[PATCH v9 06/16] unpack-trees: preserve cache_bottom

From: Derrick Stolee via GitGitGadget <gitgitgadget@gmail.com>
Date: Jul 14, 2021, 13:12 UTC
Message-ID: <18cb1f6ea9b145e7ab664c1f9de5886ffba732a2.1626268360.git.gitgitgadget@gmail.com>
In-Reply-To: <pull.932.v9.git.1626268360.gitgitgadget@gmail.com>

From: Derrick Stolee <dstolee@microsoft.com>

The cache_bottom member of 'struct unpack_trees_options' is used to track the range of index entries corresponding to a node of the cache tree. While recursing with traverse_by_cache_tree(), this value is preserved on the call stack using a local and then restored as that method returns.

The mark_ce_used() method normally modifies the cache_bottom member when it refers to the marked cache entry. However, sparse directory entries are stored as nodes in the cache-tree data structure as of 2de37c53 (cache-tree: integrate with sparse directory entries, 2021-03-30). Thus, the cache_bottom will be modified as the cache-tree walk advances. Do not update it as well within mark_ce_used().

Reviewed-by: Elijah Newren <newren@gmail.com>
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 f88a69f8e71..87c1ed204c8 100644
--- a/unpack-trees.c
+++ b/unpack-trees.c
@@ -600,6 +600,13 @@ static void mark_ce_used(struct cache_entry *ce, struct unpack_trees_options *o)
 {
 	ce->ce_flags |= CE_UNPACKED;
 
+	/*
+	 * If this is a sparse directory, don't advance cache_bottom.
+	 * That will be advanced later using the cache-tree data.
+	 */
+	if (S_ISSPARSEDIR(ce->ce_mode))
+		return;
+
 	if (o->cache_bottom < o->src_index->cache_nr &&
 	    o->src_index->cache[o->cache_bottom] == ce) {
 		int bottom = o->cache_bottom;

-- 
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