feat(stats): populate receiver wire counters on both receive paths

The single-threaded and -m receivers never populated ReceiverStats.matched_data
or .deleted_files, so --stats always printed 0 for both even when rsync
reported nonzero.  Track the bytes reconstructed from the basis file while
applying a delta, and tally the delete-commit counts (manifest and
per-directory sessions) into the receiver stats.  The -m pipeline now carries
its own stats/would-delete fields and emits the STATUS_STATS frame before the
terminal success, so --threads finally reports the counters and renders
-n --delete  lines.

Also normalize the -n --delete would-delete enumeration's absolute basis
prefixes exactly like the real commit path (fixing an over-report) and fix the
basis_delete_relative off-by-one when the receive root is '/'.  Unit tests
cover the root mapping and the basis protection; integration tests cover
matched/deleted stats for both receivers and the --threads dry-run delete
lines.

src/server/receiver.c

@@ -83,6 +83,13 @@ bool receiver_send_stats_frame(int fd, const Config* config, const ReceiverStats
   return true;
 }
 
+/* Add a delete commit's tally to the sink's end-of-transfer wire counters (when
+   the sink reports them).  Runs on the receiving thread, so no locking. */
+static void receiver_tally_deleted(const ReceiverSink* sink, size_t deleted) {
+  if (sink && sink->stats && deleted > 0)
+    sink->stats->deleted_files += deleted;
+}
+
 static bool receiver_process_chunk(Chunk* chunk, const ReceiverSink* sink) {
   if (!chunk || !sink || !sink->store_file)
     return false;
@@ -390,9 +397,12 @@ int receiver_process_pending(Config* config, int file_descriptor, const Receiver
            A later transfer failure does not restore these deletions.  A
            --max-delete-capped commit still succeeds and the transfer proceeds;
            the terminal success frame reports the cap. */
-        DeleteCommitResult deletion = (config->use_delete || config->delete_missing_args)
+        size_t deleted = 0;
-                                          ? manifest_delete_all(config, manifest)
+        DeleteCommitResult deletion =
-                                          : DELETE_COMMIT_OK;
+            (config->use_delete || config->delete_missing_args)
+                ? manifest_delete_all_counted(config, manifest, &deleted)
+                : DELETE_COMMIT_OK;
+        receiver_tally_deleted(sink, deleted);
         delete_manifest_free(manifest);
         if (deletion == DELETE_COMMIT_ERROR) {
           send_status(file_descriptor, STATUS_ERROR);
@@ -469,7 +479,10 @@ int receiver_process_pending(Config* config, int file_descriptor, const Receiver
       *pending_manifest = deferred_manifest;
       deferred_manifest = NULL;
     } else {
-      DeleteCommitResult deletion = manifest_delete_all(config, deferred_manifest);
+      size_t deleted = 0;
+      DeleteCommitResult deletion =
+          manifest_delete_all_counted(config, deferred_manifest, &deleted);
+      receiver_tally_deleted(sink, deleted);
       delete_manifest_free(deferred_manifest);
       deferred_manifest = NULL;
       if (deletion == DELETE_COMMIT_ERROR) {
@@ -496,6 +509,7 @@ int receiver_process_pending(Config* config, int file_descriptor, const Receiver
     } else {
       DeleteCommitResult deletion = delete_plan_session_commit(plan_session, config);
       bool limit = delete_plan_session_limit_reached(plan_session);
+      receiver_tally_deleted(sink, delete_plan_session_deleted(plan_session));
       delete_plan_session_destroy(plan_session);
       plan_session = NULL;
       if (deletion == DELETE_COMMIT_ERROR) {
@@ -572,6 +586,10 @@ static bool receiver_save_file(File* file, void* context_pointer) {
   } else {
     result = file_save_to_disk_full(context->config->receive_root_directory, file, context->config);
   }
+  /* Wire-stats tally: bytes reconstructed from the basis file (delta matches)
+     count as matched data in the end-of-transfer report. */
+  if (result != FILE_SAVE_ERROR && file->matched_bytes > 0)
+    context->stats.matched_data += file->matched_bytes;
   /* A directory's metadata is deferred, never applied inline: collect it now
      and apply it at the end.  -O/--omit-dir-times and --preserve_perms/-times
      are honored by dir_metadata_list_apply's caller (see

