1 files changed, 25 insertions, 0 deletions
diff --git a/gui/internal/model/plan.go b/gui/internal/model/plan.go
index ccbf17b..c3e9654 100644
--- a/gui/internal/model/plan.go
+++ b/gui/internal/model/plan.go
@@ -7,6 +7,7 @@ package model
 
 import (
 	"context"
+	"errors"
 	"fmt"
 	"sort"
 	"time"
@@ -50,8 +51,24 @@ type PlanTab struct {
 	sess *engine.Session
 	dp   *engine.DirPlan
 	lock *lock.Lock
+
+	// applying is set while Apply is in flight. Close must refuse then:
+	// releasing the lock and closing the log under a running apply moves
+	// files the log never records, so undo cannot see them, and unlocks a
+	// directory krino is still working in. The window can reach Close from
+	// several places while an apply runs - saving rules or settings, adding
+	// a directory, closing the window - so the refusal lives here rather
+	// than in whichever of them remembers.
+	applying bool
+
+	// testBeforeApply, when set, is called just before the engine's Apply
+	// begins, so a test can act while the apply is in flight.
+	testBeforeApply func()
 }
 
+// ErrApplying is returned by Close while an apply is still running.
+var ErrApplying = errors.New("krino is still applying this plan")
+
 // Counts is the plan's summary line.
 type Counts struct {
 	Scanned, Acting, Excluded, Skipped, Unmatched, Warned int
@@ -95,6 +112,9 @@ func (t *PlanTab) Run() string { return t.sess.Run() }
 // Close releases the directory's lock and ends the run, which Apply also
 // does once the plan is history. Closing twice is not an error.
 func (t *PlanTab) Close() error {
+	if t.applying {
+		return ErrApplying
+	}
 	if t.lock == nil {
 		return nil
 	}
@@ -303,7 +323,12 @@ func (t *PlanTab) Apply(ctx context.Context) (*engine.ApplyResult, error) {
 			approved[r.Rel] = true
 		}
 	}
+	t.applying = true
+	if t.testBeforeApply != nil {
+		t.testBeforeApply()
+	}
 	res, err := t.sess.Apply(ctx, t.dp, approved)
+	t.applying = false
 	t.Applied = true
 	// An applied plan is history: the run is over and the directory free
 	// again, without closing the window (GUI design §3).