fix(daemon): refuse a same-peer switch during a purge as unavailable and keep its offer

commit: 1d86a915a91a3574d16123d5fe481e4a73786532
author: brice · 15d ago · 2026-10-08 08:55 UTC
committer: brice · 15d ago · 2026-10-08 09:31 UTC
parent: c002b88
signature: GPG VerifiedCD88F9E564E0102646FB6077A1A07C7C7C3E349D · arch-gpg Verified for the committer email

2 files · +18 -10

M internal/usecase/daemon/same_peer_switch.go +8 -7


@@ -69,17 +69,13 @@ func (d Daemon) switchSamePeerForAttachment(effect attachmentEffect, request p
69	69		if err := request.Validate(); err != nil \|\| !effect.current() \|\| effect.sess == nil \|\| effect.ac == nil {
70	70		return
71	71		}
72		-	if !effect.ac.consumeSamePeerOffer(request.Target) {
73		-	d.sendSamePeerSwitchFailure(effect, request.RequestID, protocol.SamePeerSwitchStaleTarget)
74		-	return
75		-	}
76		-
77	72		// The switch moves an attachment between sessions, so it must not run
78		-	// inside the exact set a KillAll purge has captured.
	73	+	// inside the exact set a KillAll purge has captured. A purge is retry
	74	+	// state, so it is checked first and keeps any pending daemon offer.
79	75		d.mu.Lock()
80	76		if d.purgeAdmissionClosedLocked() {
81	77		d.mu.Unlock()
82		-	d.sendSamePeerSwitchFailure(effect, request.RequestID, protocol.SamePeerSwitchStaleTarget)
	78	+	d.sendSamePeerSwitchFailure(effect, request.RequestID, protocol.SamePeerSwitchUnavailable)
83	79		return
84	80		}
85	81		d.purgeAdmissionActive++

@@ -90,6 +86,11 @@ func (d Daemon) switchSamePeerForAttachment(effect attachmentEffect, request p
90	86		release := func() { releaseOnce.Do(d.releasePurgeAdmission) }
91	87		defer release()
92	88
	89	+	if !effect.ac.consumeSamePeerOffer(request.Target) {
	90	+	d.sendSamePeerSwitchFailure(effect, request.RequestID, protocol.SamePeerSwitchStaleTarget)
	91	+	return
	92	+	}
	93	+
93	94		target, targetTabIndex, ok := d.samePeerTarget(request)
94	95		if !ok \|\| target == effect.sess {
95	96		d.sendSamePeerSwitchFailure(effect, request.RequestID, protocol.SamePeerSwitchStaleTarget)

 	if err := request.Validate(); err != nil || !effect.current() || effect.sess == nil || effect.ac == nil {
 		return
 	}
-	if !effect.ac.consumeSamePeerOffer(request.Target) {
-		d.sendSamePeerSwitchFailure(effect, request.RequestID, protocol.SamePeerSwitchStaleTarget)
-		return
-	}
 	// The switch moves an attachment between sessions, so it must not run
-	// inside the exact set a KillAll purge has captured.
+	// inside the exact set a KillAll purge has captured. A purge is retry
+	// state, so it is checked first and keeps any pending daemon offer.
 	d.mu.Lock()
 	if d.purgeAdmissionClosedLocked() {
 		d.mu.Unlock()
-		d.sendSamePeerSwitchFailure(effect, request.RequestID, protocol.SamePeerSwitchStaleTarget)
+		d.sendSamePeerSwitchFailure(effect, request.RequestID, protocol.SamePeerSwitchUnavailable)
 		return
 	}
 	d.purgeAdmissionActive++
 	release := func() { releaseOnce.Do(d.releasePurgeAdmission) }
 	defer release()
+	if !effect.ac.consumeSamePeerOffer(request.Target) {
+		d.sendSamePeerSwitchFailure(effect, request.RequestID, protocol.SamePeerSwitchStaleTarget)
+		return
+	}
 	target, targetTabIndex, ok := d.samePeerTarget(request)
 	if !ok || target == effect.sess {
 		d.sendSamePeerSwitchFailure(effect, request.RequestID, protocol.SamePeerSwitchStaleTarget)

