fix(core): harden the fullscreen cascade band

Re-requests no longer re-split bands, the expelled column drops stale
shares and slot only when the slot window left, the source workspace
promotes its demoted floats after a fullscreen move, and restoreBand
looks past an emptied band so maximize round-trips still restore.

commit: aa552bf9a14032dcd310ff2b88d92502b9213b2b
author: brice · 7h ago · 2026-10-22 19:51 UTC
parent: c73000c
signature: GPG VerifiedCD88F9E564E0102646FB6077A1A07C7C7C3E349D · arch-gpg Verified for the committer email

4 files · +137 -9

M internal/core/action.go +3 -1


@@ -394,6 +394,7 @@ func (c *Core) dispatchAction(a Action) Effect {
394	394		from := c.cur()
395	395		c.focusScreen = i
396	396		moveFloat(w, c.cur().mon.Current(), fid)
	397	+	w.reconcileFloats()
397	398		from.mon.normalize()
398	399		c.cur().mon.normalize()
399	400		}

@@ -412,6 +413,7 @@ func (c *Core) dispatchAction(a Action) Effect {
412	413		if !ok {
413	414		return Effect{}
414	415		}
	416	+	w.reconcileFloats() // floats the fullscreen kept demoted show again
415	417		from := c.cur()
416	418		c.focusScreen = i
417	419		to := c.cur().mon.Current()

@@ -421,7 +423,7 @@ func (c *Core) dispatchAction(a Action) Effect {
421	423		}
422	424		to.receive(col, at)
423	425		if full {
424		-	to.ToggleFullscreen()
	426	+	to.SetFullscreen(fid, true)
425	427		}
426	428		from.mon.normalize()
427	429		c.cur().mon.normalize()

 				from := c.cur()
 				c.focusScreen = i
 				moveFloat(w, c.cur().mon.Current(), fid)
+				w.reconcileFloats()
 				from.mon.normalize()
 				c.cur().mon.normalize()
 			}
 			if !ok {
 				return Effect{}
 			}
+			w.reconcileFloats() // floats the fullscreen kept demoted show again
 			from := c.cur()
 			c.focusScreen = i
 			to := c.cur().mon.Current()
 			}
 			to.receive(col, at)
 			if full {
-				to.ToggleFullscreen()
+				to.SetFullscreen(fid, true)
 			}
 			from.mon.normalize()
 			c.cur().mon.normalize()

M internal/core/cascade.go +19 -3


@@ -438,18 +438,25 @@ func (w *Workspace) fullscreenBand(id WindowID) {
438	438		}
439	439		fc := w.Columns[w.Focus]
440	440		focus := fc.Windows[fc.Focus]
441		-	w.dropSlotOf(id)
442	441		bands := w.bandList()
443	442		col := bands[b][i-first]
444	443		nc := col
445	444		if len(col.Windows) == 1 {
	445	+	// The column leaves its lane, as deleteColumn: manual widths of the
	446	+	// lane no longer add up. It keeps its slot and its own width.
	447	+	w.clearSpans(i)
446	448		bands[b] = slices.Delete(bands[b], i-first, i-first+1)
447	449		} else {
448	450		j := slices.Index(col.Windows, id)
	451	+	// The expelled window gets a plain column: no Span (a manual width
	452	+	// is the stack's, and the new band is alone), no shares.
449	453		nc = Column{Windows: []WindowID{id}, Cells: col.Cells}
450	454		col.Windows = slices.Delete(slices.Clone(col.Windows), j, j+1)
451		-	switch {
452		-	case col.Focus > j, col.Focus >= len(col.Windows):
	455	+	col.Shares = nil
	456	+	if j == 0 {
	457	+	col.Slot = 0 // the slot window left
	458	+	}
	459	+	if col.Focus > j \|\| col.Focus >= len(col.Windows) {
453	460		col.Focus = max(min(col.Focus-1, len(col.Windows)-1), 0)
454	461		}
455	462		bands[b][i-first] = col

@@ -533,8 +540,17 @@ func (w *Workspace) restoreBand() bool {
533	540		}
534	541		return got
535	542		}
	543	+	// A band the take left empty (a fullscreen column that split off its
	544	+	// own band meanwhile) is looked past: the remembered columns may lie
	545	+	// one band farther.
536	546		above := take(b-1, up, true)
	547	+	if b >= 2 && len(bands[b-1]) == 0 {
	548	+	above = slices.Concat(take(b-2, up, true), above)
	549	+	}
537	550		below := take(b+1, down, false)
	551	+	if b+2 < len(bands) && len(bands[b+1]) == 0 {
	552	+	below = slices.Concat(below, take(b+2, down, false))
	553	+	}
538	554		bands[b] = slices.Concat(above, bands[b], below)
539	555		w.setBands(bands, id)
540	556		return true

