feat(delete): per-directory delete plans for --delete-during/--delete-delay (protocol 2.24.0)

Stream one delete plan per source directory from sender to receiver instead of
a single whole-tree keep-set manifest:

- --delete-during applies each directory's extras as its plan arrives, before
  that directory's data (rsync's generator-order deletion).
- --delete-delay snapshots each directory's extras while the plan arrives and
  commits the removals only after a fully-successful transfer, so files created
  after the scan survive (matching rsync's delete-delay, not delete-after).
- Type conflicts (a destination file blocking a source directory, or vice
  versa) are cleared immediately in both modes, so the nested write succeeds.

The plan carries the destination-relative directory, its kept child directory
names and its kept child file names; the first frame also carries the global
protected prefixes, size-skipped prefixes and --delete-missing-args paths.
--delete-before keeps the existing whole-tree early manifest; plain --delete and
--delete-after keep the end-of-transfer manifest commit.

Preserves the existing safety surface: protected/size-skipped prefixes and the
--delay-updates/basis skips are honored at any depth, deletion is scoped to the
synchronized directories (--files-from), MAX_SERVER_DELETE_COUNT and
--max-delete (partial + exit 25) are shared across plans, symlinks are never
followed, and paths are confined to the receive root.

tests/integration/test_fault_injection.py

@@ -36,7 +36,7 @@ from common import (  # noqa: E402
     verify_transfer,
 )
 
-PROTOCOL_VERSION = b"2.23.0"
+PROTOCOL_VERSION = b"2.24.0"
 STATUS_MANIFEST = 5
 STATUS_OK = 0
 

tests/integration/test_features.py

@@ -3755,15 +3755,15 @@ class TestDeleteTiming:
             assert _read_file(os.path.join(received, "sub", "deep.txt")) == b"deeply nested file\n", \
                 f"{flag}: nested file was not written after the early deletion"
 
-    @pytest.mark.parametrize("flag", ["--delete", "--delete-after", "--delete-delay"])
+    @pytest.mark.parametrize("flag", ["--delete", "--delete-after"])
     @pytest.mark.parametrize("mt", [False, True])
     def test_late_flags_commit_only_after_success(self, flag, mt):
-        """Plain --delete/--delete-after/--delete-delay defer deletion until the
-        whole transfer succeeds: a mid-transfer write failure must leave every
-        extra in place (commit-style safety).  The -m receiver must also keep
-        the extras: the deferred keep-set is committed by the server only after
-        the disk-writer thread has finished, and a failing writer means the
-        manifest is freed, never applied."""
+        """Plain --delete/--delete-after defer deletion until the whole transfer
+        succeeds: a mid-transfer write failure must leave every extra in place
+        (commit-style safety).  The -m receiver must also keep the extras: the
+        deferred keep-set is committed by the server only after the disk-writer
+        thread has finished, and a failing writer means the manifest is freed,
+        never applied."""
         source = self._seed("late")
         dest = os.path.join(TEST_DATA_DIR, "deltiming_late_dst")
         clean_dir(dest)
@@ -3789,6 +3789,37 @@ class TestDeleteTiming:
             assert os.path.isfile(blocker), \
                 f"{flag} (mt={mt}) deleted the blocker although the transfer failed"
 
