libra fast-import

Import a git fast-import stream into the repository — a focused subset of git fast-import. The natural counterpart to fast-export.

Synopsis

libra fast-import [--input <file>] [--max-count <n>] [--quiet]

Description

fast-import reads a fast-import stream from stdin (or --input <file>) and writes the objects and refs it describes. Supported directives:

blob with mark / data;
commit <ref> with mark, author, committer, data (message), from, merge, and the file operations M <mode> <dataref> <path>, D <path>, and deleteall;
reset <ref> with an optional from;
checkpoint, done;
the lenient preamble feature / option / progress (accepted, ignored).

tag, cat-blob, ls, get-mark, note (N), and copy/rename (C / R) are not yet supported and are rejected.

Transaction model

Objects are written as they are parsed, but ref updates are buffered and applied only at a checkpoint, at done, or at a clean end-of-stream. A stream that is truncated mid-object fails before that flush, so branches are never left half-updated; the orphaned objects are unreferenced and reclaimed by a later libra gc. To recover after an interrupted import, run libra fsck then libra gc.

Safety and resource limits

Total input is capped (default 1 GiB, configurable via fastimport.maxInputSize).
The number of blobs and commits created is capped (default 1,000,000); raise it with --max-count <n>. (Trees are derived and written through the shared write-tree path and are not separately counted.)
Refs must be under refs/…, well-formed, and never escape the repository.
Object ids referenced literally must match the repository's hash length (SHA-1 / SHA-256); duplicate marks are rejected.

Options

Option	Description
`--input <file>`	Read the stream from a file instead of stdin.
`--max-count <n>`	Raise the blob+commit-count ceiling for this import.
`--quiet`	Suppress the final summary line.

Exit codes

Code	Meaning
`0`	The stream imported successfully.
`128`	Not inside a repository, a malformed stream, a duplicate mark, an invalid/out-of-repo ref, a hash-format mismatch, a resource-limit overflow, or an IO error.

Examples

# Round-trip history through a stream
libra fast-export main | libra fast-import

# Import a saved stream
libra fast-import < repo.fastimport
libra fast-import --input repo.fastimport

Comparison with Git

Task	Libra	Git
Import a stream	`libra fast-import`	`git fast-import`

Differences and deferred features: only branch refs (refs/heads/*) are persisted (other namespaces are parsed but not yet written); tag, cat-blob, ls, get-mark, notes, copy/rename, marks-file import/export (--import-marks / --export-marks), and true streaming of multi-gigabyte inputs are not yet implemented.