fix(runtime): only discard extension sources if a snapshot is provided (#22023)

Fixes #21928.

We have a code path which empties the extension sources because they're
expected to be pre-executed in the snapshot. Instead of using
conditional compilation for that, we now just check if a snapshot was
provided.

Removes the `dont_use_runtime_snapshot` feature. We didn't allow not
providing a snapshot unless this feature was provided, now we always do.

Adds the `only_snapshotted_js_sources` feature for us to use in CLI.
This asserts that a snapshot is provided and gates the runtime
transpilation code so it isn't included in the executable.

4 files changed, 26 insertions, 41 deletions

diff --git a/cli/Cargo.toml b/cli/Cargo.toml
index e42b22947..16b561c05 100644
--- a/cli/Cargo.toml
+++ b/cli/Cargo.toml
@@ -39,7 +39,7 @@ __runtime_js_sources = ["deno_runtime/__runtime_js_sources"]
 __vendored_zlib_ng = ["flate2/zlib-ng-compat", "libz-sys/zlib-ng"]
 
 [build-dependencies]
-deno_runtime = { workspace = true, features = ["include_js_files_for_snapshotting"] }
+deno_runtime = { workspace = true, features = ["include_js_files_for_snapshotting", "only_snapshotted_js_sources"] }
 deno_core = { workspace = true, features = ["include_js_files_for_snapshotting"] }
 lazy-regex.workspace = true
 serde.workspace = true
diff --git a/runtime/Cargo.toml b/runtime/Cargo.toml
index 0b07839b2..c3bcfb9bf 100644
--- a/runtime/Cargo.toml
+++ b/runtime/Cargo.toml
@@ -12,8 +12,6 @@ description = "Provides the deno runtime library"
 [features]
 # "fake" feature that allows to generate docs on docs.rs
 docsrs = []
-# A feature that disables the requirement for startup snapshot to be provided.
-dont_use_runtime_snapshot = []
 # A feature that allows excluding `./js/99_main.js` from the exported extension.
 exclude_runtime_main_js = []
 # A feature that disables embedding of the JavaScript source files in the binary.
@@ -24,7 +22,11 @@ include_js_files_for_snapshotting = [
 ]
 # A dev feature to disable creations and loading of snapshots in favor of
 # loading JS sources at runtime.
-__runtime_js_sources = []
+__runtime_js_sources = ["include_js_files_for_snapshotting"]
+# Signal that only snapshotted JS sources should be used. This will
+# conditionally exclude the runtime source transpilation logic, and add an
+# assertion that a snapshot is provided.
+only_snapshotted_js_sources = ["include_js_files_for_snapshotting"]
 
 [lib]
 name = "deno_runtime"
diff --git a/runtime/web_worker.rs b/runtime/web_worker.rs
index 2b6eb19c9..78674af02 100644
--- a/runtime/web_worker.rs
+++ b/runtime/web_worker.rs
@@ -490,14 +490,16 @@ impl WebWorker {
       ops::web_worker::deno_web_worker::init_ops_and_esm(),
     ];
 
+    #[cfg(__runtime_js_sources)]
+    assert!(cfg!(not(feature = "only_snapshotted_js_sources")), "'__runtime_js_sources' is incompatible with 'only_snapshotted_js_sources'.");
+
     for extension in &mut extensions {
-      #[cfg(not(feature = "__runtime_js_sources"))]
-      {
+      if options.startup_snapshot.is_some() {
         extension.js_files = std::borrow::Cow::Borrowed(&[]);
         extension.esm_files = std::borrow::Cow::Borrowed(&[]);
         extension.esm_entry_point = None;
       }
-      #[cfg(feature = "__runtime_js_sources")]
+      #[cfg(not(feature = "only_snapshotted_js_sources"))]
       {
         use crate::shared::maybe_transpile_source;
         for source in extension.esm_files.to_mut() {
@@ -511,17 +513,8 @@ impl WebWorker {
 
     extensions.extend(std::mem::take(&mut options.extensions));
 
