8a6ac287b2
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>
129 lines
4.4 KiB
Plaintext
129 lines
4.4 KiB
Plaintext
git-commit-graph(1)
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===================
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NAME
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----
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git-commit-graph - Write and verify Git commit-graph files
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SYNOPSIS
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--------
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[verse]
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'git commit-graph verify' [--object-dir <dir>] [--shallow] [--[no-]progress]
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'git commit-graph write' <options> [--object-dir <dir>] [--[no-]progress]
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DESCRIPTION
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-----------
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Manage the serialized commit-graph file.
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OPTIONS
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-------
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--object-dir::
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Use given directory for the location of packfiles and commit-graph
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file. This parameter exists to specify the location of an alternate
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that only has the objects directory, not a full `.git` directory. The
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commit-graph file is expected to be in the `<dir>/info` directory and
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the packfiles are expected to be in `<dir>/pack`. If the directory
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could not be made into an absolute path, or does not match any known
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object directory, `git commit-graph ...` will exit with non-zero
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status.
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--[no-]progress::
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Turn progress on/off explicitly. If neither is specified, progress is
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shown if standard error is connected to a terminal.
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COMMANDS
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--------
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'write'::
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Write a commit-graph file based on the commits found in packfiles.
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+
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With the `--stdin-packs` option, generate the new commit graph by
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walking objects only in the specified pack-indexes. (Cannot be combined
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with `--stdin-commits` or `--reachable`.)
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+
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With the `--stdin-commits` option, generate the new commit graph by
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walking commits starting at the commits specified in stdin as a list
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of OIDs in hex, one OID per line. (Cannot be combined with
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`--stdin-packs` or `--reachable`.)
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+
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With the `--reachable` option, generate the new commit graph by walking
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commits starting at all refs. (Cannot be combined with `--stdin-commits`
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or `--stdin-packs`.)
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+
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With the `--append` option, include all commits that are present in the
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existing commit-graph file.
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+
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With the `--split[=<strategy>]` option, write the commit-graph as a
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chain of multiple commit-graph files stored in
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`<dir>/info/commit-graphs`. Commit-graph layers are merged based on the
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strategy and other splitting options. The new commits not already in the
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commit-graph are added in a new "tip" file. This file is merged with the
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existing file if the following merge conditions are met:
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* If `--split=no-merge` is specified, a merge is never performed, and
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the remaining options are ignored. `--split=replace` overwrites the
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existing chain with a new one. A bare `--split` defers to the remaining
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options. (Note that merging a chain of commit graphs replaces the
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existing chain with a length-1 chain where the first and only
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incremental holds the entire graph).
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+
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* If `--size-multiple=<X>` is not specified, let `X` equal 2. If the new
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tip file would have `N` commits and the previous tip has `M` commits and
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`X` times `N` is greater than `M`, instead merge the two files into a
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single file.
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+
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* If `--max-commits=<M>` is specified with `M` a positive integer, and the
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new tip file would have more than `M` commits, then instead merge the new
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tip with the previous tip.
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+
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Finally, if `--expire-time=<datetime>` is not specified, let `datetime`
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be the current time. After writing the split commit-graph, delete all
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unused commit-graph whose modified times are older than `datetime`.
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'verify'::
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Read the commit-graph file and verify its contents against the object
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database. Used to check for corrupted data.
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+
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With the `--shallow` option, only check the tip commit-graph file in
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a chain of split commit-graphs.
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EXAMPLES
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--------
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* Write a commit-graph file for the packed commits in your local `.git`
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directory.
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+
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------------------------------------------------
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$ git commit-graph write
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------------------------------------------------
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* Write a commit-graph file, extending the current commit-graph file
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using commits in `<pack-index>`.
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+
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------------------------------------------------
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$ echo <pack-index> | git commit-graph write --stdin-packs
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------------------------------------------------
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* Write a commit-graph file containing all reachable commits.
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+
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------------------------------------------------
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$ git show-ref -s | git commit-graph write --stdin-commits
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------------------------------------------------
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* Write a commit-graph file containing all commits in the current
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commit-graph file along with those reachable from `HEAD`.
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+
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------------------------------------------------
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$ git rev-parse HEAD | git commit-graph write --stdin-commits --append
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------------------------------------------------
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GIT
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---
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Part of the linkgit:git[1] suite
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