fix(parity): client quick wins for rsync 3.4.1 (copy-links exit 23, info/debug flags, empty files-from, -F ordering, delete edges)

src/client/client_cli.c

@@ -395,6 +395,39 @@ static void apply_output_buffering(const Config* config) {
 static int read_patterns_from_file(const char* filepath, char*** patterns, int* count,
                                    Config* config, char sign, const char* optname);
 
+/* Split one --debug/--info item into its category name and an optional rsync
+ * verbosity level suffix (e.g. "io2", "all4", "none0").  The output `name` is
+ * NUL-terminated and `level` is >= 0 (0 silences the item).  Returns false for
+ * an empty token or a token that is all digits. */
+static bool split_flag_level(const char* token, char* name, size_t name_size, int* level) {
+  size_t len = strlen(token);
+  if (len == 0 || name_size == 0)
+    return false;
+  size_t end = len;
+  while (end > 0 && token[end - 1] >= '0' && token[end - 1] <= '9')
+    end--;
+  if (end == 0)
+    return false; /* all digits: not a category name */
+  size_t name_len = end < name_size - 1 ? end : name_size - 1;
+  for (size_t i = 0; i < name_len; i++) {
+    char c = token[i];
+    name[i] = (c >= 'A' && c <= 'Z') ? (char)(c - 'A' + 'a') : c;
+  }
+  name[name_len] = '\0';
+  int lvl = 1;
+  if (end < len) {
+    lvl = 0;
+    for (size_t i = end; i < len; i++) {
+      int digit = token[i] - '0';
+      if (lvl > (1000 - digit) / 10)
+        return false;
+      lvl = lvl * 10 + digit;
+    }
+  }
+  *level = lvl;
+  return true;
+}
+
 static int parse_debug_flags(const char* value, Config* config) {
   if (!value || value[0] == '\0' || value[0] == ',' || value[strlen(value) - 1] == ',' ||
       strstr(value, ",,")) {
@@ -412,30 +445,40 @@ static int parse_debug_flags(const char* value, Config* config) {
   for (char* token = strtok_r(flags, ",", &saveptr); token != NULL;
        token = strtok_r(NULL, ",", &saveptr)) {
     uint32_t flag = 0;
-    if (strcmp(token, "help") == 0) {
+    char name[32];
+    int level = 1;
+    if (!split_flag_level(token, name, sizeof(name), &level)) {
+      log_message(LOG_LEVEL_ERROR, "unsupported --debug flag: %s", token);
+      free(flags);
+      return -1;
+    }
+    if (strcmp(name, "help") == 0) {
       print_debug_usage();
       free(flags);
       return 1;
-    } else if (strcmp(token, "all") == 0) {
-      parsed = LOG_DEBUG_ALL;
+    } else if (strcmp(name, "all") == 0) {
+      parsed = level == 0 ? 0 : LOG_DEBUG_ALL;
       continue;
-    } else if (strcmp(token, "none") == 0) {
+    } else if (strcmp(name, "none") == 0) {
       parsed = 0;
       continue;
-    } else if (strcmp(token, "io") == 0) {
+    } else if (strcmp(name, "io") == 0) {
       flag = LOG_DEBUG_IO;
-    } else if (strcmp(token, "proto") == 0) {
+    } else if (strcmp(name, "proto") == 0) {
       flag = LOG_DEBUG_PROTO;
-    } else if (strcmp(token, "pack") == 0) {
+    } else if (strcmp(name, "pack") == 0) {
       flag = LOG_DEBUG_PACK;
-    } else if (strcmp(token, "util") == 0) {
+    } else if (strcmp(name, "util") == 0) {
       flag = LOG_DEBUG_UTIL;
     } else {
       log_message(LOG_LEVEL_ERROR, "unsupported --debug flag: %s", token);
       free(flags);
       return -1;
     }
-    parsed |= flag;
+    if (level == 0)
+      parsed &= ~flag;
+    else
+      parsed |= flag;
   }
   free(flags);
   config->debug_level = (int)parsed;
@@ -461,28 +504,43 @@ static int parse_info_flags(const char* value, Config* config) {
   for (char* token = strtok_r(flags, ",", &saveptr); token != NULL;
        token = strtok_r(NULL, ",", &saveptr)) {
     uint32_t flag = 0;
-    if (strcmp(token, "all") == 0) {
-      parsed = LOG_INFO_ALL;
+    char name[32];
+    int level = 1;
+    if (!split_flag_level(token, name, sizeof(name), &level)) {
+      log_message(LOG_LEVEL_ERROR, "unsupported --info flag: %s", token);
+      free(flags);
+      return -1;
+    }
+    if (strcmp(name, "all") == 0) {
+      parsed = level == 0 ? 0 : LOG_INFO_ALL;
       continue;
     }
-    if (strcmp(token, "none") == 0) {
+    if (strcmp(name, "none") == 0) {
       parsed = 0;
       continue;
     }
-    if (strcmp(token, "copy") == 0)
+    if (strcmp(name, "help") == 0) {
+      print_info_usage();
+      free(flags);
+      return 1;
+    }
+    if (strcmp(name, "copy") == 0 || strcmp(name, "name") == 0)
       flag = LOG_INFO_COPY;
-    else if (strcmp(token, "misc") == 0)
+    else if (strcmp(name, "misc") == 0)
       flag = LOG_INFO_MISC;
-    else if (strcmp(token, "skip") == 0)
+    else if (strcmp(name, "skip") == 0)
       flag = LOG_INFO_SKIP;
-    else if (strcmp(token, "stats") == 0)
+    else if (strcmp(name, "stats") == 0)
       flag = LOG_INFO_STATS;
     else {
       log_message(LOG_LEVEL_ERROR, "unsupported --info flag: %s", token);
       free(flags);
       return -1;
     }
-    parsed |= flag;
+    if (level == 0)
+      parsed &= ~flag;
+    else
+      parsed |= flag;
   }
   free(flags);
   config->info_level = (int)parsed;
@@ -1027,17 +1085,22 @@ typedef struct {
 } CliParseCtx;
 
