refactor(ast): Change AST parsing error to return struct with message and location (#10911)

* Remove unused check js emit option.
* Improve parse error.
* Format.

cli/ast.rs

@@ -11,23 +11,16 @@ use std::error::Error;
 use std::fmt;
 use std::ops::Range;
 use std::rc::Rc;
-use std::sync::Arc;
-use std::sync::Mutex;
 use swc_common::chain;
 use swc_common::comments::Comment;
 use swc_common::comments::CommentKind;
 use swc_common::comments::SingleThreadedComments;
-use swc_common::errors::Diagnostic;
-use swc_common::errors::DiagnosticBuilder;
-use swc_common::errors::Emitter;
-use swc_common::errors::Handler;
-use swc_common::errors::HandlerFlags;
 use swc_common::FileName;
 use swc_common::Globals;
-use swc_common::Loc;
 use swc_common::SourceFile;
 use swc_common::SourceMap;
 use swc_common::Span;
+use swc_common::Spanned;
 use swc_ecmascript::ast::Module;
 use swc_ecmascript::ast::Program;
 use swc_ecmascript::codegen::text_writer::JsWriter;
@@ -89,57 +82,18 @@ impl std::fmt::Display for Location {
   }
 }
 
-/// A buffer for collecting diagnostic messages from the AST parser.
-#[derive(Debug)]
-pub struct DiagnosticBuffer(Vec<String>);
+/// A diagnostic from the AST parser.
+#[derive(Debug, Clone, Eq, PartialEq)]
+pub struct Diagnostic {
+  pub location: Location,
+  pub message: String,
+}
 
-impl Error for DiagnosticBuffer {}
+impl Error for Diagnostic {}
 
-impl fmt::Display for DiagnosticBuffer {
+impl fmt::Display for Diagnostic {
   fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
-    let s = self.0.join(",");
-    f.pad(&s)
-  }
-}
-
-impl DiagnosticBuffer {
-  pub fn from_error_buffer<F>(error_buffer: ErrorBuffer, get_loc: F) -> Self
-  where
-    F: Fn(Span) -> Loc,
-  {
-    let s = error_buffer.0.lock().unwrap().clone();
-    let diagnostics = s
-      .iter()
-      .map(|d| {
-        let mut msg = d.message();
-
-        if let Some(span) = d.span.primary_span() {
-          let loc = get_loc(span);
-          let file_name = match &loc.file.name {
-            FileName::Custom(n) => n,
-            _ => unreachable!(),
-          };
-          msg = format!(
-            "{} at {}:{}:{}",
-            msg, file_name, loc.line, loc.col_display
-          );
-        }
-
-        msg
-      })
-      .collect::<Vec<String>>();
-
-    Self(diagnostics)
-  }
-}
-
-/// A buffer for collecting errors from the AST parser.
-#[derive(Debug, Clone, Default)]
-pub struct ErrorBuffer(Arc<Mutex<Vec<Diagnostic>>>);
-
-impl Emitter for ErrorBuffer {
-  fn emit(&mut self, db: &DiagnosticBuilder) {
-    self.0.lock().unwrap().push((**db).clone());
+    write!(f, "{} at {}", self.message, self.location)
   }
 }
 
@@ -192,9 +146,6 @@ pub enum ImportsNotUsedAsValues {
 /// Options which can be adjusted when transpiling a module.
 #[derive(Debug, Clone)]
 pub struct EmitOptions {
-  /// Indicate if JavaScript is being checked/transformed as well, or if it is
-  /// only TypeScript.
-  pub check_js: bool,
   /// When emitting a legacy decorator, also emit experimental decorator meta
   /// data.  Defaults to `false`.
   pub emit_metadata: bool,
@@ -221,7 +172,6 @@ pub struct EmitOptions {
 impl Default for EmitOptions {
   fn default() -> Self {
     EmitOptions {
-      check_js: false,
       emit_metadata: false,
       imports_not_used_as_values: ImportsNotUsedAsValues::Remove,
       inline_source_map: true,
@@ -244,7 +194,6 @@ impl From<config_file::TsConfig> for EmitOptions {
         _ => ImportsNotUsedAsValues::Remove,
       };
     EmitOptions {
-      check_js: options.check_js,
       emit_metadata: options.emit_decorator_metadata,
       imports_not_used_as_values,
       inline_source_map: options.inline_source_map,
@@ -424,31 +373,17 @@ pub fn parse_with_source_map(
     FileName::Custom(specifier.to_string()),
     source.to_string(),
   );
-  let error_buffer = ErrorBuffer::default();
   let syntax = get_syntax(media_type);
   let input = StringInput::from(&*source_file);
   let comments = SingleThreadedComments::default();
 
-  let handler = Handler::with_emitter_and_flags(
-    Box::new(error_buffer.clone()),
-    HandlerFlags {
-      can_emit_warnings: true,
-      dont_buffer_diagnostics: true,
-      ..HandlerFlags::default()
-    },
-  );
-
   let lexer = Lexer::new(syntax, TARGET, input, Some(&comments));
   let mut parser = swc_ecmascript::parser::Parser::new_from(lexer);
 
   let sm = &source_map;
-  let module = parser.parse_module().map_err(move |err| {
-    let mut diagnostic = err.into_diagnostic(&handler);
-    diagnostic.emit();
-
-    DiagnosticBuffer::from_error_buffer(error_buffer, |span| {
-      sm.lookup_char_pos(span.lo)
-    })
+  let module = parser.parse_module().map_err(move |err| Diagnostic {
+    location: sm.lookup_char_pos(err.span().lo).into(),
+    message: err.into_kind().msg().to_string(),
   })?;
   let leading_comments =
     comments.with_leading(module.span.lo, |comments| comments.to_vec());