2 files changed, 25 insertions, 41 deletions

diff --git a/cmd/krino/sort.go b/cmd/krino/sort.go
index 4c0a0d8..54d5574 100644
--- a/cmd/krino/sort.go
+++ b/cmd/krino/sort.go
@@ -104,6 +104,13 @@ func cmdSort(g *globals, names []string, stdout, stderr io.Writer) int {
 		fmt.Fprintf(stderr, "krino: %v\n", err)
 		return 1
 	}
+	// Sorting opens the log before the first directory, as it always has:
+	// the run id is fixed for every directory, and a failure to open is
+	// reported before anything is planned.
+	if err := sess.OpenLog(); err != nil {
+		fmt.Fprintf(stderr, "krino: %v\n", err)
+		return 1
+	}
 	defer func() {
 		if cerr := sess.Close(); cerr != nil {
 			fmt.Fprintf(stderr, "krino: %v\n", cerr)
diff --git a/cmd/krino/undo.go b/cmd/krino/undo.go
index ecab2f3..5a7db4b 100644
--- a/cmd/krino/undo.go
+++ b/cmd/krino/undo.go
@@ -15,9 +15,7 @@ import (
 
 	"golang.org/x/term"
 
-	"krino/internal/config"
 	"krino/internal/engine"
-	"krino/internal/journal"
 	"krino/internal/lock"
 	"krino/internal/xdg"
 )
@@ -113,7 +111,18 @@ func cmdUndo(g *globals, args []string, stdout, stderr io.Writer) int {
 
 	// PlanUndo only reads the log; nothing is touched yet (spec §10), which
 	// is what makes it safe to call before any lock is taken.
-	up, err := e.PlanUndo(runID)
+	sess, err := e.NewSession(g.dry)
+	if err != nil {
+		fmt.Fprintf(stderr, "krino: %v\n", err)
+		return 1
+	}
+	defer func() {
+		if cerr := sess.Close(); cerr != nil {
+			fmt.Fprintf(stderr, "krino: %v\n", cerr)
+		}
+	}()
+
+	up, err := sess.PlanUndo(runID)
 	if err != nil {
 		fmt.Fprintf(stderr, "krino: %v\n", err)
 		return 1
@@ -137,7 +146,7 @@ func cmdUndo(g *globals, args []string, stdout, stderr io.Writer) int {
 	// right after acquisition.
 	var locks []*lock.Lock
 	if !g.dry {
-		locks, err = acquireUndoLocks(ctx, e.Config, undoDirNames(up.Files), !g.yes)
+		locks, err = sess.LockDirs(ctx, undoDirNames(up.Files), !g.yes)
 		if err != nil {
 			if errors.Is(err, context.Canceled) || errors.Is(err, context.DeadlineExceeded) {
 				return 130
@@ -197,26 +206,12 @@ func cmdUndo(g *globals, args []string, stdout, stderr io.Writer) int {
 
 	// Ruling 2 (Task 7), carried over: journal.Open creates the state
 	// directory and the log file as a side effect of merely being called,
-	// so it is opened only once we know something will actually be
+	// so the session opens it only now, when something will actually be
 	// applied - never for -n (returned above), and not merely because -y
-	// or a review session ran, unlike cmdSort's own eager-open (which opens
-	// before it knows whether anything is actionable, a difference forced
-	// by cmdSort not yet having a plan to inspect at that point in its
-	// flow; undo already does, so it opens later, and never opens if
-	// undoActionableCount was 0 or the user chose [s]/[q] above).
-	j, err := journal.Open(e.Config.LogFile())
-	if err != nil {
-		fmt.Fprintf(stderr, "krino: %v\n", err)
-		return 1
-	}
-	defer func() {
-		if cerr := j.Close(); cerr != nil {
-			fmt.Fprintf(stderr, "krino: %v\n", cerr)
-		}
-	}()
-	run := journal.NewRunID(e.Now())
-
-	res, aerr := e.ApplyUndo(ctx, toApply, j, run)
+	// or a review session ran, unlike cmdSort, which opens before it knows
+	// whether anything is actionable (a difference forced by cmdSort not
+	// yet having a plan to inspect at that point in its flow).
+	res, aerr := sess.ApplyUndo(ctx, toApply)
 	if aerr != nil {
 		if errors.Is(aerr, context.Canceled) || errors.Is(aerr, context.DeadlineExceeded) {
 			// Interrupted mid-apply: the ctx.Err() check below turns this
@@ -269,24 +264,6 @@ func undoDirNames(files []engine.UndoFile) []string {
 	return out
 }
 
-// acquireUndoLocks takes the lock for every name in dirs, in order,
-// mirroring cmdSort's per-directory lock.Acquire call. If any acquisition
-// fails - held with wait false, or ctx cancelled while waiting - every lock
-// already taken is released before returning, so a partial lock set is
-// never left held while the caller reports the error and stops.
-func acquireUndoLocks(ctx context.Context, cfg *config.Config, dirs []string, wait bool) ([]*lock.Lock, error) {
-	locks := make([]*lock.Lock, 0, len(dirs))
-	for _, name := range dirs {
-		l, err := lock.Acquire(ctx, cfg.LockFile(name), wait)
-		if err != nil {
-			releaseUndoLocks(locks)
-			return nil, fmt.Errorf("%s: %w", name, err)
-		}
-		locks = append(locks, l)
-	}
-	return locks, nil
-}
-
 // releaseUndoLocks releases every lock in locks and returns any release
 // errors, one lock's failure never stopping the rest from being released -
 // the same "release on every path" guarantee cmdSort gives its own single