fix(opencode): a purge takes its child sessions' 1.x rows, the background service alone holds no session, XDG_DATA_HOME is followed (Issue #60, review)

- Review 614b6263 (codex, P2): `opencode session delete` removes the child
  sessions with their parent, but their 1.x rows stayed and the parent's
  residual was empty. The child sessions (session_v2 and a 1.x session
  table, any depth) are taken before the delete; the 1.x tables (message,
  part, todo, session_share, session) are cleaned for all of them, and the
  residual also reports a child still on record (a failed delete).
- The in-use check counted any process holding the shared opencode.db; the
  per-user 2.x background service (`serve --service`) holds it for every
  session, so every opencode purge was refused while it ran (it does on
  this Mac). It no longer counts; any other holder and a command line
  naming the session still do.
- The data dir follows the caller's XDG_DATA_HOME when ctx is the caller's
  own home (else <home>/.local/share), for debug paths, the fallback and the
  residual scan (review 614b6263 / f4cedbae N4).
- resident_children = ('opencode',): the --standalone server stays the TUI's
  idle child; what runs under it still counts (review 1abe0a90).
- Tests: child sessions on a migrated database, a failed delete, the service
  holder, XDG, resident children, drift C pinning the parent over a newer
  child session (review f4cedbae N2), and the real-binary test no longer
  depends on PATH (N1).

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01VCgu9Fa9iT7TbJUSzdq4Ff

tests/test_issue60_opencode_v2.py

@@ -18,6 +18,7 @@ import shutil
 import sqlite3
 import subprocess
 import sys
+import time
 from pathlib import Path
 
 import pytest
@@ -145,6 +146,122 @@ def test_a_failed_delete_is_warned_and_reported(oc, monkeypatch, capsys, broken)
     assert f"{adapter._resolve_db(ctx)} (session_v2.id: 1 rows)" in adapter.residual_artifacts("ses_main", ctx)
 
