fix(xwm): drop stale TARGETS replies after Wayland takes ownership

commit: a50e31e5c9b5f4f2d66a0b2237cb33a3c1c84096
author: brice · 13h ago · 2026-10-22 16:50 UTC
committer: brice · 12h ago · 2026-10-22 17:55 UTC
parent: 4afca7a
signature: GPG VerifiedCD88F9E564E0102646FB6077A1A07C7C7C3E349D · arch-gpg Verified for the committer email

2 files · +33 -4

M internal/adapters/wayland/xwm/selection.go +8 -4


@@ -32,6 +32,7 @@ var (
32	32		type selState struct {
33	33		atom uint32
34	34		gen uint32 // bumped on every ownership change; stales TARGETS probes
	35	+	probe uint32 // gen when the TARGETS ConvertSelection was issued
35	36		owner uint32 // X owner window other than selWin, 0 none
36	37		ours bool // selWin owns the selection (Wayland -> X)
37	38		// wl is what the Wayland side offers while ours: raw text availability.

@@ -206,6 +207,7 @@ func (x XWM) onXFixesSelection(ev xturbo.Event) {
206	207		x.host.SelectionOwned(k, nil)
207	208		return
208	209		}
	210	+	st.probe = st.gen
209	211		x.log.Debug().Int("kind", k).Uint32("owner", owner).Msg("selection: X owner")
210	212		xproto.ConvertSelection(x.conn.Buf(), xproto.Window(x.selWin), xproto.Atom(st.atom),
211	213		xproto.Atom(x.atoms[atomTargets]), xproto.Atom(x.atoms[atomNeferwlTargets]), 0)

@@ -227,10 +229,12 @@ func (x XWM) onSelectionNotify(ev xturbo.Event) {
227	229		return
228	230		}
229	231		{
	232	+	st := &x.sel.st[k]
	233	+	if st.ours \|\| st.owner == 0 \|\| st.probe != st.gen { // stale probe
	234	+	return
	235	+	}
230	236		if e.Property() == 0 {
231		-	if x.sel.st[k].owner != 0 {
232		-	x.host.SelectionOwned(k, nil)
233		-	}
	237	+	x.host.SelectionOwned(k, nil)
234	238		return
235	239		}
236	240		seq := xproto.GetProperty(x.conn.Buf(), true, xproto.Window(x.selWin), xproto.Atom(x.atoms[atomNeferwlTargets]), 0, 0, 256)

@@ -244,7 +248,7 @@ func (x XWM) onSelectionNotify(ev xturbo.Event) {
244	248		// to Wayland: the text subset, empty for images, files and the like.
245	249		func (x XWM) onTargetsReply(r xturbo.Reply) {
246	250		k := int(r.Args[0])
247		-	if k < 0 \|\| k >= selKinds \|\| r.Args[1] != x.sel.st[k].gen {
	251	+	if k < 0 \|\| k >= selKinds \|\| r.Args[1] != x.sel.st[k].gen \|\| x.sel.st[k].ours \|\| x.sel.st[k].owner == 0 \|\| x.sel.st[k].probe != r.Args[1] {
248	252		return
249	253		}
250	254		g, ok := xproto.ParseGetPropertyReply(r.Raw)

 type selState struct {
 	atom  uint32
 	gen   uint32 // bumped on every ownership change; stales TARGETS probes
+	probe uint32 // gen when the TARGETS ConvertSelection was issued
 	owner uint32 // X owner window other than selWin, 0 none
 	ours  bool   // selWin owns the selection (Wayland -> X)
 	// wl is what the Wayland side offers while ours: raw text availability.
 		x.host.SelectionOwned(k, nil)
 		return
 	}
+	st.probe = st.gen
 	x.log.Debug().Int("kind", k).Uint32("owner", owner).Msg("selection: X owner")
 	xproto.ConvertSelection(x.conn.Buf(), xproto.Window(x.selWin), xproto.Atom(st.atom),
 		xproto.Atom(x.atoms[atomTargets]), xproto.Atom(x.atoms[atomNeferwlTargets]), 0)
 		return
 	}
 	{
+		st := &x.sel.st[k]
+		if st.ours || st.owner == 0 || st.probe != st.gen { // stale probe
+			return
+		}
 		if e.Property() == 0 {
-			if x.sel.st[k].owner != 0 {
+			x.host.SelectionOwned(k, nil)
-				x.host.SelectionOwned(k, nil)
-			}
 			return
 		}
 		seq := xproto.GetProperty(x.conn.Buf(), true, xproto.Window(x.selWin), xproto.Atom(x.atoms[atomNeferwlTargets]), 0, 0, 256)
 // to Wayland: the text subset, empty for images, files and the like.
 func (x *XWM) onTargetsReply(r *xturbo.Reply) {
 	k := int(r.Args[0])
-	if k < 0 || k >= selKinds || r.Args[1] != x.sel.st[k].gen {
+	if k < 0 || k >= selKinds || r.Args[1] != x.sel.st[k].gen || x.sel.st[k].ours || x.sel.st[k].owner == 0 || x.sel.st[k].probe != r.Args[1] {
 		return
 	}
 	g, ok := xproto.ParseGetPropertyReply(r.Raw)

