Speedup CI and Git by enforcing index-version 4 via update-index

[sambacha]

Is your feature request related to a problem? Please describe.
Monorepo speedups are nice, this is an easy change that will be easily adoptable.

Describe the solution you'd like

Enforce monorepo git configuration

Suggested settings

These settings along with defining a ~/.gitconfig.monorepo configuration file to support commitgraph and native fsmonitor

git config --global pack.allowPackReuse multi
git multi-pack-index write --bitmap
git update-index --verbose --index-version 4

~/.gitconfig.monorepo

[core]
    commitgraph = true
    fsmonitor = true
    writeCommitGraph = true
[feature]
    manyFiles = true

which can be imported through your .gitconfig by

[include]
    path = ~/.gitconfig.monorepo

Update Index version 4

$ git update-index --verbose --show-index-version
2

$ git update-index --verbose --index-version 4
index-version: was 2, set to 4

fsmonitor daemon

see https://github.blog/2022-06-29-improve-git-monorepo-performance-with-a-file-system-monitor/

git config core.fsmonitor true

git fsmonitor--daemon start

core.commitgraph

Git will use a commit history cache to significantly speed up history operations, such as git log with the --graph option.

fetch.writeCommitGraph

Improves performance of commands like git push -f and git log --graph by writing a commit-graph on every git fetch.

References

Faster pack generation with multi-pack reuse

https://github.blog/2024-02-23-highlights-from-git-2-44/

Measuring Git Performance with OpenTel

https://github.blog/2023-10-16-measuring-git-performance-with-opentelemetry/

[tynes]

Do you have an estimate on how much of a performance boost this would enable?

If i understand correctly, the solution involves adding a config file to the monorepo and then a config file to the host and references the config file in the monorepo? I wish there was a way around that second file