aaecd3369f
Summary: EdenFS assumes in several places that even materialized directories will receive readdir requests. This assumption is slightly wrong on Windows in the case where a directory hierarchy is completely removed, and then reconstructed at the identical, with say a filesystem revert operation. In that case, EdenFS will not participate in any readdir requests in this directory hierarchy as no directories are placeholder. During checkout, this assumption is used to dematerialize directories in saveOverlayPostCheckout, in some cases however, this can lead to dematerialized directories being contained in a non-placeholder directory on Windows. This case in particular is fraught with issues. For instance, invalidateChildrenNotMaterialized may invalidate these dematerialized directories but doing so would make these disappear entirely due to EdenFS not participating in non-placeholder directories! I believe a similar issue may also be possible with future checkout operations, although the exact steps elude me. To solve the above, one easy way is to simply force directories traversed by checkout to always have a placeholder added to them. This is achieved by invalidating the directory. Since it's unclear if we could also always invalidate the directory on Linux and macOS, let's add a config so we can roll this out slowly. Reviewed By: kmancini Differential Revision: D42483525 fbshipit-source-id: 9d8c9fe3db8914ca2a46a77f10cf77f2ff871ad9 |
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| .github/workflows | ||
| addons | ||
| build | ||
| ci | ||
| CMake | ||
| common | ||
| configerator/structs/scm | ||
| eden | ||
| website | ||
| .gitignore | ||
| .projectid | ||
| build.bat | ||
| build.sh | ||
| CMakeLists.txt | ||
| CODE_OF_CONDUCT.md | ||
| CONTRIBUTING.md | ||
| LICENSE | ||
| make-client.py | ||
| README.md | ||
| requirements_ubuntu.txt | ||
| rustfmt.toml | ||
| SAPLING_VERSION | ||
Sapling SCM
Sapling SCM is a cross-platform, highly scalable, Git-compatible source control system.
It aims to provide both user-friendly and powerful interfaces for users, as well as extreme scalability to deal with repositories containing many millions of files and many millions of commits.
Using Sapling
To start using Sapling, see the Getting Started page for how to clone your existing Git repositories. Checkout the Overview for a peek at the various features. Coming from Git? Checkout the Git Cheat Sheet.
Sapling also comes with an Interactive Smartlog (ISL) web UI for seeing and interacting with your repository, as well as a VS Code integrated Interactive Smartlog.
The Sapling Ecosystem
Sapling SCM is comprised of three main components:
- The Sapling client: The client-side
slcommand line and web interface for users to interact with Sapling SCM. - Mononoke: A highly scalable distributed source control server. (Not yet supported publicly.)
- EdenFS: A virtual filesystem for efficiently checking out large repositories. (Not yet supported publicly.)
Sapling SCM's scalability goals are to ensure that all source control operations scale with the number of files in use by a developer, and not with the size of the repository itself. This enables fast, performant developer experiences even in massive repositories with millions of files and extremely long commit histories.
Sapling CLI
The Sapling CLI, sl, was originally based on
Mercurial, and shares various aspects of the UI
and features of Mercurial.
The CLI code can be found in the eden/scm subdirectory.
Mononoke
Mononoke is the server-side component of Sapling SCM.
While it is used in production within Meta, it currently does not build in an open source context and is not yet supported for external usage.
EdenFS
EdenFS is a virtual file system for managing Sapling checkouts.
While it is used in production within Meta, it currently does not build in an open source context and is not yet supported for external usage.
EdenFS speeds up operations in large repositories by only populating working
directory files on demand, as they are accessed. This makes operations like
checkout much faster, in exchange for a small performance hit when first
accessing new files. This is quite beneficial in large repositories where
developers often only work with a small subset of the repository at a time.
More detailed EdenFS design documentation can be found at eden/fs/docs/Overview.md.
Building the Sapling CLI
The Sapling CLI currently builds and runs on Linux, Mac, and Windows. It can be
built by running make oss in the eden/scm directory and running the
resulting sl executable.
Building the Sapling CLI requires Python 3.8, Rust, cmake, and OpenSSL for the main cli, and Node and Yarn for the ISL web UI.
License
See LICENSE.