test: cover rsync delete-timing flags, config wire, and semantics

- CLI: each timing flag (+ --del alias) accepted and implies --delete;
  conflicting timings and a timing with --no-delete are rejected.
- Config: delete_during/delete_delay survive config_send/config_receive;
  two simultaneous timings are rejected by the receiver-side validation;
  config_delete_timing_early() mapping is unit-tested.
- Integration (TCP, single- and multithreaded): every flag removes extras on
  a successful transfer; early modes (--delete-before/--delete-during/--del)
  delete before data is applied so a destination file blocking a nested
  write is removed and the transfer succeeds, while plain --delete /
  --delete-after / --delete-delay keep it and fail with every extra intact
  (commit-style). Early timing also completes (without deleting) when the
  server refuses deletion.

tests/integration/test_features.py

@@ -1971,3 +1971,129 @@ class TestFilters:
     """--filter/-C/-F rule layer: excludes prune, ordering is first-match-wins,
     the default with no matching rule is include, and legacy --exclude remains
     an independent layer."""
+
+
+class TestDeleteTiming:
+    """rsync deletion-timing family.  --delete-before/--delete-during transmit
+    the keep-set manifest BEFORE any file data (the receiver deletes extras and
+    acks first); --delete/--delete-after/--delete-delay commit deletions only
+    after the whole transfer succeeded.  Every timing flag implies --delete."""
+
+    def _seed(self, tag):
+        source = os.path.join(TEST_DATA_DIR, f"deltiming_{tag}_src")
+        clean_dir(source)
+        entries = {
+            "top.txt": b"top level\n",
+            "sub/deep.txt": b"deeply nested file\n",
+        }
+        for rel, content in entries.items():
+            full = os.path.join(source, rel)
+            os.makedirs(os.path.dirname(full), exist_ok=True)
+            with open(full, "wb") as fh:
+                fh.write(content)
+        return source
+
+    @pytest.mark.parametrize("flag", ["--delete-before", "--delete-during", "--del",
+                                      "--delete-after", "--delete-delay"])
+    @pytest.mark.parametrize("mt", [False, True])
+    def test_flag_removes_extras_on_success(self, flag, mt):
+        """Every timing flag is accepted, implies --delete, and on a successful
+        transfer removes the destination extras exactly like plain --delete."""
+        source = self._seed("ok")
+        dest = os.path.join(TEST_DATA_DIR, "deltiming_ok_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"should be deleted")
+
+            flags = [flag] + (["-m"] if mt else [])
+            result, _ = run_client(source, dest, flags=flags, port=server.port)
+            assert result.returncode == 0, \
+                f"{flag} sync failed: {(result.stderr or result.stdout)[:300]}"
+            assert not os.path.exists(extra), f"{flag} did not remove the extra file"
+            mismatches, missing = verify_transfer(source, received)
+            assert not missing, f"{flag} missing files: {missing}"
+            assert not mismatches, f"{flag} mismatched files: {mismatches}"
+
+    @pytest.mark.parametrize("flag", ["--delete-before", "--delete-during", "--del"])
+    @pytest.mark.parametrize("mt", [False, True])
+    def test_early_flags_delete_before_data(self, flag, mt):
+        """--delete-before/--delete-during remove extras (and a file blocking a
+        destination directory) BEFORE data is applied, so a nested write that
+        would fail while the blocker still exists succeeds."""
+        source = self._seed("early")
+        dest = os.path.join(TEST_DATA_DIR, "deltiming_early_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 = [flag] + (["-m"] if mt else [])
+            result, _ = run_client(source, dest, flags=flags, port=server.port)
+            assert result.returncode == 0, \
+                f"{flag} (early delete) did not remove the blocker in time: " \
+                f"{(result.stderr or result.stdout)[:300]}"
+            assert not os.path.exists(extra), f"{flag} did not delete the extra before data"
+            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"])
+    def test_late_flags_commit_only_after_success(self, flag):
+        """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)."""
+        source = self._seed("late")
+        dest = os.path.join(TEST_DATA_DIR, "deltiming_late_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")
+
+            result, _ = run_client(source, dest, flags=[flag], port=server.port)
+            assert result.returncode != 0, \
+                f"{flag} unexpectedly succeeded (deletion must be deferred)"
+            assert os.path.exists(extra), \
+                f"{flag} removed an extra although the transfer failed"
+            assert os.path.isfile(blocker), \
+                f"{flag} deleted the blocker although the transfer failed"
+
+    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,
+        exactly like the plain server policy."""
+        source = self._seed("refused")
+        dest = os.path.join(TEST_DATA_DIR, "deltiming_refused_dst")
+        clean_dir(dest)
+        result, _ = run_client(source, dest, port=shared_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")
+        result, _ = run_client(source, dest, flags=["--delete-before"], port=shared_server.port)
+        assert result.returncode == 0, \
+            f"--delete-before against a refuse-delete server failed: {result.stderr[:300]}"
+        assert os.path.exists(extra), "unauthorized delete removed an extra file"

