Re: [PATCH v2 12/22] tree-diff.c: move S_DIFFTREE_IFXMIN_NEQ define from cache.h

> > --- a/tree-diff.c
> > +++ b/tree-diff.c
> > @@ -6,6 +6,19 @@
> >  #include "diffcore.h"
> >  #include "tree.h"
> >
> > +/*
> > + * Some mode bits are also used internally for computations.
> > + *
> > + * They *must* not overlap with any valid modes, and they *must* not be emitted
> > + * to outside world - i.e. appear on disk or network. In other words, it's just
> > + * temporary fields, which we internally use, but they have to stay in-house.
> > + *
> > + * ( such approach is valid, as standard S_IF* fits into 16 bits, and in Git
> > + *   codebase mode is `unsigned int` which is assumed to be at least 32 bits )
> > + */
> > +
> > +#define S_DIFFTREE_IFXMIN_NEQ        0x80000000
> > +
> >  /*
> >   * internal mode marker, saying a tree entry != entry of tp[imin]
> >   * (see ll_diff_tree_paths for what it means there)
>
> As it's only used in tree-diff.c, should this change not be instead
> changing how we define S_IFXMIN_NEQ itself, and combining the two
> comments seen here (the latter only partially, in the context).
>
> Not that this makes things worse or anything...