Skip to content

git.md

Latest commit

 

History

History
76 lines (60 loc) · 3.42 KB

git.md

File metadata and controls

76 lines (60 loc) · 3.42 KB
Raw

Fetching project sources

tine wraps Buck's git_fetch() as git.fetch() so local development can use a checkout without changing the pinned source. The wrapper normally fetches the requested commit. It uses a directory in the current Buck package instead when that directory is non-empty and its name matches the target after removing a trailing .git.

Declaring a git fetch

For example, a packages/hello/BUCK can declare:

load("@tine//cargo:defs.bzl", "cargo")
load("@tine//git:defs.bzl", "git")

git.fetch(
    name = "hello.git",
    repo = "https://github.com/example/hello",
    rev = "1c9e0f4b0f7d2a5e8b3c6d1a4f7b2e5c8d0a3f6b",
)

cargo.package(
    name = "hello",
    binaries = ["hello-cli"],
    box = ":rust.box",
    src = ":hello.git",
)

Building from a local checkout instead

The target above looks for a checkout at packages/hello/hello/: the package path followed by the target name without .git. Use tine mount to place a working checkout there without copying it into the project:

tine mount list                                        # includes packages/hello/hello
tine mount add packages/hello/hello ~/Projects/hello   # use the working checkout
tine mount remove packages/hello/hello                 # use the pinned commit again

A mount is also what makes a cargo.package(), go.package() or rpm.package() build incremental: then its build directory survives between runs, and an edit recompiles just what changed. See Rust source builds.

The override has a few constraints:

  • Only a git.fetch() or git.checkout() target can be mounted, anything else is rejected.
  • The directory must contain at least one file. An empty mount point or uninitialized submodule falls back to the remote fetch.
  • Every file not excluded by .gitignore or [project] ignore is a build input. tine merges both, plus VCS metadata directories, into the generated ignore list; put build outputs in .gitignore and anything Git tracks but Buck should not see in [project] ignore.
  • A build reads the checkout as it is on disk, including the files that Buck ignores, such as build output, .git and the files listed in [project] ignore. Buck does not hash an ignored file, so an ignored file can change what a build produces without changing the cache key. Keep the files a build reads out of [project] ignore.
  • The local checkout is not checked against rev. Remove the mount before a release build to restore the pinned source, and build releases from a fresh clone of the project.
  • A BUCK file in the checkout creates a package boundary that the source glob cannot cross. Projects containing Buck packages must use the remote fetch.

Checkout slots without a fetch

git.checkout() declares the directory named after the target as a source tree that may be empty: a slot to commit sources into or to tine mount a checkout over. rpm.package() declares one per package, <name>.source, and builds from it in place of the source archives once it holds anything; see Building from a source checkout.

A consumer reads a populated slot as it is on disk, like a mounted checkout. An image.ops.copy() of a path in the slot therefore also copies the files that Buck ignores below that path into the image.