Better exception output.

BUILD.gn

@@ -24,7 +24,10 @@ config("deno_config") {
 
 rust_executable("deno") {
   source_root = "src/main.rs"
-  extern = [ "$rust_build:libc" ]
+  extern = [
+    "$rust_build:libc",
+    "$rust_build:log",
+  ]
   deps = [
     ":libdeno",
   ]
@@ -35,7 +38,10 @@ rust_executable("deno") {
 # extra process of building a snapshot and instead load the bundle from disk.
 rust_executable("deno_nosnapshot") {
   source_root = "src/main.rs"
-  extern = [ "$rust_build:libc" ]
+  extern = [
+    "$rust_build:libc",
+    "$rust_build:log",
+  ]
   deps = [
     ":libdeno_nosnapshot",
   ]

js/runtime.ts

@@ -36,7 +36,7 @@ window.onerror = (
   // Error.prepareStackTrace handler. Users will get unmapped stack traces on
   // uncaught exceptions until this issue is fixed.
   //Error.prepareStackTrace = null;
-  console.log(error.message, error.stack);
+  console.log(error.stack);
   os.exit(1);
 };
 

js/util.ts

@@ -15,9 +15,9 @@ export function log(...args: any[]): void {
   }
 }
 
-export function assert(cond: boolean, msg = "") {
+export function assert(cond: boolean, msg = "assert") {
   if (!cond) {
-    throw Error(`Assert fail. ${msg}`);
+    throw Error(msg);
   }
 }
 

src/handlers.rs

@@ -177,9 +177,6 @@ pub extern "C" fn handle_code_fetch(
     module_specifier_: *const c_char,
     containing_file_: *const c_char,
 ) {
-    // TODO(ry) Move this to main.
-    log::set_max_level(log::LevelFilter::Debug);
-
     let module_specifier = string_from_ptr(module_specifier_);
     let containing_file = string_from_ptr(containing_file_);
 

src/main.rs

@@ -1,4 +1,6 @@
 extern crate libc;
+#[macro_use]
+extern crate log;
 
 use libc::c_char;
 use libc::c_int;
@@ -107,6 +109,8 @@ impl Drop for Deno {
 }
 
 fn main() {
+    log::set_max_level(log::LevelFilter::Debug);
+
     unsafe { deno_init() };
 
     set_flags();
@@ -122,7 +126,7 @@ fn main() {
 
     d.execute("deno_main.js", "denoMain();")
         .unwrap_or_else(|err| {
-            println!("Error {}\n", err);
+            error!("{}", err);
             std::process::exit(1);
         });
 }