src/server/receiver_pipeline.c

@@ -29,6 +29,8 @@ PipelineContextReceiver* pipeline_context_receiver_create(Config* config, Queue*
   context->deferred_manifest = NULL;
   context->deferred_plans = NULL;
   context->delete_limit_reached = false;
+  memset(&context->stats, 0, sizeof(context->stats));
+  context->would_delete = NULL;
   atomic_init(&context->cancelled, false);
   int init = 0;
   if (mtx_init(&context->mutex, mtx_plain) != thrd_success)
@@ -41,6 +43,9 @@ PipelineContextReceiver* pipeline_context_receiver_create(Config* config, Queue*
     goto fail;
   // cppcheck-suppress unreadVariable
   init++;
+  context->would_delete = array_list_create(free);
+  if (!context->would_delete)
+    goto fail;
   return context;
 
 fail:
@@ -64,6 +69,8 @@ void pipeline_context_receiver_destroy(PipelineContextReceiver* context) {
   queue_destroy(context->queue);
   receiver_outcomes_destroy(&context->outcomes);
   dir_time_list_free(&context->dir_times);
+  if (context->would_delete)
+    array_list_delete(context->would_delete);
   mtx_destroy(&context->mutex);
   cnd_destroy(&context->condition_not_full);
   cnd_destroy(&context->condition_not_empty);
@@ -136,6 +143,11 @@ bool pipeline_context_receiver_enqueue_file(PipelineContextReceiver* context, Fi
 
 static bool receiver_enqueue_file(File* file, void* context_pointer) {
   PipelineContextReceiver* context = (PipelineContextReceiver*)context_pointer;
+  if (file && file->matched_bytes > 0) {
+    mtx_lock(&context->mutex);
+    context->stats.matched_data += file->matched_bytes;
+    mtx_unlock(&context->mutex);
+  }
   return pipeline_context_receiver_enqueue_file(context, file);
 }
 
@@ -171,8 +183,8 @@ int receive_thread(void* pipeline_context) {
                        false,
                        NULL,
                        receiver_pipeline_note_delete_limit,
-                       NULL,
+                       &context->stats,
-                       NULL};
+                       context->would_delete};
   if (receiver_process_pending((Config*)config, file_descriptor, &sink, &context->deferred_manifest,
                                &context->deferred_plans) != 0) {
     receiver_thread_fail(context);

src/server/receiver_pipeline.h

@@ -54,6 +54,13 @@ typedef struct PipelineContextReceiver {
      directory entries.  Only write_thread mutates it (before it joins); the
      caller (server.c) applies it after the delete/delay-updates phase. */
   DirTimeList dir_times;
+  /* End-of-transfer wire counters (protocol 2.25.0).  receive_thread accumulates
+     matched_data under `mutex`; server.c adds the delete-commit tallies after
+     both threads join and emits the STATUS_STATS frame. */
+  ReceiverStats stats;
+  /* -n/--dry-run --delete would-delete path list, collected by receive_thread
+     and reported in the STATUS_STATS frame. */
+  struct ArrayList* would_delete;
 } PipelineContextReceiver;
 
 PipelineContextReceiver* pipeline_context_receiver_create(Config* config, Queue* queue_receiver,

