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| author | Junio C Hamano <gitster@pobox.com> | 2022-03-16 17:53:09 -0700 |
|---|---|---|
| committer | Junio C Hamano <gitster@pobox.com> | 2022-03-16 17:53:09 -0700 |
| commit | a54cc523ad7736cb5768dc10c1873260738cb4a4 (patch) | |
| tree | 403f86970bc2f0207a7350008a2cda25face40d6 /Documentation/technical | |
| parent | a2fc9c3c404f2ef6384281e3a0fe824a8b0049bb (diff) | |
| parent | 6dbf4b8172ef9edd50bdf9ca2da4681ba9153f75 (diff) | |
| download | git-a54cc523ad7736cb5768dc10c1873260738cb4a4.tar.gz | |
Merge branch 'ds/commit-graph-gen-v2-fixes'
Fixes to the way generation number v2 in the commit-graph files are
(not) handled.
* ds/commit-graph-gen-v2-fixes:
commit-graph: declare bankruptcy on GDAT chunks
commit-graph: fix generation number v2 overflow values
commit-graph: start parsing generation v2 (again)
commit-graph: fix ordering bug in generation numbers
t5318: extract helpers to lib-commit-graph.sh
test-read-graph: include extra post-parse info
Diffstat (limited to 'Documentation/technical')
| -rw-r--r-- | Documentation/technical/commit-graph-format.txt | 12 |
1 files changed, 10 insertions, 2 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. |