On 04/01/2013 09:10 PM, Rémy Lefevre wrote: > Rémy. > > > 2013/4/1 Pádraig Brady <[email protected] <mailto:[email protected]>> > > On 04/01/2013 03:40 PM, Rémy Lefevre wrote: > > Overwriting relative symlink leads to undesirable behavior. Consider the > > following example: > > > > # Create some directories > > mkdir test > > mkdir test/folder1 > > mkdir test/folder2 > > > > #Create some files > > touch test/folder1/file1 > > touch test/folder1/file2 > > > > #Create a relative symlink in folder2 to file1 > > ln -sr test/folder1/file1 test/folder2/link > > > > #Check the link > > ls -l test/folder2/link > > # Correctly output a link to ../folder1/file1 > > > > #Overwrite the symlink to point to file2 > > ln -sfr test/folder1/file2 test/folder2/link > > > > #Check the link > > ls -l test/folder2/link > > # Wrongly output a link to file2 instead of ../folder1/file2 > > > > > > This undesirable behavior is due to a dereferencing of the target when > the > > relative path is computed. Passing CAN_NOLINKS flag to > > canonicalize_filename_mode solves the problem. > > Doing that though breaks `ln -sr target1 target2 dir` where dir is a > symlink. > Also if /some/other/component of the path is a symlink, you probably want > that resolved? You might even want the final component of the link name > resolved in some cases. So perhaps the approach here is to only disable > dereferencing when -n is set, and even then only for the last_component()? > > In other words, `ln -nsf ...` means update the specified link name no > matter what it is. > -n used only be significant when the link name was to a directory, > but with -r it's also significant if linking outside its containing > directory. > > I'll sort out a patch later. > > You are right. It breaks any path composed of link. Sorry for this bad patch. > > But could you provide me an example where the final component of the link > should be resolved ? Does it make sense as the link will be overwritten? I > must be missing something.
Yes resolving the last component would be a departure from existing behavior. So it there is no need to conditionalize this on -n, and we just need to resolve the path without the last_component() and then tack that on. thanks, Pádraig.
