The “git commit-graph” command is a Git command used to manage and work with commit-graph files in a Git repository. The commit-graph feature was introduced in Git version 2.18 to improve the performance of certain Git operations, such as commit traversal and revision history queries.
The commit-graph is a data structure that represents the commit history of a Git repository in a more efficient way. It organizes commit information into a directed acyclic graph (DAG), allowing Git to quickly traverse and query the commit history.
The “git commit-graph” command provides several subcommands that allow you to perform various operations related to commit-graph files:
- git commit-graph write: This subcommand generates or updates the commit-graph file based on the existing commit history in the repository. It analyzes the commit objects and their relationships to build an optimized commit-graph file.
- git commit-graph verify: This subcommand checks the integrity and validity of an existing commit-graph file. It verifies that the commit-graph matches the actual commit history in the repository and detects any inconsistencies or corruption.
- git commit-graph read: This subcommand displays information about the commit-graph file, such as the number of commits, the number of chunks, and the size of the commit-graph data.
The commit-graph file is stored in the .git/objects/info directory of a Git repository and has a .commit-graph extension. It is automatically used by Git to accelerate certain operations, such as commit graph traversal during log generation or revision walking.
By using the “git commit-graph” command, you can manage the commit-graph file, generate or update it when necessary, and verify its integrity. This can help improve the performance of operations that involve traversing or querying the commit history in large Git repositories.
git commit-graph Command Examples
1. Write a commit-graph file for the packed commits in the repository’s local .git directory:
# git commit-graph write
2. Write a commit-graph file containing all reachable commits:
# git show-ref --hash | git commit-graph write --stdin-commits
3. Write a commit-graph file containing all commits in the current commit-graph file along with those reachable from HEAD:
# git rev-parse HEAD | git commit-graph write --stdin-commits --append