Add clippy for denying print and eprints (#3967)

* Remove leftover eprintln from JsPromise::await_blocking

* Add clippy for denying print and eprints

And remove usage of println or allow them.

* Address comment

Cargo.toml

@@ -3,27 +3,22 @@ resolver = "2"
 members = [
     # CORE
     "core/*",
-
     # FFI
     "ffi/*",
-
     # TESTS
     "tests/*",
-
     # TOOLS
     "tools/*",
-
     # OTHERS
     "examples",
     "cli",
-
     # TOOLS
     "tools/*",
 ]
 
 exclude = [
     "tests/fuzz", # Does weird things on Windows tests
-    "tests/src",  # Just a hack to have fuzz inside tests
+    "tests/src", # Just a hack to have fuzz inside tests
 ]
 
 [workspace.package]
@@ -73,7 +68,7 @@ serde = "1.0.208"
 static_assertions = "1.1.0"
 textwrap = "0.16.0"
 thin-vec = "0.2.13"
-time = {version = "0.3.36", default-features = false, features = ["local-offset", "large-dates", "wasm-bindgen", "parsing", "formatting", "macros"]}
+time = { version = "0.3.36", default-features = false, features = ["local-offset", "large-dates", "wasm-bindgen", "parsing", "formatting", "macros"] }
 tinystr = "0.7.5"
 log = "0.4.22"
 simple_logger = "5.0.0"
@@ -226,6 +221,8 @@ bare_urls = "warn"
 [workspace.lints.clippy]
 # clippy allowed by default
 dbg_macro = "warn"
+print_stdout = "warn"
+print_stderr = "warn"
 
 # clippy categories https://doc.rust-lang.org/clippy/
 all = { level = "warn", priority = -1 }

cli/src/main.rs

@@ -5,6 +5,7 @@
     html_favicon_url = "https://raw.githubusercontent.com/boa-dev/boa/main/assets/logo.svg"
 )]
 #![cfg_attr(not(test), deny(clippy::unwrap_used))]
+#![allow(clippy::print_stdout, clippy::print_stderr)]
 
 mod debug;
 mod helper;

clippy.toml

@@ -1 +1,2 @@
 doc-valid-idents = ['ECMAScript', 'JavaScript', 'SpiderMonkey', 'GitHub']
+allow-print-in-tests = true

core/engine/src/object/builtins/jspromise.rs

@@ -1102,7 +1102,6 @@ impl JsPromise {
     /// ```
     pub fn await_blocking(&self, context: &mut Context) -> Result<JsValue, JsValue> {
         loop {
-            eprintln!("await_blocking: {:?}", self.state());
             match self.state() {
                 PromiseState::Pending => {
                     context.run_jobs();

core/engine/src/optimizer/mod.rs

@@ -114,6 +114,8 @@ impl<'context> Optimizer<'context> {
     /// Apply optimizations inplace.
     pub(crate) fn apply(&mut self, statement_list: &mut StatementList) -> OptimizerStatistics {
         self.visit_statement_list_mut(statement_list);
+
+        #[allow(clippy::print_stdout)]
         if self
             .context
             .optimizer_options()

core/engine/src/vm/mod.rs

@@ -277,6 +277,7 @@ pub(crate) enum CompletionType {
     Yield,
 }
 
+#[allow(clippy::print_stdout)]
 #[cfg(feature = "trace")]
 impl Context {
     const COLUMN_WIDTH: usize = 26;

core/runtime/src/console/mod.rs

@@ -19,11 +19,11 @@ use boa_engine::{
     native_function::NativeFunction,
     object::{JsObject, ObjectInitializer},
     value::{JsValue, Numeric},
-    Context, JsArgs, JsData, JsResult, JsStr, JsString,
+    Context, JsArgs, JsData, JsError, JsResult, JsStr, JsString,
 };
 use boa_gc::{Finalize, Trace};
 use rustc_hash::FxHashMap;
-use std::{cell::RefCell, collections::hash_map::Entry, rc::Rc, time::SystemTime};
+use std::{cell::RefCell, collections::hash_map::Entry, io::Write, rc::Rc, time::SystemTime};
 
 /// A trait that can be used to forward console logs to an implementation.
 pub trait Logger: Trace + Sized {
@@ -64,8 +64,7 @@ impl Logger for DefaultLogger {
     #[inline]
     fn log(&self, msg: String, state: &Console) -> JsResult<()> {
         let indent = 2 * state.groups.len();
-        println!("{msg:>indent$}");
-        Ok(())
+        writeln!(std::io::stdout(), "{msg:>indent$}").map_err(JsError::from_rust)
     }
 
     #[inline]
@@ -81,8 +80,7 @@ impl Logger for DefaultLogger {
     #[inline]
     fn error(&self, msg: String, state: &Console) -> JsResult<()> {
         let indent = 2 * state.groups.len();
-        eprintln!("{msg:>indent$}");
-        Ok(())
+        writeln!(std::io::stderr(), "{msg:>indent$}").map_err(JsError::from_rust)
     }
 }
 

tests/tester/src/main.rs

@@ -6,7 +6,9 @@
 #![allow(
     clippy::too_many_lines,
     clippy::redundant_pub_crate,
-    clippy::cast_precision_loss
+    clippy::cast_precision_loss,
+    clippy::print_stderr,
+    clippy::print_stdout
 )]
 
 use std::{