[PATCH v3 1/4] gitformat-commit-graph: describe version 2 of BDAT

From

JTJonathan Tan <jonathantanmy@google.com>

Date

Jun 8, 2023, 19:21 UTC

Message-ID

<d4b63945f6d52e68a4760393f787acde0fccc312.1686251688.git.jonathantanmy@google.com>

In-Reply-To

<cover.1686251688.git.jonathantanmy@google.com>

Signed-off-by: Jonathan Tan <jonathantanmy@google.com>
---
 Documentation/gitformat-commit-graph.txt | 9 ++++++---
 1 file changed, 6 insertions(+), 3 deletions(-)

diff --git a/Documentation/gitformat-commit-graph.txt b/Documentation/gitformat-commit-graph.txt
index 31cad585e2..9dab222830 100644
--- a/Documentation/gitformat-commit-graph.txt
+++ b/Documentation/gitformat-commit-graph.txt
@@ -142,13 +142,16 @@ All multi-byte numbers are in network byte order.
 
 ==== Bloom Filter Data (ID: {'B', 'D', 'A', 'T'}) [Optional]
     * It starts with header consisting of three unsigned 32-bit integers:
-      - Version of the hash algorithm being used. We currently only support
-	value 1 which corresponds to the 32-bit version of the murmur3 hash
+      - Version of the hash algorithm being used. We currently support
+	value 2 which corresponds to the 32-bit version of the murmur3 hash
 	implemented exactly as described in
 	https://en.wikipedia.org/wiki/MurmurHash#Algorithm and the double
 	hashing technique using seed values 0x293ae76f and 0x7e646e2 as
 	described in https://doi.org/10.1007/978-3-540-30494-4_26 "Bloom Filters
-	in Probabilistic Verification"
+	in Probabilistic Verification". Version 1 bloom filters have a bug that appears
+	when int is signed and the repository has path names that have characters >=
+	0x80; Git supports reading and writing them, but this ability will be removed
+	in a future version of Git.
       - The number of times a path is hashed and hence the number of bit positions
 	      that cumulatively determine whether a file is present in the commit.
       - The minimum number of bits 'b' per entry in the Bloom filter. If the filter

-- 
2.41.0.162.gfafddb0af9-goog