Importing Contributions

Importing External Contributions

The reverse of open sourcing: importing pull requests from external contributors back to your internal repository.

The Challenge

External contributions need to:

• Be reviewed internally before integration
• Have paths adjusted for internal structure
• Have internal references restored
• Preserve original authorship

Basic Import Workflow

copy.bara.sky

core.workflow(
    name = "import",

    # Read from external PRs
    origin = git.github_pr_origin(
        url = "https://github.com/company/public-repo",
        branch = "main",
        required_labels = ["ready-to-import"],  # Only labeled PRs
    ),

    # Create internal change for review
    destination = git.gerrit_destination(
        url = "https://gerrit.internal.company.com/internal-repo",
        fetch = "main",
        push_to_refs_for = "main",
    ),

    # Preserve external contributor info
    authoring = authoring.pass_thru(
        default = "External Contributor <external@company.com>",
    ),

    transformations = [
        # Reverse the export structure
        core.move("docs/", "docs/public/"),
        core.move("src/", "src/public/"),

        # Restore internal URLs (reverse of export)
        core.replace("api.company.io", "internal.company.com"),

        # Preserve contribution metadata
        metadata.expose_label("Co-authored-by"),
        metadata.expose_label("Signed-off-by"),

        # Add import tracking
        metadata.add_header("Imported-From: github.com/company/public-repo"),
    ],

    mode = "CHANGE_REQUEST_FROM_SOT",
)

Filtering PRs

Control which PRs are eligible for import:

origin = git.github_pr_origin(
    url = "https://github.com/company/public-repo",
    branch = "main",

    # Only PRs with this label
    required_labels = ["ready-to-import"],

    # Only merged PRs
    state = "MERGED",

    # Only if CI passed
    required_status_context_names = ["ci/build", "ci/test"],
)

To Gerrit (Internal Code Review)

destination = git.gerrit_destination(
    url = "https://gerrit.internal/repo",
    fetch = "main",
    push_to_refs_for = "main",
    topic = "external-contribution",
)

Note

CHANGE_REQUEST_FROM_SOT mode creates a Gerrit CL for internal review before the changes land.

To GitHub (Internal Repo)

destination = git.github_pr_destination(
    url = "https://github.internal/repo",
    destination_ref = "main",
    pr_branch = "import/${CONTEXT_REFERENCE}",
    title = "Import: ${COPYBARA_WORKFLOW_NAME}",
    labels = ["external-contribution"],
)

Bidirectional Setup

Combine export and import in one config:

copy.bara.sky

INTERNAL = "https://github.com/company/internal"
EXTERNAL = "https://github.com/company/public"

# Reusable transforms with reversal
url_transforms = core.transform(
    transformations = [
        core.replace("internal.company.com", "api.company.io"),
    ],
    reversal = [
        core.replace("api.company.io", "internal.company.com"),
    ],
)

# Export: internal → external
core.workflow(
    name = "export",
    origin = git.github_origin(url = INTERNAL, ref = "main"),
    destination = git.github_destination(url = EXTERNAL, push = "main"),
    transformations = [url_transforms],
    mode = "SQUASH",
)

# Import: external → internal
core.workflow(
    name = "import",
    origin = git.github_pr_origin(url = EXTERNAL, branch = "main"),
    destination = git.gerrit_destination(url = INTERNAL, ...),
    transformations = [url_transforms],  # Uses reversal automatically
    mode = "CHANGE_REQUEST_FROM_SOT",
)

Preserving Authorship

External contributors should get credit:

authoring = authoring.pass_thru(
    default = "External <external@company.com>",
)

transformations = [
    # Preserve co-author information
    metadata.expose_label("Co-authored-by"),
    metadata.expose_label("Signed-off-by"),
]

Feedback Workflow

Notify when PRs are ready to import:

core.feedback(
    name = "notify-on-pr",
    origin = git.github_trigger(
        url = "https://github.com/company/public-repo",
        events = ["pull_request"],
    ),
    destination = git.github_api(
        url = "https://github.internal/internal-repo",
    ),
    actions = [
        # Create internal issue when external PR is merged
        core.action(impl = _create_import_issue),
    ],
)

Complete Example

# Full bidirectional workflow
INTERNAL = "https://github.com/company/internal"
EXTERNAL = "https://github.com/company/public"
BOT = "Sync Bot <sync@company.com>"

core.workflow(
    name = "import-pr",
    origin = git.github_pr_origin(
        url = EXTERNAL,
        branch = "main",
        required_labels = ["approved"],
    ),
    destination = git.github_pr_destination(
        url = INTERNAL,
        destination_ref = "main",
        pr_branch = "import/external-${CONTEXT_REFERENCE}",
        title = "Import: External contribution",
        labels = ["external-contribution", "needs-review"],
    ),
    authoring = authoring.pass_thru(BOT),
    origin_files = glob(["src/**", "docs/**"]),
    transformations = [
        core.move("", "external/"),
        metadata.expose_label("Co-authored-by"),
        metadata.add_header("Imported-From: external repository"),
    ],
    mode = "SQUASH",
)

Next Steps

• Open sourcing
• Feedback workflows