src/server/server.c

@@ -955,7 +955,10 @@ void handler(int file_descriptor) {
          --delay-updates run; the walker skips the staging directory.  A
          server-contacting --dry-run deletes nothing (no manifest is sent). */
       if (context->deferred_manifest) {
-        DeleteCommitResult deletion = manifest_delete_all(config, context->deferred_manifest);
+        size_t deleted = 0;
+        DeleteCommitResult deletion =
+            manifest_delete_all_counted(config, context->deferred_manifest, &deleted);
+        context->stats.deleted_files += deleted;
         if (deletion == DELETE_COMMIT_ERROR) {
           transfer_ok = false;
         } else if (deletion == DELETE_COMMIT_LIMIT_REACHED) {
@@ -975,6 +978,7 @@ void handler(int file_descriptor) {
         DeleteCommitResult deletion = config->dry_run ? DELETE_COMMIT_OK
                                                       : delete_plan_session_commit(
                                                             context->deferred_plans, config);
+        context->stats.deleted_files += delete_plan_session_deleted(context->deferred_plans);
         if (deletion == DELETE_COMMIT_ERROR) {
           transfer_ok = false;
         } else if (deletion == DELETE_COMMIT_LIMIT_REACHED) {
@@ -1003,7 +1007,11 @@ void handler(int file_descriptor) {
     }
     if (transfer_ok) {
       Status final_status = context->delete_limit_reached ? STATUS_DELETE_LIMIT : STATUS_OK;
-      if (!receiver_send_final_success(file_descriptor, config, &context->outcomes, final_status))
+      /* Emit the optional wire-stats record first (protocol 2.25.0), then the
+         success/outcome frame, exactly like the single-threaded receiver. */
+      if (!receiver_send_stats_frame(file_descriptor, config, &context->stats,
+                                     context->would_delete) ||
+          !receiver_send_final_success(file_descriptor, config, &context->outcomes, final_status))
         transfer_ok = false;
     } else {
       send_error_detail(file_descriptor, "transfer failed on receiver");

src/shared/delete_plan.c

@@ -444,6 +444,10 @@ bool delete_plan_session_limit_reached(const DeletePlanSession* session) {
   return session && session->limit_hit;
 }
 
+size_t delete_plan_session_deleted(const DeletePlanSession* session) {
+  return session ? session->deleted : 0;
+}
+
 /* True for a destination-relative path section entry (non-empty, relative,
  * traversal-free). */
 static bool valid_rel_path(const char* value) {

src/shared/delete_plan.h

@@ -70,5 +70,8 @@ int delete_plan_session_receive(DeletePlanSession* session, const Config* config
 DeleteCommitResult delete_plan_session_commit(DeletePlanSession* session, const Config* config);
 /* True once the shared --max-delete budget stopped part of a deletion. */
 bool delete_plan_session_limit_reached(const DeletePlanSession* session);
+/* Number of destination entries the session's plans removed (or, for
+   --delete-delay, snapshotted for removal), for the end-of-transfer stats. */
+size_t delete_plan_session_deleted(const DeletePlanSession* session);
 
 #endif

src/shared/file_receive.c

@@ -1093,6 +1093,13 @@ static File* receive_delta_file(int fd, const Config* config, const char* check_
       *failed = true;
       return NULL;
     }
+    /* Wire-stats tally: bytes taken straight from the basis file (matched
+       delta blocks).  Computed before the delta is destroyed. */
+    unsigned long long matched = 0;
+    for (uint32_t k = 0; k < delta->instruction_count; k++) {
+      if (delta->instructions[k].type == DELTA_INSTR_BLOCK_MATCH)
+        matched += delta->instructions[k].match.length;
+    }
     void* new_data = delta_apply(old_data, old_size, delta, config->delta_block_size);
     delta_destroy(delta);
 
@@ -1111,6 +1118,7 @@ static File* receive_delta_file(int fd, const Config* config, const char* check_
       *failed = true;
       return NULL;
     }
+    file->matched_bytes = matched;
 