 	}
 	fc := w.Columns[w.Focus]
 	focus := fc.Windows[fc.Focus]
-	w.dropSlotOf(id)
 	bands := w.bandList()
 	col := bands[b][i-first]
 	nc := col
 	if len(col.Windows) == 1 {
+		// The column leaves its lane, as deleteColumn: manual widths of the
+		// lane no longer add up. It keeps its slot and its own width.
+		w.clearSpans(i)
 		bands[b] = slices.Delete(bands[b], i-first, i-first+1)
 	} else {
 		j := slices.Index(col.Windows, id)
+		// The expelled window gets a plain column: no Span (a manual width
+		// is the stack's, and the new band is alone), no shares.
 		nc = Column{Windows: []WindowID{id}, Cells: col.Cells}
 		col.Windows = slices.Delete(slices.Clone(col.Windows), j, j+1)
-		switch {
+		col.Shares = nil
-		case col.Focus > j, col.Focus >= len(col.Windows):
+		if j == 0 {
+			col.Slot = 0 // the slot window left
+		}
+		if col.Focus > j || col.Focus >= len(col.Windows) {
 			col.Focus = max(min(col.Focus-1, len(col.Windows)-1), 0)
 		}
 		bands[b][i-first] = col
 		}
 		return got
 	}
+	// A band the take left empty (a fullscreen column that split off its
+	// own band meanwhile) is looked past: the remembered columns may lie
+	// one band farther.
 	above := take(b-1, up, true)
+	if b >= 2 && len(bands[b-1]) == 0 {
+		above = slices.Concat(take(b-2, up, true), above)
+	}
 	below := take(b+1, down, false)
+	if b+2 < len(bands) && len(bands[b+1]) == 0 {
+		below = slices.Concat(below, take(b+2, down, false))
+	}
 	bands[b] = slices.Concat(above, bands[b], below)
 	w.setBands(bands, id)
 	return true

M internal/core/cascade_fullscreen_band_test.go +114 -4


@@ -7,15 +7,15 @@ import "testing"
7	7		func TestCascadeFullscreenOwnBand(t *testing.T) {
8	8		for _, tc := range []struct {
9	9		name string
10		-	do func(c Core, w Workspace)
	10	+	do func(w *Workspace)
11	11		}{
12		-	{"toggle", func(_ Core, w Workspace) { w.ToggleFullscreen() }},
13		-	{"client request", func(_ Core, w Workspace) { w.SetFullscreen(3, true) }},
	12	+	{"toggle", func(w *Workspace) { w.ToggleFullscreen() }},
	13	+	{"client request", func(w *Workspace) { w.SetFullscreen(3, true) }},
14	14		} {
15	15		t.Run(tc.name, func(t *testing.T) {
16	16		c, w := cascadeMovesCore(t, 3, 3, false)
17	17		wantBands(t, w, []WindowID{1, 2, 3})
18		-	tc.do(c, w)
	18	+	tc.do(w)
19	19		wantBands(t, w, []WindowID{1, 2}, []WindowID{3})
20	20		wantFocus(t, c, "M", 3)
21	21		if w.fullscreen != 3 {

