Re: [PATCH v2 10/11] merge-ort: add implementation of normal rename handling

> From: Elijah Newren <newren@gmail.com>
> 
> Implement handling of normal renames.  This code replaces the following
> from merge-recurisve.c:
> 
>   * the code relevant to RENAME_NORMAL in process_renames()
>   * the RENAME_NORMAL case of process_entry()
> 
> Also, there is some shared code from merge-recursive.c for multiple
> different rename cases which we will no longer need for this case (or
> other rename cases):
> 
>   * handle_rename_normal()
>   * setup_rename_conflict_info()
> 
> The consolidation of four separate codepaths into one is made possible
> by a change in design: process_renames() tweaks the conflict_info
> entries within opt->priv->paths such that process_entry() can then
> handle all the non-rename conflict types (directory/file, modify/delete,
> etc.) orthogonally.  This means we're much less likely to miss special
> implementation of some kind of combination of conflict types (see
> commits brought in by 66c62eaec6 ("Merge branch 'en/merge-tests'",
> 2020-11-18), especially commit ef52778708 ("merge tests: expect improved
> directory/file conflict handling in ort", 2020-10-26) for more details).
> That, together with letting worktree/index updating be handled
> orthogonally in the merge_switch_to_result() function, dramatically
> simplifies the code for various special rename cases.
> 
> (To be fair, the code for handling normal renames wasn't all that
> complicated beforehand, but it's still much simpler now.)

> +				memcpy(&newinfo->stages[other_source_index],
> +				       &oldinfo->stages[other_source_index],
> +				       sizeof(newinfo->stages[0]));
> +				newinfo->filemask |= (1 << other_source_index);
> +				newinfo->pathnames[other_source_index] = oldpath;