Merge CB-576: release preserves a dirty worktree instead of deleting it

Verified by the lead on b525b0f: mvn -f bridged/pom.xml clean install, unpiped, in a scratch
worktree — MVN_EXIT=0, Tests run: 686, Failures: 0, Errors: 0, BUILD SUCCESS.

Review accepted the required-interface-method shape (no defaulting overload) and the decision to
count untracked files as dirty — the work lost in the incident was a file that was never added.

One blocking defect was found and fixed in b525b0f: hasUncommitted called git with no existence
check, so a missing worktree threw WorktreeException from inside release() after registry.remove()
but before notifyReleased() and launcher.stop(), orphaning the pane and stranding a blocked
bridge_send caller. It now mirrors remove()'s already-gone tolerance.

Waived on merge, tracked as follow-up: a SessionManager-level test that teardown completes when the
worktree is gone, and the stronger fix behind it — reapIdle calls release() with no try/catch while
drainAll wraps it, so any exception in that window aborts the whole reaping pass.

bridged/src/main/java/dev/ltms/bridged/session/GitWorktrees.java

@@ -167,6 +167,22 @@ public final class GitWorktrees implements Worktrees {
         exec("git", "-C", repoRoot, "worktree", "remove", "--force", worktreePath);
     }
 
+    @Override
+    public boolean hasUncommitted(String worktreePath) {
+        // A worktree that is already gone holds no work to lose, and it must not break teardown:
+        // git -C <missing-dir> status exits non-zero and would throw where release() is mid-way
+        // through stopping a pane. Mirror remove()'s already-gone tolerance by treating it as clean.
+        Path p = Path.of(worktreePath);
+        if (!Files.exists(p)) {
+            log.debug("worktree {} already gone — nothing can be uncommitted", worktreePath);
+            return false;
+        }
+        // No --untracked-files=no: the exact shape of the work lost in CB-576 was a new file
+        // that was never added, so an untracked-only worktree is still dirty.
+        String out = exec("git", "-C", worktreePath, "status", "--porcelain");
+        return !out.isBlank();
+    }
+
     @Override
     public void overlayParity(String repoRoot, String worktreePath, List<String> overlay) {
         if (overlay == null || overlay.isEmpty()) {

bridged/src/main/java/dev/ltms/bridged/session/SessionManager.java

@@ -201,6 +201,16 @@ public final class SessionManager implements TurnListener {
                     removed.paneId(), removed.terminalId(), removed.state(), cause);
             if (preserveWorktree && removed.worktree() != null) {
                 logPreservedForShutdown(removed);
+            } else if (removed.worktree() != null && worktrees.hasUncommitted(removed.worktree())) {
+                // CB-576: a release that would otherwise remove the worktree finds it holding
+                // uncommitted work the bridge cannot see. A worker that ends a turn without
+                // committing (normally because it stopped to ask a question or refused the turn)
+                // has its only copy of that work in the worktree. Remove would --force-delete it,
+                // so preserve the directory and tell an operator where to find it.
+                preserveWorktree = true;
+                log.warn("release {} preserves dirty worktree {} for pane={} terminal={}: "
+                        + "the worktree holds uncommitted changes that --force remove would destroy",
+                        cause, removed.worktree(), removed.paneId(), removed.terminalId());
             }
             // CB-516: a send still waiting on this worker can never be answered now. Tell the
             // listener BEFORE the pane is torn down, so a blocked caller fails fast with a real

bridged/src/main/java/dev/ltms/bridged/session/Worktrees.java

@@ -10,6 +10,18 @@ public interface Worktrees {
     /** git -C <repoRoot> worktree remove --force <path>. Idempotent (already-gone tolerated). */
     void remove(String repoRoot, String worktreePath);
 
