Merge pull request #3240 from Xanewok/parser-panic

Catch possible tokenizer panics

src/formatting.rs

@@ -8,7 +8,7 @@ use std::time::{Duration, Instant};
 
 use syntax::ast;
 use syntax::errors::emitter::{ColorConfig, EmitterWriter};
-use syntax::errors::Handler;
+use syntax::errors::{DiagnosticBuilder, Handler};
 use syntax::parse::{self, ParseSess};
 use syntax::source_map::{FilePathMapping, SourceMap, Span};
 
@@ -73,7 +73,12 @@ fn format_project<T: FormatHandler>(
  let source_map = Rc::new(SourceMap::new(FilePathMapping::empty()));
  let mut parse_session = make_parse_sess(source_map.clone(), config);
  let mut report = FormatReport::new();
- let krate = parse_crate(input, &parse_session, config, &mut report)?;
+ let krate = match parse_crate(input, &parse_session, config, &mut report) {
+ Ok(krate) => krate,
+ // Surface parse error via Session (errors are merged there from report)
+ Err(ErrorKind::ParseError) => return Ok(report),
+ Err(e) => return Err(e),
+ };
  timer = timer.done_parsing();
 
  // Suppress error output if we have to do any further parsing.
@@ -604,30 +609,41 @@ fn parse_crate(
 ) -> Result<ast::Crate, ErrorKind> {
  let input_is_stdin = input.is_text();
 
- let mut parser = match input {
- Input::File(file) => parse::new_parser_from_file(parse_session, &file),
- Input::Text(text) => parse::new_parser_from_source_str(
+ let parser = match input {
+ Input::File(file) => Ok(parse::new_parser_from_file(parse_session, &file)),
+ Input::Text(text) => parse::maybe_new_parser_from_source_str(
  parse_session,
  syntax::source_map::FileName::Custom("stdin".to_owned()),
  text,
- ),
+ )
+ .map_err(|diags| {
+ diags
+ .into_iter()
+ .map(|d| DiagnosticBuilder::new_diagnostic(&parse_session.span_diagnostic, d))
+ .collect::<Vec<_>>()
+ }),
  };
 
- parser.cfg_mods = false;
- if config.skip_children() {
- parser.recurse_into_file_modules = false;
- }
+ let result = match parser {
+ Ok(mut parser) => {
+ parser.cfg_mods = false;
+ if config.skip_children() {
+ parser.recurse_into_file_modules = false;
+ }
 
- let mut parser = AssertUnwindSafe(parser);
- let result = catch_unwind(move || parser.0.parse_crate_mod());
+ let mut parser = AssertUnwindSafe(parser);
+ catch_unwind(move || parser.0.parse_crate_mod().map_err(|d| vec![d]))
+ }
+ Err(db) => Ok(Err(db)),
+ };
 
  match result {
  Ok(Ok(c)) => {
  if !parse_session.span_diagnostic.has_errors() {
  return Ok(c);
  }
  }
- Ok(Err(mut e)) => e.emit(),
+ Ok(Err(mut diagnostics)) => diagnostics.iter_mut().for_each(|d| d.emit()),
  Err(_) => {
  // Note that if you see this message and want more information,
  // then run the `parse_crate_mod` function above without

src/test/mod.rs

@@ -286,6 +286,18 @@ fn stdin_formatting_smoke_test() {
  assert_eq!(buf, "fn main() {}\r\n".as_bytes());
 }
 
+#[test]
+fn stdin_parser_panic_caught() {
+ // https://github.com/rust-lang/rustfmt/issues/3239
+ for text in ["{", "}"].iter().cloned().map(String::from) {
+ let mut buf = vec![];
+ let mut session = Session::new(Default::default(), Some(&mut buf));
+ let _ = session.format(Input::Text(text));
+
+ assert!(session.has_parsing_errors());
+ }
+}
+
 #[test]
 fn stdin_disable_all_formatting_test() {
  match option_env!("CFG_RELEASE_CHANNEL") {