@@ -122,3 +122,113 @@ func TestFullscreenFloatNoNeighborStays(t *testing.T) {
122	122		t.Fatalf("float moved: %v fullscreen %d", w.Floats, w.fullscreen)
123	123		}
124	124		}
	125	+
	126	+	func TestCascadeFullscreenRepeatedRequestKeepsBands(t *testing.T) {
	127	+	_, w := cascadeMovesCore(t, 3, 3, false)
	128	+	w.SetFullscreen(3, true)
	129	+	w.SetFullscreen(3, true)
	130	+	w.SetFullscreen(3, true)
	131	+	wantBands(t, w, []WindowID{1, 2}, []WindowID{3})
	132	+	}
	133	+
	134	+	func TestCascadeFullscreenStackedFixups(t *testing.T) {
	135	+	for _, tc := range []struct {
	136	+	name string
	137	+	focus WindowID
	138	+	rest WindowID
	139	+	slotKept bool
	140	+	}{{"last row", 3, 2, true}, {"first row", 2, 3, false}} {
	141	+	t.Run(tc.name, func(t *testing.T) {
	142	+	c, w := cascadeMovesCore(t, 3, 3, false)
	143	+	w.FocusID(3)
	144	+	c.applyAction(ActionConsumeOrExpelLeft) // 3 stacks under 2
	145	+	w.FocusID(tc.focus)
	146	+	w.Columns[1].Shares = []int{5000, 5000}
	147	+	w.Columns[1].Span = 3000
	148	+	w.Columns[1].Slot = 4
	149	+	w.SetFullscreen(tc.focus, true)
	150	+	wantBands(t, w, []WindowID{1, tc.rest}, []WindowID{tc.focus})
	151	+	col := w.Columns[1]
	152	+	if len(col.Windows) != 1 \|\| col.Windows[0] != tc.rest \|\| col.Shares != nil \|\| col.Focus != 0 \|\| (col.Slot == 4) != tc.slotKept {
	153	+	t.Fatalf("remaining column %+v", col)
	154	+	}
	155	+	if got, _ := w.Focused(); got != tc.focus {
	156	+	t.Fatalf("focus %d, want %d", got, tc.focus)
	157	+	}
	158	+	if w.Columns[2].Span != 0 \|\| w.Columns[2].Slot != 0 {
	159	+	t.Fatalf("expelled column %+v", w.Columns[2])
	160	+	}
	161	+	})
	162	+	}
	163	+	}
	164	+
	165	+	func TestCascadeFullscreenKeepsSlotOfIntactColumn(t *testing.T) {
	166	+	_, w := cascadeMovesCore(t, 3, 3, false)
	167	+	w.Columns[2].Slot = 4
	168	+	w.ToggleFullscreen()
	169	+	if i := w.columnOf(3); w.Columns[i].Slot != 4 {
	170	+	t.Fatalf("slot %d, want 4", w.Columns[i].Slot)
	171	+	}
	172	+	}
	173	+
	174	+	func TestCascadeFullscreenAfterMaximizeRestores(t *testing.T) {
	175	+	_, w := cascadeMovesCore(t, 3, 3, false)
	176	+	w.FocusID(1)
	177	+	w.ToggleFullWidth()
	178	+	before := columnOrder(w)
	179	+	w.FocusID(3)
	180	+	w.ToggleFullscreen()
	181	+	w.ToggleFullscreen()
	182	+	w.FocusID(1)
	183	+	w.ToggleFullWidth()
	184	+	t.Logf("before %v bands after %v", before, columnOrder(w))
	185	+	wantBands(t, w, []WindowID{1, 2, 3})
	186	+	}
	187	+
	188	+	func TestFullscreenMoveEdges(t *testing.T) {
	189	+	t.Run("destination fullscreen elsewhere", func(t *testing.T) {
	190	+	c, w := cascadeMovesCore(t, 2, 3, true)
	191	+	dst := screenWorkspace(c, "R")
	192	+	dst.AddWindow(20)
	193	+	dst.SetFullscreen(20, true)
	194	+	w.ToggleFullscreen()
	195	+	c.applyAction(ActionMoveColumnRight)
	196	+	if dst.fullscreen != 2 {
	197	+	t.Fatalf("fullscreen %d, want 2", dst.fullscreen)
	198	+	}
	199	+	wantFocus(t, c, "R", 2)
	200	+	})
	201	+	t.Run("scroll layout", func(t *testing.T) {
	202	+	c, w := cascadeMovesCore(t, 2, 3, true)
	203	+	w.Overflow = OverflowScroll
	204	+	w.ToggleFullscreen()
	205	+	c.applyAction(ActionMoveColumnLeft)
	206	+	dst := screenWorkspace(c, "L")
	207	+	wantColumns(t, dst, 2)
	208	+	if dst.fullscreen != 2 \|\| w.fullscreen != 0 {
	209	+	t.Fatalf("fullscreen dst %d src %d", dst.fullscreen, w.fullscreen)
	210	+	}
	211	+	})
	212	+	t.Run("source floats promoted", func(t *testing.T) {
	213	+	for _, float := range []bool{false, true} {
	214	+	c, w := cascadeMovesCore(t, 2, 3, true)
	215	+	w.AddFloating(9, 100, 100)
	216	+	w.SetFullscreen(9, true)
	217	+	if !float {
	218	+	w.FocusID(2)
	219	+	w.ToggleFullscreen()
	220	+	}
	221	+	demoted := w.Floats[0].below
	222	+	c.applyAction(ActionMoveColumnRight)
	223	+	if float {
	224	+	demoted = false
	225	+	}
	226	+	_ = demoted
	227	+	for _, f := range w.Floats {
	228	+	if f.below {
	229	+	t.Fatalf("float=%v: float %d still demoted", float, f.ID)
	230	+	}
	231	+	}
	232	+	}
	233	+	})
	234	+	}


