feat: Deprecate "import assertions" with a warning (#24743)

This commit deprecates "import assertions" proposal that has been
replaced with "import attributes".

Any time an import assertion is encountered a warning will be printed
to the terminal. This warning will be printed for both local and 
remote files (ie. user code and dependencies).

Import assertions support will be removed in Deno 2.

3 files changed, 40 insertions, 11 deletions

diff --git a/runtime/shared.rs b/runtime/shared.rs
index 1b2136c63..c52521690 100644
--- a/runtime/shared.rs
+++ b/runtime/shared.rs
@@ -116,3 +116,26 @@ pub fn maybe_transpile_source(
 
   Ok((source_text.into(), maybe_source_map))
 }
+
+pub fn import_assertion_callback(
+  args: deno_core::ImportAssertionsSupportCustomCallbackArgs,
+) {
+  let mut msg = deno_terminal::colors::yellow("⚠️  Import assertions are deprecated. Use `with` keyword, instead of 'assert' keyword.").to_string();
+  if let Some(specifier) = args.maybe_specifier {
+    if let Some(source_line) = args.maybe_source_line {
+      msg.push_str("\n\n");
+      msg.push_str(&source_line);
+      msg.push_str("\n\n");
+    }
+    msg.push_str(&format!(
+      "  at {}:{}:{}\n",
+      specifier,
+      args.maybe_line_number.unwrap(),
+      args.column_number
+    ));
+    #[allow(clippy::print_stderr)]
+    {
+      eprintln!("{}", msg);
+    }
+  }
+}
diff --git a/runtime/web_worker.rs b/runtime/web_worker.rs
index ed1e19c9e..3e95045db 100644
--- a/runtime/web_worker.rs
+++ b/runtime/web_worker.rs
@@ -538,6 +538,13 @@ impl WebWorker {
       options.bootstrap.enable_op_summary_metrics,
       options.strace_ops,
     );
+    let import_assertions_support = if options.bootstrap.future {
+      deno_core::ImportAssertionsSupport::Error
+    } else {
+      deno_core::ImportAssertionsSupport::CustomCallback(Box::new(
+        crate::shared::import_assertion_callback,
+      ))
+    };
 
     let mut js_runtime = JsRuntime::new(RuntimeOptions {
       module_loader: Some(options.module_loader.clone()),
@@ -558,6 +565,7 @@ impl WebWorker {
       validate_import_attributes_cb: Some(Box::new(
         validate_import_attributes_callback,
       )),
+      import_assertions_support,
       ..Default::default()
     });
 
diff --git a/runtime/worker.rs b/runtime/worker.rs
index 696786b56..c1c918d08 100644
--- a/runtime/worker.rs
+++ b/runtime/worker.rs
@@ -476,6 +476,14 @@ impl MainWorker {
       }
     });
 
+    let import_assertions_support = if options.bootstrap.future {
+      deno_core::ImportAssertionsSupport::Error
+    } else {
+      deno_core::ImportAssertionsSupport::CustomCallback(Box::new(
+        crate::shared::import_assertion_callback,
+      ))
+    };
+
     let mut js_runtime = JsRuntime::new(RuntimeOptions {
       module_loader: Some(options.module_loader.clone()),
       startup_snapshot: options.startup_snapshot,
@@ -501,6 +509,7 @@ impl MainWorker {
       validate_import_attributes_cb: Some(Box::new(
         validate_import_attributes_callback,
       )),
+      import_assertions_support,
       eval_context_code_cache_cbs: options.v8_code_cache.map(|cache| {
         let cache_clone = cache.clone();
         (
@@ -544,17 +553,6 @@ impl MainWorker {
     if let Some(op_summary_metrics) = op_summary_metrics {
       js_runtime.op_state().borrow_mut().put(op_summary_metrics);
     }
-    extern "C" fn message_handler(
-      _msg: v8::Local<v8::Message>,
-      _exception: v8::Local<v8::Value>,
-    ) {
-      // TODO(@littledivy): Propogate message to users.
-    }
-
-    // Register message listener
-    js_runtime
-      .v8_isolate()
-      .add_message_listener(message_handler);
 
     if let Some(server) = options.maybe_inspector_server.clone() {
       server.register_inspector(