Re: [PATCH 3/8] odb: return newly created in-memory sources

[Patrick Steinhardt <ps@pks.im>]

On Wed, Aug 06, 2025 at 06:40:23PM +0200, Toon Claes wrote:
> Patrick Steinhardt <ps@pks.im> writes:
> > diff --git a/odb.c b/odb.c
> > index 61104b7cb8..7793816f81 100644
> > --- a/odb.c
> > +++ b/odb.c
> > @@ -316,17 +315,23 @@ void odb_add_to_alternates_file(struct object_database *odb,
> >  	free(alts);
> >  }
> >  
> > -void odb_add_to_alternates_memory(struct object_database *odb,
> > -				  const char *reference)
> > +struct odb_source *odb_add_to_alternates_memory(struct object_database *odb,
> > +						const char *reference)
> >  {
> > +	struct odb_source *alternate;
> > +	char *objdir;
> > +
> >  	/*
> >  	 * Make sure alternates are initialized, or else our entry may be
> >  	 * overwritten when they are.
> >  	 */
> >  	odb_prepare_alternates(odb);
> >  
> > -	link_alt_odb_entries(odb, reference,
> > -			     '\n', NULL, 0);
> > +	objdir = real_pathdup(odb->sources->path, 1);
> > +	alternate = link_alt_odb_entry(odb, reference, NULL, 0, objdir);
> 
> If I understand correctly, instead of using real_pathdup() we could
> instead call:
> 
>     alternate = link_alt_odb_entry(odb, reference, "/", 0, odb->sources->path);
> 
> I did not test this, but it would avoid duplicating the path here. I'm
> not sure though whether it's easier to read.

We can't quite, as the call to `alt_odb_usable()` needs the normalized
object directory path so that it can figure out whether its local object
directory is the same as the proposed new object directory.

But what I noticed is that we're passing in redundant information: the
path is already stored in `struct object_database`, and all callers of
`link_alt_odb_entry()` pass both that ODB and its path. So we can drop
the parameter and make it an internal implementation detail.

Patrick