feat: warn when using --unstable, prefer granular flags (#21452)

This commit deprecates "--unstable" flag. 

When "--unstable" flag is encountered a warning like this is printed:
```
The `--unstable` flag is deprecated, use granular `--unstable-*` flags instead.
Learn more at: https://docs.deno.com/runtime/manual/tools/unstable_flags
```
When "--unstable" flag is used and an unstable API is called an
additional warning like this is printed for each API call:
```
The `Deno.dlopen` API was used with `--unstable` flag. The `--unstable` flag is deprecated, use granular `--unstable-ffi` instead. 
Learn more at: https://docs.deno.com/runtime/manual/tools/unstable_flags
```
When no "--unstable-*" flag is provided and an unstable API is called
following
warning is issued before exiting:
```
Unstable API 'Deno.dlopen'. The `--unstable-ffi` flag must be provided.
```

---------

Signed-off-by: Divy Srivastava <dj.srivastava23@gmail.com>
Signed-off-by: Bartek Iwańczuk <biwanczuk@gmail.com>
Co-authored-by: Divy Srivastava <dj.srivastava23@gmail.com>
Co-authored-by: Asher Gomez <ashersaupingomez@gmail.com>

cli/factory.rs

@@ -678,11 +678,10 @@ impl CliFactory {
     self.services.feature_checker.get_or_init(|| {
       let mut checker = FeatureChecker::default();
       checker.set_exit_cb(Box::new(crate::unstable_exit_cb));
-      // TODO(bartlomieju): enable, once we deprecate `--unstable` in favor
-      // of granular --unstable-* flags.
-      // feature_checker.set_warn_cb(Box::new(crate::unstable_warn_cb));
+      checker.set_warn_cb(Box::new(crate::unstable_warn_cb));
       if self.options.legacy_unstable_flag() {
         checker.enable_legacy_unstable();
+        checker.warn_on_legacy_unstable();
       }
       let unstable_features = self.options.unstable_features();
       for (flag_name, _, _) in crate::UNSTABLE_GRANULAR_FLAGS {

cli/main.rs

@@ -33,6 +33,8 @@ use crate::util::display;
 use crate::util::v8::get_v8_flags_from_env;
 use crate::util::v8::init_v8_flags;
 
+pub use deno_runtime::UNSTABLE_GRANULAR_FLAGS;
+
 use deno_core::anyhow::Context;
 use deno_core::error::AnyError;
 use deno_core::error::JsError;
@@ -279,85 +281,22 @@ fn unwrap_or_exit<T>(result: Result<T, AnyError>) -> T {
   }
 }
 
-// NOTE(bartlomieju): keep IDs in sync with `runtime/90_deno_ns.js` (search for `unstableFeatures`)
-pub(crate) static UNSTABLE_GRANULAR_FLAGS: &[(
-  // flag name
-  &str,
-  // help text
-  &str,
-  // id to enable it in runtime/99_main.js
-  i32,
-)] = &[
-  (
-    deno_runtime::deno_broadcast_channel::UNSTABLE_FEATURE_NAME,
-    "Enable unstable `BroadcastChannel` API",
-    1,
-  ),
-  (
-    deno_runtime::deno_cron::UNSTABLE_FEATURE_NAME,
-    "Enable unstable Deno.cron API",
-    2,
-  ),
-  (
-    deno_runtime::deno_ffi::UNSTABLE_FEATURE_NAME,
-    "Enable unstable FFI APIs",
-    3,
-  ),
-  (
-    deno_runtime::deno_fs::UNSTABLE_FEATURE_NAME,
-    "Enable unstable file system APIs",
-    4,
-  ),
-  (
-    deno_runtime::ops::http::UNSTABLE_FEATURE_NAME,
-    "Enable unstable HTTP APIs",
-    5,
-  ),
-  (
-    deno_runtime::deno_kv::UNSTABLE_FEATURE_NAME,
-    "Enable unstable Key-Value store APIs",
-    6,
-  ),
-  (
-    deno_runtime::deno_net::UNSTABLE_FEATURE_NAME,
-    "Enable unstable net APIs",
-    7,
-  ),
-  (
-    "temporal",
-    "Enable unstable Temporal API",
-    // Not used in JS
-    8,
-  ),
-  (
-    "unsafe-proto",
-    "Enable unsafe __proto__ support. This is a security risk.",
-    // This number is used directly in the JS code. Search
-    // for "unstableIds" to see where it's used.
-    9,
-  ),
-  (
-    deno_runtime::deno_webgpu::UNSTABLE_FEATURE_NAME,
-    "Enable unstable `WebGPU` API",
-    10,
-  ),
-  (
-    deno_runtime::ops::worker_host::UNSTABLE_FEATURE_NAME,
-    "Enable unstable Web Worker APIs",
-    11,
-  ),
-];
-
-pub(crate) fn unstable_exit_cb(_feature: &str, api_name: &str) {
-  // TODO(bartlomieju): change to "The `--unstable-{feature}` flag must be provided.".
-  eprintln!("Unstable API '{api_name}'. The --unstable flag must be provided.");
+pub(crate) fn unstable_exit_cb(feature: &str, api_name: &str) {
+  eprintln!(
+    "Unstable API '{api_name}'. The `--unstable-{}` flag must be provided.",
+    feature
+  );
   std::process::exit(70);
 }
 