+    /**
+     * True when the worktree holds uncommitted changes the bridge cannot see: tracked
+     * modifications, staged files, or untracked files. {@code git status --porcelain} is the
+     * test; an empty result means clean. Callers use this to decide whether removing the
+     * worktree would silently destroy a worker's only copy of its work.
+     *
+     * <p>An already-gone worktree is reported as clean (no throw), matching {@link #remove}'s
+     * idempotent contract: a path that does not exist holds no work to lose, and must not break
+     * a teardown that is mid-way through stopping the pane.
+     */
+    boolean hasUncommitted(String worktreePath);
+
     /** Copy each existing overlay path repoRoot→worktree; mark tracked ones --skip-worktree. */
     void overlayParity(String repoRoot, String worktreePath, List<String> overlay);
 

bridged/src/test/java/dev/ltms/bridged/session/FakeWorktrees.java

@@ -29,6 +29,7 @@ public final class FakeWorktrees implements Worktrees {
     private final Set<String> existingPaths = ConcurrentHashMap.newKeySet();
     private final Set<String> trackedPaths = ConcurrentHashMap.newKeySet();
     private volatile RuntimeException addFailure;
+    private volatile boolean dirty = false;
     private volatile String repoRoot = "/repo";
     private volatile String prefix = "/worktrees";
 
@@ -61,6 +62,12 @@ public final class FakeWorktrees implements Worktrees {
         return this;
     }
 
+    /** Mark the worktree dirty so {@link #hasUncommitted} reports true (simulates uncommitted work). */
+    public FakeWorktrees withDirty(boolean dirty) {
+        this.dirty = dirty;
+        return this;
+    }
+
     @Override
     public String add(String repoRoot, String branch, String baseRef) {
         addCalls.add(new AddCall(repoRoot, branch, baseRef));
@@ -77,6 +84,11 @@ public final class FakeWorktrees implements Worktrees {
         removeCalls.add(new RemoveCall(repoRoot, worktreePath));
     }
 
+    @Override
+    public boolean hasUncommitted(String worktreePath) {
+        return dirty;
+    }
+
     @Override
     public void overlayParity(String repoRoot, String worktreePath, List<String> overlay) {
         List<String> copied = new java.util.ArrayList<>();

bridged/src/test/java/dev/ltms/bridged/session/GitWorktreesTest.java

@@ -175,6 +175,46 @@ class GitWorktreesTest {
         assertTrue(Files.exists(Path.of(wt).resolve(".mcp.json")), ".mcp.json stub was dropped");
     }
 
+    /**
+     * CB-576. {@code hasUncommitted} must treat a freshly-provisioned worktree as clean, but a
+     * worktree holding a brand-new, never-added file as dirty. The untracked-file-only shape is
+     * exactly the work lost in the incident — a worker's draft that compiled but was never
+     * committed because it stopped to ask its lead a question.
+     */
+    @Test
+    void anUntrackedOnlyWorktreeCountsAsDirty(@TempDir Path tmp) throws Exception {
+        Path repo = initRepo(tmp.resolve("repo"));
+        GitWorktrees gitWorktrees = new GitWorktrees(tmp.resolve("wts").toString());
+        String wt = gitWorktrees.add(repo.toString(), "cb-576-u", "HEAD");
+
+        assertFalse(gitWorktrees.hasUncommitted(wt),
+                "a freshly provisioned worktree must read as clean");
+
+        Files.writeString(Path.of(wt).resolve("brand-new.txt"), "draft that was never added\n");
+
+        assertTrue(gitWorktrees.hasUncommitted(wt),
+                "an untracked-only file must count as dirty");
+
+        Files.writeString(Path.of(wt).resolve("README.md"), "edited tracked file\n");
+        assertTrue(gitWorktrees.hasUncommitted(wt),
+                "a tracked modification must also count as dirty");
+    }
+
+    /**
+     * CB-576 review. {@code hasUncommitted} must tolerate a missing worktree exactly like
+     * {@code remove}: an already-gone directory holds no work to lose, and throwing here would
+     * break teardown — SessionManager.release() calls it before stopping the pane, so an
+     * exception would orphan a live pane and skip the release notification (CB-516).
+     */
+    @Test
+    void hasUncommittedOnAMissingWorktreeReturnsFalseWithoutThrowing(@TempDir Path tmp) {
+        GitWorktrees gitWorktrees = new GitWorktrees(tmp.resolve("wts").toString());
+        String gone = tmp.resolve("wts").resolve("does-not-exist").toString();
+
+        assertFalse(gitWorktrees.hasUncommitted(gone),
+                "a missing worktree is reported clean, not an error");
+    }
+
     /** All three protected configs are covered: each one present in a worktree is neutralized and hidden. */
     @Test
     void allThreeConfigsAreNeutralizedWhenPresent(@TempDir Path tmp) throws Exception {