+    @pytest.mark.parametrize("mt", [False, True])
+    def test_delete_delay_clears_type_conflict_like_rsync(self, mt):
+        """rsync clears a destination file that blocks a source directory even
+        when the deletion itself is deferred (--delete-delay); the type conflict
+        is resolved immediately so the nested write succeeds.  The transfer must
+        therefore succeed and the unrelated extra must still be removed."""
+        source = self._seed("delayconflict")
+        dest = os.path.join(TEST_DATA_DIR, "deltiming_delayconflict_dst")
+        clean_dir(dest)
+        with ServerManager() as server:
+            server.start(extra_args=["--allow-delete"])
+            result, _ = run_client(source, dest, port=server.port)
+            assert result.returncode == 0, f"seed sync failed: {result.stderr[:200]}"
+            received = get_dest_received_dir(dest, source)
+            extra = os.path.join(received, "extra.txt")
+            with open(extra, "wb") as fh:
+                fh.write(b"extra file")
+            blocker = os.path.join(received, "sub")
+            shutil.rmtree(blocker)
+            with open(blocker, "wb") as fh:
+                fh.write(b"blocks the nested destination directory")
+
+            flags = ["--delete-delay"] + (["--threads"] if mt else [])
+            result, _ = run_client(source, dest, flags=flags, port=server.port)
+            assert result.returncode == 0, \
+                f"--delete-delay (mt={mt}) did not clear the type conflict: " \
+                f"{(result.stderr or result.stdout)[:300]}"
+            assert os.path.isdir(blocker), "blocker file was not replaced by the source directory"
+            assert _read_file(os.path.join(received, "sub", "deep.txt")) == b"deeply nested file\n"
+            assert not os.path.exists(extra), "--delete-delay did not remove the extra"
+
     def test_early_flag_respected_when_server_refuses_delete(self, shared_server):
         """With an --allow-delete-less server the client's early timing still
         completes (no deadlock on the pre-delete ack) and simply never deletes,

tests/integration/test_preflight.py

@@ -94,14 +94,14 @@ def _seed_protocol_source(source):
 class TestProtocol:
     @pytest.mark.ci
     def test_protocol_current_version_accepted(self, shared_server):
-        """--protocol=2.23.0 (the current PROTOCOL_VERSION) is accepted and the
+        """--protocol=2.24.0 (the current PROTOCOL_VERSION) is accepted and the
         transfer completes normally."""
         source = os.path.join(TEST_DATA_DIR, "proto_ok_src")
         dest = os.path.join(TEST_DATA_DIR, "proto_ok_dst")
         shutil.rmtree(dest, ignore_errors=True)
         os.makedirs(dest)
         _seed_protocol_source(source)
-        result, _ = run_client(source, dest, flags=["--protocol=2.23.0"],
+        result, _ = run_client(source, dest, flags=["--protocol=2.24.0"],
                                port=shared_server.port)
         assert result.returncode == 0, \
             f"--protocol current run failed: {(result.stderr or result.stdout)[:400]}"

tests/test_client_cli.c

@@ -317,7 +317,7 @@ static void test_parse_args_protocol_accept_current() {
   Config* cfg = valid_client_config();
   EXPECT_NOT_NULL(cfg);
   char* argv_equals[] = {"fastsync",   "--source-dir", "/src",
-                         "--dest-dir", "/dst",         "--protocol=2.23.0"};
+                         "--dest-dir", "/dst",         "--protocol=2.24.0"};
   int positional_args[2];
   int positional_count = 0;
   EXPECT_EQ_INT(parse_args(cfg, 6, argv_equals, positional_args, &positional_count), 0);
@@ -327,7 +327,7 @@ static void test_parse_args_protocol_accept_current() {
   cfg = valid_client_config();
   EXPECT_NOT_NULL(cfg);
   char* argv_space[] = {"fastsync", "--source-dir", "/src",  "--dest-dir",
-                        "/dst",     "--protocol",   "2.23.0"};
+                        "/dst",     "--protocol",   "2.24.0"};
   positional_count = 0;
   EXPECT_EQ_INT(parse_args(cfg, 7, argv_space, positional_args, &positional_count), 0);
   EXPECT_EQ_STR(cfg->version, PROTOCOL_VERSION);

tests/test_config.c

@@ -852,13 +852,15 @@ static void test_config_delete_timing_early_helper() {
   cfg->use_delete = true;
   cfg->delete_before = true;
   EXPECT_TRUE(config_delete_timing_early(cfg));
+  EXPECT_FALSE(config_delete_timing_per_dir(cfg));
   EXPECT_TRUE(config_has_valid_delete_timing(cfg));
   config_delete(cfg);
 
   cfg = config_create();
   cfg->use_delete = true;
   cfg->delete_during = true;
-  EXPECT_TRUE(config_delete_timing_early(cfg));
+  EXPECT_FALSE(config_delete_timing_early(cfg));
+  EXPECT_TRUE(config_delete_timing_per_dir(cfg));
   EXPECT_TRUE(config_has_valid_delete_timing(cfg));
   config_delete(cfg);
 