-#[allow(dead_code)]
-pub(crate) fn unstable_warn_cb(feature: &str) {
+// TODO(bartlomieju): remove when `--unstable` flag is removed.
+pub(crate) fn unstable_warn_cb(feature: &str, api_name: &str) {
   eprintln!(
-    "The `--unstable` flag is deprecated, use --unstable-{feature} instead."
+    "⚠️  {}",
+    colors::yellow(format!(
+      "The `{}` API was used with `--unstable` flag. The `--unstable` flag is deprecated and will be removed in Deno 2.0. Use granular `--unstable-{}` instead.\nLearn more at: https://docs.deno.com/runtime/manual/tools/unstable_flags",
+      api_name, feature
+    ))
   );
 }
 
@@ -404,6 +343,25 @@ pub fn main() {
       Err(err) => unwrap_or_exit(Err(AnyError::from(err))),
     };
 
+    // TODO(bartlomieju): remove when `--unstable` flag is removed.
+    if flags.unstable_config.legacy_flag_enabled {
+      if matches!(flags.subcommand, DenoSubcommand::Check(_)) {
+        eprintln!(
+          "⚠️  {}",
+          colors::yellow(
+            "The `--unstable` flag is not needed for `deno check` anymore."
+          )
+        );
+      } else {
+        eprintln!(
+          "⚠️  {}",
+          colors::yellow(
+            "The `--unstable` flag is deprecated and will be removed in Deno 2.0. Use granular `--unstable-*` flags instead.\nLearn more at: https://docs.deno.com/runtime/manual/tools/unstable_flags"
+          )
+        );
+      }
+    }
+
     let default_v8_flags = match flags.subcommand {
       // Using same default as VSCode:
       // https://github.com/microsoft/vscode/blob/48d4ba271686e8072fc6674137415bc80d936bc7/extensions/typescript-language-features/src/configuration/configuration.ts#L213-L214
@@ -434,20 +392,3 @@ pub fn main() {
 
   std::process::exit(exit_code);
 }
-
-#[cfg(test)]
-mod test {
-  use super::*;
-
-  #[test]
-  fn unstable_granular_flag_names_sorted() {
-    let flags = UNSTABLE_GRANULAR_FLAGS
-      .iter()
-      .map(|(name, _, _)| name.to_string())
-      .collect::<Vec<_>>();
-    let mut sorted_flags = flags.clone();
-    sorted_flags.sort();
-    // sort the flags by name so they appear nicely in the help text
-    assert_eq!(flags, sorted_flags);
-  }
-}

cli/tests/integration/doc_tests.rs

@@ -28,7 +28,7 @@ fn deno_doc() {
 }
 
 itest!(deno_doc_import_map {
-  args: "doc --unstable --import-map=doc/import_map.json doc/use_import_map.js",
+  args: "doc --import-map=doc/import_map.json doc/use_import_map.js",
   output: "doc/use_import_map.out",
 });
 

cli/tests/integration/info_tests.rs

@@ -51,12 +51,12 @@ itest!(info_flag_location {
 });
 
 itest!(info_json {
-  args: "info --json --unstable",
+  args: "info --json",
   output: "info/info_json.out",
 });
 
 itest!(info_json_location {
-  args: "info --json --unstable --location https://deno.land",
+  args: "info --json --location https://deno.land",
   output: "info/info_json_location.out",
 });
 
@@ -67,7 +67,7 @@ itest!(info_flag_script_jsx {
 });
 
 itest!(json_file {
-  args: "info --quiet --json --unstable info/json_output/main.ts",
+  args: "info --quiet --json info/json_output/main.ts",
   output: "info/json_output/main.out",
   exit_code: 0,
 });
@@ -79,7 +79,7 @@ itest!(import_map_info {
 });
 
 itest!(info_json_deps_order {
-  args: "info --unstable --json info/076_info_json_deps_order.ts",
+  args: "info --json info/076_info_json_deps_order.ts",
   output: "info/076_info_json_deps_order.out",
 });
 

cli/tests/integration/lint_tests.rs

@@ -4,7 +4,7 @@ use test_util::assert_contains;
 use test_util::TestContextBuilder;
 
