Artifact [2c65756f08]

Artifact 2c65756f08c99ea072b3b262c97b868a728a4c3528374e4f29b8770f5e367df4:

• File checkout_undo.go — part of check-in [294a537880] at 2026-10-19 16:10:06 on branch feat/submanifest-reader — fix(checkout): save undo state in Update, as fossil does

  Update saved no undo state, so nothing could reverse it. It now reads the file of every step that writes or removes one before writing, as fossil's update calls undo_save, and saves those files with copies of vfile and vmerge and the checked-out version in the same transaction that moves the checkout to the target. If a write fails partway the files are put back, as fossil's undo_rollback does.

  Checkout.Undo and Checkout.Redo (internal and public) swap that state back and forth and keep checkout-hash naming the restored version. The undo package gains ReadFile, SaveTx and RestoreFiles, and its undo table now has fossil's schema (isExe, unique pathname, rowid order, the executable bit read from disk), so fossil undo reverses a go-libfossil update and Checkout.Undo reverses fossil update; fossil 2.28 interop tests check both. Under js/wasm, which has no undo package, Update saves nothing.

  Tracked in #446 (user: [email protected], size: 648) [annotate] [blame] [check-ins using] [more...]

//go:build !js

package libfossil

import "fmt"

// Undo reverses the last operation that saved undo state, such as Update,
// as fossil's undo does: the files it changed come back, and the checkout's
// file list and version are as they were before it. Fossil's undo reads
// the same state, so either tool can undo the other's update.
func (c *Checkout) Undo() error {
	if err := c.inner.Undo(); err != nil {
		return fmt.Errorf("libfossil: undo: %w", err)
	}
	return nil
}

// Redo reverses the last Undo.
func (c *Checkout) Redo() error {
	if err := c.inner.Redo(); err != nil {
		return fmt.Errorf("libfossil: redo: %w", err)
	}
	return nil
}