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Editorial Team
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Asked: 2026-06-15T04:16:36+00:00

I’d like to write a set of elisp functions to manipulate commits identified by

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I’d like to write a set of elisp functions to manipulate commits identified by the currently selected region when viewing a git log in Git-Log-View mode of vc.el. A common subcomponent of these functions would need to be a function that would obtain the commit metadata for the list of commits selected by the region in the Git-Log-View buffer, but I have no idea how to write such a routine. I was hoping that vc.el provided such a mechanism directly, but from what I can see via apropos it doesn’t.

I’ve poked around in vc.el and vc-git.el to try to get some idea of how vc.el works, but it is a fairly complex bit of elisp and I’m by no means an elisp expert. It seems reasonable to me though that vc.el/vc-git.el has the commit metadata available somewhere, since in Git-Log-View mode you can do things like select a region and ask for a changeset diff over that region, or expand a given commit to see the detailed commit info, and I just want to build some similar functionality.

Any thoughts on how to do this? I suppose I could just directly get the currently selected text and parse the abbreviated log format myself, but that seems like a huge amount of work that I’d like to avoid if vc-mode can help me out.

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  1. Editorial Team

    vc-git and other backends don’t really keep the whole bulk of metadata anywhere. For most operations, the backend calls the respective command to get the required data.

    For example, Git-Log-View is a prettified output of git log [-- filename]. The summary you see when expanding a commit was already present in the command output, just hidden, so it’s easier for the user to scan. To show the changeset over a region, log-view-diff-changeset looks which commits correspond to the region bounds, and delegates to vc-diff-internal, which eventually calls git diff FROM TO.

    So you’ll get the hashes of each commit in the region, then call some git command (git show?) with vc-git-command, vc-git--call or maybe vc-git--run-command-string for each of them and parse the results. Maybe just call git log for all of them at once if you manage to make it include all the relevant data.

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