 itest!(ignore_unexplicit_files {
-  args: "lint --unstable --ignore=./",
+  args: "lint --ignore=./",
   output_str: Some("error: No target files found.\n"),
   exit_code: 1,
 });

cli/tests/integration/npm_tests.rs

@@ -30,14 +30,14 @@ itest!(esm_module_eval {
 });
 
 itest!(esm_module_deno_test {
-  args: "test --allow-read --allow-env --unstable npm/esm/test.js",
+  args: "test --allow-read --allow-env npm/esm/test.js",
   output: "npm/esm/test.out",
   envs: env_vars_for_npm_tests(),
   http_server: true,
 });
 
 itest!(esm_import_cjs_default {
-  args: "run --allow-read --allow-env --unstable --quiet --check=all npm/esm_import_cjs_default/main.ts",
+  args: "run --allow-read --allow-env --quiet --check=all npm/esm_import_cjs_default/main.ts",
   output: "npm/esm_import_cjs_default/main.out",
   envs: env_vars_for_npm_tests(),
   http_server: true,
@@ -123,7 +123,7 @@ itest!(translate_cjs_to_esm {
 });
 
 itest!(compare_globals {
-  args: "run --allow-read --unstable --check=all npm/compare_globals/main.ts",
+  args: "run --allow-read --check=all npm/compare_globals/main.ts",
   output: "npm/compare_globals/main.out",
   envs: env_vars_for_npm_tests(),
   http_server: true,
@@ -160,14 +160,15 @@ itest!(child_process_fork_test {
 });
 
 itest!(cjs_module_export_assignment {
-  args: "run -A --unstable --quiet --check=all npm/cjs_module_export_assignment/main.ts",
+  args: "run -A --quiet --check=all npm/cjs_module_export_assignment/main.ts",
   output: "npm/cjs_module_export_assignment/main.out",
   envs: env_vars_for_npm_tests(),
   http_server: true,
 });
 
 itest!(cjs_module_export_assignment_number {
-  args: "run -A --unstable --quiet --check=all npm/cjs_module_export_assignment_number/main.ts",
+  args:
+    "run -A --quiet --check=all npm/cjs_module_export_assignment_number/main.ts",
   output: "npm/cjs_module_export_assignment_number/main.out",
   envs: env_vars_for_npm_tests(),
   http_server: true,
@@ -401,7 +402,7 @@ itest!(no_types_cjs {
 });
 
 itest!(no_types_in_conditional_exports {
-  args: "run --check --unstable npm/no_types_in_conditional_exports/main.ts",
+  args: "run --check npm/no_types_in_conditional_exports/main.ts",
   output: "npm/no_types_in_conditional_exports/main.out",
   exit_code: 0,
   envs: env_vars_for_npm_tests(),
@@ -1542,7 +1543,7 @@ fn auto_discover_lock_file() {
 
   let output = context
     .new_command()
-    .args("run --unstable -A npm:@denotest/bin/cli-esm test")
+    .args("run -A npm:@denotest/bin/cli-esm test")
     .run();
   output
     .assert_matches_text(

cli/tests/integration/run_tests.rs

@@ -143,9 +143,8 @@ itest!(_023_no_ext {
   output: "run/023_no_ext.out",
 });
 
-// TODO(lucacasonato): remove --unstable when permissions goes stable
 itest!(_025_hrtime {
-  args: "run --quiet --allow-hrtime --unstable --reload run/025_hrtime.ts",
+  args: "run --quiet --allow-hrtime --reload run/025_hrtime.ts",
   output: "run/025_hrtime.ts.out",
 });
 
@@ -199,14 +198,14 @@ itest!(_033_import_map_in_flag_has_precedence {
 
 itest!(_033_import_map_remote {
   args:
-    "run --quiet --reload --import-map=http://127.0.0.1:4545/import_maps/import_map_remote.json --unstable import_maps/test_remote.ts",
+    "run --quiet --reload --import-map=http://127.0.0.1:4545/import_maps/import_map_remote.json import_maps/test_remote.ts",
   output: "run/033_import_map_remote.out",
   http_server: true,
 });
 
 itest!(_033_import_map_vendor_dir_remote {
   args:
-    "run --quiet --reload --import-map=http://127.0.0.1:4545/import_maps/import_map_remote.json --vendor --unstable $TESTDATA/import_maps/test_remote.ts",
+    "run --quiet --reload --import-map=http://127.0.0.1:4545/import_maps/import_map_remote.json --vendor $TESTDATA/import_maps/test_remote.ts",
   output: "run/033_import_map_remote.out",
   http_server: true,
   temp_cwd: true,
@@ -250,9 +249,8 @@ itest!(_044_bad_resource {
   exit_code: 1,
 });
 
