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[PATCH v2 1/4] odb: use size_t for the length of objects to write

From
Elia Pinto <gitter.spiros@gmail.com>
Date
Oct 30, 2026, 09:58 UTC
Message-ID
<8fcb9f10f13962acd5cdac652bea8fc4164f2e78.1793352943.git.gitter.spiros@gmail.com>
In-Reply-To
<cover.1793352943.git.gitter.spiros@gmail.com>

c6a4629e32 (odb: use size_t for object_info.sizep and the size APIs, 2026-06-15) widened the read side of the object database API, and the write_object() callback of odb_source already takes a size_t. But odb_write_object_ext(), odb_write_object() and odb_source_write_object() in front of it, as well as write_loose_object() behind it, still take an "unsigned long", which is only 32 bits wide on Windows.

Most callers hand them a size_t from a strbuf or from odb_read_object(), which silently gets truncated. The most visible case is index_mem() and index_stream_convert_blob(): when "git add" or "git hash-object -w" runs a file over 4GiB through a conversion (core.autocrlf, which is on by default in Git for Windows, an eol or ident attribute, or a clean filter), we write a blob made of the first "size mod 2^32" bytes. The index records it with the stat data of the real file, so "git status" stays clean and nobody notices until the file is checked out again. "git hash-object" without "-w" uses hash_object_file(), which takes a size_t, so the two disagree on the object ID of the same file.

Use size_t throughout, including for the size kept by the in-memory source.

The existing "hash filtered files over 4GB correctly" test in t1007 only hashes, so add a variant that writes the object with "git hash-object -w" and checks both its object ID and its size. Like the other tests over 4GB, it needs EXPENSIVE and SIZE_T_IS_64BIT. Truncating the length to 32 bits in odb_write_object_ext(), as happens on Windows without this patch, makes it fail with a different object ID.

Signed-off-by: Elia Pinto <gitter.spiros@gmail.com>
---
 odb.c                  |  2 +-
 odb.h                  |  4 ++--
 odb/source-inmemory.c  |  2 +-
 odb/source-loose.c     |  2 +-
 odb/source.h           |  2 +-
 t/t1007-hash-object.sh | 13 +++++++++++++
 6 files changed, 19 insertions(+), 6 deletions(-)
diff --git a/odb.c b/odb.c
index 2c93a9490c..1f173625b7 100644
--- a/odb.c
+++ b/odb.c
@@ -640,7 +640,7 @@ void odb_assert_oid_type(struct object_database *odb,
 }
 
 int odb_write_object_ext(struct object_database *odb,
-			 const void *buf, unsigned long len,
+			 const void *buf, size_t len,
 			 enum object_type type,
 			 struct object_id *oid,
 			 const struct object_id *compat_oid_in,
diff --git a/odb.h b/odb.h
index dd85b880a7..45182d28cb 100644
--- a/odb.h
+++ b/odb.h
@@ -621,14 +621,14 @@ enum odb_write_object_flags {
  * Returns 0 on success, a negative error code otherwise.
  */
 int odb_write_object_ext(struct object_database *odb,
-			 const void *buf, unsigned long len,
+			 const void *buf, size_t len,
 			 enum object_type type,
 			 struct object_id *oid,
 			 const struct object_id *compat_oid,
 			 enum odb_write_object_flags flags);
 
 static inline int odb_write_object(struct object_database *odb,
-				   const void *buf, unsigned long len,
+				   const void *buf, size_t len,
 				   enum object_type type,
 				   struct object_id *oid)
 {
diff --git a/odb/source-inmemory.c b/odb/source-inmemory.c
index 75cf29fa9d..c13cffc805 100644
--- a/odb/source-inmemory.c
+++ b/odb/source-inmemory.c
@@ -10,7 +10,7 @@
 struct inmemory_object {
 	enum object_type type;
 	const void *buf;
-	unsigned long size;
+	size_t size;
 };
 
 static const struct inmemory_object *find_cached_object(struct odb_source_inmemory *source,
diff --git a/odb/source-loose.c b/odb/source-loose.c
index 50cb388c35..60801e70e8 100644
--- a/odb/source-loose.c
+++ b/odb/source-loose.c
@@ -758,7 +758,7 @@ static int end_loose_object_common(struct odb_source_loose *loose,
 
