gui: a menu, a switch or a press that lays the batch screen out reads the form once

CHANGELOG.md

@@ -509,6 +509,10 @@ because it turns other people's test suites red.
   long as before. On the `Several batches` screen with a preset switched on,
   a key typed into a box now works the preset out once rather than twice.
 
+- **Choosing a format, switching the base or choosing a base preset on
+  `Several batches` works the form out once instead of twice.** Switching
+  the base to `upload-validation` took half as long as before.
+
 - **A preview or a run refused while it was being planned no longer leaves
   "Working out what this would cost..." standing over the refusal.**
 

internal/guard/settleonce_test.go

@@ -6,6 +6,7 @@ import (
 	"github.com/donislawdev/TestingFilesGenerator/internal/engine"
 	"github.com/donislawdev/TestingFilesGenerator/internal/format"
 	"github.com/donislawdev/TestingFilesGenerator/internal/gui/parts"
+	"github.com/donislawdev/TestingFilesGenerator/internal/gui/text"
 	"github.com/donislawdev/TestingFilesGenerator/internal/gui/window"
 	"github.com/donislawdev/TestingFilesGenerator/internal/recipe"
 )
@@ -67,6 +68,86 @@ func TestOneChangeOfABoxReadsTheFormOnce(t *testing.T) {
 	}
 }
 
+// A menu, a switch or a press that lays the batch screen out again reads the
+// form once.
+//
+// The batch screen lays itself out again when a batch's format changes, when
+// the base is switched or chosen, and when a press adds, copies or takes away
+// a batch or what an archive holds. The layout said what the form comes to,
+// and until 2026-09-24 a menu or a switch was then followed by the live check,
+// which said it again: two readings, and with a base preset two expansions -
+// switching the base to upload-validation took 278-321 ms in the real window
+// (docs/GUI-MEMORY-2026-09-23.md section 4j).
+//
+// Exactly one, for the reason the guard above gives, and it matters here in
+// the other direction too: a press is followed by no check, so nought is a
+// press after which the line under the buttons still describes the old form.
+func TestAChangeThatLaysTheBatchScreenOutAgainReadsTheFormOnce(t *testing.T) {
+	host := newFakeHost(t)
+	rec := window.NewRecipe(host)
+	body := rec.Object()
+	once := func(what string, act func()) {
+		t.Helper()
+		host.settles = 0
+		act()
+		switch {
+		case host.settles == 0:
+			t.Fatalf("%s told the host of no reading of the form - either nothing changed or the line under the buttons was not said, and this guard cannot tell which",
+				what)
+		case host.settles > 1:
+			t.Errorf("%s read the form %d times, expected once", what, host.settles)
+		}
+	}
+	press := func(name string) func() {
+		return func() {
+			t.Helper()
+			b := buttonNamed(body, name)
+			if b == nil {
+				t.Fatalf("the batch screen has no %q button, so this guard cannot press it", name)
+			}
+			b.OnTapped()
+		}
+	}
+	base := func() *parts.Chooser {
+		for _, c := range reportingControls(findField(rec.Fields(), recipe.KeyExtends).Control) {
+			if pick, is := c.(*parts.Chooser); is {
+				return pick
+			}
+		}
+		t.Fatal("the base is switched on and there is no menu of presets under it")
+		return nil
+	}
+
+	once("choosing png for the first batch", func() {
+		chooserIn(t, rec.Fields(), recipe.TargetAddress(1, recipe.KeyFormat)).SetSelected("png")
+	})
+	once("switching the base on", func() { toggleIn(t, rec.Fields(), "start_from_preset").SetChecked(true) })
+	once("choosing text-encoding as the base", func() { base().SetSelected("text-encoding") })
+	once("switching the base off", func() { toggleIn(t, rec.Fields(), "start_from_preset").SetChecked(false) })
+
+	once("adding a batch", press(text.ButtonAddBatch()))
+	once("duplicating a batch", press(text.ButtonDuplicateBatch()))
+	once("removing a batch", press(text.ButtonRemoveBatch()))
+	once("choosing zip for the first batch", func() {
+		chooserIn(t, rec.Fields(), recipe.TargetAddress(1, recipe.KeyFormat)).SetSelected("zip")
+	})
+	once("adding what an archive holds", press(text.ButtonAddContents()))
+	once("removing what an archive holds", press(text.ButtonRemoveContents()))
+
+	// The base switched off with no batch left, which brings a batch back and
+	// is the one way a switch and a press meet. Raised by the review of #133
+	// (docs/REVIEW-133-2026-09-24.md): the batch came back through the press's
+	// path, which says the line, and the switch's check then said it again.
+	once("switching the base on again", func() { toggleIn(t, rec.Fields(), "start_from_preset").SetChecked(true) })
+	for findField(rec.Fields(), recipe.TargetAddress(1, recipe.KeyID)) != nil {
+		once("removing a batch with the base on", press(text.ButtonRemoveBatch()))
+	}
+	once("switching the base off with no batch left", func() { toggleIn(t, rec.Fields(), "start_from_preset").SetChecked(false) })
+	if findField(rec.Fields(), recipe.TargetAddress(1, recipe.KeyID)) == nil {
+		t.Error("the base was switched off with no batch left and no batch came back, so the screen can produce nothing")
+	}
+}
+
 // Typing into a box a preset is not given does not expand the preset again.
 //
 // The seed and the output directory are read with the preset's values but are