     if (config->use_metadata) {
       int meta_ok = 1;
@@ -3149,8 +3157,9 @@ typedef struct {
    compares paths relative to the receive root, so a relative entry is already
    in the right form; an absolute entry that lies below the root is converted to
    its root-relative form, and one outside the root returns NULL (the walk
-   cannot reach it, and it is not protected data beneath the root). */
+   cannot reach it, and it is not protected data beneath the root).  Exposed so
-static char* basis_delete_relative(const Config* config, const char* path) {
+   tests can exercise the root-of-"/" child mapping directly. */
+char* file_receive_basis_delete_relative(const Config* config, const char* path) {
   if (!path)
     return NULL;
   if (path[0] != '/')
@@ -3163,6 +3172,13 @@ static char* basis_delete_relative(const Config* config, const char* path) {
     root_len--;
   if (strncmp(path, root, root_len) != 0)
     return NULL;
+  if (root_len == 1 && root[0] == '/') {
+    /* The receive root is "/": every absolute path is below it, and the child
+       relative form is everything after the leading '/'. */
+    if (path[1] == '\0')
+      return NULL; /* identical to the root, not a child */
+    return str_dup(path + 1);
+  }
   if (path[root_len] != '/')
     return NULL; /* identical or a sibling sharing a name prefix */
   return str_dup(path + root_len + 1);
@@ -3217,7 +3233,7 @@ static bool delete_extras_budgeted(const Config* config, DeleteManifest* manifes
     for (int i = 0; i < config->basis_count; i++) {
       /* An absolute basis outside the receive root is unreachable by this walk,
          so it contributes no protection prefix (and no slot). */
-      char* prefix = basis_delete_relative(config, config->basis_dirs[i].path);
+      char* prefix = file_receive_basis_delete_relative(config, config->basis_dirs[i].path);
       if (!prefix)
         continue;
       owned_prefixes[i] = prefix;
@@ -3304,7 +3320,7 @@ static bool delete_missing_args_budgeted(const Config* config, DeleteManifest* m
       idx++;
     }
     for (int i = 0; i < config->basis_count; i++) {
-      char* prefix = basis_delete_relative(config, config->basis_dirs[i].path);
+      char* prefix = file_receive_basis_delete_relative(config, config->basis_dirs[i].path);
       if (!prefix)
         continue;
       owned_prefixes[i] = prefix;
@@ -3469,10 +3485,16 @@ bool manifest_would_delete_list(const Config* config, DeleteManifest* manifest,
   int skip_count = (config->delay_updates ? 1 : 0) + config->basis_count +
                    (manifest->protected ? manifest->protected->size : 0);
   DeleteSkipEntry* skips = NULL;
+  char** owned_prefixes = NULL;
+  int used = 0;
   if (skip_count > 0) {
     skips = calloc((size_t)skip_count, sizeof(DeleteSkipEntry));
-    if (!skips)
+    owned_prefixes = calloc((size_t)config->basis_count, sizeof(char*));
+    if (!skips || (config->basis_count > 0 && !owned_prefixes)) {
+      free(skips);
+      free(owned_prefixes);
       return false;
+    }
     int idx = 0;
     if (config->delay_updates) {
       skips[idx].prefix = DELAY_UPDATES_STAGING_DIR;
@@ -3480,7 +3502,14 @@ bool manifest_would_delete_list(const Config* config, DeleteManifest* manifest,
       idx++;
     }
     for (int i = 0; i < config->basis_count; i++) {
-      skips[idx].prefix = config->basis_dirs[i].path;
+      /* Normalize exactly like the real commit path: a relative entry is
+         already root-relative, an absolute one inside the receive root is
+         converted, and one outside contributes no protection prefix. */
+      char* prefix = file_receive_basis_delete_relative(config, config->basis_dirs[i].path);
+      if (!prefix)
+        continue;
+      owned_prefixes[i] = prefix;
+      skips[idx].prefix = prefix;
       skips[idx].top_level_only = false;
       idx++;
     }
@@ -3489,9 +3518,15 @@ bool manifest_would_delete_list(const Config* config, DeleteManifest* manifest,
       skips[idx].top_level_only = false;
       idx++;
     }
+    used = idx;
   }
   bool ok = delete_extras_list(config->receive_root_directory, manifest->keeps, manifest->dirs,
-                               skips, skip_count, out, count_out);
+                               skips, used, out, count_out);
+  if (owned_prefixes) {
+    for (int i = 0; i < config->basis_count; i++)
+      free(owned_prefixes[i]);
+  }
+  free(owned_prefixes);
   free(skips);
   return ok;
 }
@@ -3531,6 +3566,13 @@ bool manifest_delete_missing_args_limited(const Config* config, DeleteManifest*
    Both draw from one --max-delete budget; the result reports a cap-stopped
    (partial) commit distinctly so the client can exit 25 like rsync. */
 DeleteCommitResult manifest_delete_all(const Config* config, DeleteManifest* manifest) {
+  return manifest_delete_all_counted(config, manifest, NULL);
+}
+
+DeleteCommitResult manifest_delete_all_counted(const Config* config, DeleteManifest* manifest,
+                                               size_t* deleted) {
+  if (deleted)
+    *deleted = 0;
   if (!config || !manifest)
     return DELETE_COMMIT_ERROR;
   /* Central no-mutation guard: a dry-run never deletes.  No manifest is sent on
@@ -3551,6 +3593,8 @@ DeleteCommitResult manifest_delete_all(const Config* config, DeleteManifest* man
     return DELETE_COMMIT_ERROR;
   if (config->use_delete && !delete_extras_budgeted(config, manifest, &budget))
     return DELETE_COMMIT_ERROR;
+  if (deleted)
+    *deleted = budget.deleted;
   if (budget.limit_hit) {
     if (user_limited) {
       log_message(LOG_LEVEL_ERROR, "Deletions stopped due to --max-delete limit (%zu skipped)",

