[pacman-dev] [PATCH] Perform limited conflict checking with --force

[Allan McRae]

On 16/02/13 05:42, Andrew Gregory wrote:
> On Fri, 15 Feb 2013 15:06:17 +1000
> Allan McRae <allan at archlinux.org> wrote:
> 
>> On 12/02/13 22:23, Allan McRae wrote:
>>> On 12/02/13 22:05, Allan McRae wrote:
>>>> Pacman currently bails when trying to extract a file over a directory
>>>> when using --force.  Instead of ignoring all conflict, perform the
>>>> check and skip any file-file conflicts. Conflicts between directories
>>>> and files are still flagged and cause the transation to abort.
>>>>
>>>> As a bonus, we now know about files changing packages when using
>>>> --force, so we can skip removing them fixing upgrade046.
>>>>
>>>> Signed-off-by: Allan McRae <allan at archlinux.org>
>>>> ---
>>>>  doc/pacman.8.txt                |  2 ++
>>>>  lib/libalpm/conflict.c          | 26 ++++++++++++++++++++++++--
>>>>  lib/libalpm/sync.c              |  2 +-
>>>>  src/pacman/sync.c               |  3 +++
>>>>  test/pacman/tests/upgrade046.py |  2 --
>>>>  5 files changed, 30 insertions(+), 5 deletions(-)
>>>>
>>>> diff --git a/doc/pacman.8.txt b/doc/pacman.8.txt
>>>> index 358d506..33a9421 100644
>>>> --- a/doc/pacman.8.txt
>>>> +++ b/doc/pacman.8.txt
>>>> @@ -205,6 +205,8 @@ Upgrade Options (apply to '-S' and '-U')[[UO]]
>>>>  	Bypass file conflict checks and overwrite conflicting files. If the
>>>>  	package that is about to be installed contains files that are already
>>>>  	installed, this option will cause all those files to be overwritten.
>>>> +	Using '--force' will not allow overwriting a directory with a file or
>>>> +	installing packages with conflicting files and directories.
>>>>  	This option should be used with care, ideally not at all.
>>>>  
>>>>  *\--asdeps*::
>>>> diff --git a/lib/libalpm/conflict.c b/lib/libalpm/conflict.c
>>>> index 610e5ad..6195c9c 100644
>>>> --- a/lib/libalpm/conflict.c
>>>> +++ b/lib/libalpm/conflict.c
>>>> @@ -439,8 +439,10 @@ alpm_list_t *_alpm_db_find_fileconflicts(alpm_handle_t *handle,
>>>>  			alpm_pkg_t *p2 = j->data;
>>>>  			_alpm_filelist_resolve(handle, alpm_pkg_get_files(p2));
>>>>  
>>>> -			common_files = _alpm_filelist_intersection(alpm_pkg_get_files(p1),
>>>> -					alpm_pkg_get_files(p2));
>>>> +			alpm_filelist_t *p1_files = alpm_pkg_get_files(p1);
>>>> +			alpm_filelist_t *p2_files = alpm_pkg_get_files(p2);
>>>> +
>>>> +			common_files = _alpm_filelist_intersection(p1_files, p2_files);
>>>>  
>>>>  			if(common_files) {
>>>>  				alpm_list_t *k;
>>>> @@ -448,6 +450,18 @@ alpm_list_t *_alpm_db_find_fileconflicts(alpm_handle_t *handle,
>>>>  				for(k = common_files; k; k = k->next) {
>>>>  					alpm_file_t *file = k->data;
>>>>  					snprintf(path, PATH_MAX, "%s%s", handle->root, file->name);
>>>> +
>>>> +					/* can skip file-file conflicts when forced */
>>
>> Clarified comment:
>>
>> /* can skip file-file conflicts when forced
>>  * the trailing "/" has been stripped from directories when
>>  * calculating the intersection, so only files will succeed in
>>  * alpm_filelist_contains() */
>>
> 
> It strips the trailing '/' for the comparison, but the files returned
> include it.  Since dir-dir intersections are not returned, just
> checking p2_files would be enough to ensure that the path is a file in
> both lists. 
> 

So...  that comment is wrong, but we still need to check both of them.
We want to detect file-file conflicts for skipping, and not dir-file
conflicts.  So, the file string must be in both packages (whether or not
the trailing "/" is there - which is somewhat random...).

Allan