bridged/src/test/java/dev/ltms/bridged/session/WorktreeSessionManagerTest.java

@@ -6,10 +6,15 @@ import dev.ltms.bridged.guard.SubscriptionGuard;
 import dev.ltms.bridged.herdr.AgentControl;
 import dev.ltms.bridged.herdr.FakeHerdr;
 import dev.ltms.bridged.herdr.WorkspaceControl;
+import ch.qos.logback.classic.Level;
+import ch.qos.logback.classic.LoggerContext;
+import ch.qos.logback.classic.spi.ILoggingEvent;
+import ch.qos.logback.core.read.ListAppender;
 import dev.ltms.bridged.member.ClaudeCodeLauncher;
 import dev.ltms.bridged.msg.TestTurnTokens;
 import dev.ltms.bridged.peer.MemberRole;
 import org.junit.jupiter.api.Test;
+import org.slf4j.LoggerFactory;
 
 import java.util.List;
 import java.util.Map;
@@ -179,6 +184,49 @@ class WorktreeSessionManagerTest {
         assertTrue(sessions.get(paneId).isEmpty(), "released session is no longer retrievable");
     }
 
+    /**
+     * CB-576. A normal {@code COMPLETED} release whose worktree holds uncommitted work must NOT
+     * remove it — {@code --force} would destroy the worker's only copy. The bridge cannot see
+     * uncommitted files, so the worktree is preserved and the release logged at WARN naming the
+     * path, the session, and the cause an operator needs to find the work.
+     */
+    @Test
+    void releasePreservesDirtyWorktreeAndLogsWarn() {
+        FakeHerdr herdr = new FakeHerdr();
+        FakeWorktrees worktrees = new FakeWorktrees().withRepoRoot("/repo").withPrefix("/wt")
+                .withDirty(true);
+        SessionManager sessions = new SessionManager(workerService(herdr), worktrees);
+        MemberSession s = sessions.acquire("ltms-local", null, "/caller/proj", null,
+                new WorktreeRequest("cb-576", null));
+
+        LoggerContext ctx = (LoggerContext) LoggerFactory.getILoggerFactory();
+        ch.qos.logback.classic.Logger sessionLog =
+                (ch.qos.logback.classic.Logger) LoggerFactory.getLogger(SessionManager.class);
+        ListAppender<ILoggingEvent> appender = new ListAppender<>();
+        appender.setContext(ctx);
+        appender.start();
+        sessionLog.addAppender(appender);
+        sessionLog.setLevel(Level.WARN);
+        try {
+            sessions.release(s.paneId());
+
+            assertTrue(herdr.called("pane.close"), "release still tears the worker pane down");
+            assertTrue(worktrees.removeCalls().isEmpty(),
+                    "a dirty worktree is never removed — it holds the only copy of the work");
+            String warn = appender.list.stream()
+                    .filter(e -> e.getLevel().equals(Level.WARN))
+                    .map(ILoggingEvent::getFormattedMessage)
+                    .filter(m -> m.contains("dirty worktree"))
+                    .findFirst()
+                    .orElse("no dirty-release WARN logged");
+            assertTrue(warn.contains(s.worktree()), "the WARN names the worktree path: " + warn);
+            assertTrue(warn.contains(s.terminalId()), "the WARN names the session: " + warn);
+            assertTrue(warn.contains("COMPLETED"), "the WARN names the release cause: " + warn);
+        } finally {
+            sessionLog.detachAppender(appender);
+        }
+    }
+
     @Test
     void drainAllPreservesWorktreeOfIdleSession() {
         FakeHerdr herdr = new FakeHerdr();

docs/M4-Fleet-Health.md

@@ -237,7 +237,7 @@ state never presents stop as the only action.
 | Release cause | Process action | Provisioned worktree |
 |---|---|---|
 | `SPAWN_ROLLBACK` before registration or delivery | Stop and clean up | Remove |
-| `COMPLETED` for `READY` or `DONE` without pending work, idle TTL, or successful context-cap completion | Stop | Remove under completed policy |
+| `COMPLETED` for `READY` or `DONE` without pending work, idle TTL, or successful context-cap completion | Stop | Remove only if clean; preserve a dirty worktree (CB-576) |
 | `NEVER_READY` | Stop | Preserve |
 | `GONE` | Best-effort stop | Preserve |
 | `TURN_FAILED` or lead abort while `BUSY` or `FAILED` | Stop | Preserve |