-// TODO(bartlomieju): remove --unstable once Deno.Command is stabilized
 itest!(_045_proxy {
-  args: "run -L debug --unstable --allow-net --allow-env --allow-run --allow-read --reload --quiet run/045_proxy_test.ts",
+  args: "run -L debug --allow-net --allow-env --allow-run --allow-read --reload --quiet run/045_proxy_test.ts",
   output: "run/045_proxy_test.ts.out",
   http_server: true,
 });
@@ -1442,43 +1440,42 @@ itest!(exit_error42 {
 });
 
 itest!(set_exit_code_0 {
-  args: "run --no-check --unstable run/set_exit_code_0.ts",
+  args: "run --no-check run/set_exit_code_0.ts",
   output_str: Some(""),
   exit_code: 0,
 });
 
 itest!(set_exit_code_1 {
-  args: "run --no-check --unstable run/set_exit_code_1.ts",
+  args: "run --no-check run/set_exit_code_1.ts",
   output_str: Some(""),
   exit_code: 42,
 });
 
 itest!(set_exit_code_2 {
-  args: "run --no-check --unstable run/set_exit_code_2.ts",
+  args: "run --no-check run/set_exit_code_2.ts",
   output_str: Some(""),
   exit_code: 42,
 });
 
 itest!(op_exit_op_set_exit_code_in_worker {
-  args: "run --no-check --unstable --allow-read run/op_exit_op_set_exit_code_in_worker.ts",
+  args: "run --no-check --allow-read run/op_exit_op_set_exit_code_in_worker.ts",
   exit_code: 21,
   output_str: Some(""),
 });
 
 itest!(deno_exit_tampering {
-  args: "run --no-check --unstable run/deno_exit_tampering.ts",
+  args: "run --no-check run/deno_exit_tampering.ts",
   output_str: Some(""),
   exit_code: 42,
 });
 
 itest!(heapstats {
-  args: "run --quiet --unstable --v8-flags=--expose-gc run/heapstats.js",
+  args: "run --quiet --v8-flags=--expose-gc run/heapstats.js",
   output: "run/heapstats.js.out",
 });
 
 itest!(finalization_registry {
-  args:
-    "run --quiet --unstable --v8-flags=--expose-gc run/finalization_registry.js",
+  args: "run --quiet --v8-flags=--expose-gc run/finalization_registry.js",
   output: "run/finalization_registry.js.out",
 });
 
@@ -1733,12 +1730,12 @@ itest!(unstable_disabled_js {
 });
 
 itest!(unstable_enabled_js {
-  args: "run --quiet --reload --unstable run/unstable.ts",
+  args: "run --quiet --reload --unstable-fs run/unstable.ts",
   output: "run/unstable_enabled_js.out",
 });
 
 itest!(unstable_worker {
-  args: "run --reload --unstable --quiet --allow-read run/unstable_worker.ts",
+  args: "run --reload --quiet --allow-read run/unstable_worker.ts",
   output: "run/unstable_worker.ts.out",
 });
 
@@ -2237,7 +2234,7 @@ itest!(worker_drop_handle_race {
 });
 
 itest!(worker_drop_handle_race_terminate {
-  args: "run --unstable run/worker_drop_handle_race_terminate.js",
+  args: "run run/worker_drop_handle_race_terminate.js",
   output: "run/worker_drop_handle_race_terminate.js.out",
 });
 
@@ -3045,7 +3042,7 @@ mod permissions {
 }
 
 itest!(tls_starttls {
-  args: "run --quiet --reload --allow-net --allow-read --unstable --cert tls/RootCA.pem run/tls_starttls.js",
+  args: "run --quiet --reload --allow-net --allow-read --cert tls/RootCA.pem run/tls_starttls.js",
   output: "run/tls.out",
 });
 
@@ -3610,8 +3607,7 @@ itest!(event_listener_error_immediate_exit {
 
 // https://github.com/denoland/deno/pull/14159#issuecomment-1092285446
 itest!(event_listener_error_immediate_exit_worker {
-  args:
-    "run --quiet --unstable -A run/event_listener_error_immediate_exit_worker.ts",
+  args: "run --quiet -A run/event_listener_error_immediate_exit_worker.ts",
   output: "run/event_listener_error_immediate_exit_worker.ts.out",
   exit_code: 1,
 });
@@ -3691,7 +3687,7 @@ itest!(check_js_points_to_ts {
 });
 
 itest!(no_prompt_flag {
-  args: "run --quiet --unstable --no-prompt run/no_prompt.ts",
+  args: "run --quiet --no-prompt run/no_prompt.ts",
   output_str: Some(""),
 });
 
@@ -3740,7 +3736,7 @@ itest!(queue_microtask_error_handled {
 });
 
 itest!(spawn_stdout_inherit {
-  args: "run --quiet --unstable -A run/spawn_stdout_inherit.ts",
+  args: "run --quiet -A run/spawn_stdout_inherit.ts",
   output: "run/spawn_stdout_inherit.ts.out",
 });
 
