Use svn cat_at_BASE to get the file.
File is moved to revertbase to allow replacement with history.
Bert (mobile phone)
----- Oorspronkelijk bericht -----
Van: Neels J Hofmeyr <neels_at_elego.de>
Verzonden: zaterdag 16 januari 2010 23:48
Aan: dev_at_subversion.apache.org
Onderwerp: libsvn_wc bug: pristine contents for locally replaced file
Hi,
is there a good reason why a local replace has to get rid of the pristine
base file? Because, if the file was kept, the problems described below would
be resolved.
<tell-mode>
I stumbled over an error using 'svn cat <wc_path>' on a locally replaced
file. (Not a common use case, but read on.) 'svn cat <wc_path>' appears to
want to output the pristine base content (which is not documented).
But when a file is locally replaced (not committed), it currently has no
pristine base file, apparently;
'svn cat wc/locally_replaced_file'
calls
svn_wc__get_pristine_contents()
which errors with:
[[[
$ svn cat file
subversion/svn/cat-cmd.c:81: (apr_err=2)
subversion/svn/util.c:960: (apr_err=2)
subversion/libsvn_client/cat.c:88: (apr_err=2)
subversion/libsvn_client/cat.c:88: (apr_err=2)
subversion/libsvn_subr/stream.c:774: (apr_err=2)
subversion/libsvn_subr/stream.c:774: (apr_err=2)
subversion/libsvn_subr/io.c:2711: (apr_err=2)
svn: Can't open file '/tmp/wc/.svn/text-base/file.svn-base': No such file or
directory
]]]
(reproduction script attached)
'svn cat' is just an example of how to hit this. This same function is used
in many other places. A quick impact grep study suggests at least export,
copy, update, diff, and probably others.
(Todo: investigation on whether current callers can hit a locally replaced
file and whether they work around it.)
</tell-mode>
<bug-hunting>
I guess svn_wc__get_pristine_contents() wants to return the contents of the
file that were committed in revision <BASE>. But the implementation expects
a file to exist which isn't there:
[[[
svn_error_t *
svn_wc__get_pristine_contents(svn_stream_t **contents,
svn_wc__db_t *db,
const char *local_abspath,
apr_pool_t *result_pool,
apr_pool_t *scratch_pool)
{
const char *text_base;
SVN_ERR(svn_wc__text_base_path(&text_base, db, local_abspath, FALSE,
scratch_pool));
if (text_base == NULL)
{
*contents = NULL;
return SVN_NO_ERROR;
}
return svn_stream_open_readonly(contents, text_base, result_pool,
scratch_pool);
// ^^^^^ hits error here, file *text_base does not exist.
}
]]]
I see two ill things:
(1) Looking at the function's intention, it should return an empty stream if
there is no base file. But svn_wc__text_base_path() returns a path that
doesn't exist.
(2) When the file is locally replaced, it theoretically *does* have a
pristine base, i.e. the file's content committed at revision <BASE>. The
function fails to return that content.
</bug-hunting>
So, back to the question: is there a good reason why a local delete followed
by a local add has to get rid of the pristine base file?
Thanks,
~Neels
Received on 2010-01-17 09:51:08 CET