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-rw-r--r--Documentation/technical/commit-graph-format.txt12
-rw-r--r--Documentation/technical/reftable.txt2
2 files changed, 11 insertions, 3 deletions
diff --git a/Documentation/technical/commit-graph-format.txt b/Documentation/technical/commit-graph-format.txt
index 87971c27dd..484b185ba9 100644
--- a/Documentation/technical/commit-graph-format.txt
+++ b/Documentation/technical/commit-graph-format.txt
@@ -93,7 +93,7 @@ CHUNK DATA:
2 bits of the lowest byte, storing the 33rd and 34th bit of the
commit time.
- Generation Data (ID: {'G', 'D', 'A', 'T' }) (N * 4 bytes) [Optional]
+ Generation Data (ID: {'G', 'D', 'A', '2' }) (N * 4 bytes) [Optional]
* This list of 4-byte values store corrected commit date offsets for the
commits, arranged in the same order as commit data chunk.
* If the corrected commit date offset cannot be stored within 31 bits,
@@ -104,7 +104,7 @@ CHUNK DATA:
by compatible versions of Git and in case of split commit-graph chains,
the topmost layer also has Generation Data chunk.
- Generation Data Overflow (ID: {'G', 'D', 'O', 'V' }) [Optional]
+ Generation Data Overflow (ID: {'G', 'D', 'O', '2' }) [Optional]
* This list of 8-byte values stores the corrected commit date offsets
for commits with corrected commit date offsets that cannot be
stored within 31 bits.
@@ -156,3 +156,11 @@ CHUNK DATA:
TRAILER:
H-byte HASH-checksum of all of the above.
+
+== Historical Notes:
+
+The Generation Data (GDA2) and Generation Data Overflow (GDO2) chunks have
+the number '2' in their chunk IDs because a previous version of Git wrote
+possibly erroneous data in these chunks with the IDs "GDAT" and "GDOV". By
+changing the IDs, newer versions of Git will silently ignore those older
+chunks and write the new information without trusting the incorrect data.
diff --git a/Documentation/technical/reftable.txt b/Documentation/technical/reftable.txt
index d7c3b645cf..6a67cc4174 100644
--- a/Documentation/technical/reftable.txt
+++ b/Documentation/technical/reftable.txt
@@ -443,7 +443,7 @@ Obj block format
Object blocks are optional. Writers may choose to omit object blocks,
especially if readers will not use the object name to ref mapping.
-Object blocks use unique, abbreviated 2-32 object name keys, mapping to
+Object blocks use unique, abbreviated 2-31 byte object name keys, mapping to
ref blocks containing references pointing to that object directly, or as
the peeled value of an annotated tag. Like ref blocks, object blocks use
the file's standard block size. The abbreviation length is available in