tests/test_client_cli.c

@@ -595,8 +595,9 @@ static void test_parse_args_relative_no_implied_mkpath() {
   config_delete(cfg);
 }
 
-/* --del is recognized as the rsync alias, but its timing mode is not implemented. */
-static void test_parse_args_delete_during_alias_unimplemented() {
+/* --del is accepted as the rsync alias for --delete-during: it enables
+ * deletion with the during (early) timing. */
+static void test_parse_args_delete_during_alias() {
   static const char* const options[] = {"--del", "--delete-during"};
 
   for (size_t i = 0; i < sizeof(options) / sizeof(options[0]); i++) {
@@ -605,12 +606,81 @@ static void test_parse_args_delete_during_alias_unimplemented() {
     int positional_args[2];
     int positional_count = 0;
 
-    EXPECT_EQ_INT(parse_args(cfg, 4, argv, positional_args, &positional_count), -1);
-    EXPECT_FALSE(cfg->use_delete);
+    EXPECT_EQ_INT(parse_args(cfg, 4, argv, positional_args, &positional_count), 0);
+    EXPECT_TRUE(cfg->use_delete);
+    EXPECT_TRUE(cfg->delete_during);
+    EXPECT_FALSE(cfg->delete_before);
+    EXPECT_FALSE(cfg->delete_delay);
+    EXPECT_FALSE(cfg->delete_after);
     config_delete(cfg);
   }
 }
 