-    #[cfg(all(
-      feature = "include_js_files_for_snapshotting",
-      not(feature = "__runtime_js_sources")
-    ))]
-    options
-      .startup_snapshot
-      .as_ref()
-      .expect("Sources are not embedded and a user snapshot was not provided.");
-
-    #[cfg(not(feature = "dont_use_runtime_snapshot"))]
-    options.startup_snapshot.as_ref().expect("A user snapshot was not provided, if you want to create a runtime without a snapshot use 'dont_use_runtime_snapshot' Cargo feature.");
+    #[cfg(feature = "only_snapshotted_js_sources")]
+    options.startup_snapshot.as_ref().expect("A user snapshot was not provided, even though 'only_snapshotted_js_sources' is used.");
 
     // Hook up the summary metrics if the user or subcommand requested them
     let (op_summary_metrics, op_metrics_factory_fn) =
diff --git a/runtime/worker.rs b/runtime/worker.rs
index 5dc5db71d..e6da93d78 100644
--- a/runtime/worker.rs
+++ b/runtime/worker.rs
@@ -418,16 +418,13 @@ impl MainWorker {
       ops::signal::deno_signal::init_ops_and_esm(),
       ops::tty::deno_tty::init_ops_and_esm(),
       ops::http::deno_http_runtime::init_ops_and_esm(),
-      ops::bootstrap::deno_bootstrap::init_ops_and_esm({
-        #[cfg(feature = "__runtime_js_sources")]
-        {
-          Some(Default::default())
-        }
-        #[cfg(not(feature = "__runtime_js_sources"))]
-        {
+      ops::bootstrap::deno_bootstrap::init_ops_and_esm(
+        if options.startup_snapshot.is_some() {
           None
-        }
-      }),
+        } else {
+          Some(Default::default())
+        },
+      ),
       deno_permissions_worker::init_ops_and_esm(
         permissions,
         enable_testing_features,
@@ -435,14 +432,16 @@ impl MainWorker {
       runtime::init_ops_and_esm(),
     ];
 
+    #[cfg(__runtime_js_sources)]
+    assert!(cfg!(not(feature = "only_snapshotted_js_sources")), "'__runtime_js_sources' is incompatible with 'only_snapshotted_js_sources'.");
+
     for extension in &mut extensions {
-      #[cfg(not(feature = "__runtime_js_sources"))]
-      {
+      if options.startup_snapshot.is_some() {
         extension.js_files = std::borrow::Cow::Borrowed(&[]);
         extension.esm_files = std::borrow::Cow::Borrowed(&[]);
         extension.esm_entry_point = None;
       }
-      #[cfg(feature = "__runtime_js_sources")]
+      #[cfg(not(feature = "only_snapshotted_js_sources"))]
       {
         use crate::shared::maybe_transpile_source;
         for source in extension.esm_files.to_mut() {
@@ -456,17 +455,8 @@ impl MainWorker {
 
     extensions.extend(std::mem::take(&mut options.extensions));
 
-    #[cfg(all(
-      feature = "include_js_files_for_snapshotting",
-      not(feature = "__runtime_js_sources")
-    ))]
-    options
-      .startup_snapshot
-      .as_ref()
-      .expect("Sources are not embedded and a user snapshot was not provided.");
-
-    #[cfg(not(feature = "dont_use_runtime_snapshot"))]
-    options.startup_snapshot.as_ref().expect("A user snapshot was not provided, if you want to create a runtime without a snapshot use 'dont_use_runtime_snapshot' Cargo feature.");
+    #[cfg(feature = "only_snapshotted_js_sources")]
+    options.startup_snapshot.as_ref().expect("A user snapshot was not provided, even though 'only_snapshotted_js_sources' is used.");
 
     let has_notified_of_inspector_disconnect = AtomicBool::new(false);
     let wait_for_inspector_disconnect_callback = Box::new(move || {