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author | Taylor Blau <me@ttaylorr.com> | 2020-04-14 04:04:17 (GMT) |
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committer | Junio C Hamano <gitster@pobox.com> | 2020-04-15 16:20:28 (GMT) |
commit | 8a6ac287b2ba5f75bb2d9409dd97e9b501daf253 (patch) | |
tree | ed0fc9f67c9d9369cd12530cf885da21128d797d /commit-graph.h | |
parent | fdbde82fe523374b3c5d1f0f01f3c43dcaca9465 (diff) | |
download | git-8a6ac287b2ba5f75bb2d9409dd97e9b501daf253.zip git-8a6ac287b2ba5f75bb2d9409dd97e9b501daf253.tar.gz git-8a6ac287b2ba5f75bb2d9409dd97e9b501daf253.tar.bz2 |
builtin/commit-graph.c: introduce split strategy 'replace'
When using split commit-graphs, it is sometimes useful to completely
replace the commit-graph chain with a new base.
For example, consider a scenario in which a repository builds a new
commit-graph incremental for each push. Occasionally (say, after some
fixed number of pushes), they may wish to rebuild the commit-graph chain
with all reachable commits.
They can do so with
$ git commit-graph write --reachable
but this removes the chain entirely and replaces it with a single
commit-graph in 'objects/info/commit-graph'. Unfortunately, this means
that the next push will have to move this commit-graph into the first
layer of a new chain, and then write its new commits on top.
Avoid such copying entirely by allowing the caller to specify that they
wish to replace the entirety of their commit-graph chain, while also
specifying that the new commit-graph should become the basis of a fresh,
length-one chain.
This addresses the above situation by making it possible for the caller
to instead write:
$ git commit-graph write --reachable --split=replace
which writes a new length-one chain to 'objects/info/commit-graphs',
making the commit-graph incremental generated by the subsequent push
relatively cheap by avoiding the aforementioned copy.
In order to do this, remove an assumption in 'write_commit_graph_file'
that chains are always at least two incrementals long.
Signed-off-by: Taylor Blau <me@ttaylorr.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Diffstat (limited to 'commit-graph.h')
-rw-r--r-- | commit-graph.h | 3 |
1 files changed, 2 insertions, 1 deletions
diff --git a/commit-graph.h b/commit-graph.h index 8752afb..718433d 100644 --- a/commit-graph.h +++ b/commit-graph.h @@ -84,7 +84,8 @@ enum commit_graph_write_flags { enum commit_graph_split_flags { COMMIT_GRAPH_SPLIT_UNSPECIFIED = 0, - COMMIT_GRAPH_SPLIT_MERGE_PROHIBITED = 1 + COMMIT_GRAPH_SPLIT_MERGE_PROHIBITED = 1, + COMMIT_GRAPH_SPLIT_REPLACE = 2 }; struct split_commit_graph_opts { |