 /* Apply output controls before processing other options so their order is
- * irrelevant.  Returns 0 on success, -1 on error. */
+ * irrelevant.  Returns 0 on success, a positive code for a help request
+ * (parse_args returns it verbatim), or -1 on error. */
 static int cli_apply_output_controls(Config* config, int argc, char* argv[]) {
   for (int i = 1; i < argc; i++) {
     if (strcmp(argv[i], "-v") == 0 || strcmp(argv[i], "--verbose") == 0) {
       set_log_level(LOG_LEVEL_DEBUG);
     } else if (strncmp(argv[i], "--info=", 7) == 0) {
-      if (parse_info_flags(argv[i] + 7, config) != 0)
-        return -1;
+      int ret = parse_info_flags(argv[i] + 7, config);
+      if (ret != 0)
+        return ret;
     } else if (strcmp(argv[i], "--info") == 0) {
-      if (i + 1 >= argc || parse_info_flags(argv[++i], config) != 0)
+      if (i + 1 >= argc)
         return -1;
+      int ret = parse_info_flags(argv[++i], config);
+      if (ret != 0)
+        return ret;
     }
   }
   return 0;
@@ -1842,13 +1905,19 @@ static bool cli_handle_logging_options(CliParseCtx* ctx) {
     return true;
   }
   if (strncmp(arg, "--info=", 7) == 0) {
-    if (parse_info_flags(arg + 7, config) != 0)
-      ctx->exit_code = -1;
+    int info_ret = parse_info_flags(arg + 7, config);
+    if (info_ret != 0)
+      ctx->exit_code = info_ret;
     return true;
   }
   if (opt_is(arg, "--info", NULL)) {
-    if (ctx->i + 1 >= ctx->argc || parse_info_flags(ctx->argv[++ctx->i], config) != 0)
+    if (ctx->i + 1 >= ctx->argc) {
       ctx->exit_code = -1;
+      return true;
+    }
+    int info_ret = parse_info_flags(ctx->argv[++ctx->i], config);
+    if (info_ret != 0)
+      ctx->exit_code = info_ret;
     return true;
   }
   if (strncmp(arg, "--skip-compress=", 16) == 0) {
@@ -2436,8 +2505,11 @@ int parse_args(Config* config, int argc, char* argv[], int* positional_args,
   }
 
   int result = -1;
-  if (cli_apply_output_controls(config, exp_argc, exp_argv) != 0)
+  int output_ret = cli_apply_output_controls(config, exp_argc, exp_argv);
+  if (output_ret != 0) {
+    result = output_ret;
     goto done;
+  }
 
   CliParseCtx ctx = {
       .config = config,

src/client/client_send.c

@@ -328,15 +328,15 @@ static char* files_from_missing_dest_path(const Config* config, const char* entr
 