+/* Each rsync deletion-timing flag is accepted and implies --delete. */
+static void test_parse_args_delete_timing_flags() {
+  Config* cfg = config_create();
+  char* argv[] = {"fastsync", "--delete-before", "/src", "/dst"};
+  int positional_args[2];
+  int positional_count = 0;
+  EXPECT_EQ_INT(parse_args(cfg, 4, argv, positional_args, &positional_count), 0);
+  EXPECT_TRUE(cfg->use_delete);
+  EXPECT_TRUE(cfg->delete_before);
+  config_delete(cfg);
+
+  cfg = config_create();
+  char* argv_after[] = {"fastsync", "--delete-after", "/src", "/dst"};
+  positional_count = 0;
+  EXPECT_EQ_INT(parse_args(cfg, 4, argv_after, positional_args, &positional_count), 0);
+  EXPECT_TRUE(cfg->use_delete);
+  EXPECT_TRUE(cfg->delete_after);
+  EXPECT_FALSE(cfg->delete_before);
+  config_delete(cfg);
+
+  cfg = config_create();
+  char* argv_delay[] = {"fastsync", "--delete-delay", "/src", "/dst"};
+  positional_count = 0;
+  EXPECT_EQ_INT(parse_args(cfg, 4, argv_delay, positional_args, &positional_count), 0);
+  EXPECT_TRUE(cfg->use_delete);
+  EXPECT_TRUE(cfg->delete_delay);
+  EXPECT_FALSE(cfg->delete_before);
+  EXPECT_FALSE(cfg->delete_after);
+  config_delete(cfg);
+}
+
+/* Two different delete-timing flags on one command line are a conflict, not a
+ * silent last-one-wins choice. */
+static void test_parse_args_delete_timing_conflict_rejected() {
+  Config* cfg = config_create();
+  char* argv[] = {"fastsync", "--delete-before", "--delete-after", "/src", "/dst"};
+  int positional_args[2];
+  int positional_count = 0;
+  EXPECT_EQ_INT(parse_args(cfg, 5, argv, positional_args, &positional_count), 0);
+  EXPECT_TRUE(cfg->use_delete);
+  EXPECT_FALSE(validate_config(cfg));
+  config_delete(cfg);
+
+  cfg = config_create();
+  char* argv2[] = {"fastsync", "--delete-during", "--delete-delay", "/src", "/dst"};
+  positional_count = 0;
+  EXPECT_EQ_INT(parse_args(cfg, 5, argv2, positional_args, &positional_count), 0);
+  EXPECT_FALSE(validate_config(cfg));
+  config_delete(cfg);
+}
+
+/* A timing flag whose --delete was then negated away must be rejected: timing
+ * without deletion is meaningless. */
+static void test_parse_args_delete_timing_without_delete_rejected() {
+  Config* cfg = config_create();
+  char* argv[] = {"fastsync", "--delete-before", "--no-delete", "/src", "/dst"};
+  int positional_args[2];
+  int positional_count = 0;
+  EXPECT_EQ_INT(parse_args(cfg, 5, argv, positional_args, &positional_count), 0);
+  EXPECT_FALSE(cfg->use_delete);
+  EXPECT_TRUE(cfg->delete_before);
+  EXPECT_FALSE(validate_config(cfg));
+  config_delete(cfg);
+}
+
 /* Parsed-but-unimplemented options must fail instead of being silently accepted. */
 static void test_parse_args_rejects_unimplemented_options() {
   static const char* const options[] = {"--silent",
@@ -626,7 +696,6 @@ static void test_parse_args_rejects_unimplemented_options() {
                                         "--append",
                                         "--append-verify",
                                         "--delete-excluded",
-                                        "--delete-after",
                                         "--max-delete",
                                         "--prune-empty-dirs",
                                         "-e",
@@ -635,7 +704,6 @@ static void test_parse_args_rejects_unimplemented_options() {
                                         "--compare-dest",
                                         "--copy-dest",
                                         "--link-dest",
-                                        "--delete-before",
                                         "--address",
                                         "--bind-address",
                                         "--ipv6",
@@ -1542,7 +1610,10 @@ void test_client_cli() {
   test_parse_args_unknown_option();
   test_parse_args_dirs_aliases();
   test_parse_args_relative_no_implied_mkpath();
-  test_parse_args_delete_during_alias_unimplemented();
+  test_parse_args_delete_during_alias();
+  test_parse_args_delete_timing_flags();
+  test_parse_args_delete_timing_conflict_rejected();
+  test_parse_args_delete_timing_without_delete_rejected();
   test_parse_args_rejects_unimplemented_options();
   test_parse_args_quiet();
   test_parse_args_human_readable();

tests/test_config.c

@@ -438,6 +438,129 @@ static void test_config_delay_updates_reserved_backup_rejected() {
   config_delete(c);
 }
 