M internal/usecase/daemon/same_peer_switch_test.go +10 -3


@@ -133,11 +133,13 @@ func TestSamePeerSwitchClientInitiated(t *testing.T) {
133	133		offer *protocol.ExactSessionTarget
134	134		purging bool
135	135		switched bool
	136	+	wantCode protocol.SamePeerSwitchFailureCode
136	137		}{
137	138		{name: "no pending offer switches", switched: true},
138	139		{name: "matching offer switches", offer: &requestTarget, switched: true},
139		-	{name: "another pending offer refuses", offer: &otherOffer},
140		-	{name: "a running purge refuses", purging: true},
	140	+	{name: "another pending offer refuses", offer: &otherOffer, wantCode: protocol.SamePeerSwitchStaleTarget},
	141	+	{name: "a running purge refuses", purging: true, wantCode: protocol.SamePeerSwitchUnavailable},
	142	+	{name: "a running purge keeps the pending offer", offer: &requestTarget, purging: true, wantCode: protocol.SamePeerSwitchUnavailable},
141	143		}
142	144		for _, tt := range tests {
143	145		t.Run(tt.name, func(t *testing.T) {

@@ -179,7 +181,12 @@ func TestSamePeerSwitchClientInitiated(t *testing.T) {
179	181		}
180	182		require.Same(t, source, ac.currentAttachmentSession())
181	183		failure := decodeServerMessage(t, awaitFrame(t, sends, "SamePeerSwitchFailure")).(protocol.SamePeerSwitchFailure)
182		-	require.Equal(t, protocol.SamePeerSwitchStaleTarget, failure.Code)
	184	+	require.Equal(t, tt.wantCode, failure.Code)
	185	+	if tt.offer != nil {
	186	+	ac.samePeerOfferMu.Lock()
	187	+	defer ac.samePeerOfferMu.Unlock()
	188	+	require.Equal(t, tt.offer, ac.samePeerOffer, "a refused switch keeps the pending offer")
	189	+	}
183	190		})
184	191		}
185	192		}

 		offer    *protocol.ExactSessionTarget
 		purging  bool
 		switched bool
+		wantCode protocol.SamePeerSwitchFailureCode
 	}{
 		{name: "no pending offer switches", switched: true},
 		{name: "matching offer switches", offer: &requestTarget, switched: true},
-		{name: "another pending offer refuses", offer: &otherOffer},
+		{name: "another pending offer refuses", offer: &otherOffer, wantCode: protocol.SamePeerSwitchStaleTarget},
-		{name: "a running purge refuses", purging: true},
+		{name: "a running purge refuses", purging: true, wantCode: protocol.SamePeerSwitchUnavailable},
+		{name: "a running purge keeps the pending offer", offer: &requestTarget, purging: true, wantCode: protocol.SamePeerSwitchUnavailable},
 	}
 	for _, tt := range tests {
 		t.Run(tt.name, func(t *testing.T) {
 			}
 			require.Same(t, source, ac.currentAttachmentSession())
 			failure := decodeServerMessage(t, awaitFrame(t, sends, "SamePeerSwitchFailure")).(protocol.SamePeerSwitchFailure)
-			require.Equal(t, protocol.SamePeerSwitchStaleTarget, failure.Code)
+			require.Equal(t, tt.wantCode, failure.Code)
+			if tt.offer != nil {
+				ac.samePeerOfferMu.Lock()
+				defer ac.samePeerOfferMu.Unlock()
+				require.Equal(t, tt.offer, ac.samePeerOffer, "a refused switch keeps the pending offer")
+			}
 		})
 	}
 }