git-cvsexportcommit

Merge a specific patch into CVS

$ git cvsexportcommit -v -c -w [path/to/project_cvs_checkout] [commit_sha1]

git-cvsexportcommit <commit-ish>

commit-ish
    The Git commit object (e.g., hash, branch name, tag, or other Git reference) to be exported as a CVS changeset. The command analyzes the differences introduced by this commit relative to its first parent (or an empty tree for the initial commit) to generate corresponding CVS operations.

The git-cvsexportcommit command is an internal helper utility used by the git-remote-cvs bridge to export a single Git commit as a series of CVS operations. It takes a Git commit object and translates its changes—including additions, deletions, modifications, and directory changes—into a format suitable for CVS. This process involves determining the differences between the commit's tree and its first parent's tree (or an empty tree for the initial commit) and then generating the necessary cvs add, cvs remove, cvs update, and cvs commit commands. It ensures that the Git history can be accurately represented in a CVS repository, facilitating two-way synchronization between Git and CVS. Users typically interact with git-remote-cvs directly, which invokes git-cvsexportcommit behind the scenes.

Internal Command: This command is not intended for direct end-user interaction. It is an internal plumbing command primarily invoked by the git-remote-cvs utility.

CVS Limitations: CVS has inherent limitations compared to Git, such as lack of atomic renames, inability to track empty directories, and different handling of merge conflicts. These differences can lead to imperfect or lossy translation of complex Git history into CVS.

Performance: Exporting commits, especially large ones with many file changes, can be slow due to the nature of CVS operations which often involve file-by-file processing.

Dependency: Requires a properly configured and accessible CVS client and repository.

Compatibility: The git-cvsbridge project, which includes this command, might not be actively developed or maintained for all Git versions or operating systems, potentially leading to compatibility issues.

The primary purpose of git-cvsexportcommit is to act as a crucial link in the push operation from a Git repository to a CVS repository via git-remote-cvs. When a user pushes changes from Git, git-remote-cvs identifies the Git commits that need to be transferred to CVS. For each such commit, it invokes git-cvsexportcommit, passing the commit ID. This command then calculates the necessary CVS operations (adds, removes, modifications) required to represent that Git commit's changes in the CVS repository. These operations are then executed against the CVS repository, effectively synchronizing the Git commit's state with CVS.

git-cvsexportcommit works by performing a git diff-tree operation between the specified commit and its immediate parent (or the empty tree for the initial commit). The output of this diff, which details file changes, additions, and deletions, is then parsed. Based on this information, the command generates the appropriate sequence of cvs commands. This includes cvs add for new files, cvs remove for deleted files, and cvs commit for modified files, along with directory updates. The commit message and author/committer information from Git are also translated for the CVS commit.

The git-cvsexportcommit command emerged as a component of the broader git-cvsbridge project, designed to provide a two-way bridge between Git and CVS repositories. Its development was driven by the need to facilitate migration from CVS to Git, as well as to enable ongoing interoperability for projects that still relied on CVS while some contributors preferred Git. Initially, such bridge components were often implemented as shell scripts, leveraging existing command-line tools. While CVS usage has declined, the git-cvsbridge and its utilities like git-cvsexportcommit remain important for legacy system integration and historical data access.

git-remote-cvs(1), git-cvsimport(1), git(1), cvs(1)