CB-547b: opencode session identity — resume (-s) + post-hoc session discovery

bridged/src/test/java/dev/ltms/bridged/worker/OpenCodeLauncherTest.java

@@ -37,7 +37,7 @@ class OpenCodeLauncherTest {
     private OpenCodeLauncher service(FakeHerdr herdr, Path configRoot, BridgedConfig.Worker cfg) {
         return new OpenCodeLauncher(new AgentControl(herdr), new WorkspaceControl(herdr),
                 Map.of(cfg.profile(), cfg), cfg.profile(), k -> "GITEA_ACCESS_TOKEN".equals(k) ? "tok" : null,
-                0, System::currentTimeMillis, () -> { }, configRoot);
+                0, System::currentTimeMillis, () -> { }, configRoot, configRoot);
     }
 
     @SuppressWarnings("unchecked")
@@ -130,14 +130,65 @@ class OpenCodeLauncherTest {
     @Test
     void capabilitiesDeclareOrphanReapAndMcpAskAndConditionalSelfPr(@TempDir Path root) {
         FakeHerdr herdr = new FakeHerdr();
-        assertEquals(java.util.Set.of(Capability.MID_TURN_ASK, Capability.WORKTREE, Capability.ORPHAN_REAP),
+        assertEquals(java.util.Set.of(Capability.MID_TURN_ASK, Capability.WORKTREE, Capability.ORPHAN_REAP,
+                        Capability.SESSION_RESUME),
                 service(herdr, root, opencodeCfg(null, null, null)).capabilities(),
-                "no git token → no SELF_PR");
+                "opencode can be resumed by its own session id, so SESSION_RESUME is always declared");
+        assertFalse(service(herdr, root, opencodeCfg(null, null, null))
+                        .capabilities().contains(Capability.SESSION_NAME),
+                "opencode has no display-name flag, so SESSION_NAME must NOT be declared");
         assertTrue(service(herdr, root, opencodeCfg(null, null, "GITEA_ACCESS_TOKEN"))
                         .capabilities().contains(Capability.SELF_PR),
                 "a git-token profile adds SELF_PR");
     }
 
+    // --- CB-547: resume + post-hoc session discovery --------------------------------------------
+
+    @Test
+    void aResumeSpawnPassesTheSessionIdAsDashS(@TempDir Path root) {
+        FakeHerdr herdr = new FakeHerdr();
+        service(herdr, root, opencodeCfg("google/gemini-2.5-pro", null, null))
+                .spawn(new SpawnRequest(null, null, null, null, "ses_41b79fc90ffeI9E8uZv6VprUn2"));
+
+        List<String> args = startArgs(herdr);
+        int s = args.indexOf("-s");
+        assertTrue(s >= 0, "a resumed spawn carries opencode's -s flag");
+        assertEquals("ses_41b79fc90ffeI9E8uZv6VprUn2", args.get(s + 1),
+                "the resume target id follows -s");
+    }
+
+    @Test
+    void aFreshSpawnCarriesNoSessionFlag(@TempDir Path root) {
+        FakeHerdr herdr = new FakeHerdr();
+        service(herdr, root, opencodeCfg(null, null, null))
+                .spawn(new SpawnRequest(null, null, null, null, null));
+
+        assertFalse(startArgs(herdr).contains("-s"),
+                "no resume target → a fresh session with no -s flag");
+    }
+
+    @Test
+    void theHandleDiscoversTheSessionIdForTheWorkersCwdOnlyAfterItAppears(@TempDir Path root,
+                                                                          @TempDir Path discRoot)
+            throws Exception {
+        FakeHerdr herdr = new FakeHerdr();
+        OpenCodeLauncher launcher = new OpenCodeLauncher(new AgentControl(herdr),
+                new WorkspaceControl(herdr), Map.of("gemini", opencodeCfg(null, null, null)),
+                "gemini", _ -> null, 0, System::currentTimeMillis, () -> { }, root, discRoot);
+
+        PeerHandle handle = launcher.spawn(new SpawnRequest(null, "/work/dir", null));
+
+        // opencode writes the record only when the session is first persisted — the instant the
+        // pane is ready it does not exist, so agentSessionId() is null (never a spawn failure).
+        assertNull(handle.agentSessionId(), "no record yet → null, not a spawn-time block");
+        // Once the record appears (here: same cwd), lazy discovery resolves it — the handle's
+        // session id matches its own worktree, not another's.
+        OpenCodeSessionDiscoveryTest.writeRecord(discRoot, "p1", "ses_a.json",
+                "ses_resolved", "/work/dir", 1000L);
+        assertEquals("ses_resolved", handle.agentSessionId(),
+                "agentSessionId() re-scans and picks up a record that has since been written");
+    }
+
     @Test
     void foreignWorkerMatchesOpencodePrefixButNotClaude() {
         String nonce = "abc123";
@@ -169,7 +220,7 @@ class OpenCodeLauncherTest {
         long[] clock = {0};
         OpenCodeLauncher svc = new OpenCodeLauncher(new AgentControl(herdr), new WorkspaceControl(herdr),
                 Map.of("gemini", opencodeCfg(null, null, null)), "gemini", _ -> null,
-                1000, () -> clock[0], () -> clock[0] += 50, root);
+                1000, () -> clock[0], () -> clock[0] += 50, root, root);
 
