fleetd #669: report collaborator reload restart

fleetd/src/main/java/dev/ltms/fleet/config/ConfigRef.java

@@ -615,7 +615,7 @@ public final class ConfigRef implements Supplier<FleetConfig> {
         // may bind to, AND what a slot already bound still grants) through its own instance of that
         // same supplier shape — see MemberRegistry.live and its class doc for the binding rule:
         // removing a slot revokes ARCHITECT on the bound pane's very next request, and only the slot
-        // OCCUPANCY survives, so the demoted session keeps its slot key until it unbinds. Only
+        // OCCUPANCY survives, so the demoted session keeps its slot key until it unbinds.
         // fleet.leaders is frozen (Fleetd.java:281 reads cfg.fleet().leaders() off the startup
         // snapshot to build both the LeadTabScanner's tab-label-to-name map, wired into
         // CallerResolver.withLeadsAndMembers at Fleetd.java:620/624, and — when herdr answered —
@@ -635,6 +635,11 @@ public final class ConfigRef implements Supplier<FleetConfig> {
                     + "live through that same supplier for placement AND through a separate supplier "
                     + "on MemberRegistry for spawn-time identity — both already applied");
         }
+        if (!Objects.equals(collaboratorsOf(old), collaboratorsOf(fresh))) {
+            changed.add("fleet: fleet.collaborators (each collaborator's tab) is read once at "
+                    + "startup to build the LeadTabScanner's identity map, which is not rebuilt on "
+                    + "reload, so a collaborator added, removed, or given a new tab: needs a restart");
+        }
         // Kept in step with SPLIT_KEYS the same way changedColdKeys is kept in step with COLD_KEYS —
         // every message here must be traceable to one of the split keys the class doc documents.
         // NOTE what this does NOT prove, per the javadoc above: it does not catch a SPLIT_KEYS
@@ -650,6 +655,11 @@ public final class ConfigRef implements Supplier<FleetConfig> {
         return cfg.fleet() == null ? Map.of() : cfg.fleet().leaders();
     }
 
+    /** {@code cfg.fleet().collaborators()}, defensively, in case a caller hands in a non-defaulted config. */
+    private static Map<String, FleetConfig.Collaborator> collaboratorsOf(FleetConfig cfg) {
+        return cfg.fleet() == null ? Map.of() : cfg.fleet().collaborators();
+    }
+
     /**
      * {@link FleetConfig.Profile} record components deliberately left out of
      * {@link #sameLaunchSettings} because they are read <em>live</em>, not baked in at spawn — see

fleetd/src/test/java/dev/ltms/fleet/config/ConfigRefTest.java

@@ -107,6 +107,8 @@ class ConfigRefTest {
 
         assertTrue(out.applied());
         assertTrue(out.deferred().isEmpty());
+        assertTrue(out.split().stream().noneMatch(s -> s.contains("fleet.collaborators")),
+                out.split().toString());
         assertEquals("new charter", ref.get().fleet().charterFor(
                 dev.ltms.fleet.peer.MemberRole.ARCHITECT));
     }
@@ -786,14 +788,100 @@ class ConfigRefTest {
         assertTrue(out.split().getFirst().startsWith("fleet:"), out.split().toString());
         assertTrue(out.split().getFirst().contains("restart"), out.split().toString());
         assertTrue(out.split().getFirst().contains("live"), out.split().toString());
+        assertTrue(out.split().stream().noneMatch(s -> s.contains("fleet.collaborators")),
+                out.split().toString());
         assertTrue(out.summary().contains("partially live"), out.summary());
         // The snapshot still carries the new value — the LeadTabScanner's identity map and
         // LeadLauncher's auto-launch are what wait for a restart; a reload rebuilds neither.
         assertEquals("lead: opus-b", ref.get().fleet().leaders().get("opus").tab());
     }
 
+    @Test
+    void addingAFleetCollaboratorIsReportedAsSplit(@TempDir Path dir) throws Exception {
+        assertCollaboratorChangeIsReported(dir, """
+                fleet:
+                  collaborators:
+                    alex:
+                      tab: "collaborator: alex"
+                """, "add a collaborator");
+    }
+
+    @Test
+    void removingAFleetCollaboratorIsReportedAsSplit(@TempDir Path dir) throws Exception {
+        Path f = dir.resolve("fleetd.yaml");
+        Files.writeString(f, yaml("""
+                fleet:
+                  collaborators:
+                    alex:
+                      tab: "collaborator: alex"
+                """));
+        ConfigRef ref = refFor(f);
+
+        Files.writeString(f, yaml("fleet: {}\n"));
+        assertCollaboratorSplit(ref.reload(), "remove a collaborator");
+    }
+
+    @Test
+    void changingAFleetCollaboratorTabIsReportedAsSplit(@TempDir Path dir) throws Exception {
+        Path f = dir.resolve("fleetd.yaml");
+        Files.writeString(f, yaml("""
+                fleet:
+                  collaborators:
+                    alex:
+                      tab: "collaborator: alex-a"
+                """));
+        ConfigRef ref = refFor(f);
+
+        Files.writeString(f, yaml("""
+                fleet:
+                  collaborators:
+                    alex:
+                      tab: "collaborator: alex-b"
+                """));
+        assertCollaboratorSplit(ref.reload(), "change a collaborator tab");
+    }
+
+    @Test
+    void unchangedFleetCollaboratorsProduceNoSplitReport(@TempDir Path dir) throws Exception {
+        Path f = dir.resolve("fleetd.yaml");
+        String config = yaml("""
+                fleet:
+                  collaborators:
+                    alex:
+                      tab: "collaborator: alex"
+                """);
+        Files.writeString(f, config);
+        ConfigRef ref = refFor(f);
+
+        Files.writeString(f, config);
+        ConfigRef.Outcome out = ref.reload();
+
+        assertTrue(out.applied());
+        assertTrue(out.split().isEmpty(), out.split().toString());
+    }
+
+    private static void assertCollaboratorChangeIsReported(Path dir, String changed, String action)
+            throws Exception {
+        Path f = dir.resolve("fleetd.yaml");
+        Files.writeString(f, yaml("fleet: {}\n"));
+        ConfigRef ref = refFor(f);
+
+        Files.writeString(f, yaml(changed));
+        assertCollaboratorSplit(ref.reload(), action);
+    }
+
+    private static void assertCollaboratorSplit(ConfigRef.Outcome out, String action) {
+        assertTrue(out.applied(), action);
+        assertTrue(out.deferred().isEmpty(), out.deferred().toString());
+        assertEquals(1, out.split().size(), out.split().toString());
+        String report = out.split().getFirst();
+        assertTrue(report.startsWith("fleet: fleet.collaborators"), report);
+        assertTrue(report.contains("read once at startup"), report);
+        assertTrue(report.contains("restart"), report);
+    }
+
     /**
-     * fleetd #333: {@code fleet.leaders} is the ONLY frozen part of {@code fleet:}. A reload that
+     * fleetd #333: {@code fleet.leaders} is a frozen part of {@code fleet:}. A reload that
      * changes {@code tabLabel} (or charters, or a role pool) without touching {@code fleet.leaders}
      * must stay fully hot with nothing reported — proving {@link ConfigRef#changedSplitKeys}
      * compares {@code fleet.leaders} specifically rather than the whole {@code Fleet} record, which