+static void test_config_delete_timing_early_helper() {
+  Config* cfg = config_create();
+  EXPECT_NOT_NULL(cfg);
+  EXPECT_FALSE(config_delete_timing_early(cfg));
+  EXPECT_TRUE(config_has_valid_delete_timing(cfg));
+  cfg->use_delete = true;
+  EXPECT_TRUE(config_has_valid_delete_timing(cfg));
+  EXPECT_FALSE(config_delete_timing_early(cfg));
+  config_delete(cfg);
+
+  cfg = config_create();
+  cfg->use_delete = true;
+  cfg->delete_before = true;
+  EXPECT_TRUE(config_delete_timing_early(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_TRUE(config_has_valid_delete_timing(cfg));
+  config_delete(cfg);
+
+  cfg = config_create();
+  cfg->use_delete = true;
+  cfg->delete_delay = true;
+  EXPECT_FALSE(config_delete_timing_early(cfg));
+  EXPECT_TRUE(config_has_valid_delete_timing(cfg));
+  config_delete(cfg);
+
+  cfg = config_create();
+  cfg->use_delete = true;
+  cfg->delete_after = true;
+  EXPECT_FALSE(config_delete_timing_early(cfg));
+  EXPECT_TRUE(config_has_valid_delete_timing(cfg));
+  config_delete(cfg);
+
+  /* Two simultaneous timings are invalid. */
+  cfg = config_create();
+  cfg->use_delete = true;
+  cfg->delete_before = true;
+  cfg->delete_after = true;
+  EXPECT_TRUE(config_delete_timing_early(cfg));
+  EXPECT_FALSE(config_has_valid_delete_timing(cfg));
+  config_delete(cfg);
+
+  /* A timing flag without deletion is invalid. */
+  cfg = config_create();
+  cfg->delete_delay = true;
+  EXPECT_FALSE(config_has_valid_delete_timing(cfg));
+  EXPECT_FALSE(config_delete_timing_early(cfg));
+  config_delete(cfg);
+}
+
+/* New delete-timing fields must survive config_send/config_receive unchanged,
+   and a config carrying two conflicting timings must be rejected. */
+static void test_config_delete_timing_wire_roundtrip() {
+  if (is_running_under_valgrind())
+    return;
+
+  struct {
+    bool before, during, delay, after;
+  } cases[] = {
+      {false, false, false, false}, {true, false, false, false}, {false, true, false, false},
+      {false, false, true, false},  {false, false, false, true},
+  };
+  for (size_t i = 0; i < sizeof(cases) / sizeof(cases[0]); i++) {
+    int p[2];
+    EXPECT_EQ_INT(socketpair(AF_UNIX, SOCK_STREAM, 0, p), 0);
+    pid_t pid = fork();
+    if (pid == 0) {
+      close(p[1]);
+      io_set_fds(p[0], p[0]);
+      Config* recv = config_receive(p[0]);
+      bool ok = recv != NULL;
+      if (ok) {
+        ok = recv->use_delete && recv->delete_before == cases[i].before &&
+             recv->delete_during == cases[i].during && recv->delete_delay == cases[i].delay &&
+             recv->delete_after == cases[i].after;
+      }
+      config_delete(recv);
+      close(p[0]);
+      _exit(ok ? 0 : 1);
+    } else {
+      close(p[0]);
+      io_set_fds(p[1], p[1]);
+      Config* send_cfg = config_create();
+      EXPECT_NOT_NULL(send_cfg);
+      send_cfg->send_directory = str_dup("/src");
+      send_cfg->receive_root_directory = str_dup("/dst");
+      send_cfg->use_delete = true;
+      send_cfg->delete_before = cases[i].before;
+      send_cfg->delete_during = cases[i].during;
+      send_cfg->delete_delay = cases[i].delay;
+      send_cfg->delete_after = cases[i].after;
+      bool sent = config_send(p[1], send_cfg);
+      int status;
+      waitpid(pid, &status, 0);
+      close(p[1]);
+      config_delete(send_cfg);
+      EXPECT_TRUE(sent);
+      EXPECT_TRUE(WIFEXITED(status) && WEXITSTATUS(status) == 0);
+    }
+  }
+}
+
+/* The receiver-side wire validation rejects a keep-set config with two
+   conflicting delete-timing flags. */
+static void test_config_delete_timing_conflict_rejected() {
+  if (is_running_under_valgrind())
+    return;
+  Config* c = config_create();
+  EXPECT_NOT_NULL(c);
+  c->send_directory = str_dup("/src");
+  c->receive_root_directory = str_dup("/dst");
+  c->use_delete = true;
+  c->delete_before = true;
+  c->delete_delay = true;
+  EXPECT_FALSE(roundtrip_config_ok(c));
+  config_delete(c);
+}
+
 static void test_config_is_remote_dest() {
   /* Valid SSH-style destinations */
   EXPECT_TRUE(config_is_remote_dest("user@host:/path"));
@@ -474,6 +597,9 @@ void test_config() {
     test_config_string_null_vs_empty_roundtrip();
     test_config_temp_dir_roundtrip();
     test_config_delay_updates_reserved_backup_rejected();
+    test_config_delete_timing_wire_roundtrip();
+    test_config_delete_timing_conflict_rejected();
   }
+  test_config_delete_timing_early_helper();
   test_config_is_remote_dest();
 }