@@ -866,6 +868,7 @@ static void test_config_delete_timing_early_helper() {
   cfg->use_delete = true;
   cfg->delete_delay = true;
   EXPECT_FALSE(config_delete_timing_early(cfg));
+  EXPECT_TRUE(config_delete_timing_per_dir(cfg));
   EXPECT_TRUE(config_has_valid_delete_timing(cfg));
   config_delete(cfg);
 
@@ -873,6 +876,7 @@ static void test_config_delete_timing_early_helper() {
   cfg->use_delete = true;
   cfg->delete_after = true;
   EXPECT_FALSE(config_delete_timing_early(cfg));
+  EXPECT_FALSE(config_delete_timing_per_dir(cfg));
   EXPECT_TRUE(config_has_valid_delete_timing(cfg));
   config_delete(cfg);
 
@@ -2763,14 +2767,14 @@ static void golden_config_populate(Config* c) {
   c->copy_as_gid = 222;
 }
 
-/* The pinned golden frame (protocol 2.23.0).  The values below are the only
+/* The pinned golden frame (protocol 2.24.0).  The values below are the only
  * thing that ties the generated table to the historical wire format; update
- * them ONLY with a PROTOCOL_VERSION bump and a documented reason.  The 2.23.0
- * rsync-parity wave changes the config-frame layout (map-entry range + TO name,
- * one report_dest_info bool, and other wire changes landing in this version);
- * the byte-exact values are recomputed for the merged layout. */
+ * them ONLY with a PROTOCOL_VERSION bump and a documented reason.  The 2.24.0
+ * per-directory delete-plan wave changes only the version string in the config
+ * frame (the frame layout itself is unchanged from 2.23.0); the byte-exact hash
+ * is recomputed for the new version bytes. */
 #define GOLDEN_WIRE_LEN 697
-#define GOLDEN_WIRE_HASH 7835017034643051109ULL
+#define GOLDEN_WIRE_HASH 13736055061412501670ULL
 
 static unsigned long long fnv1a_64(const unsigned char* buf, size_t len) {
   unsigned long long h = 1469598103934665603ULL;
@@ -2852,7 +2856,7 @@ static unsigned long long capture_wire_hash(const Config* cfg, size_t* out_len)
   return h;
 }
 
-/* Byte-for-byte wire compatibility guard (protocol 2.23.0).  The expected hash
+/* Byte-for-byte wire compatibility guard (protocol 2.24.0).  The expected hash
  * pins the pre-X-macro byte stream; the refactor MUST NOT change it. */
 static void test_config_wire_golden() {
   if (is_running_under_valgrind())

tests/test_receiver_timeout.c

@@ -65,7 +65,7 @@ static void test_receiver_aborts_idle_keepalive() {
   ssize_t wrote = write(sv[0], &keepalive, sizeof(keepalive));
   int result = -2;
   if (wrote == (ssize_t)sizeof(keepalive))
-    result = receiver_process_pending(config, sv[1], &sink, NULL);
+    result = receiver_process_pending(config, sv[1], &sink, NULL, NULL);
   Status reply = STATUS_OK;
   ssize_t got = -1;
   if (result == -1)

tests/test_server.c

@@ -566,7 +566,7 @@ static Config* make_late_delete_config(const char* root) {
 
 static int run_pending_receiver(Config* cfg, int fd, DeleteManifest** pending) {
   ReceiverSink sink = {0};
-  return receiver_process_pending(cfg, fd, &sink, pending);
+  return receiver_process_pending(cfg, fd, &sink, pending, NULL);
 }
 
 static void test_late_manifest_abort_frees_keepset() {
@@ -797,7 +797,7 @@ static void test_receiver_pending_commits_missing_args() {
   /* NULL pending: the single-threaded commit path deletes at FINISHED.  The
      sink sends the terminal STATUS_OK success frame. */
   ReceiverSink sink = {.send_success = true};
-  EXPECT_EQ_INT(receiver_process_pending(cfg, p[0], &sink, NULL), 0);
+  EXPECT_EQ_INT(receiver_process_pending(cfg, p[0], &sink, NULL, NULL), 0);
   Status ack;
   EXPECT_TRUE(receive_status(p[1], &ack));
   EXPECT_EQ_INT(ack, STATUS_OK);