@@ -7,15 +7,15 @@ import "testing"
7		func TestCascadeFullscreenOwnBand(t *testing.T) {	7		func TestCascadeFullscreenOwnBand(t *testing.T) {
8		for _, tc := range []struct {	8		for _, tc := range []struct {
9		name string	9		name string
10	-	do func(c Core, w Workspace)	10	+	do func(w *Workspace)
11		}{	11		}{
12	-	{"toggle", func(_ Core, w Workspace) { w.ToggleFullscreen() }},	12	+	{"toggle", func(w *Workspace) { w.ToggleFullscreen() }},
13	-	{"client request", func(_ Core, w Workspace) { w.SetFullscreen(3, true) }},	13	+	{"client request", func(w *Workspace) { w.SetFullscreen(3, true) }},
14		} {	14		} {
15		t.Run(tc.name, func(t *testing.T) {	15		t.Run(tc.name, func(t *testing.T) {
16		c, w := cascadeMovesCore(t, 3, 3, false)	16		c, w := cascadeMovesCore(t, 3, 3, false)
17		wantBands(t, w, []WindowID{1, 2, 3})	17		wantBands(t, w, []WindowID{1, 2, 3})
18	-	tc.do(c, w)	18	+	tc.do(w)
19		wantBands(t, w, []WindowID{1, 2}, []WindowID{3})	19		wantBands(t, w, []WindowID{1, 2}, []WindowID{3})
20		wantFocus(t, c, "M", 3)	20		wantFocus(t, c, "M", 3)
21		if w.fullscreen != 3 {	21		if w.fullscreen != 3 {

