fix: preserve explicit rsync option negations

src/client/client_cli.c

@@ -201,6 +201,7 @@ static const NegatableOption NEGATABLE_OPTIONS[] = {
 
     /* These options are also implied by --archive or handled outside the table. */
     {"compress", "c", offsetof(Config, use_compression)},
+    {"compress", "z", offsetof(Config, use_compression)},
     {"multithreading", "m", offsetof(Config, use_multithreading)},
     {"preserve", "M", offsetof(Config, use_metadata)},
     {"sendfile", "f", offsetof(Config, use_sendfile)},
@@ -238,6 +239,8 @@ static int apply_negation(Config* config, const char* arg) {
     return -1;
   }
   *(bool*)((char*)config + entry->offset) = false;
+  if (entry->offset == offsetof(Config, use_metadata))
+    config->metadata_explicitly_disabled = true;
   return 0;
 }
 
@@ -437,6 +440,12 @@ int parse_args(Config* config, int argc, char* argv[], int* positional_args,
       }
     }
   }
+  /* Incremental and delta transfers need metadata unless the user disabled it. */
+  if ((config->use_incremental || config->use_delta) && !config->use_metadata &&
+      !config->metadata_explicitly_disabled) {
+    log_message(LOG_LEVEL_INFO, "Enabling metadata preservation for incremental/delta transfer");
+    config->use_metadata = true;
+  }
   return 0;
 }
 
@@ -543,16 +552,6 @@ int main(int argc, char* argv[]) {
     goto cleanup;
   }
 
-  /* Enable implicit flags */
-  if (config->use_incremental && !config->use_metadata) {
-    log_message(LOG_LEVEL_INFO, "Enabling metadata preservation for --incremental");
-    config->use_metadata = true;
-  }
-  if (config->use_delta && !config->use_metadata) {
-    log_message(LOG_LEVEL_INFO, "Enabling metadata preservation for --delta");
-    config->use_metadata = true;
-  }
-
   /* Initialize TLS if needed */
   if (config->use_tls)
     tls_global_init();

src/shared/config.c

@@ -17,6 +17,7 @@ static void config_set_defaults(Config* config) {
   config->use_chunk_serialization = false;
   config->use_compression = false;
   config->use_metadata = false;
+  config->metadata_explicitly_disabled = false;
   config->show_progress = false;
   config->dry_run = false;
   config->use_delete = false;

src/shared/config.h

@@ -18,6 +18,7 @@ typedef struct Config {
   bool use_compression;
   bool use_sendfile;
   bool use_metadata;
+  bool metadata_explicitly_disabled;
   bool show_progress;
   bool dry_run;
   bool use_delete;

tests/test_client_cli.c

@@ -358,7 +358,7 @@ static void test_parse_args_negations() {
 
 static void test_parse_args_negation_order() {
   Config* cfg = config_create();
-  char* argv[] = {"fastsync", "--no-compress", "-c", "/src", "/dst"};
+  char* argv[] = {"fastsync", "--no-z", "-c", "/src", "/dst"};
   int positional_args[2];
   int positional_count = 0;
 
@@ -367,6 +367,28 @@ static void test_parse_args_negation_order() {
   config_delete(cfg);
 }
 
+static void test_parse_args_no_preserve_blocks_implicit_metadata() {
+  static const char* const options[][3] = {
+      {"--incremental", "--no-preserve", "/src"},
+      {"--no-preserve", "--incremental", "/src"},
+      {"--delta", "--no-preserve", "/src"},
+      {"--no-preserve", "--delta", "/src"},
+  };
+
+  for (size_t i = 0; i < sizeof(options) / sizeof(options[0]); i++) {
+    Config* cfg = config_create();
+    char* argv[] = {"fastsync", (char*)options[i][0], (char*)options[i][1], (char*)options[i][2],
+                    "/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_metadata);
+    EXPECT_TRUE(cfg->metadata_explicitly_disabled);
+    config_delete(cfg);
+  }
+}
+
 static void test_parse_args_rejects_unsafe_negation() {
   static const char* const options[] = {"--no-archive", "--no-timeout", "--no-unknown"};
   for (size_t i = 0; i < sizeof(options) / sizeof(options[0]); i++) {
@@ -403,5 +425,6 @@ void test_client_cli() {
   test_parse_args_archive();
   test_parse_args_negations();
   test_parse_args_negation_order();
+  test_parse_args_no_preserve_blocks_implicit_metadata();
   test_parse_args_rejects_unsafe_negation();
 }