Hi Stolee, On Wed, 17 Nov 2021, Derrick Stolee wrote: > On 11/17/2021 9:19 AM, Johannes Schindelin via GitGitGadget wrote: > > From: Johannes Schindelin <johannes.schindelin@xxxxxx> > > > > The Scalar command will be contributed incrementally, over a bunch of > > patch series. Let's document what Scalar is about, and then describe the > > patch series that are planned. > > > > Signed-off-by: Johannes Schindelin <johannes.schindelin@xxxxxx> > > --- > > contrib/scalar/README.md | 71 ++++++++++++++++++++++++++++++++++++++++ > > 1 file changed, 71 insertions(+) > > create mode 100644 contrib/scalar/README.md > > > > diff --git a/contrib/scalar/README.md b/contrib/scalar/README.md > > new file mode 100644 > > index 00000000000..7898a683ba5 > > --- /dev/null > > +++ b/contrib/scalar/README.md > > @@ -0,0 +1,71 @@ > > +# Scalar - an opinionated repository management tool > > + > > +Scalar is an add-on to Git, helping Git scale to very large repositories and > > +worktrees. > > I would rephrase this as "Scalar is an add-on to Git that helps users take > advantage of advanced performance features in Git." Good idea! > Git scales just fine, only it helps to enable some features that are off > by default. > > > Originally implemented in C# using .NET Core, based on the learnings > > +from the VFS for Git project, most of the techniques developed by the Scalar > > +project have been integrated into core Git already: > > + > > +* partial clone, > > +* commit graphs, > > +* multi-pack index, > > +* sparse checkout (cone mode), > > +* scheduled background maintenance, > > +* etc > > + > > +This directory contains the remaining parts of Scalar that are not (yet) in > > +core Git. > > + > > +## Roadmap > > + > > +The idea is to populate this directory via incremental patch series and > > +eventually move to a top-level directory next to `gitk-git/` and to `git-gui/`. The > > +current plan involves the following patch series: > > + > > +- `scalar-the-beginning`: The initial patch series which sets up > > + `contrib/scalar/` and populates it with a minimal `scalar` command that > > + demonstrates the fundamental ideas. > > + > > +- `scalar-c-and-C`: The `scalar` command learns about two options that can be > > + specified before the command, `-c <key>=<value>` and `-C <directory>`. > > + > > +- `scalar-diagnose`: The `scalar` command is taught the `diagnose` subcommand. > > + > > +- `scalar-and-builtin-fsmonitor`: The built-in FSMonitor is enabled in `scalar > > + init` and in `scalar clone`, for an enormous performance boost when working > > + in large worktrees. This patch series necessarily depends on Jeff Hostetler's > > + FSMonitor patch series to be integrated into Git. > > You say 'scalar init' but do you mean 'scalar register'? D'oh. Yes, I meant `scalar register`. I was thinking of `git init` too much when I wrote that. > > +- `scalar-gentler-config-locking`: Scalar enlistments are registered in the > > + user's Git config. This usually does not represent any problem because it is > > + rare for a user to register an enlistment. However, in Scalar's functional > > + tests, Scalar enlistments are created galore, and in parallel, which can lead > > + to lock contention. This patch series works around that problem by re-trying > > + to lock the config file in a gentle fashion. > > + > > +- `scalar-extra-docs`: Add some extensive documentation that has been written > > + in the original Scalar project (all subject to discussion, of course). > > + > > +- `optionally-install-scalar`: Now that Scalar is feature (and documentation) > > + complete and is verified in CI builds, let's offer to install it. > > + > > +- `move-scalar-to-toplevel`: Now that Scalar is complete, let's move it next to > > + `gitk-git/` and to `git-gui/`, making it a top-level command. > > This final one is where we can make the final call about where Scalar should > exist in the tree and how optional it should be. This would also move the > Scalar man pages into Documentation/, along with possibly the docs from > 'scalar-extra-docs', and the tests into t/. The benefit of leaving this until > the end is that we can see the entirety of Scalar before making a final call. Yes. It allows the current patch series to focus on the core functionality of Scalar. The `move-scalar-to-toplevel` patch series will present an excellent opportunity to discuss the merits and complications of accepting Scalar as a top-level command into Git, without having to delay the current patch series any further. > > +The following two patch series exist, but there is no plan to integrate them > > +into Git's source tree: > > + > > +- `scalar-with-gvfs`: The primary purpose of this patch series is to support > > + existing Scalar users whose repositories are hosted in Azure Repos (which > > + does not support Git's partial clones, but supports its predecessor, the GVFS > > + protocol, which is used by Scalar to emulate the partial clone). > > + > > + Since the GVFS protocol will never be supported by core Git, this patch > > + series will remain in Microsoft's fork of Git. > > + > > +- `run-scalar-functional-tests`: The Scalar project developed a quite > > + comprehensive set of integration tests (or, "Functional Tests"). They are the > > + sole remaining part of the original C#-based Scalar project, and this patch > > + adds a GitHub workflow that runs them all. > > + > > + Since the tests partially depend on features that are only provided in the > > + `scalar-with-gvfs` patch series, this patch cannot be upstreamed. > > These topics (in some form or another) exist on microsoft/git and are available > via GPL, so we don't intend to say "we are withholding these patches" but instead > are saying "We don't think the Git community is interested in these patches." > There are some interesting ideas there, but the implementation is too specific to > Azure Repos to be of much help in general. These still exist mainly because the > GVFS protocol is what Azure Repos has instead of partial clone. We are focused > instead on improving partial clone. Good point. What I wrote does not fully reflect that. I have changed it. Do you see anything in the remainder of the patch series that still needs to be improved? Thanks, Dscho