src/shared/file_receive.h

@@ -142,6 +142,10 @@ typedef enum {
    do or everything committed, DELETE_COMMIT_LIMIT_REACHED when the budget
    stopped part of the work, or DELETE_COMMIT_ERROR on a genuine failure. */
 DeleteCommitResult manifest_delete_all(const Config* config, DeleteManifest* manifest);
+/* Like manifest_delete_all, but reports how many destination entries the commit
+   removed (for the end-of-transfer wire stats).  `deleted` may be NULL. */
+DeleteCommitResult manifest_delete_all_counted(const Config* config, DeleteManifest* manifest,
+                                               size_t* deleted);
 
 /* -n/--dry-run --delete would-delete reporting: walk the destination exactly as
    the delete pass would and append (strdup'd) destination-relative paths that
@@ -150,6 +154,10 @@ DeleteCommitResult manifest_delete_all(const Config* config, DeleteManifest* man
    clean walk; `*count_out` receives the number of paths appended. */
 bool manifest_would_delete_list(const Config* config, DeleteManifest* manifest, ArrayList* out,
                                 size_t* count_out);
+/* Convert one basis-directory path to the receive-root-relative protection
+   prefix the delete walker uses (NULL when it lies outside the root).  Exposed
+   for unit tests of the root-of-"/" and normalization edge cases. */
+char* file_receive_basis_delete_relative(const Config* config, const char* path);
 
 /* Outcome of a single file_save_to_disk operation.  The receiver needs to
    distinguish "written" from "skipped" so --remove-source-files can be told

src/shared/file_types.h

@@ -93,6 +93,10 @@ typedef struct {
    * no report was requested/received, in which case -i/--out-format treats the
    * entry conservatively as newly created. */
   OutputDestState dest_state;
+  /* Receiver-only wire-stats tally: the number of bytes reconstructed from the
+   * basis file (matched delta blocks) for this entry.  0 when the file was sent
+   * whole.  Accumulated into ReceiverStats.matched_data by the receiver sink. */
+  unsigned long long matched_bytes;
 } File;
 