@@ -3785,17 +3781,17 @@ itest!(test_and_bench_are_noops_in_run {
 
 #[cfg(not(target_os = "windows"))]
 itest!(spawn_kill_permissions {
-  args: "run --quiet --unstable --allow-run=cat spawn_kill_permissions.ts",
+  args: "run --quiet --allow-run=cat spawn_kill_permissions.ts",
   output_str: Some(""),
 });
 
 itest!(followup_dyn_import_resolved {
-  args: "run --unstable --allow-read run/followup_dyn_import_resolves/main.ts",
+  args: "run --allow-read run/followup_dyn_import_resolves/main.ts",
   output: "run/followup_dyn_import_resolves/main.ts.out",
 });
 
 itest!(allow_run_allowlist_resolution {
-  args: "run --quiet --unstable -A allow_run_allowlist_resolution.ts",
+  args: "run --quiet -A allow_run_allowlist_resolution.ts",
   output: "allow_run_allowlist_resolution.ts.out",
 });
 
@@ -3834,7 +3830,7 @@ itest!(nested_error {
 });
 
 itest!(node_env_var_allowlist {
-  args: "run --unstable --no-prompt run/node_env_var_allowlist.ts",
+  args: "run --no-prompt run/node_env_var_allowlist.ts",
   output: "run/node_env_var_allowlist.ts.out",
   exit_code: 1,
 });

cli/tests/integration/test_tests.rs

@@ -50,7 +50,7 @@ itest!(ignore {
 });
 
 itest!(ignore_permissions {
-  args: "test --unstable test/ignore_permissions.ts",
+  args: "test test/ignore_permissions.ts",
   exit_code: 0,
   output: "test/ignore_permissions.out",
 });
@@ -200,25 +200,25 @@ itest!(no_check {
 });
 
 itest!(no_run {
-  args: "test --unstable --no-run test/no_run.ts",
+  args: "test --no-run test/no_run.ts",
   output: "test/no_run.out",
   exit_code: 1,
 });
 
 itest!(allow_all {
-  args: "test --unstable --allow-all test/allow_all.ts",
+  args: "test --allow-all test/allow_all.ts",
   exit_code: 0,
   output: "test/allow_all.out",
 });
 
 itest!(allow_none {
-  args: "test --unstable test/allow_none.ts",
+  args: "test test/allow_none.ts",
   exit_code: 1,
   output: "test/allow_none.out",
 });
 
 itest!(ops_sanitizer_unstable {
-  args: "test --unstable --trace-ops test/ops_sanitizer_unstable.ts",
+  args: "test --trace-ops test/ops_sanitizer_unstable.ts",
   exit_code: 1,
   output: "test/ops_sanitizer_unstable.out",
 });
@@ -449,7 +449,7 @@ fn captured_output() {
   let context = TestContext::default();
   let output = context
     .new_command()
-    .args("test --allow-run --allow-read --unstable test/captured_output.ts")
+    .args("test --allow-run --allow-read test/captured_output.ts")
     .env("NO_COLOR", "1")
     .run();
 

cli/tests/integration/watcher_tests.rs

@@ -216,7 +216,6 @@ async fn lint_watch_test() {
     .arg("lint")
     .arg(&badly_linted)
     .arg("--watch")
-    .arg("--unstable")
     .piped_output()
     .spawn()
     .unwrap();
@@ -273,7 +272,6 @@ async fn lint_watch_without_args_test() {
     .current_dir(t.path())
     .arg("lint")
     .arg("--watch")
-    .arg("--unstable")
     .piped_output()
     .spawn()
     .unwrap();
@@ -365,7 +363,6 @@ async fn fmt_watch_test() {
     .arg("fmt")
     .arg(&badly_formatted)
     .arg("--watch")
-    .arg("--unstable")
     .piped_output()
     .spawn()
     .unwrap();
@@ -420,7 +417,6 @@ async fn fmt_watch_without_args_test() {
     .current_dir(t.path())
     .arg("fmt")
     .arg("--watch")
-    .arg("--unstable")
     .piped_output()
     .spawn()
     .unwrap();
@@ -514,7 +510,6 @@ async fn bundle_js_watch() {
     .arg(&file_to_watch)
     .arg(&bundle)
     .arg("--watch")
-    .arg("--unstable")
     .env("NO_COLOR", "1")
     .piped_output()
     .spawn()
@@ -586,7 +581,6 @@ async fn bundle_watch_not_exit() {
     .arg(&file_to_watch)
     .arg(&target_file)
     .arg("--watch")
-    .arg("--unstable")
     .env("NO_COLOR", "1")
     .piped_output()
     .spawn()
@@ -891,7 +885,6 @@ async fn run_watch_with_import_map_and_relative_paths() {
   let mut child = util::deno_cmd()
     .current_dir(temp_directory.path())
     .arg("run")
-    .arg("--unstable")
     .arg("--watch")
     .arg("--import-map")
     .arg(&import_map_path)
@@ -1191,7 +1184,6 @@ async fn test_watch_module_graph_error_referrer() {
     .current_dir(util::testdata_path())
     .arg("run")
     .arg("--watch")
-    .arg("--unstable")
     .arg(&file_to_watch)
     .env("NO_COLOR", "1")
     .piped_output()
@@ -1315,7 +1307,6 @@ async fn bench_watch_basic() {
     .current_dir(util::testdata_path())
     .arg("bench")
     .arg("--watch")
-    .arg("--unstable")
     .arg("--no-check")
     .arg(t.path())
     .env("NO_COLOR", "1")

