sparse-index API: BUG() out on NULL ensure_full_index()

Make the ensure_full_index() function stricter, and have it only
accept a non-NULL "struct index_state". This function (and this
behavior) was added in [1].

The only reason it needed to be this lax was due to interaction with
repo_index_has_changes(). See the addition of that code in [2].

The other reason for why this was needed dates back to interaction
with code added in [3]. In [4] we started calling ensure_full_index()
in unpack_trees(), but the caller added in 34110cd4e39 wants to pass
us a NULL "dst_index". Let's instead do the NULL check in
unpack_trees() itself.

1. 4300f8442a2 (sparse-index: implement ensure_full_index(), 2021-03-30)
2. 0c18c059a15 (read-cache: ensure full index, 2021-04-01)
3. 34110cd4e39 (Make 'unpack_trees()' have a separate source and
   destination index, 2008-03-06)
4. 6863df35503 (unpack-trees: ensure full index, 2021-03-30)

Signed-off-by: Ævar Arnfjörð Bjarmason <avarab@gmail.com>
Acked-by: Derrick Stolee <derrickstolee@github.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

diff --git a/sparse-index.c b/sparse-index.c
index 65a08d33c73e84428db386fa92641f59cda0b02f..86e3b99870bd79bdd9c36ed5d2d1ba7ad49f1154 100644 (file)
--- a/sparse-index.c
+++ b/sparse-index.c
@@ -299,7 +299,7 @@ void expand_index(struct index_state *istate, struct pattern_list *pl)
         * If the index is already full, then keep it full. We will convert
         * it to a sparse index on write, if possible.
         */
-       if (!istate || istate->sparse_index == INDEX_EXPANDED)
+       if (istate->sparse_index == INDEX_EXPANDED)
                return;
 
        /*
@@ -424,6 +424,8 @@ void expand_index(struct index_state *istate, struct pattern_list *pl)
 
 void ensure_full_index(struct index_state *istate)
 {
+       if (!istate)
+               BUG("ensure_full_index() must get an index!");
        expand_index(istate, NULL);
 }
 

diff --git a/unpack-trees.c b/unpack-trees.c
index ea09023b0158e6945e8750f435ce7addd2b2bda2..2381cd7cac4b0f9b3595ab03bc2bdef55d01126b 100644 (file)
--- a/unpack-trees.c
+++ b/unpack-trees.c
@@ -1880,7 +1880,8 @@ int unpack_trees(unsigned len, struct tree_desc *t, struct unpack_trees_options
        prepare_repo_settings(repo);
        if (repo->settings.command_requires_full_index) {
                ensure_full_index(o->src_index);
-               ensure_full_index(o->dst_index);
+               if (o->dst_index)
+                       ensure_full_index(o->dst_index);
        }
 
        if (o->reset == UNPACK_RESET_OVERWRITE_UNTRACKED &&