delta/git.git/Documentation, branch ds/commit-graph

commit-graph: implement "--additive" option

2018-03-14T21:01:36+00:00

Teach git-commit-graph to add all commits from the existing
commit-graph file to the file about to be written. This should be
used when adding new commits without performing garbage collection.

Signed-off-by: Derrick Stolee 
Signed-off-by: Junio C Hamano

commit-graph: build graph from starting commits

2018-03-14T21:01:27+00:00

Teach git-commit-graph to read commits from stdin when the
--stdin-commits flag is specified. Commits reachable from these
commits are added to the graph. This is a much faster way to construct
the graph than inspecting all packed objects, but is restricted to
known tips.

For the Linux repository, 700,000+ commits were added to the graph
file starting from 'master' in 7-9 seconds, depending on the number
of packfiles in the repo (1, 24, or 120).

Signed-off-by: Derrick Stolee 
Signed-off-by: Junio C Hamano

commit-graph: read only from specific pack-indexes

2018-03-14T20:58:15+00:00

Teach git-commit-graph to inspect the objects only in a certain list
of pack-indexes within the given pack directory. This allows updating
the commit graph iteratively.

Signed-off-by: Derrick Stolee 
Signed-off-by: Junio C Hamano

commit-graph: add core.commitGraph setting

2018-03-14T20:58:14+00:00

The commit graph feature is controlled by the new core.commitGraph config
setting. This defaults to 0, so the feature is opt-in.

The intention of core.commitGraph is that a user can always stop checking
for or parsing commit graph files if core.commitGraph=0.

Signed-off-by: Derrick Stolee 
Signed-off-by: Junio C Hamano

commit-graph: implement git commit-graph read

2018-03-14T20:58:14+00:00

Teach git-commit-graph to read commit graph files and summarize their contents.

Use the read subcommand to verify the contents of a commit graph file in the
tests.

Signed-off-by: Derrick Stolee 
Signed-off-by: Junio C Hamano

commit-graph: implement 'git-commit-graph write'

2018-03-14T20:58:14+00:00

Teach git-commit-graph to write graph files. Create new test script to verify
this command succeeds without failure.

Signed-off-by: Derrick Stolee 
Signed-off-by: Junio C Hamano

commit-graph: create git-commit-graph builtin

2018-03-14T20:58:14+00:00

Teach git the 'commit-graph' builtin that will be used for writing and
reading packed graph files. The current implementation is mostly
empty, except for an '--object-dir' option.

Signed-off-by: Derrick Stolee 
Signed-off-by: Junio C Hamano

graph: add commit graph design document

2018-03-14T20:58:14+00:00

Add Documentation/technical/commit-graph.txt with details of the planned
commit graph feature, including future plans.

Signed-off-by: Derrick Stolee 
Signed-off-by: Junio C Hamano

commit-graph: add format document

2018-03-14T20:58:14+00:00

Add document specifying the binary format for commit graphs. This
format allows for:

* New versions.
* New hash functions and hash lengths.
* Optional extensions.

Basic header information is followed by a binary table of contents
into "chunks" that include:

* An ordered list of commit object IDs.
* A 256-entry fanout into that list of OIDs.
* A list of metadata for the commits.
* A list of "large edges" to enable octopus merges.

The format automatically includes two parent positions for every
commit. This favors speed over space, since using only one position
per commit would cause an extra level of indirection for every merge
commit. (Octopus merges suffer from this indirection, but they are
very rare.)

Signed-off-by: Derrick Stolee 
Signed-off-by: Junio C Hamano

Merge branch 'jk/cached-commit-buffer' into HEAD

2018-03-13T20:35:25+00:00

* jk/cached-commit-buffer:
  revision: drop --show-all option
  commit: drop uses of get_cached_commit_buffer()
  Git 2.16.2