Re: [Monotone-devel] fatal: std::logic_error: roster_merge.cc:528: invariant 'I(left_name == right_name)' violated

[Markus Schiltknecht]

Hi,

Brian May wrote:
> I don't understand this; I thought Monotone only considered two file/dir 
> to be the same if they shared a common ancestor. In this case, it would 
> appear both files have different ancestors, and the filenames are 
> different at the time of merge, so I don't see why they should conflict.

Well, the full file_path is different, yes. But the parent directory, to 
which the file should be added is the same. It only got renamed in between.

Condider this:

        base_rev          o   containing dir "foo/"
        /     \
       /       \
  rename      add file
 "foo" to     "foo/x"
  "bar"

The left revision contains no directory named "foo", although the right 
revision adds a file "foo/x". Now, because monotone tracks renames, it 
known directory "foo" had been renamed to "bar", and thus the merged 
revision contains a file "bar/x".

With me so far?

Now, if the left revision adds a file "bar/x", monotone has a problem. 
It knows the directory "foo" has been renamed to "bar" on the left. It's 
the same directory. But both revisions want to add a file "x" to that 
directory. Now it exits with:

conflict: duplicate name 'x' for the directory
          named 'bar' on the left and
          named 'foo' on the right.

I know this is somewhat confusing. But the *same* directory can have 
different names, if you decide to track renames.

Regards

Markus