diff options
| author | Junio C Hamano <gitster@pobox.com> | 2018-10-16 16:15:59 +0900 |
|---|---|---|
| committer | Junio C Hamano <gitster@pobox.com> | 2018-10-16 16:15:59 +0900 |
| commit | 6d8f8ebb74d21b51cfbf427a436094134af36ee2 (patch) | |
| tree | 0b50647db06413e2f43487b2bfca167105b7f701 /Documentation | |
| parent | 36d767d02e12c1ff991511b7bd8c1d023340f2ca (diff) | |
| parent | 829a321569d8e8f2c582aef9f0c990df976ab842 (diff) | |
| download | git-6d8f8ebb74d21b51cfbf427a436094134af36ee2.tar.gz | |
Merge branch 'ds/commit-graph-with-grafts'
The recently introduced commit-graph auxiliary data is incompatible
with mechanisms such as replace & grafts that "breaks" immutable
nature of the object reference relationship. Disable optimizations
based on its use (and updating existing commit-graph) when these
incompatible features are in use in the repository.
* ds/commit-graph-with-grafts:
commit-graph: close_commit_graph before shallow walk
commit-graph: not compatible with uninitialized repo
commit-graph: not compatible with grafts
commit-graph: not compatible with replace objects
test-repository: properly init repo
commit-graph: update design document
refs.c: upgrade for_each_replace_ref to be a each_repo_ref_fn callback
refs.c: migrate internal ref iteration to pass thru repository argument
Diffstat (limited to 'Documentation')
| -rw-r--r-- | Documentation/technical/commit-graph.txt | 18 |
1 files changed, 15 insertions, 3 deletions
diff --git a/Documentation/technical/commit-graph.txt b/Documentation/technical/commit-graph.txt index c664acbd76..001395e950 100644 --- a/Documentation/technical/commit-graph.txt +++ b/Documentation/technical/commit-graph.txt @@ -112,12 +112,24 @@ Design Details - The file format includes parameters for the object ID hash function, so a future change of hash algorithm does not require a change in format. +- Commit grafts and replace objects can change the shape of the commit + history. The latter can also be enabled/disabled on the fly using + `--no-replace-objects`. This leads to difficultly storing both possible + interpretations of a commit id, especially when computing generation + numbers. The commit-graph will not be read or written when + replace-objects or grafts are present. + +- Shallow clones create grafts of commits by dropping their parents. This + leads the commit-graph to think those commits have generation number 1. + If and when those commits are made unshallow, those generation numbers + become invalid. Since shallow clones are intended to restrict the commit + history to a very small set of commits, the commit-graph feature is less + helpful for these clones, anyway. The commit-graph will not be read or + written when shallow commits are present. + Future Work ----------- -- The commit graph feature currently does not honor commit grafts. This can - be remedied by duplicating or refactoring the current graft logic. - - After computing and storing generation numbers, we must make graph walks aware of generation numbers to gain the performance benefits they enable. This will mostly be accomplished by swapping a commit-date-ordered |