feat(cli): accept --inc-recursive no-op and in-root absolute --temp-dir

tests/integration/test_temp_dir_absolute.py

@@ -0,0 +1,120 @@
+"""Parity coverage for an absolute ``--temp-dir`` that lies inside the receive root.
+
+FastSync confines the ``--temp-dir`` scratch directory to the receive root.  It
+previously rejected *every* absolute path; it now canonicalizes an absolute path
+with ``realpath(3)`` and accepts it when it resolves inside the canonical receive
+root (the destination is identical, so this is a pure parity win), while an
+absolute path that escapes the root stays rejected with a clear error.
+
+Two paths exercise the same receiver-side resolution:
+
+* the local ``--read-batch`` apply (no network; the batch destination is the
+  receive root), and
+* a real TCP transfer against the shared server (the destination root is the
+  client-supplied absolute path).
+
+The out-of-root case asserts the run fails without writing a single scratch
+file, so the confinement invariant is preserved.
+"""
+import os
+import subprocess
+import sys
+
+import pytest
+
+sys.path.insert(0, os.path.dirname(__file__))
+from common import CLIENT_CMD, TEST_DATA_DIR, clean_dir, get_dest_received_dir, run_client
+
+FILES = {
+    "top.txt": b"top level\n",
+    "sub/nested.txt": b"nested file\n" * 16,
+}
+
+
+def _run(args):
+    return subprocess.run(CLIENT_CMD + args, capture_output=True, text=True, timeout=180)
+
+
+def _seed_source(root):
+    clean_dir(root)
+    for rel, data in FILES.items():
+        full = os.path.join(root, rel)
+        os.makedirs(os.path.dirname(full), exist_ok=True)
+        with open(full, "wb") as fh:
+            fh.write(data)
+
+
+def _make_batch(tmp, source):
+    batch = os.path.join(tmp, "tree.batch")
+    result = _run(["--only-write-batch", batch, source])
+    assert result.returncode == 0, (result.stdout, result.stderr)
+    return batch
+
+
+def _read(path):
+    with open(path, "rb") as fh:
+        return fh.read()
+
+
+@pytest.mark.ci
+def test_read_batch_absolute_temp_dir_inside_root_accepted(tmp_path):
+    source = os.path.join(tmp_path, "src")
+    dest = os.path.join(tmp_path, "dst")
+    _seed_source(source)
+    clean_dir(dest)
+    scratch = os.path.join(dest, "scratch")
+    os.makedirs(scratch)
+
+    batch = _make_batch(str(tmp_path), source)
+    result = _run(["--read-batch", batch, dest, "--temp-dir", scratch])
+    assert result.returncode == 0, (result.stdout, result.stderr)
+
+    received = get_dest_received_dir(dest, source)
+    for rel, data in FILES.items():
+        assert _read(os.path.join(received, rel)) == data, f"content mismatch for {rel}"
+    assert os.listdir(scratch) == [], "scratch dir was not left clean"
+
+
+@pytest.mark.ci
+def test_read_batch_absolute_temp_dir_outside_root_rejected(tmp_path):
+    source = os.path.join(tmp_path, "src")
+    dest = os.path.join(tmp_path, "dst")
+    _seed_source(source)
+    clean_dir(dest)
+    outside = os.path.join(tmp_path, "outside")
+    os.makedirs(outside)
+
+    batch = _make_batch(str(tmp_path), source)
+    result = _run(["--read-batch", batch, dest, "--temp-dir", outside])
+    assert result.returncode != 0, "an absolute temp dir outside the receive root must be rejected"
+    assert os.listdir(outside) == [], "receiver wrote into an unconfined temp dir"
+    assert "temp-dir" in (result.stdout + result.stderr), (result.stdout, result.stderr)
+
+
+def test_tcp_absolute_temp_dir_inside_root_accepted(shared_server):
+    source = os.path.join(TEST_DATA_DIR, "tempdir_abs_in_src")
+    dest = os.path.join(TEST_DATA_DIR, "tempdir_abs_in_dst")
+    _seed_source(source)
+    clean_dir(dest)
+    scratch = os.path.join(dest, "scratch")
+    os.makedirs(scratch)
+
+    result, _ = run_client(source, dest, flags=["--temp-dir", scratch], port=shared_server.port)
+    assert result.returncode == 0, (result.stdout, result.stderr)[:300]
+    received = get_dest_received_dir(dest, source)
+    for rel, data in FILES.items():
+        assert _read(os.path.join(received, rel)) == data, f"content mismatch for {rel}"
+    assert os.listdir(scratch) == [], "scratch dir was not left clean"
+
+
+def test_tcp_absolute_temp_dir_outside_root_rejected(shared_server):
+    source = os.path.join(TEST_DATA_DIR, "tempdir_abs_out_src")
+    dest = os.path.join(TEST_DATA_DIR, "tempdir_abs_out_dst")
+    _seed_source(source)
+    clean_dir(dest)
+    outside = os.path.join(TEST_DATA_DIR, "tempdir_abs_out_scratch")
+    clean_dir(outside)
+
+    result, _ = run_client(source, dest, flags=["--temp-dir", outside], port=shared_server.port)
+    assert result.returncode != 0, "an absolute temp dir outside the receive root must be rejected"
+    assert os.listdir(outside) == [], "receiver wrote into an unconfined temp dir"