         PeerUnreachableException ex = assertThrows(PeerUnreachableException.class,
                 () -> svc.spawn(new SpawnRequest(null, null, null)));

bridged/src/test/java/dev/ltms/bridged/worker/OpenCodeSessionDiscoveryTest.java

@@ -0,0 +1,90 @@
+package dev.ltms.bridged.worker;
+
+import org.junit.jupiter.api.Test;
+import org.junit.jupiter.api.io.TempDir;
+
+import java.nio.file.Files;
+import java.nio.file.Path;
+import java.nio.file.attribute.FileTime;
+
+import static org.junit.jupiter.api.Assertions.*;
+
+/**
+ * {@link OpenCodeSessionDiscovery} matches an opencode session record by the worker's cwd (its
+ * {@code directory}) against opencode's on-disk storage. These tests populate a TEMP storage root
+ * themselves — never the operator's real {@code ~/.local/share/opencode}.
+ */
+class OpenCodeSessionDiscoveryTest {
+
+    /**
+     * Write a session record {@code {"id":..., "directory":...}} under
+     * {@code <root>/session/<projectID>/<fileName>} and stamp it with a known last-modified time,
+     * so "most recently modified wins" is deterministic. Static so the launcher test can reuse it.
+     */
+    static void writeRecord(Path root, String projectId, String fileName, String id,
+                            String directory, long lastModifiedEpochMillis) throws Exception {
+        Path dir = root.resolve("session").resolve(projectId);
+        Files.createDirectories(dir);
+        Path file = dir.resolve(fileName);
+        Files.writeString(file, "{\"id\":\"" + id + "\",\"directory\":\"" + directory
+                + "\",\"projectID\":\"" + projectId + "\",\"version\":\"1.1.31\"}");
+        Files.setLastModifiedTime(file, FileTime.fromMillis(lastModifiedEpochMillis));
+    }
+
+    @Test
+    void findsTheRecordWhoseDirectoryEqualsTheCwd(@TempDir Path root) throws Exception {
+        writeRecord(root, "p1", "ses_a.json", "ses_aaa", "/w/a", 1000L);
+        writeRecord(root, "p2", "ses_b.json", "ses_bbb", "/w/b", 2000L);
+
+        assertEquals("ses_bbb", new OpenCodeSessionDiscovery(root).sessionIdForDirectory("/w/b"),
+                "the record whose directory equals the cwd is the one found");
+        assertEquals("ses_aaa", new OpenCodeSessionDiscovery(root).sessionIdForDirectory("/w/a"));
+    }
+
+    @Test
+    void aNonMatchingDirectoryYieldsNullRatherThanAMismatch(@TempDir Path root) throws Exception {
+        writeRecord(root, "p1", "ses_a.json", "ses_aaa", "/w/a", 1000L);
+
+        assertNull(new OpenCodeSessionDiscovery(root).sessionIdForDirectory("/w/other"),
+                "no record for this cwd yet → null, not a wrong session");
+    }
+
+    @Test
+    void prefersTheMostRecentlyModifiedRecordWhenSeveralMatch(@TempDir Path root) throws Exception {
+        writeRecord(root, "p1", "old.json", "ses_old", "/w/a", 1000L);
+        writeRecord(root, "p2", "new.json", "ses_new", "/w/a", 5000L);
+
+        assertEquals("ses_new", new OpenCodeSessionDiscovery(root).sessionIdForDirectory("/w/a"),
+                "the freshest record for the cwd wins");
+    }
+
+    @Test
+    void aMissingOrEmptyStorageRootYieldsNullWithoutThrowing(@TempDir Path root) throws Exception {
+        // Missing: no session dir at all under the root.
+        assertNull(new OpenCodeSessionDiscovery(root).sessionIdForDirectory("/w/a"));
+
+        // Present but empty: a session dir with nothing in it produces no match, not a throw.
+        Path emptyRoot = root.resolve("empty");
+        Files.createDirectories(emptyRoot.resolve("session"));
+        assertNull(new OpenCodeSessionDiscovery(emptyRoot).sessionIdForDirectory("/w/a"));
+    }
+
+    @Test
+    void aBlankOrNullDirectoryYieldsNull(@TempDir Path root) {
+        OpenCodeSessionDiscovery discovery = new OpenCodeSessionDiscovery(root);
+        assertNull(discovery.sessionIdForDirectory(null));
+        assertNull(discovery.sessionIdForDirectory("   "));
+    }
+
+    @Test
+    void aMalformedRecordIsSkippedRatherThanFatal(@TempDir Path root) throws Exception {
+        // A record that fails to parse must not abort the scan of its siblings.
+        Path dir = root.resolve("session").resolve("p1");
+        Files.createDirectories(dir);
+        Files.writeString(dir.resolve("broken.json"), "{not valid json");
+        writeRecord(root, "p1", "good.json", "ses_good", "/w/a", 1000L);
+
+        assertEquals("ses_good", new OpenCodeSessionDiscovery(root).sessionIdForDirectory("/w/a"),
+                "an unreadable record is skipped; a later valid one still matches");
+    }
+}