Authoring

Authoring

Authoring controls how commit author information is handled during synchronization.

authoring.pass_thru

Preserve original author when possible:

authoring = authoring.pass_thru(
    default = "Bot <bot@example.com>",
)

If the original author can be resolved, it’s preserved. Otherwise, the default is used.

Example

authoring = authoring.pass_thru(
    default = "Sync Bot <sync@example.com>",
)
# Alice commits → Alice's name preserved
# Unknown author → Sync Bot used

authoring.overwrite

Replace all authors with a single identity:

authoring = authoring.overwrite(
    "Sync Bot <sync@example.com>",
)

When to Use

• When all commits should appear from a bot account
• When original authors shouldn’t be exposed
• For automated sync workflows

Note

overwrite is useful for privacy, but loses contributor attribution.

authoring.allowed

Only pass through specific authors:

authoring = authoring.allowed(
    default = "Bot <bot@example.com>",
    allowlist = [
        "alice@example.com",
        "bob@example.com",
    ],
)

Example

authoring = authoring.allowed(
    default = "External Contributor <external@example.com>",
    allowlist = [
        "maintainer1@org.com",
        "maintainer2@org.com",
    ],
)
# maintainer1@ commits → maintainer1@ preserved
# random@ commits → External Contributor used

Author Format

Authors use Git’s standard format:

Name <email@example.com>

# Full format
authoring = authoring.pass_thru("John Doe <john@example.com>")

# Minimal
authoring = authoring.pass_thru("bot <bot@example.com>")

Common Patterns

Open Source Export

Preserve contributor attribution:

authoring = authoring.pass_thru(
    default = "Open Source Bot <oss-bot@company.com>",
)

Import External Contributions

Allow external contributors:

authoring = authoring.allowed(
    default = "External Contribution <external@company.com>",
    allowlist = [
        "*@company.com",  # Internal emails pass through
    ],
)

Automated Sync

Use bot for all commits:

authoring = authoring.overwrite(
    "Copybara Sync <copybara@company.com>",
)

Map Internal to External

Combine with metadata transform:

authoring = authoring.pass_thru("Bot <bot@example.com>")

transformations = [
    metadata.map_author({
        "alice@internal.corp": "alice@public.example.com",
        "bob@internal.corp": "bob@public.example.com",
    }),
]

Author Mapping

Use metadata.map_author for complex mappings:

# In transformations
metadata.map_author({
    "old-email@company.com": "new-email@company.com",
    "internal@corp.com": "external@example.com",
})

Multiple Authors (Squash)

In SQUASH mode, author of the last commit is used by default.

Use metadata to preserve author information:

mode = "SQUASH"

transformations = [
    metadata.squash_notes(
        show_author = True,  # Include authors in commit message
    ),
]

Commit message will include:

Sync from internal:
- Alice <alice@example.com>: Fix bug
- Bob <bob@example.com>: Add feature

GitOrigin-RevId: abc123

Verification

Check author configuration:

# Preview the sync
java -jar copybara.jar migrate copy.bara.sky workflow \
  --folder-destination /tmp/output

# Check the commit
cd /tmp/output
git log --format="%an <%ae>"

Next Steps

• Labels & Markers
• Metadata transformations