cli/tests/integration/worker_tests.rs

@@ -64,7 +64,7 @@ itest!(worker_permissions_remote_remote {
   });
 
 itest!(worker_permissions_dynamic_remote {
-    args: "run --quiet --reload --allow-net --unstable workers/permissions_dynamic_remote.ts",
+    args: "run --quiet --reload --allow-net --unstable-worker-options workers/permissions_dynamic_remote.ts",
     output: "workers/permissions_dynamic_remote.ts.out",
     http_server: true,
     exit_code: 1,

cli/tests/testdata/npm/registry/@denotest/child-process-fork/1.0.0/index.js

@@ -2,7 +2,7 @@ const path = require("path");
 
 function childProcessFork(path) {
   const command = new Deno.Command(Deno.execPath(), {
-    args: ["run", "--unstable", "-A", path],
+    args: ["run", "-A", path],
     env: {
       "DENO_DONT_USE_INTERNAL_NODE_COMPAT_STATE": Deno[Deno.internal].core.ops.op_npm_process_state(),
     }

cli/tests/testdata/run/ffi/unstable_ffi_1.js.out

@@ -1 +1 @@
-Unstable API 'Deno.dlopen'. The --unstable flag must be provided.
+Unstable API 'Deno.dlopen'. The `--unstable-ffi` flag must be provided.

cli/tests/testdata/run/ffi/unstable_ffi_10.js.out

@@ -1 +1 @@
-Unstable API 'Deno.UnsafePointerView#getInt16'. The --unstable flag must be provided.
+Unstable API 'Deno.UnsafePointerView#getInt16'. The `--unstable-ffi` flag must be provided.

cli/tests/testdata/run/ffi/unstable_ffi_11.js.out

@@ -1 +1 @@
-Unstable API 'Deno.UnsafePointerView#getUint32'. The --unstable flag must be provided.
+Unstable API 'Deno.UnsafePointerView#getUint32'. The `--unstable-ffi` flag must be provided.

cli/tests/testdata/run/ffi/unstable_ffi_12.js.out

@@ -1 +1 @@
-Unstable API 'Deno.UnsafePointerView#getInt32'. The --unstable flag must be provided.
+Unstable API 'Deno.UnsafePointerView#getInt32'. The `--unstable-ffi` flag must be provided.

cli/tests/testdata/run/ffi/unstable_ffi_13.js.out

@@ -1 +1 @@
-Unstable API 'Deno.UnsafePointerView#getBigUint64'. The --unstable flag must be provided.
+Unstable API 'Deno.UnsafePointerView#getBigUint64'. The `--unstable-ffi` flag must be provided.

cli/tests/testdata/run/ffi/unstable_ffi_14.js.out

@@ -1 +1 @@
-Unstable API 'Deno.UnsafePointerView#getFloat32'. The --unstable flag must be provided.
+Unstable API 'Deno.UnsafePointerView#getFloat32'. The `--unstable-ffi` flag must be provided.

cli/tests/testdata/run/ffi/unstable_ffi_15.js.out

@@ -1 +1 @@
-Unstable API 'Deno.UnsafePointerView#getFloat64'. The --unstable flag must be provided.
+Unstable API 'Deno.UnsafePointerView#getFloat64'. The `--unstable-ffi` flag must be provided.

cli/tests/testdata/run/ffi/unstable_ffi_16.js.out

@@ -1 +1 @@
-Unstable API 'Deno.UnsafePointer#value'. The --unstable flag must be provided.
+Unstable API 'Deno.UnsafePointer#value'. The `--unstable-ffi` flag must be provided.

cli/tests/testdata/run/ffi/unstable_ffi_17.js.out

@@ -1 +1 @@
-Unstable API 'Deno.UnsafePointerView#getArrayBuffer'. The --unstable flag must be provided.
+Unstable API 'Deno.UnsafePointerView#getArrayBuffer'. The `--unstable-ffi` flag must be provided.