 /* --files-from semantics: every listed entry must resolve under the source
  * root, otherwise rsync reports a hard error instead of silently transferring
- * nothing. An empty list is also an error. An entry of "." (the whole tree)
- * and listed-but-empty directories are valid.  With --ignore-missing-args
+ * nothing. An entry of "." (the whole tree) and listed-but-empty directories
+ * are valid.  An empty list is valid too: rsync transfers nothing and exits 0.
+ * With --ignore-missing-args
  * (implied by --delete-missing-args) a listed-but-missing entry is instead
  * skipped: nothing is transferred for it, it never enters the keep-set and the
  * run succeeds for the rest (an all-missing non-empty list succeeds
  * transferring nothing, matching rsync).  With --delete-missing-args
  * `missing_dest` (when non-NULL) collects the entry's destination-relative
- * mirror for the receiver's exact-deletion request.  An empty list stays a
- * hard error in every mode (nothing was requested at all).  Runs before any
+ * mirror for the receiver's exact-deletion request.  Runs before any
  * transfer so the failure/skip is surfaced uniformly in the single-threaded,
  * -m, dry-run and --list-only paths. */
 static bool files_from_list_check(const Config* config, ArrayList* missing_dest, int* skipped_out) {
@@ -349,12 +349,11 @@ static bool files_from_list_check(const Config* config, ArrayList* missing_dest,
     return false;
   }
   if (set->count == 0) {
-    char* escaped_list =
-        output_escape(config->files_from ? config->files_from : "", log_get_8_bit_output());
-    log_message(LOG_LEVEL_ERROR, "--files-from file '%s' contains no entries; nothing to transfer",
-                escaped_list ? escaped_list : "<allocation failed>");
-    free(escaped_list);
-    return false;
+    /* rsync treats an empty --files-from list as "nothing to transfer" and
+       exits 0 (the source directory is still a valid source arg), so this is
+       not an error.  Nothing passes the (empty) allow-set, so no file is sent
+       and no keep-set entry is produced. */
+    return true;
   }
   bool ignore = config->ignore_missing_args || config->delete_missing_args;
   for (int i = 0; i < set->count; i++) {
@@ -2679,12 +2678,15 @@ int send_files(Config* config) {
   report_transfer_stats(config, total_files, total_bytes, start);
   log_info_message(LOG_INFO_STATS, "Transfer summary: %d files, %.1f MB", total_files,
                    (double)total_bytes / (double)BYTES_PER_MIB);
-  /* --ignore-errors: an unreadable source directory was skipped but the run
-     still completed (and deleted); report the run as errored like rsync does.
-     A --max-delete-capped commit is a successful transfer that rsync reports
+  /* A skipped source entry (--ignore-errors past an unreadable directory, or a
+     dereferenced symlink with no referent) makes rsync report a partial
+     transfer (exit 23) even though the rest of the run succeeded.  A
+     --max-delete-capped commit is a successful transfer that rsync reports
      with exit code 25. */
-  if (!ok || had_scan_io)
+  if (!ok)
     ret = 1;
+  else if (had_scan_io)
+    ret = 23;
   else
     ret = delete_limit ? 25 : 0;
 
@@ -2921,12 +2923,15 @@ int send_files_multithreaded(Config** config_ptr) {
   mtx_unlock(&context->mutex_scanner);
   bool sender_ok = sender_result == thrd_success;
   bool delete_limit = context->delete_limit;
-  /* --ignore-errors: the run completed (and deleted) past an unreadable source
-     directory; report it as errored like rsync does.  A --max-delete-capped
-     commit is a successful transfer that rsync reports with exit code 25. */
+  /* A skipped source entry (--ignore-errors past an unreadable directory, or a
+     dereferenced symlink with no referent) makes rsync report a partial
+     transfer (exit 23).  A --max-delete-capped commit is a successful transfer
+     that rsync reports with exit code 25. */
   pipeline_context_sender_destroy(context);
   client_set_abort_armed(false);
-  if (!sender_ok || scan_io)
+  if (!sender_ok)
     return 1;
+  if (scan_io)
+    return 23;
   return delete_limit ? 25 : 0;
 }

src/client/scanner.c

@@ -163,6 +163,12 @@ typedef struct {
      Size pruning protects the destination mirror even under --delete-excluded,
      so it is recorded into a separate sink from `excluded`. */
   bool size_excluded;
+  /* True when a symlink selected for dereferencing (-L/--copy-links or an
+     unsafe target under --copy-unsafe-links) had no usable referent (a broken
+     link or a stat() failure).  rsync still reports this as a partial transfer
+     (exit 23) even though the entry is skipped, so the scanner records it as a
+     non-fatal I/O error. */
+  bool referent_error;
 } ScannerEntry;
 