@@ -122,3 +122,113 @@ func TestFullscreenFloatNoNeighborStays(t *testing.T) {
122		t.Fatalf("float moved: %v fullscreen %d", w.Floats, w.fullscreen)	122		t.Fatalf("float moved: %v fullscreen %d", w.Floats, w.fullscreen)
123		}	123		}
124		}	124		}
			125	+
			126	+	func TestCascadeFullscreenRepeatedRequestKeepsBands(t *testing.T) {
			127	+	_, w := cascadeMovesCore(t, 3, 3, false)
			128	+	w.SetFullscreen(3, true)
			129	+	w.SetFullscreen(3, true)
			130	+	w.SetFullscreen(3, true)
			131	+	wantBands(t, w, []WindowID{1, 2}, []WindowID{3})
			132	+	}
			133	+
			134	+	func TestCascadeFullscreenStackedFixups(t *testing.T) {
			135	+	for _, tc := range []struct {
			136	+	name string
			137	+	focus WindowID
			138	+	rest WindowID
			139	+	slotKept bool
			140	+	}{{"last row", 3, 2, true}, {"first row", 2, 3, false}} {
			141	+	t.Run(tc.name, func(t *testing.T) {
			142	+	c, w := cascadeMovesCore(t, 3, 3, false)
			143	+	w.FocusID(3)
			144	+	c.applyAction(ActionConsumeOrExpelLeft) // 3 stacks under 2
			145	+	w.FocusID(tc.focus)
			146	+	w.Columns[1].Shares = []int{5000, 5000}
			147	+	w.Columns[1].Span = 3000
			148	+	w.Columns[1].Slot = 4
			149	+	w.SetFullscreen(tc.focus, true)
			150	+	wantBands(t, w, []WindowID{1, tc.rest}, []WindowID{tc.focus})
			151	+	col := w.Columns[1]
			152	+	if len(col.Windows) != 1 \|\| col.Windows[0] != tc.rest \|\| col.Shares != nil \|\| col.Focus != 0 \|\| (col.Slot == 4) != tc.slotKept {
			153	+	t.Fatalf("remaining column %+v", col)
			154	+	}
			155	+	if got, _ := w.Focused(); got != tc.focus {
			156	+	t.Fatalf("focus %d, want %d", got, tc.focus)
			157	+	}
			158	+	if w.Columns[2].Span != 0 \|\| w.Columns[2].Slot != 0 {
			159	+	t.Fatalf("expelled column %+v", w.Columns[2])
			160	+	}
			161	+	})
			162	+	}
			163	+	}
			164	+
			165	+	func TestCascadeFullscreenKeepsSlotOfIntactColumn(t *testing.T) {
			166	+	_, w := cascadeMovesCore(t, 3, 3, false)
			167	+	w.Columns[2].Slot = 4
			168	+	w.ToggleFullscreen()
			169	+	if i := w.columnOf(3); w.Columns[i].Slot != 4 {
			170	+	t.Fatalf("slot %d, want 4", w.Columns[i].Slot)
			171	+	}
			172	+	}
			173	+
			174	+	func TestCascadeFullscreenAfterMaximizeRestores(t *testing.T) {
			175	+	_, w := cascadeMovesCore(t, 3, 3, false)
			176	+	w.FocusID(1)
			177	+	w.ToggleFullWidth()
			178	+	before := columnOrder(w)
			179	+	w.FocusID(3)
			180	+	w.ToggleFullscreen()
			181	+	w.ToggleFullscreen()
			182	+	w.FocusID(1)
			183	+	w.ToggleFullWidth()
			184	+	t.Logf("before %v bands after %v", before, columnOrder(w))
			185	+	wantBands(t, w, []WindowID{1, 2, 3})
			186	+	}
			187	+
			188	+	func TestFullscreenMoveEdges(t *testing.T) {
			189	+	t.Run("destination fullscreen elsewhere", func(t *testing.T) {
			190	+	c, w := cascadeMovesCore(t, 2, 3, true)
			191	+	dst := screenWorkspace(c, "R")
			192	+	dst.AddWindow(20)
			193	+	dst.SetFullscreen(20, true)
			194	+	w.ToggleFullscreen()
			195	+	c.applyAction(ActionMoveColumnRight)
			196	+	if dst.fullscreen != 2 {
			197	+	t.Fatalf("fullscreen %d, want 2", dst.fullscreen)
			198	+	}
			199	+	wantFocus(t, c, "R", 2)
			200	+	})
			201	+	t.Run("scroll layout", func(t *testing.T) {
			202	+	c, w := cascadeMovesCore(t, 2, 3, true)
			203	+	w.Overflow = OverflowScroll
			204	+	w.ToggleFullscreen()
			205	+	c.applyAction(ActionMoveColumnLeft)
			206	+	dst := screenWorkspace(c, "L")
			207	+	wantColumns(t, dst, 2)
			208	+	if dst.fullscreen != 2 \|\| w.fullscreen != 0 {
			209	+	t.Fatalf("fullscreen dst %d src %d", dst.fullscreen, w.fullscreen)
			210	+	}
			211	+	})
			212	+	t.Run("source floats promoted", func(t *testing.T) {
			213	+	for _, float := range []bool{false, true} {
			214	+	c, w := cascadeMovesCore(t, 2, 3, true)
			215	+	w.AddFloating(9, 100, 100)
			216	+	w.SetFullscreen(9, true)
			217	+	if !float {
			218	+	w.FocusID(2)
			219	+	w.ToggleFullscreen()
			220	+	}
			221	+	demoted := w.Floats[0].below
			222	+	c.applyAction(ActionMoveColumnRight)
			223	+	if float {
			224	+	demoted = false
			225	+	}
			226	+	_ = demoted
			227	+	for _, f := range w.Floats {
			228	+	if f.below {
			229	+	t.Fatalf("float=%v: float %d still demoted", float, f.ID)
			230	+	}
			231	+	}
			232	+	}
			233	+	})
			234	+	}

M internal/core/layout.go +1 -1


@@ -1445,7 +1445,7 @@ func (w *Workspace) SetFullscreen(id WindowID, on bool) {
1445	1445		// Another window covers: the override was for the old cover.
1446	1446		w.dropStashOver()
1447	1447		}
1448		-	if !w.isFloat(id) {
	1448	+	if !w.isFloat(id) && w.fullscreen != id {
1449	1449		w.fullscreenBand(id)
1450	1450		}
1451	1451		w.fullscreen = id


@@ -1445,7 +1445,7 @@ func (w *Workspace) SetFullscreen(id WindowID, on bool) {
1445		// Another window covers: the override was for the old cover.	1445		// Another window covers: the override was for the old cover.
1446		w.dropStashOver()	1446		w.dropStashOver()
1447		}	1447		}
1448	-	if !w.isFloat(id) {	1448	+	if !w.isFloat(id) && w.fullscreen != id {
1449		w.fullscreenBand(id)	1449		w.fullscreenBand(id)
1450		}	1450		}
1451		w.fullscreen = id	1451		w.fullscreen = id