cli/tests/testdata/run/ffi/unstable_ffi_18.js.out

@@ -1 +1 @@
-Unstable API 'Deno.UnsafePointer#create'. The --unstable flag must be provided.
+Unstable API 'Deno.UnsafePointer#create'. The `--unstable-ffi` flag must be provided.

cli/tests/testdata/run/ffi/unstable_ffi_19.js.out

@@ -1 +1 @@
-Unstable API 'Deno.UnsafePointer#equals'. The --unstable flag must be provided.
+Unstable API 'Deno.UnsafePointer#equals'. The `--unstable-ffi` flag must be provided.

cli/tests/testdata/run/ffi/unstable_ffi_2.js.out

@@ -1 +1 @@
-Unstable API 'Deno.UnsafeFnPointer#call'. The --unstable flag must be provided.
+Unstable API 'Deno.UnsafeFnPointer#call'. The `--unstable-ffi` flag must be provided.

cli/tests/testdata/run/ffi/unstable_ffi_3.js.out

@@ -1 +1 @@
-Unstable API 'Deno.UnsafeFnPointer#call'. The --unstable flag must be provided.
+Unstable API 'Deno.UnsafeFnPointer#call'. The `--unstable-ffi` flag must be provided.

cli/tests/testdata/run/ffi/unstable_ffi_4.js.out

@@ -1 +1 @@
-Unstable API 'Deno.UnsafePointer#of'. The --unstable flag must be provided.
+Unstable API 'Deno.UnsafePointer#of'. The `--unstable-ffi` flag must be provided.

cli/tests/testdata/run/ffi/unstable_ffi_5.js.out

@@ -1 +1 @@
-Unstable API 'Deno.UnsafePointerView#copyInto'. The --unstable flag must be provided.
+Unstable API 'Deno.UnsafePointerView#copyInto'. The `--unstable-ffi` flag must be provided.

cli/tests/testdata/run/ffi/unstable_ffi_6.js.out

@@ -1 +1 @@
-Unstable API 'Deno.UnsafePointerView#getCString'. The --unstable flag must be provided.
+Unstable API 'Deno.UnsafePointerView#getCString'. The `--unstable-ffi` flag must be provided.

cli/tests/testdata/run/ffi/unstable_ffi_7.js.out

@@ -1 +1 @@
-Unstable API 'Deno.UnsafePointerView#getUint8'. The --unstable flag must be provided.
+Unstable API 'Deno.UnsafePointerView#getUint8'. The `--unstable-ffi` flag must be provided.

cli/tests/testdata/run/ffi/unstable_ffi_8.js.out

@@ -1 +1 @@
-Unstable API 'Deno.UnsafePointerView#getInt8'. The --unstable flag must be provided.
+Unstable API 'Deno.UnsafePointerView#getInt8'. The `--unstable-ffi` flag must be provided.

cli/tests/testdata/run/ffi/unstable_ffi_9.js.out

@@ -1 +1 @@
-Unstable API 'Deno.UnsafePointerView#getUint16'. The --unstable flag must be provided.
+Unstable API 'Deno.UnsafePointerView#getUint16'. The `--unstable-ffi` flag must be provided.

cli/tests/testdata/run/unstable_worker_options.disabled.out

@@ -1 +1 @@
-Unstable API 'Worker.deno.permissions'. The --unstable flag must be provided.
+Unstable API 'Worker.deno.permissions'. The `--unstable-worker-options` flag must be provided.

ext/node/polyfills/child_process.ts

@@ -9,6 +9,7 @@
 import { core, internals } from "ext:core/mod.js";
 const {
   op_node_child_ipc_pipe,
+  op_bootstrap_unstable_args,
 } = core.ensureFastOps();
 const {
   op_npm_process_state,
@@ -130,7 +131,7 @@ export function fork(
   }
   args = [
     "run",
-    "--unstable", // TODO(kt3k): Remove when npm: is stable
+    ...op_bootstrap_unstable_args(),
     "--node-modules-dir",
     "-A",
     ...stringifiedV8Flags,

runtime/lib.rs

@@ -43,3 +43,89 @@ pub use worker_bootstrap::WorkerLogLevel;
 