 
+def test_purge_takes_the_1x_rows_of_the_child_sessions_too(oc):
+    """A migrated database: the child sessions opencode deletes with their
+    parent keep 1.x rows that only the purge removes (review 614b6263)."""
+    adapter, ctx, db, ws, calls = oc
+    conn = sqlite3.connect(str(db))
+    conn.execute("CREATE TABLE session (id TEXT PRIMARY KEY, parent_id TEXT)")
+    conn.execute("CREATE TABLE message (id TEXT PRIMARY KEY, session_id TEXT)")
+    conn.execute("CREATE TABLE todo (id TEXT, session_id TEXT)")
+    conn.commit()
+    conn.close()
+    tree = [("ses_main", None), ("ses_child", "ses_main"), ("ses_grand", "ses_child"), ("ses_other", None)]
+    for sid, parent in tree:
+        _add(db, sid, ws, 2_000_000, parent=parent)
+        conn = sqlite3.connect(str(db))
+        conn.execute("INSERT INTO session VALUES (?, ?)", (sid, parent))
+        conn.execute("INSERT INTO message VALUES (?, ?)", (f"m-{sid}", sid))
+        conn.execute("INSERT INTO todo VALUES ('t', ?)", (sid,))
+        conn.commit()
+        conn.close()
+
+    assert any(r.endswith("[child session ses_grand]") for r in adapter.residual_artifacts("ses_main", ctx))
+    purged = adapter.purge_artifacts("ses_main", ctx)
+    assert purged == ["opencode session (with its child sessions): ses_main",
+                      "sqlite rows for session: ses_main and 2 child session(s)"]
+    for sid in ("ses_main", "ses_child", "ses_grand"):
+        assert adapter.residual_artifacts(sid, ctx) == [], sid
+    # the unrelated session is untouched: session_v2, session_message, event_sequence, session, message, todo
+    assert len(adapter.residual_artifacts("ses_other", ctx)) == 6
+
+
+def test_a_failed_delete_reports_the_child_sessions_left(oc, monkeypatch):
+    adapter, ctx, db, ws, calls = oc
+    _add(db, "ses_main", ws, 2_000_000)
+    _add(db, "ses_child", ws, 2_000_000, parent="ses_main")
+    monkeypatch.setattr(adapter, "_bin", lambda ctx: None)
+    adapter.purge_artifacts("ses_main", ctx)
+    residual = adapter.residual_artifacts("ses_main", ctx)
+    assert f"{db} (session_v2.id: 1 rows) [child session ses_child]" in residual
+    assert f"{db} (session_v2.id: 1 rows)" in residual
+
+
+def _holder(tmp_path, db, *argv):
+    """A live process holding `db` open, with `argv` on its command line."""
+    ready = tmp_path / f"ready-{len(argv)}"
+    code = ("import sys, time; f = open(sys.argv[1]); open(sys.argv[2], 'w').close(); time.sleep(60)")
+    p = subprocess.Popen([sys.executable, "-c", code, str(db), str(ready), *argv])
+    for _ in range(100):
+        if ready.exists():
+            break
+        time.sleep(0.05)
+    return p
+
+
+@pytest.mark.skipif(shutil.which("lsof") is None, reason="no lsof")
+def test_the_background_service_alone_does_not_hold_a_session(oc, tmp_path):
+    """The per-user service keeps the shared database open for every session
+    (2.x); MAM runs none of its sessions there."""
+    adapter, ctx, db, ws, calls = oc
+    _add(db, "ses_main", ws, 2_000_000)
+    assert adapter.conversation_in_use("ses_main", ctx) is False
+    service = _holder(tmp_path, db, "serve", "--service")
+    try:
+        assert adapter.conversation_in_use("ses_main", ctx) is False
+        other = _holder(tmp_path, db, "--auto", "--standalone")   # another session's TUI or its server
+        try:
+            assert adapter.conversation_in_use("ses_main", ctx) is True
+        finally:
+            other.kill()
+            other.wait()
+    finally:
+        service.kill()
+        service.wait()
+    named = subprocess.Popen([sys.executable, "-c", "import time; time.sleep(60)", "--session", "ses_main"])
+    try:
+        time.sleep(0.2)
+        assert adapter.conversation_in_use("ses_main", ctx) is True
+    finally:
+        named.kill()
+        named.wait()
+
+
+def test_the_data_dir_follows_the_callers_xdg_data_home_only_for_its_own_home(tmp_path, monkeypatch):
+    adapter = get_adapter("opencode")
+    monkeypatch.setattr(adapter, "_bin", lambda ctx: None)
+    own, other, xdg = tmp_path / "own", tmp_path / "other", tmp_path / "xdg"
+    monkeypatch.setenv("HOME", str(own))
+    monkeypatch.setenv("XDG_DATA_HOME", str(xdg))
+    ws = str(tmp_path)
+    assert adapter._resolve_db(DiscoveryContext(workspace=ws, agent_name="opencode", home_dir=str(own))) \
+        == f"{xdg}/opencode/opencode.db"
+    assert adapter._resolve_db(DiscoveryContext(workspace=ws, agent_name="opencode", home_dir=str(other))) \
+        == f"{other}/.local/share/opencode/opencode.db"
+    monkeypatch.delenv("XDG_DATA_HOME")
+    assert adapter._resolve_db(DiscoveryContext(workspace=ws, agent_name="opencode", home_dir=str(own))) \
+        == f"{own}/.local/share/opencode/opencode.db"
+
+
+def test_the_standalone_server_is_a_resident_child_but_its_tools_are_work():
+    """--standalone keeps `opencode serve --stdio` under the TUI while idle;
+    the stall watcher skips it but still sees what runs under it."""
+    from lib_py.stall_watch import background_children
+    resident = get_adapter("opencode").resident_children
+    tui = subprocess.Popen(["bash", "-c", "(exec -a opencode sleep 300) & exec sleep 300"], start_new_session=True)
+    busy = subprocess.Popen(["bash", "-c", "(exec -a opencode bash -c 'sleep 300; :') & exec sleep 300"],
+                            start_new_session=True)
+    try:
+        time.sleep(0.5)
+        assert background_children(tui.pid, ()) != []
+        assert background_children(tui.pid, resident) == []
+        assert background_children(busy.pid, resident) != []
+    finally:
+        for p in (tui, busy):
+            os.killpg(p.pid, 9)   # the whole group: children and grandchildren
+            p.wait()
+
+
 def test_spawn_and_resume_never_pass_agent_and_run_standalone():
     """The shell copies of the opencode command line match the adapter."""
     adapter = get_adapter("opencode")
@@ -214,6 +331,9 @@ def test_real_opencode_2x_contract(tmp_path, monkeypatch):
                            json.dumps({"title": "mam child", "parentID": parent})).stdout)["data"]["id"]
 
     adapter = get_adapter("opencode")
+    # The binary was found with the real HOME; under the test's HOME only a
+    # PATH entry would find it (review f4cedbae N1).
+    monkeypatch.setattr(adapter, "_bin", lambda ctx: REAL)
     ctx = DiscoveryContext(workspace=ws_real, agent_name="opencode", home_dir=str(home))
     db = adapter._resolve_db(ctx)
     assert db == str(home / ".local" / "share" / "opencode" / "opencode.db")