M internal/adapters/wayland/xwm/selection_test.go +25 -0


@@ -683,3 +683,28 @@ func TestSelectionCopyAllocationsWaylandToX(t *testing.T) {
683	683		require.Zero(t, allocs)
684	684		require.Equal(t, outFree, x.sel.out[0].state)
685	685		}
	686	+
	687	+	// A TARGETS reply that arrives after Wayland took the selection is dropped.
	688	+	func TestSelectionStaleTargetsAfterWaylandOwner(t *testing.T) {
	689	+	x, p, h, _, _ := attached(t)
	690	+	const owner = 0x500010
	691	+	clip := p.atom("CLIPBOARD")
	692	+	tgt := p.atom("TARGETS")
	693	+	p.xfixesSelection(owner, clip)
	694	+	req, _ := pumpReq(t, x, p, 0, func(r xpeerReq) bool { return r.major == 24 })
	695	+	prop := req.u32(16)
	696	+	x.WaylandSelection(SelClipboard, []string{"text/plain"})
	697	+	p.setProp(x.selWin, prop, 4, 32, le32(tgt, p.atom("UTF8_STRING")))
	698	+	p.selectionNotify(x.selWin, clip, tgt, prop) // the mock fails on SelectionOwned
	699	+	ev := x.Stats().Events
	700	+	readUntil(t, x, func() bool { return x.Stats().Events > ev })
	701	+	x.flush()
	702	+	require.True(t, x.sel.st[SelClipboard].ours)
	703	+	for i := 0; i < 20; i++ { // let any (wrong) GetProperty round trip finish
	704	+	x.onReadable()
	705	+	x.flush()
	706	+	time.Sleep(time.Millisecond)
	707	+	}
	708	+	require.Zero(t, getProps(p, 0, x.selWin), "the stale TARGETS reply is not fetched")
	709	+	_ = h
	710	+	}


@@ -683,3 +683,28 @@ func TestSelectionCopyAllocationsWaylandToX(t *testing.T) {
683	require.Zero(t, allocs)	683		require.Zero(t, allocs)
684	require.Equal(t, outFree, x.sel.out[0].state)	684		require.Equal(t, outFree, x.sel.out[0].state)
685	}	685		}
		686	+
		687	+	// A TARGETS reply that arrives after Wayland took the selection is dropped.
		688	+	func TestSelectionStaleTargetsAfterWaylandOwner(t *testing.T) {
		689	+	x, p, h, _, _ := attached(t)
		690	+	const owner = 0x500010
		691	+	clip := p.atom("CLIPBOARD")
		692	+	tgt := p.atom("TARGETS")
		693	+	p.xfixesSelection(owner, clip)
		694	+	req, _ := pumpReq(t, x, p, 0, func(r xpeerReq) bool { return r.major == 24 })
		695	+	prop := req.u32(16)
		696	+	x.WaylandSelection(SelClipboard, []string{"text/plain"})
		697	+	p.setProp(x.selWin, prop, 4, 32, le32(tgt, p.atom("UTF8_STRING")))
		698	+	p.selectionNotify(x.selWin, clip, tgt, prop) // the mock fails on SelectionOwned
		699	+	ev := x.Stats().Events
		700	+	readUntil(t, x, func() bool { return x.Stats().Events > ev })
		701	+	x.flush()
		702	+	require.True(t, x.sel.st[SelClipboard].ours)
		703	+	for i := 0; i < 20; i++ { // let any (wrong) GetProperty round trip finish
		704	+	x.onReadable()
		705	+	x.flush()
		706	+	time.Sleep(time.Millisecond)
		707	+	}
		708	+	require.Zero(t, getProps(p, 0, x.selWin), "the stale TARGETS reply is not fetched")
		709	+	_ = h
		710	+	}