 /* --one-file-system (-x) decision. Only directories can carry a different
@@ -412,6 +418,7 @@ static int scanner_inspect_entry(const ScannerOptions* options, const char* cont
                                  const char* link_rel, const char* name, ScannerEntry* entry) {
   entry->excluded = false;
   entry->size_excluded = false;
+  entry->referent_error = false;
   entry->is_symlink = false;
   entry->link_target = NULL;
   entry->path = path_cat(containing_dir, name);
@@ -438,12 +445,13 @@ static int scanner_inspect_entry(const ScannerOptions* options, const char* cont
     goto skip;
   case LINK_ACTION_DEREF:
     if (stat(entry->path, &entry->stats) != 0) {
-      /* rsync reports "symlink has no referent" and continues (exit 23); we
-         surface the same condition rather than silently dropping the entry. */
+      /* rsync reports "symlink has no referent" and continues with a partial
+         transfer (exit 23); record the error so the run exits 23 too. */
       char* escaped = output_escape(entry->path, log_get_8_bit_output());
       log_message(LOG_LEVEL_WARNING, "symlink has no referent: %s",
                   escaped ? escaped : "<allocation failed>");
       free(escaped);
+      entry->referent_error = true;
       goto skip;
     }
     entry->is_directory = S_ISDIR(entry->stats.st_mode);
@@ -1118,6 +1126,10 @@ Chunk* directory_scanner_next(DirectoryScanner* scanner) {
       break;
     }
     if (inspection == 0) {
+      /* A dereferenced symlink with no referent is a partial-transfer error
+         (rsync exit 23): record it as a non-fatal scan I/O error. */
+      if (inspected.referent_error)
+        scanner->io_error = true;
       /* A user-selection exclude protects its destination mirror from --delete
          unless --delete-excluded; a size prune is always protected.  Other
          skips (unreadable, symlink policy) protect nothing.  Under -R +
@@ -1511,6 +1523,8 @@ static void scan_root_entry(const ScannerOptions* options, const FilterNode* roo
     return;
   }
   if (inspection == 0) {
+    if (inspected.referent_error)
+      ps->io_error = true;
     ArrayList* sink = NULL;
     if (inspected.excluded)
       sink = inspected.size_excluded ? options->size_skipped_paths : options->excluded_paths;

src/client/usage.c

@@ -171,8 +171,8 @@ void print_usage(void) {
   printf("  -v, --verbose       Enable debug logging\n");
   printf("  -q, --quiet         Suppress non-error output\n");
   printf("  --debug=FLAGS       Fine-grained debug logging (use --debug=help for flags)\n");
-  printf("  --info=FLAGS        Fine-grained info: copy,misc,skip,stats,all,none\n");
-  printf("                      none suppresses info even with --verbose\n");
+  printf("  --info=FLAGS        Fine-grained info: copy,name,misc,skip,stats,all,none\n");
+  printf("                      (use --info=help for flags; none suppresses --verbose)\n");
   printf("  --preserve          Preserve permissions and times (= -pt; long form only)\n");
   printf("  --no-perms          Negate -p/--perms\n");
   printf("  --no-times          Negate -t/--times\n");
@@ -340,5 +340,13 @@ void print_usage(void) {
 void print_debug_usage(void) {
   printf("Supported debug flags: IO,PROTO,PACK,UTIL,ALL,NONE\n");
   printf("Flags may be comma-separated, for example: --debug=io,proto\n");
-  printf("Other rsync debug flags are unsupported and rejected.\n");
+  printf("An optional level suffix is accepted (e.g. --debug=io2); level 0\n");
+  printf("silences that item.  Other rsync debug flags are unsupported and rejected.\n");
+}
+
+void print_info_usage(void) {
+  printf("Supported info flags: COPY,NAME,MISC,SKIP,STATS,ALL,NONE\n");
+  printf("Flags may be comma-separated, for example: --info=name,stats\n");
+  printf("An optional level suffix is accepted (e.g. --info=stats2); level 0\n");
+  printf("silences that item.  Other rsync info flags are unsupported and rejected.\n");
 }

src/client/usage.h

@@ -3,5 +3,6 @@
 
 void print_usage(void);
 void print_debug_usage(void);
+void print_info_usage(void);
 
 #endif