[PATCH 07/27] unpack-trees: ensure full index

From: Derrick Stolee via GitGitGadget <gitgitgadget@gmail.com>
Date: Jan 25, 2021, 17:41 UTC
Message-ID: <175c3c62543f89144b03b3bdff750ad29d17ba03.1611596534.git.gitgitgadget@gmail.com>
In-Reply-To: <pull.847.git.1611596533.gitgitgadget@gmail.com>

From: Derrick Stolee <dstolee@microsoft.com>

The next change will translate full indexes into sparse indexes at write time. The existing logic provides a way for every sparse index to be expanded to a full index at read time. However, there are cases where an index is written and then continues to be used in-memory to perform further updates.

unpack_trees() is frequently called after such a write. In particular, commands like 'git reset' do this double-update of the index.

Ensure that we have a full index when entering unpack_trees(), but only when command_requires_full_index is true. This is always true at the moment, but we will later relax that after unpack_trees() is updated to handle sparse directory entries.

Signed-off-by: Derrick Stolee <dstolee@microsoft.com>
---
 unpack-trees.c | 7 +++++++
 1 file changed, 7 insertions(+)

diff --git a/unpack-trees.c b/unpack-trees.c
index f5f668f532d..4dd99219073 100644
--- a/unpack-trees.c
+++ b/unpack-trees.c
@@ -1567,6 +1567,7 @@ static int verify_absent(const struct cache_entry *,
  */
 int unpack_trees(unsigned len, struct tree_desc *t, struct unpack_trees_options *o)
 {
+	struct repository *repo = the_repository;
 	int i, ret;
 	static struct cache_entry *dfc;
 	struct pattern_list pl;
@@ -1578,6 +1579,12 @@ int unpack_trees(unsigned len, struct tree_desc *t, struct unpack_trees_options
 	trace_performance_enter();
 	trace2_region_enter("unpack_trees", "unpack_trees", the_repository);
 
+	prepare_repo_settings(repo);
+	if (repo->settings.command_requires_full_index) {
+		ensure_full_index(o->src_index);
+		ensure_full_index(o->dst_index);
+	}
+
 	if (!core_apply_sparse_checkout || !o->update)
 		o->skip_sparse_checkout = 1;
 	if (!o->skip_sparse_checkout && !o->pl) {

-- 
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