Add overlays to git_repository and http_archive

[Clement-Jean]

Description of the feature request:

It would be great to have a way to add new files to a git_repository or http_archive without having to generate a dummy diff file for them.

An example for this is the following. Let us say that we have the following directory:

.
├── MODULE.bazel
├── overlays
│   └── src
│       └── a.go
└── patches
    └── b.diff

where a.txt is a new file and b.diff is a regular patch on ./main.go.

I could then have a git_repository like the following:

.
├── main.go // patched
└── src
    ├── a.go // copied over (overlay)
    └── c.go

I think that in the MODULE.bazel, it could look like the following:

git_repository = use_repo_rule("@bazel_tools//tools/build_defs/repo:git.bzl", "git_repository")
git_repository(
    //...
    patch_args = ["-p1"],
    patches = [
        "//patches:b.diff",
    ],
    overlays_root = "//:overlays",
    overlays = [ # this could also be a call to glob function
        "//overlays/src:a.go",
    ],
)

it would take the path of each overlay and substitute the overlays_root by the %worskpace% of the repo.

Which category does this issue belong to?

Configurability

What underlying problem are you trying to solve with this feature?

I'm trying to avoid having to go through all my new files (overlays) and execute something like git diff /dev/null $file. We should not have to create dummy patch files for new files. They can simply be copied over.

Which operating system are you running Bazel on?

MacOS

What is the output of bazel info release?

release 7.1.2

If bazel info release returns development version or (@non-git), tell us how you built Bazel.

No response

What's the output of git remote get-url origin; git rev-parse HEAD ?

No response

Have you found anything relevant by searching the web?

I only found something similar in bazel-gazelle but this is now deprecated (see: https://github.com/bazelbuild/bazel-gazelle/blob/master/repository.md#git_repository).

Any other information, logs, or outputs that you want to share?

No response