 mod shared;
 pub use shared::runtime;
+
+// NOTE(bartlomieju): keep IDs in sync with `runtime/90_deno_ns.js` (search for `unstableFeatures`)
+pub static UNSTABLE_GRANULAR_FLAGS: &[(
+  // flag name
+  &str,
+  // help text
+  &str,
+  // id to enable it in runtime/99_main.js
+  i32,
+)] = &[
+  (
+    deno_broadcast_channel::UNSTABLE_FEATURE_NAME,
+    "Enable unstable `BroadcastChannel` API",
+    1,
+  ),
+  (
+    deno_cron::UNSTABLE_FEATURE_NAME,
+    "Enable unstable Deno.cron API",
+    2,
+  ),
+  (
+    deno_ffi::UNSTABLE_FEATURE_NAME,
+    "Enable unstable FFI APIs",
+    3,
+  ),
+  (
+    deno_fs::UNSTABLE_FEATURE_NAME,
+    "Enable unstable file system APIs",
+    4,
+  ),
+  (
+    ops::http::UNSTABLE_FEATURE_NAME,
+    "Enable unstable HTTP APIs",
+    5,
+  ),
+  (
+    deno_kv::UNSTABLE_FEATURE_NAME,
+    "Enable unstable Key-Value store APIs",
+    6,
+  ),
+  (
+    deno_net::UNSTABLE_FEATURE_NAME,
+    "Enable unstable net APIs",
+    7,
+  ),
+  (
+    "temporal",
+    "Enable unstable Temporal API",
+    // Not used in JS
+    8,
+  ),
+  (
+    "unsafe-proto",
+    "Enable unsafe __proto__ support. This is a security risk.",
+    // This number is used directly in the JS code. Search
+    // for "unstableIds" to see where it's used.
+    9,
+  ),
+  (
+    deno_webgpu::UNSTABLE_FEATURE_NAME,
+    "Enable unstable `WebGPU` API",
+    10,
+  ),
+  (
+    ops::worker_host::UNSTABLE_FEATURE_NAME,
+    "Enable unstable Web Worker APIs",
+    11,
+  ),
+];
+
+#[cfg(test)]
+mod test {
+  use super::*;
+
+  #[test]
+  fn unstable_granular_flag_names_sorted() {
+    let flags = UNSTABLE_GRANULAR_FLAGS
+      .iter()
+      .map(|(name, _, _)| name.to_string())
+      .collect::<Vec<_>>();
+    let mut sorted_flags = flags.clone();
+    sorted_flags.sort();
+    // sort the flags by name so they appear nicely in the help text
+    assert_eq!(flags, sorted_flags);
+  }
+}

runtime/ops/bootstrap.rs

@@ -17,6 +17,7 @@ deno_core::extension!(
     op_bootstrap_log_level,
     op_bootstrap_no_color,
     op_bootstrap_is_tty,
+    op_bootstrap_unstable_args,
     op_snapshot_options,
   ],
   options = {
@@ -69,6 +70,23 @@ pub fn op_bootstrap_user_agent(state: &mut OpState) -> String {
   state.borrow::<BootstrapOptions>().user_agent.clone()
 }
 
+#[op2]
+#[serde]
+pub fn op_bootstrap_unstable_args(state: &mut OpState) -> Vec<String> {
+  let options = state.borrow::<BootstrapOptions>();
+  if options.unstable {
+    return vec!["--unstable".to_string()];
+  }
+
+  let mut flags = Vec::new();
+  for (name, _, id) in crate::UNSTABLE_GRANULAR_FLAGS.iter() {
+    if options.unstable_features.contains(id) {
+      flags.push(format!("--unstable-{}", name));
+    }
+  }
+  flags
+}
+
 #[op2]
 #[string]
 pub fn op_bootstrap_language(state: &mut OpState) -> String {

test_ffi/tests/integration_tests.rs

@@ -135,7 +135,7 @@ fn symbol_types() {
 
   let output = deno_cmd()
     .arg("check")
-    .arg("--unstable")
+    .arg("--unstable-ffi")
     .arg("--quiet")
     .arg("tests/ffi_types.ts")
     .env("NO_COLOR", "1")
@@ -160,7 +160,7 @@ fn thread_safe_callback() {
     .arg("run")
     .arg("--allow-ffi")
     .arg("--allow-read")
-    .arg("--unstable")
+    .arg("--unstable-ffi")
     .arg("--quiet")
     .arg("tests/thread_safe_test.js")
     .env("NO_COLOR", "1")
@@ -194,7 +194,7 @@ fn event_loop_integration() {
     .arg("run")
     .arg("--allow-ffi")
     .arg("--allow-read")
-    .arg("--unstable")
+    .arg("--unstable-ffi")
     .arg("--quiet")
     .arg("tests/event_loop_integration.ts")
     .env("NO_COLOR", "1")
@@ -246,7 +246,7 @@ fn ffi_callback_errors_test() {
     .arg("run")
     .arg("--allow-ffi")
     .arg("--allow-read")
-    .arg("--unstable")
+    .arg("--unstable-ffi")
     .arg("--quiet")
     .arg("tests/ffi_callback_errors.ts")
     .env("NO_COLOR", "1")

test_napi/cleanup_hook_test.js

@@ -15,7 +15,7 @@ if (import.meta.main) {
         "--allow-read",
         "--allow-run",
         "--allow-ffi",
-        "--unstable",
+        "--unstable-ffi",
         import.meta.url,
       ],
     }).output();