internal/gui/window/recipe.go

@@ -354,8 +354,20 @@ func (r *Recipe) rebuild() {
 	r.baseBox.Refresh()
 	r.batchBox.Refresh()
 	r.outBox.Refresh()
-	// A batch added, copied or taken away changes what the form comes to,
-	// and none of those goes through a box somebody typed in.
+	// Nothing is said here about what the form comes to. Whoever changed the
+	// form says it: a menu or a switch is followed by recheck, which reads the
+	// form once for the line and the box, and a press no box reports goes
+	// through afterAPress. This said it too until 2026-09-24, so a new format,
+	// base or preset read the form twice - and with a base preset, each
+	// reading expanded it (docs/GUI-MEMORY-2026-09-23.md section 4j).
+}
+
+// afterAPress lays the screen out again and says what the form now comes to,
+// for a change no box, menu or switch reports: a batch added, copied or taken
+// away, contents added or taken away. A function rather than a method, because
+// the screen stands near its ceiling of methods.
+func afterAPress(r *Recipe) {
+	r.rebuild()
 	r.runner.refreshLine()
 }
 
@@ -496,7 +508,7 @@ func (r *Recipe) contentsBlock(index int, b *batch) fyne.CanvasObject {
 
 	addContents := parts.NewButton(parts.Secondary, text.ButtonAddContents(), func() {
 		b.contents = append(b.contents, r.newContent())
-		r.rebuild()
+		afterAPress(r)
 	})
 	if len(b.contents) == 0 {
 		if !holds {
@@ -583,12 +595,21 @@ func (r *Recipe) outputSection() fyne.CanvasObject {
 
 // addBatch puts another batch at the end of the list.
 func (r *Recipe) addBatch() {
+	newBatchAtTheEnd(r)
+	afterAPress(r)
+}
+
+// newBatchAtTheEnd puts a batch after the last one, without saying what the
+// form comes to. Apart from addBatch for the one caller that is not a press:
+// the base switched off with no batch left brings one back, and the switch's
+// own check says the line. Through addBatch it was said twice - found by the
+// review of #133 (docs/REVIEW-133-2026-09-24.md).
+func newBatchAtTheEnd(r *Recipe) {
 	r.batches = append(r.batches, r.newBatch())
 	// A new batch has no format until one is chosen, and its declared settings
 	// come with that choice. Chosen here rather than left empty so that a batch
 	// arrives looking like the one above it.
 	r.batches[len(r.batches)-1].formatPick.SetSelected(format.IDs()[0])
-	r.rebuild()
 }
 
 // removeBatch drops one batch. The last cannot go, unless the screen builds
@@ -629,7 +650,7 @@ func (r *Recipe) duplicateBatch(index int) {
 
 	rest := append([]*batch{to}, r.batches[index+1:]...)
 	r.batches = append(r.batches[:index+1], rest...)
-	r.rebuild()
+	afterAPress(r)
 }
 
 func (r *Recipe) removeBatch(index int) {
@@ -640,15 +661,15 @@ func (r *Recipe) removeBatch(index int) {
 		return
 	}
 	r.batches = append(r.batches[:index], r.batches[index+1:]...)
-	r.rebuild()
+	afterAPress(r)
 }
 
 func (r *Recipe) removeContent(b *batch, index int) {
 	if index < 0 || index >= len(b.contents) {
 		return
 	}
 	b.contents = append(b.contents[:index], b.contents[index+1:]...)
-	r.rebuild()
+	afterAPress(r)
 }
 
 // onFormatChosen replaces the declared settings of one batch.

internal/gui/window/recipebase.go

@@ -49,10 +49,10 @@ func newBase(r *Recipe) *base {
 	b := &base{}
 	b.on = parts.NewToggle(func(on bool) {
 		// Off with no batch left is a form that can produce nothing, so a
-		// batch comes back - the one the screen opened with.
+		// batch comes back - the one the screen opened with. What the form
+		// then comes to is said by the switch's own check, as for any switch.
 		if !on && len(r.batches) == 0 {
-			r.addBatch()
-			return
+			newBatchAtTheEnd(r)
 		}
 		r.rebuild()
 	})