Dev container image builds default to BuildKit (`docker buildx`).
Docker-compatible engines that lack an integrated BuildKit — notably
[Apple Container](https://github.com/apple/container) accessed through a
Docker-API bridge — cannot resolve a locally-built image in a `FROM`,
which breaks the dev container build: Zed builds the features image,
then a second `FROM <features-image>` build (the UID remap), and
BuildKit's docker-container/remote drivers can't see the daemon's local
image, failing with `pull access denied`.
The daemon's *classic* builder resolves locally-built images, and Zed
already generates a BuildKit-free Dockerfile for the non-BuildKit path
(multi-stage `FROM` + `COPY --from`, no `RUN --mount`). This wires that
path to a setting and makes the remaining build invocations actually use
the classic builder.
## Changes
- Add a `dev_container_use_buildkit` setting (tri-state):
- unset → auto-detect via the `docker buildx` plugin (current behavior)
- `false` → force the classic builder
- `true` → force BuildKit
- When the classic builder is selected, pass `DOCKER_BUILDKIT=0` (and
`COMPOSE_DOCKER_CLI_BUILD=0` for compose) to the feature-content build,
the compose build, and the UID-remap build, so multi-stage `FROM` of a
locally-built image resolves through the daemon's classic builder.
- Document the setting in `docs/src/dev-containers.md`.
With this setting plus a Docker-API bridge, a real Rails dev container
(compose: app + mysql + valkey, with features) builds and starts on
Apple Container.
## How to Review
- `settings_content.rs` / `dev_container/src/lib.rs` — the new setting
and its plumbing into `DevContainerContext`.
- `docker.rs` — `Docker::new` honors the setting
(`supports_compose_buildkit`), `docker_compose_build` selects the
classic builder; unit test
`use_buildkit_setting_overrides_buildx_detection`.
- `devcontainer_manifest.rs` — `DOCKER_BUILDKIT=0` for the
feature-content and UID-remap builds.
## Self-Review Checklist
- [x] I've reviewed my own diff for quality, security, and reliability
- [ ] Unsafe blocks (if any) have justifying comments
- [ ] The content is consistent with the [UI/UX
checklist](https://github.com/zed-industries/zed/blob/main/CONTRIBUTING.md#uiux-checklist)
- [x] Tests cover the new/changed behavior
- [x] Performance impact has been considered and is acceptable
Release Notes:
- Added a `dev_container_use_buildkit` setting to build dev containers
with the classic Docker builder for engines without an integrated
BuildKit (e.g. Apple Container)
Self-Review Checklist:
- [x] I've reviewed my own diff for quality, security, and reliability
- [x] Unsafe blocks (if any) have justifying comments
- [x] The content is consistent with the [UI/UX
checklist](https://github.com/zed-industries/zed/blob/main/CONTRIBUTING.md#uiux-checklist)
- [x] Tests cover the new/changed behavior
- [x] Performance impact has been considered and is acceptable
Closes N/A
Release Notes:
- Improved docs for dev containers
Added a hint for `use_podman` setting.
Self-Review Checklist:
- [x] I've reviewed my own diff for quality, security, and reliability
- [x] Unsafe blocks (if any) have justifying comments
- [ ] The content is consistent with the [UI/UX
checklist](https://github.com/zed-industries/zed/blob/main/CONTRIBUTING.md#uiux-checklist)
- [ ] Tests cover the new/changed behavior
- [ ] Performance impact has been considered and is acceptable
Closes (issue to be created, but it's just about an outdated doc)
Thanks for the cool project and making it open source! Started using Zed
recently and I really enjoy it.
Made a tiny addition to devcontainer docs to specify the version. Wasn't
able to get it to work as shown in the
[docs](https://zed.dev/docs/dev-containers) (should "just work"). The
feature was introduced recently on [PR
44442](https://github.com/zed-industries/zed/pull/44442) and is only
available as of v0.218 (currently still in preview), while I was still
on the latest stable version.
So I thought of opening a small PR 😊
Thanks again for the awesome project!
Release Notes:
- N/A
---------
Co-authored-by: Danilo Leal <67129314+danilo-leal@users.noreply.github.com>
