Releasing is reached directly by its test, and its javadoc names the real case

The javadoc said a losing releaseIfCurrent CAS is the call that arrives with no
known session. releaseIfCurrent is only called by the reaper, always with a
non-null expected, so it always has one; the null-known call is an overlapping
release that finds the registry entry already gone. The same wrong claim was in
a test's failure message.

Releasing, enter and leave drop private so SessionManagerTest binds them at
compile time. The six reflection helpers are gone, and a rename now breaks the
build instead of a test run.

fleetd/src/main/java/dev/ltms/fleet/session/SessionManager.java

@@ -368,18 +368,18 @@ public final class SessionManager implements TurnListener {
     /**
      * Depth count plus the terminal/role a mid-teardown pane belongs to, for
      * {@link #spawnedMemberRole}. The terminal/role come from whichever call into
-     * {@link #releaseWindow} first knew them — a losing {@link #releaseIfCurrent} CAS has no
-     * {@code known} session of its own, so it must not blank out what the winner already recorded.
+     * {@link #releaseWindow} first knew them: a call that finds the registry entry already gone
+     * passes a {@code null} session, and must not blank out what the first call recorded.
      */
-    private record Releasing(int depth, String terminalId, MemberRole role) {
-        private static Releasing enter(Releasing prior, MemberSession known) {
+    record Releasing(int depth, String terminalId, MemberRole role) {
+        static Releasing enter(Releasing prior, MemberSession known) {
             int depth = (prior == null ? 0 : prior.depth()) + 1;
             String terminalId = known != null ? known.terminalId() : prior == null ? null : prior.terminalId();
             MemberRole role = known != null ? known.role() : prior == null ? null : prior.role();
             return new Releasing(depth, terminalId, role);
         }
 
-        private Releasing leave() {
+        Releasing leave() {
             return depth <= 1 ? null : new Releasing(depth - 1, terminalId, role);
         }
     }

fleetd/src/test/java/dev/ltms/fleet/session/SessionManagerTest.java

@@ -2558,78 +2558,38 @@ class SessionManagerTest {
     }
 
     /**
-     * {@code Releasing} is private, so its {@code enter}/{@code leave} are reached through
-     * reflection. Each is called directly, never through {@link SessionManager#release} or
-     * {@link SessionManager#spawnedMemberRole}, so a test naming one of them exercises only that
-     * one — a regression in the other can never hide behind it.
+     * {@code Releasing.enter} and {@code Releasing.leave} are called directly here, never through
+     * {@link SessionManager#release} or {@link SessionManager#spawnedMemberRole}, so a test naming
+     * one of them exercises only that one — a regression in the other can never hide behind it.
      */
-    private static Object releasingOf(int depth, String terminalId, MemberRole role) throws ReflectiveOperationException {
-        Class<?> cls = Class.forName("dev.ltms.fleet.session.SessionManager$Releasing");
-        java.lang.reflect.Constructor<?> ctor = cls.getDeclaredConstructor(int.class, String.class, MemberRole.class);
-        ctor.setAccessible(true);
-        return ctor.newInstance(depth, terminalId, role);
-    }
-
-    private static Object releasingEnter(Object prior, MemberSession known) throws ReflectiveOperationException {
-        Class<?> cls = Class.forName("dev.ltms.fleet.session.SessionManager$Releasing");
-        java.lang.reflect.Method m = cls.getDeclaredMethod("enter", cls, MemberSession.class);
-        m.setAccessible(true);
-        return m.invoke(null, prior, known);
-    }
-
-    private static Object releasingLeave(Object releasing) throws ReflectiveOperationException {
-        java.lang.reflect.Method m = releasing.getClass().getDeclaredMethod("leave");
-        m.setAccessible(true);
-        return m.invoke(releasing);
-    }
-
-    private static int depthOf(Object releasing) throws ReflectiveOperationException {
-        java.lang.reflect.Method m = releasing.getClass().getDeclaredMethod("depth");
-        m.setAccessible(true);
-        return (int) m.invoke(releasing);
-    }
-
-    private static String terminalIdOf(Object releasing) throws ReflectiveOperationException {
-        java.lang.reflect.Method m = releasing.getClass().getDeclaredMethod("terminalId");
-        m.setAccessible(true);
-        return (String) m.invoke(releasing);
-    }
-
-    private static MemberRole roleOf(Object releasing) throws ReflectiveOperationException {
-        java.lang.reflect.Method m = releasing.getClass().getDeclaredMethod("role");
-        m.setAccessible(true);
-        return (MemberRole) m.invoke(releasing);
-    }
-
     @Test
-    void releasingLeaveStepsDownADepthGreaterThanOneInsteadOfRemovingIt() throws ReflectiveOperationException {
-        Object depthTwo = releasingOf(2, "term_a", MemberRole.DEV);
+    void releasingLeaveStepsDownADepthGreaterThanOneInsteadOfRemovingIt() {
+        SessionManager.Releasing depthTwo = new SessionManager.Releasing(2, "term_a", MemberRole.DEV);
 
-        Object afterLeave = releasingLeave(depthTwo);
+        SessionManager.Releasing afterLeave = depthTwo.leave();
 
         assertNotNull(afterLeave,
                 "depth 2 means another release of the SAME pane is still mid-teardown; leave() must "
                         + "step the depth down, never remove the marker outright — removing it here "
                         + "is what a plain Set would do, and would reopen the window the still-in-"
                         + "flight release is relying on staying closed");
-        assertEquals(1, depthOf(afterLeave));
-        assertEquals("term_a", terminalIdOf(afterLeave));
-        assertEquals(MemberRole.DEV, roleOf(afterLeave));
+        assertEquals(1, afterLeave.depth());
+        assertEquals("term_a", afterLeave.terminalId());
+        assertEquals(MemberRole.DEV, afterLeave.role());
     }
 
     @Test
-    void releasingEnterPreservesThePriorTerminalWhenTheOverlappingCallHasNoSessionOfItsOwn()
-            throws ReflectiveOperationException {
-        Object prior = releasingOf(1, "term_a", MemberRole.DEV);
+    void releasingEnterPreservesThePriorTerminalWhenTheOverlappingCallHasNoSessionOfItsOwn() {
+        SessionManager.Releasing prior = new SessionManager.Releasing(1, "term_a", MemberRole.DEV);
 
-        Object afterEnter = releasingEnter(prior, null);
+        SessionManager.Releasing afterEnter = SessionManager.Releasing.enter(prior, null);
 
-        assertEquals(2, depthOf(afterEnter), "depth still increments whether or not this enter knows its session");
-        assertEquals("term_a", terminalIdOf(afterEnter),
-                "a losing CAS (the releaseIfCurrent race fleetd #702 is about) has no session of "
-                        + "its own to pass as known, and must not blank out the terminal the winning "
+        assertEquals(2, afterEnter.depth(), "depth still increments whether or not this enter knows its session");
+        assertEquals("term_a", afterEnter.terminalId(),
+                "an overlapping release that finds the registry entry already gone has no session of "
+                        + "its own to pass as known, and must not blank out the terminal the first "
                         + "call already recorded — that terminal is what spawnedMemberRole matches "
                         + "against");
-        assertEquals(MemberRole.DEV, roleOf(afterEnter));
+        assertEquals(MemberRole.DEV, afterEnter.role());
     }
 }