 static int write_loose_object(struct odb_source_loose *loose,
 			      const struct object_id *oid, char *hdr,
-			      int hdrlen, const void *buf, unsigned long len,
+			      int hdrlen, const void *buf, size_t len,
 			      const time_t *mtime, unsigned flags)
 {
 	int fd, ret;
diff --git a/odb/source.h b/odb/source.h
index 8b839caa39..07d5019aa5 100644
--- a/odb/source.h
+++ b/odb/source.h
@@ -451,7 +451,7 @@ static inline int odb_source_freshen_object(struct odb_source *source,
  * object ID and the compatibility object ID, if non-NULL.
  */
 static inline int odb_source_write_object(struct odb_source *source,
-					  const void *buf, unsigned long len,
+					  const void *buf, size_t len,
 					  enum object_type type,
 					  const struct object_id *oid,
 					  const struct object_id *compat_oid,
diff --git a/t/t1007-hash-object.sh b/t/t1007-hash-object.sh
index 463b38f990..0a89bbb455 100755
--- a/t/t1007-hash-object.sh
+++ b/t/t1007-hash-object.sh
@@ -297,4 +297,17 @@ test_expect_success EXPENSIVE,SIZE_T_IS_64BIT \
 	test_cmp expect actual
 '
 
+test_expect_success EXPENSIVE,SIZE_T_IS_64BIT \
+		'write filtered files over 4GB correctly' '
+	{ test -f big || test-tool genzeros $((5*1024*1024*1024)) >big; } &&
+	test_oid large5GB >expect &&
+	test_config filter.null-filter.clean "cat" &&
+	echo "big filter=null-filter" >.gitattributes &&
+	git hash-object -w -- big >actual &&
+	test_cmp expect actual &&
+	echo $((5*1024*1024*1024)) >expect &&
+	git cat-file -s $(cat actual) >actual &&
+	test_cmp expect actual
+'
+
 test_done
-- 
2.53.0
Previous: Elia PintoNext: Patrick Steinhardt
Message 9 of 21 in “use size_t for a few more object and buffer sizes”
  1. 0/3 use size_t for a few more object and buffer sizesElia Pinto, Oct 21, 2026
  2. 1/3 odb: use size_t for the length of objects to writeElia Pinto, Oct 21, 2026
  3. Patrick SteinhardtOct 21, 2026
  4. 2/3 diff: use size_t for the allocation size of word-diff buffersElia Pinto, Oct 21, 2026
  5. Patrick SteinhardtOct 21, 2026
  6. 3/3 convert: use size_t for buffer sizesElia Pinto, Oct 21, 2026
  7. Patrick SteinhardtOct 21, 2026
  8. 0/4 use size_t for a few more object and buffer sizesElia Pinto, Oct 30, 2026
  9. 1/4 odb: use size_t for the length of objects to writeElia Pinto, Oct 30, 2026
  10. Patrick SteinhardtOct 30, 2026
  11. Elia PintoOct 31, 2026
  12. 2/4 diff: use size_t for the allocation size of word-diff buffersElia Pinto, Oct 30, 2026
  13. 3/4 convert: use size_t for buffer sizesElia Pinto, Oct 30, 2026
  14. 4/4 convert: use size_t for text statistics and ident countsElia Pinto, Oct 30, 2026
  15. Patrick SteinhardtOct 30, 2026
  16. Elia PintoOct 31, 2026
  17. 0/4 use size_t for a few more object and buffer sizesElia Pinto, Oct 31, 2026
  18. 1/4 odb: use size_t for the length of objects to writeElia Pinto, Oct 31, 2026
  19. 2/4 diff: use size_t for the allocation size of word-diff buffersElia Pinto, Oct 31, 2026
  20. 3/4 convert: use size_t for buffer sizesElia Pinto, Oct 31, 2026
  21. 4/4 convert: use size_t for text statistics and ident countsElia Pinto, Oct 31, 2026

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