odb: allow odb_find_source() to fail

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 protected]>
Signed-off-by: Junio C Hamano <[email protected]>

Author: pks-t

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);
 	graph_name = get_commit_graph_filename(source);
 	chain_name = get_commit_graph_chain_filename(source);
 	if (open_commit_graph(graph_name, &fd, &st))
@@ -290,6 +292,8 @@ static int graph_write(int argc, const char **argv, const char *prefix,
 		flags |= COMMIT_GRAPH_WRITE_BLOOM_FILTERS;
 
 	source = odb_find_source(the_repository->objects, opts.obj_dir);
+	if (!source)
+		die(_("could not find object directory matching %s"), opts.obj_dir);
 
 	if (opts.reachable) {
 		if (write_commit_graph_reachable(source, flags, &write_opts))

midx-write.c

@@ -917,6 +917,8 @@ static struct multi_pack_index *lookup_multi_pack_index(struct repository *r,
 							const char *object_dir)
 {
 	struct odb_source *source = odb_find_source(r->objects, object_dir);
+	if (!source)
+		die(_("could not find object directory matching %s"), object_dir);
 	return get_multi_pack_index(source);
 }
 

odb.c

@@ -464,8 +464,6 @@ struct odb_source *odb_find_source(struct object_database *odb, const char *obj_
 	free(obj_dir_real);
 	strbuf_release(&odb_path_real);
 
-	if (!source)
-		die(_("could not find object directory matching %s"), obj_dir);
 	return source;
 }
 

odb.h

@@ -186,8 +186,8 @@ struct object_database *odb_new(struct repository *repo);
 void odb_clear(struct object_database *o);
 
 /*
- * Find source by its object directory path. Dies in case the source couldn't
- * be found.
+ * Find source by its object directory path. Returns a `NULL` pointer in case
+ * the source could not be found.
  */
 struct odb_source *odb_find_source(struct object_database *odb, const char *obj_dir);