Re: Slightly off topic, question about git

[David Brownlee <abs%absd.org@localhost>]

On Mon, 6 Jun 2022 at 06:59, Brian Buhrow <buhrow%nfbcal.org@localhost> wrote:
>
>         Hello.  At the risk of raising the debate about which version control system we should
> use, I have a question about git, as well as a comment about it relative to the NetBSD source
> tree.  I should preface my comments with the caveat that I am not by any means a git expert,
> and, in fact, I'm barely able to get anything I want out of it.  With that said, here are my
> questions and observations.  I'd be interested to know how others work around these issues
> and/or what you think of my observations.
>
> 1.  In CVS, I can do something like:
> cvs log sys/dev/pci/if_bge.c
> and be given a complete history of the changes to that file, as well as a list of all the
> branches that file participates in and which versions apply to each branch.  And, I can do this
> without having to download all of the history of that file onto my local storage.
>         It seems like the only way to do this with a git repository is to download the entire
> source tree, along with its history and branches, using git clone with an infinite depth.  Is
> this correct?  If not, how can I see all the branches of a given repository without having to
> download the entire repository?

git inherently looks at the local copy of the repo. So your options are
- have a local copy
- ssh to somewhere with a local copy
- use a web tool or similar to browse

> 2.  Also, in my exploration of git, it seems like the git log command shows all the commits for
> each tag, rather than the comments for a specific file or object in the repository.  Again, is
> this correct?

You can do either or both - "git log trunk" "git log build.sh" or "git
log trunk build.sh"

As an aside, I have an alias of gl -> "git log --name-status" as I
really prefer to see the filenames changed in each commit

>         If I am correct in my guesses about how git works, it seems like I would have to download
> the entire history of the NetBSD source tree if I want to browse its branches, or the commit
> history for any given file.  This is a lot of overhead to examine tiny portions of the tree,
> relatively speaking, assuming we move to git for our version control system.  It strikes me
> that requiring this much storage space from developers, would be a regression from what we
> currently do.  Since I think we're smarter than that and since we have very smart people on our
> development team, I want to understand what it is that I don't get about git that precludes me
> from having to download the entire history of the source tree from day one while still
> retaining access to that history over time.

"It's a feature". Half :) - Seriously though, the ability to actually
browse and search the full history of a source tree as git allows
compared to the godawful eye-of-the-needle view that CVS provides is a
very valuable benefit of the tradeoff of having a local history. When
looking at source tree history I use a cloned copy of the github src,
then apply to the CVS tree as needed.

For people with limited resources it will be a pain, though there are
any number of services which provide remote web access to git trees.
Having said that, the ever increasing memory requirements of modern
gcc is a much bigger pain for limited resources with a relatively
smaller benefit.

I suspect most of this also works with s/git/hg/ assuming NetBSD
switches to a mercurial repo

David