisect looks like this:

    $ svn co http://svn.collab.net/repos/svn/trunk/subversion
    [snip lots of svn checkout spam]
    Checked out revision 30958.
    
    $ cd subversion
    
    $ ack --nocolor --nogroup 'Last Changed Rev'
    svn/info-cmd.c:351:    SVN_ERR(svn_cmdline_printf(pool, _("Last Changed Rev: %ld\n"),
    
    $ date
    Fri May  2 12:52:20 PDT 2008
    
    $ svn-bisect start
    There are 13853 revs left in the pool.  Choosing r15480.
    
    $ ack --nocolor --nogroup 'Last Changed Rev'
    clients/cmdline/info-cmd.c:137:    SVN_ERR (svn_cmdline_printf (pool, _("Last Changed Rev: %ld\n"),
    
    $ svn-bisect after
    There are 6926 revs left in the pool.  Choosing r6010.
    
    $ ack --nocolor --nogroup 'Last Changed Rev'
    clients/cmdline/info-cmd.c:158:    printf ("Last Changed Rev: %" SVN_REVNUM_T_FMT "\n", entry->cmt_rev);
    
    $ svn-bisect after
    There are 3463 revs left in the pool.  Choosing r2481.
    
    $ ack --nocolor --nogroup 'Last Changed Rev'
    clients/cmdline/info-cmd.c:153:    printf ("Last Changed Rev: %" SVN_REVNUM_T_FMT "\n", entry->cmt_rev);
    
    $ svn-bisect after
    There are 1731 revs left in the pool.  Choosing r1168.
    
    $ ack --nocolor --nogroup 'Last Changed Rev'
    
    $ svn-bisect before
    There are 865 revs left in the pool.  Choosing r1800.
    
    $ ack --nocolor --nogroup 'Last Changed Rev'
    
    $ svn-bisect before
    There are 432 revs left in the pool.  Choosing r2127.
    
    $ ack --nocolor --nogroup 'Last Changed Rev'
    clients/cmdline/info-cmd.c:161:        printf ("Last Changed Rev: %" SVN_REVNUM_T_FMT "\n", entry->cmt_rev);
    
    $ svn-bisect after
    There are 216 revs left in the pool.  Choosing r1961.
    
    $ ack --nocolor --nogroup 'Last Changed Rev'
    clients/cmdline/info-cmd.c:161:        printf ("Last Changed Rev: %" SVN_REVNUM_T_FMT "\n", entry->cmt_rev);
    
    $ svn-bisect after
    There are 108 revs left in the pool.  Choosing r1881.
    
    $ ack --nocolor --nogroup 'Last Changed Rev'
    clients/cmdline/info-cmd.c:161:        printf ("Last Changed Rev: %" SVN_REVNUM_T_FMT "\n", entry->cmt_rev);
    
    $ svn-bisect after
    There are 54 revs left in the pool.  Choosing r1845.
    
    $ ack --nocolor --nogroup 'Last Changed Rev'
    clients/cmdline/info-cmd.c:150:        printf ("Last Changed Rev: %ld\n", entry->cmt_rev);
    
    $ svn-bisect after
    There are 27 revs left in the pool.  Choosing r1827.
    
    $ ack --nocolor --nogroup 'Last Changed Rev'
    clients/cmdline/info-cmd.c:150:        printf ("Last Changed Rev: %ld\n", entry->cmt_rev);
    
    $ svn-bisect after
    There are 13 revs left in the pool.  Choosing r1809.
    
    $ ack --nocolor --nogroup 'Last Changed Rev'
    clients/cmdline/info-cmd.c:153:            printf ("Last Changed Rev: %ld\n", entry->cmt_rev);
    
    $ svn-bisect after
    There are 6 revs left in the pool.  Choosing r1806.
    
    $ ack --nocolor --nogroup 'Last Changed Rev'
    
    $ svn-bisect before
    There are 2 revs left in the pool.  Choosing r1808.
    
    $ ack --nocolor --nogroup 'Last Changed Rev'
    
    $ svn-bisect before
    This is the end of the road!  The change occurred in r1809.
    
    $ svn log -r1809
    ------------------------------------------------------------------------
    r1809 | rooneg | 2002-04-27 12:23:38 -0700 (Sat, 27 Apr 2002) | 30 lines
    
    As requested by cmpilato in issue #676, add an 'svn info' command, which 
    prints out the contents of the svn_wc_entry_t for a given versioned resource.
    
    * CHANGES
      note the addition of the 'svn info' command.
    
    * subversion/clients/cmdline/cl.h
      add declaration for svn_cl__info.
    
    * subversion/clients/cmdline/info-cmd.c
      new file implementing the info command.
    
    * subversion/clients/cmdline/main.c
      hook up the info command.
    
    * subversion/clients/cmdline/man/svn.1
      document the info command.
    
    * subversion/tests/clients/cmdline/getopt_tests_data/svn--help_stdout
      update for the addition of info command.
    
    * subversion/tests/clients/cmdline/getopt_tests_data/svn_help_stdout
      ditto.
    
    * subversion/tests/clients/cmdline/getopt_tests_data/svn_stderr
      ditto.
    
    * tools/dev/bash_completion
      add 'info' to the tab completion.
    
    ------------------------------------------------------------------------
    
    $ date
    Fri May  2 12:56:00 PDT 2008

So, there it is. In 4 minutes, we've learned that "Last Changed Rev:" has been in there since the inception of the "svn info" command itself, back in 2002.

REQUIREMENTS

This tool requires:

* A computer

* A brain

* An installation of Perl, version 5.8 or above

* The IO::All module, installed from CPAN

* The YAML module, installed from CPAN

* The "svn" command somewhere in your PATH, executable by the current user

* A svn checkout with some history to bisect.

AUTHOR

    Mark Glines <mark-cpan@glines.org>

THANKS

* Thanks to the git-bisect author(s), for coming up with a user interface that I actually like.

* Thanks to Will Coleda for inspiring me to actually write and release this.

* Thanks to the Parrot project for having so much random stuff going on as to make a tool like this necessary.

SEE ALSO

App::SVNBinarySearch by Will Coleda: http://search.cpan.org/dist/App-SVNBinarySearch/

COPYRIGHT AND LICENSE

This software is copyright (c) 2008 Mark Glines.

It is distributed under the terms of the Artistic License 2.0. For details, see the "LICENSE" file packaged alongside this tool.