 /* The path that should be sent on the wire and used for the receiver-side

tests/integration/test_parity_blockers.py

@@ -80,3 +80,89 @@ class TestRelativePerDirDeleteScope:
         assert not os.path.exists(os.path.join(dest, "foo", "extra.txt"))
         assert not os.path.exists(os.path.join(rdst, "foo", "extra.txt"))
         assert _tree(dest) == _tree(rdst)
+
+
+def _stats_value(text, label):
+    for line in text.splitlines():
+        if line.startswith(label + ":"):
+            return int(line.split(":", 1)[1].strip().split()[0].replace(",", ""))
+    return None
+
+
+def _seed_delta_pair(tag):
+    """Source file plus a same-size/basis destination file whose mtime differs,
+    and an extra destination file to be deleted."""
+    source = os.path.join(TEST_DATA_DIR, f"stats_{tag}_src")
+    dest = os.path.join(TEST_DATA_DIR, f"stats_{tag}_dst")
+    rdst = os.path.join(TEST_DATA_DIR, f"stats_{tag}_rdst")
+    clean_dir(source)
+    clean_dir(dest)
+    clean_dir(rdst)
+    payload = (b"0123456789abcdef" * 16384)[:200000]
+    _write(os.path.join(source, "f.bin"), payload)
+    # Destination basis: same length, one byte changed, deliberately older.
+    basis = bytearray(payload)
+    basis[100000] ^= 0xFF
+    received = get_dest_received_dir(dest, source)
+    for root in (rdst, received):
+        _write(os.path.join(root, "f.bin"), bytes(basis))
+        _write(os.path.join(root, "extra.txt"), b"delete me\n")
+        old = 1000000
+        os.utime(os.path.join(root, "f.bin"), (old, old))
+    return source, dest, rdst
+
+
+class TestReceiverWireStats:
+    """Blocker #3/#4: the receiver must populate the STATUS_STATS counters
+    (matched data, deleted files) on both the single-threaded and -m paths."""
+
+    @requires_rsync
+    @pytest.mark.ci
+    @pytest.mark.parametrize("threads", [False, True])
+    def test_stats_reports_matched_and_deleted(self, threads):
+        source, dest, rdst = _seed_delta_pair(f"mt{int(threads)}")
+        rsync_result = _rsync(["-a", "--stats", "--delete", "--no-whole-file", source + "/",
+                               rdst + "/"])
+        assert rsync_result.returncode == 0, rsync_result.stderr
+        assert _stats_value(rsync_result.stdout, "Matched data") > 0
+        assert _stats_value(rsync_result.stdout, "Number of deleted files") == 1
+
+        with ServerManager() as server:
+            server.start(extra_args=["--allow-delete"])
+            flags = ["-a", "--stats", "--delete", "--delta", "--incremental"]
+            if threads:
+                flags.append("--threads")
+            result, _ = run_client(source, dest, flags=flags, port=server.port)
+        assert result.returncode == 0, (result.stderr or result.stdout)[:300]
+        assert _stats_value(result.stdout, "Matched data") > 0, result.stdout
+        assert _stats_value(result.stdout, "Number of deleted files") == 1, result.stdout
+
+    @requires_rsync
+    @pytest.mark.ci
+    def test_threads_dry_run_delete_lines_match_rsync(self):
+        """-n --delete --threads must emit transfer-relative `*deleting` lines."""
+        source = os.path.join(TEST_DATA_DIR, "stats_drydel_src")
+        dest = os.path.join(TEST_DATA_DIR, "stats_drydel_dst")
+        rdst = os.path.join(TEST_DATA_DIR, "stats_drydel_rdst")
+        clean_dir(source)
+        clean_dir(dest)
+        clean_dir(rdst)
+        _write(os.path.join(source, "a.txt"), b"a\n")
+        for root in (rdst, get_dest_received_dir(dest, source)):
+            _write(os.path.join(root, "extra.txt"), b"x\n")
+            _write(os.path.join(root, "sub", "y.txt"), b"y\n")
+        rsync_result = _rsync(["-a", "-n", "--delete", "-i", source + "/", rdst + "/"])
+        assert rsync_result.returncode == 0, rsync_result.stderr
+        rsync_del = sorted(
+            line for line in rsync_result.stdout.splitlines() if line.startswith("*deleting")
+        )
+        with ServerManager() as server:
+            server.start(extra_args=["--allow-delete"])
+            result, _ = run_client(source, dest,
+                                   flags=["-a", "-n", "--delete", "-i", "--threads"],
+                                   port=server.port)
+        assert result.returncode == 0, (result.stderr or result.stdout)[:300]
+        fast_del = sorted(
+            line for line in result.stdout.splitlines() if line.startswith("*deleting")
+        )
+        assert fast_del and fast_del == rsync_del, f"rsync={rsync_del}\nfastsync={fast_del}"

tests/test_file.c

@@ -2002,6 +2002,100 @@ static void test_manifest_delete_missing_dir_budget_double_count() {
   rmdir(root);
 }
 
