git backfill

For partial clones — pull objects on demand.

🎯 What & why

Lazily fetch missing blobs in a partial clone. Used after --filter=blob:none clones to materialize content on demand.

🧠 Mental model

Backfill walks the index (or the sparse cone), finds entries whose blob SHA is not present locally, and asks the promisor remote (the one set during --filter clone) for them in batches. The object DB is grown until the working tree can be materialized.

🛠️ Synopsis

git backfill [--batch-size=<n>] [--min-batch-size=<n>] [--[no-]sparse]

🎚️ Switches & options

Flag	What it does
`--batch-size=<n>`	Group requests in batches of `<n>`.
`--sparse`	Honor sparse-checkout — only backfill what would be checked out.

💡 Use cases

Catching up a partial clone.
Pre-fetching files before going offline.

🧪 Examples

After a partial clone, fill in blobs as needed.

$ git backfill --sparse

🎓 Recommendations

Pair with sparse-checkout to keep on-disk size manageable.
Run on demand or via maintenance schedules.

🪤 Common pitfalls

Requires a server that supports the partial clone protocol (most modern Git hosts do).
Newer command — older Git versions may not have it.

🔗 Related modules

📝 Quiz

Hit each option, then Check answers. Score is recorded; Next is always open.