Subject: Re: [PATCH v2 2/9] odb: allow `odb_find_source()` to fail

From: Patrick Steinhardt <[email-masked]>
Date: Mon, 11 Aug 2025 13:56:29 +0200

On Thu, Aug 07, 2025 at 06:12:59PM -0400, Taylor Blau wrote:
> On Thu, Aug 07, 2025 at 10:09:52AM +0200, Patrick Steinhardt wrote:
> > When trying to locate a source for an unknown object directory we will
> > die right away. In subsequent patches we will add new callsites though
> > that want to handle this situation gracefully instead.
> >
> > Refactor the function to return a `NULL` pointer if the source could not
> > be found and adapt the callsites to die instead.
> >
> > Signed-off-by: Patrick Steinhardt <[email-masked]>
> > ---
> >  builtin/commit-graph.c | 4 ++++
> >  midx-write.c           | 2 ++
> >  odb.c                  | 2 --
> >  odb.h                  | 4 ++--
> >  4 files changed, 8 insertions(+), 4 deletions(-)
> >
> > diff --git a/builtin/commit-graph.c b/builtin/commit-graph.c
> > index 25018a0b9d..dc2c1a5432 100644
> > --- a/builtin/commit-graph.c
> > +++ b/builtin/commit-graph.c
> > @@ -102,6 +102,8 @@ static int graph_verify(int argc, const char **argv, const char *prefix,
> >  		flags |= COMMIT_GRAPH_WRITE_PROGRESS;
> >
> >  	source = odb_find_source(the_repository->objects, opts.obj_dir);
> > +	if (!source)
> > +		die(_("could not find object directory matching %s"), opts.obj_dir);
> 
> Makes sense, and I am glad that we are trending towards having fewer
> internal functions that assume the caller wants to die() on failure. I
> wonder if it might be worth having a odb_find_source_or_die()
> counterpart here such that callers don't have to repeat the "could not
> find object directory ..." message.
> 
> Perhaps something like:
> 
>     struct odb_source *odb_find_source_or_die(struct object_database *odb,
>                                               const char *obj_dir)
>     {
>         struct odb_source *source = odb_find_source(odb, obj_dir);
>         if (!source)
>             die(_("could not find object directory matching %s"),
>                 obj_dir);
>         return source;
>     }
> 
> ?
> 
> Of course, callers that want to use a different message or otherwise
> handle a missing source differently would still be able to do so by
> calling odb_find_source() directly.

Fair, that'd allow us to get rid of the repeated calls to `die()`. Will
do, thanks!

Patrick