+/* Blocker #7: when the receive root is "/", every absolute basis path is below
+   it and its child relative form must drop only the single leading slash. */
+static void test_basis_delete_relative_root_slash() {
+  Config* cfg = config_create();
+  EXPECT_NOT_NULL(cfg);
+  cfg->receive_root_directory = str_dup("/");
+
+  char* rel = file_receive_basis_delete_relative(cfg, "/a");
+  EXPECT_NOT_NULL(rel);
+  EXPECT_EQ_STR(rel, "a");
+  free(rel);
+  rel = file_receive_basis_delete_relative(cfg, "/a/b");
+  EXPECT_NOT_NULL(rel);
+  EXPECT_EQ_STR(rel, "a/b");
+  free(rel);
+  /* The root itself is not a child. */
+  EXPECT_NULL(file_receive_basis_delete_relative(cfg, "/"));
+  /* A relative entry is already root-relative. */
+  rel = file_receive_basis_delete_relative(cfg, "x/y");
+  EXPECT_NOT_NULL(rel);
+  EXPECT_EQ_STR(rel, "x/y");
+  free(rel);
+  /* An absolute path outside a non-"/" root is unreachable. */
+  free(cfg->receive_root_directory);
+  cfg->receive_root_directory = str_dup("/root");
+  EXPECT_NULL(file_receive_basis_delete_relative(cfg, "/other/a"));
+  rel = file_receive_basis_delete_relative(cfg, "/root/a");
+  EXPECT_NOT_NULL(rel);
+  EXPECT_EQ_STR(rel, "a");
+  free(rel);
+  config_delete(cfg);
+}
+
+/* Blocker #6: -n --delete would-delete enumeration must normalize an absolute
+   basis directory under the receive root exactly like the real commit path, so
+   the basis snapshot is protected rather than reported as a deletable extra. */
+static void test_manifest_would_delete_protects_absolute_basis() {
+  char root[PATH_MAX];
+  snprintf(root, sizeof(root), "/tmp/fastsync_wdbasis_%d", (int)getpid());
+  char* basis = path_cat(root, "basis");
+  char* basis_file = path_cat(basis, "snapshot.bin");
+  char* extra = path_cat(root, "extra.txt");
+  EXPECT_NOT_NULL(basis);
+  EXPECT_NOT_NULL(basis_file);
+  EXPECT_NOT_NULL(extra);
+  mkdir(root, 0755);
+  mkdir(basis, 0755);
+  EXPECT_TRUE(file_write_to_disk(basis_file, "x", 1, false, false));
+  EXPECT_TRUE(file_write_to_disk(extra, "e", 1, false, false));
+
+  Config* cfg = config_create();
+  EXPECT_NOT_NULL(cfg);
+  cfg->receive_root_directory = str_dup(root);
+  cfg->use_delete = true;
+  EXPECT_EQ_INT(config_basis_append(cfg, BASIS_DEST_COMPARE, basis), 0);
+
+  const char* synced[] = {"."};
+  DeleteManifest manifest = {0};
+  manifest.keeps = make_manifest_string_list(NULL, 0);
+  manifest.protected = make_manifest_string_list(NULL, 0);
+  manifest.dirs = make_manifest_string_list(synced, 1);
+  EXPECT_NOT_NULL(manifest.keeps);
+  EXPECT_NOT_NULL(manifest.protected);
+  EXPECT_NOT_NULL(manifest.dirs);
+  ArrayList* out = array_list_create(free);
+  EXPECT_NOT_NULL(out);
+  size_t count = 0;
+  EXPECT_TRUE(manifest_would_delete_list(cfg, &manifest, out, &count));
+  bool saw_basis = false;
+  bool saw_extra = false;
+  for (int i = 0; i < out->size; i++) {
+    const char* p = (const char*)out->items[i];
+    if (strcmp(p, "basis") == 0 || strncmp(p, "basis/", 6) == 0)
+      saw_basis = true;
+    if (strcmp(p, "extra.txt") == 0)
+      saw_extra = true;
+  }
+  EXPECT_FALSE(saw_basis);
+  EXPECT_TRUE(saw_extra);
+
+  array_list_delete(out);
+  array_list_delete(manifest.keeps);
+  array_list_delete(manifest.protected);
+  array_list_delete(manifest.dirs);
+  config_delete(cfg);
+  unlink(basis_file);
+  rmdir(basis);
+  unlink(extra);
+  rmdir(root);
+  free(basis);
+  free(basis_file);
+  free(extra);
+}
+
 void test_file() {
   test_file_create();
   test_file_special_rdev_valid();
@@ -2057,4 +2151,6 @@ void test_file() {
   test_inplace_refuses_fifo_destination();
   test_inplace_refuses_device_destination();
   test_manifest_delete_missing_dir_budget_double_count();
+  test_basis_delete_relative_root_slash();
+  test_manifest_would_delete_protects_absolute_basis();
 }