[client] X11: release pointer after capture

Normal input now uses absolute positioning, so retaining the XI pointer
grab after capture leaves no later path to release it.

Always release the grab so leaving the window works again and the
uncapture path can align the host cursor to the guest position.

client/displayservers/X11/x11.c

@@ -2103,18 +2103,8 @@ static void x11CapturePointer(void)
 
 static void x11UncapturePointer(void)
 {
-  const bool ungrab = !app_isFormatValid() || app_isCaptureOnlyMode();
-
   LG_LOCK(x11.pointerLock);
   atomic_store_explicit(&x11.captureActive, false, memory_order_release);
-
-  /* we need to ungrab the pointer on the following conditions when exiting capture mode:
-   *   - if the format is invalid as we do not know where the guest cursor is,
-   *     which breaks edge detection as the cursor can not be warped out of the
-   *     window when we release it.
-   *   - if the user has opted to use captureInputOnly mode.
-   */
-  if (ungrab)
   x11UngrabPointerLocked();
   LG_UNLOCK(x11.pointerLock);
 }

client/tests/CMakeLists.txt

@@ -126,6 +126,7 @@ set(MOUSE_CASES
   capture-revoked
   capture-release
   capture-align
+  x11-capture-exit
   capture-fallback
   rotate-scale
   geometry

client/tests/mouse_test.c

@@ -67,6 +67,7 @@ static struct
   struct Trap           conf;
   struct Trap           lock;
   bool                  valid;
+  bool                  captureGrab;
   struct Ev             ev[256];
   unsigned int          count;
 }
@@ -152,6 +153,18 @@ static void capture(void)
     return;
   }
 
+  if (m.captureGrab)
+  {
+    m.conf.req = true;
+    if (!m.conf.hold)
+      m.conf.on = true;
+    m.lock.req = true;
+    if (!m.lock.hold)
+      m.lock.on = m.conf.on;
+    push(EV_CAPTURE, 0, 0, false);
+    return;
+  }
+
   m.conf.req = false;
   if (!m.conf.hold)
     m.conf.on = false;
@@ -171,6 +184,9 @@ static void uncapture(void)
   m.lock.req = false;
   if (!m.lock.hold)
     m.lock.on = false;
+
+  if (m.captureGrab)
+    ungrab();
 }
 
 static bool captured(void)
@@ -592,6 +608,38 @@ static void testCapAlign(void)
   CHECK(!m.ev[warp].exit);
 }
 
+static void testX11CapExit(void)
+{
+  reset();
+  setLocal(50, 50);
+  m.support     = LG_DS_WARP_SCREEN;
+  m.captureGrab = true;
+  m.conf.req    = false;
+  m.conf.on     = false;
+
+  core_setGrabQuiet(true);
+  CHECK(m.conf.on);
+  CHECK(m.lock.on);
+
+  g_cursor.guest.x += 10;
+  m.count = 0;
+  core_setGrabQuiet(false);
+
+  const int uncapture = first(EV_UNCAPTURE);
+  const int ungrab    = first(EV_UNGRAB);
+  const int warp      = first(EV_WARP);
+  CHECK(uncapture >= 0);
+  CHECK(ungrab > uncapture);
+  CHECK(warp > ungrab);
+  CHECK(m.ev[warp].x == 60);
+  CHECK(m.ev[warp].y == 50);
+  CHECK(!m.ev[warp].exit);
+  CHECK(!m.conf.req);
+  CHECK(!m.conf.on);
+  CHECK(!m.lock.req);
+  CHECK(!m.lock.on);
+}
+
 static void testCapFallback(void)
 {
   reset();
@@ -853,6 +901,7 @@ static const struct Test tests[] = {
   { "capture-revoked" , testCapRevoke    },
   { "capture-release" , testCapRelease   },
   { "capture-align"   , testCapAlign     },
+  { "x11-capture-exit", testX11CapExit   },
   { "capture-fallback", testCapFallback  },
   { "rotate-scale"    , testRotateScale  },
   { "geometry"        , testGeometry     },