checkpoint

Documentation

Overview

Package checkpoint stores per-turn PRE-IMAGES of files the agent edits, so a bad run can be rewound without touching git: before edit_file mutates a file, its current bytes (or its absence) are snapshotted under .memcode/checkpoints/<session>/<seq>/. Rewinding to turn N restores every touched file to its earliest pre-image from turns N..latest — the state the tree had before turn N ran. Shadow copies only: git stays untouched, and changes made OUTSIDE the agent's edit tool (bash, the user's editor) are not captured — this is the agent-edit undo, not a filesystem time machine.

Index

• type Checkpoint
  • func (cp *Checkpoint) Empty() bool
  • func (cp *Checkpoint) Snapshot(relPath string)
• type File
• type Log
  • func New(root, sessionID string) *Log
  • func (l *Log) Begin(label string) *Checkpoint
  • func (l *Log) List() []Manifest
  • func (l *Log) Restore(seq int) ([]string, error)
• type Manifest

Types

type Checkpoint

type Checkpoint struct {
	// contains filtered or unexported fields
}

Checkpoint is an open checkpoint accumulating snapshots for the current turn.

func (*Checkpoint) Empty

func (cp *Checkpoint) Empty() bool

Empty reports whether the checkpoint captured nothing (no edits this turn).

func (*Checkpoint) Snapshot

func (cp *Checkpoint) Snapshot(relPath string)

Snapshot records path's current state (bytes or absence) once per checkpoint. relPath may be absolute (it is normalized against the root). Best-effort: snapshot failures never block the edit itself.

type File

type File struct {
	Path    string `json:"path"`    // repo-relative
	Existed bool   `json:"existed"` // false → the edit CREATED it (rewind deletes it)
}

File is one snapshotted pre-image.

type Log

type Log struct {
	// contains filtered or unexported fields
}

Log is one session's checkpoint store.

func New

func New(root, sessionID string) *Log

New opens (or creates) the checkpoint log for a session.

func (*Log) Begin

func (l *Log) Begin(label string) *Checkpoint

Begin opens a checkpoint for one turn. Nothing is written until the first Snapshot, so turns that never edit cost nothing. Prunes old checkpoints.

func (*Log) List

func (l *Log) List() []Manifest

List returns this session's checkpoints that captured edits, oldest first.

func (*Log) Restore

func (l *Log) Restore(seq int) ([]string, error)

Restore rewinds the tree to BEFORE checkpoint seq: every file touched from seq onward is restored to its earliest pre-image (created files are deleted), and the consumed checkpoints are dropped. Returns the restored file list.

type Manifest

type Manifest struct {
	Seq   int       `json:"seq"`
	Label string    `json:"label"` // the user turn that caused the edits, trimmed
	At    time.Time `json:"at"`
	Files []File    `json:"files"`
}

Manifest describes one checkpoint (one turn that edited files).