Subject: [PATCH v3] name-hash: don't add sparse directories in threaded lazy init

From: "Alex Mironov via GitGitGadget" <[email-masked]>
Date: Wed, 21 May 2025 21:29:31 +0000

From: Alex Mironov <[email-masked]>

Ensure that logic added in 5f11669586 (name-hash: don't add directories
to name_hash, 2021-04-12) also applies in multithreaded hashtable init
path.

As per the original single-threaded change above: sparse directory entries
represent a directory that is outside the sparse-checkout definition.
These are not paths to blobs, so should not be added to the name_hash
table. Instead, they should be added to the directory hashtable when
'ignore_case' is true.

Add a condition to avoid placing sparse directories into the name_hash
hashtable. This avoids filling the table with extra entries that will
never be queried.

Signed-off-by: Alex Mironov <[email-masked]>
---
    name-hash: don't add sparse directories in threaded lazy init
    
    Changes since v2:
    
     * addressed commit message structure

Published-As: https://github.com/gitgitgadget/git/releases/tag/pr-git-1970%2Falexandrfox%2Ffix-threaded-hash-name-v3
Fetch-It-Via: git fetch https://github.com/gitgitgadget/git pr-git-1970/alexandrfox/fix-threaded-hash-name-v3
Pull-Request: https://github.com/git/git/pull/1970

Range-diff vs v2:

 1:  fb378147c73 ! 1:  b91ccb640c5 name-hash: don't add sparse directories in threaded lazy init
     @@ Commit message
          to name_hash, 2021-04-12) also applies in multithreaded hashtable init
          path.
      
     -    Sparse directory entries represent a directory that is outside the
     -    sparse-checkout definition. These are not paths to blobs, so should not
     -    be added to the name_hash table as they must never be queried.
     +    As per the original single-threaded change above: sparse directory entries
     +    represent a directory that is outside the sparse-checkout definition.
     +    These are not paths to blobs, so should not be added to the name_hash
     +    table. Instead, they should be added to the directory hashtable when
     +    'ignore_case' is true.
     +
     +    Add a condition to avoid placing sparse directories into the name_hash
     +    hashtable. This avoids filling the table with extra entries that will
     +    never be queried.
      
          Signed-off-by: Alex Mironov <[email-masked]>

 name-hash.c | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/name-hash.c b/name-hash.c
index d66de1cdfd5..b91e2762678 100644
--- a/name-hash.c
+++ b/name-hash.c
@@ -492,8 +492,10 @@ static void *lazy_name_thread_proc(void *_data)
 	for (k = 0; k < d->istate->cache_nr; k++) {
 		struct cache_entry *ce_k = d->istate->cache[k];
 		ce_k->ce_flags |= CE_HASHED;
-		hashmap_entry_init(&ce_k->ent, d->lazy_entries[k].hash_name);
-		hashmap_add(&d->istate->name_hash, &ce_k->ent);
+		if (!S_ISSPARSEDIR(ce_k->ce_mode)) {
+			hashmap_entry_init(&ce_k->ent, d->lazy_entries[k].hash_name);
+			hashmap_add(&d->istate->name_hash, &ce_k->ent);
+		}
 	}
 
 	return NULL;

base-commit: 8613c2bb6cd16ef530dc5dd74d3b818a1ccbf1c0
-- 
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