fix: backport parse bug fix

Backport the fix for the parser bug where the messages from
fatal/non-recoverable parser errors were being silently eaten by
rustfmt.

src/formatting.rs

@@ -715,37 +715,43 @@ fn parse_crate(
 struct SilentOnIgnoredFilesEmitter {
     ignore_path_set: Rc<IgnorePathSet>,
     source_map: Rc<SourceMap>,
-    emitter: EmitterWriter,
+    emitter: Box<dyn Emitter + Send>,
     has_non_ignorable_parser_errors: bool,
     can_reset: Rc<RefCell<bool>>,
 }
 
+impl SilentOnIgnoredFilesEmitter {
+    fn handle_non_ignoreable_error(&mut self, db: &Diagnostic) {
+        self.has_non_ignorable_parser_errors = true;
+        *self.can_reset.borrow_mut() = false;
+        self.emitter.emit_diagnostic(db);
+    }
+}
+
 impl Emitter for SilentOnIgnoredFilesEmitter {
     fn source_map(&self) -> Option<&Lrc<SourceMap>> {
         None
     }
+
     fn emit_diagnostic(&mut self, db: &Diagnostic) {
+        if db.level == DiagnosticLevel::Fatal {
+            return self.handle_non_ignoreable_error(db);
+        }
         if let Some(primary_span) = &db.span.primary_span() {
             let file_name = self.source_map.span_to_filename(*primary_span);
-            match file_name {
-                rustc_span::FileName::Real(ref path) => {
-                    if self
-                        .ignore_path_set
-                        .is_match(&FileName::Real(path.to_path_buf()))
-                    {
-                        if !self.has_non_ignorable_parser_errors {
-                            *self.can_reset.borrow_mut() = true;
-                        }
-                        return;
+            if let rustc_span::FileName::Real(ref path) = file_name {
+                if self
+                    .ignore_path_set
+                    .is_match(&FileName::Real(path.to_path_buf()))
+                {
+                    if !self.has_non_ignorable_parser_errors {
+                        *self.can_reset.borrow_mut() = true;
                     }
+                    return;
                 }
-                _ => (),
             };
         }
-
-        self.has_non_ignorable_parser_errors = true;
-        *self.can_reset.borrow_mut() = false;
-        self.emitter.emit_diagnostic(db);
+        self.handle_non_ignoreable_error(db);
     }
 }
 
@@ -759,7 +765,7 @@ impl Emitter for SilentEmitter {
     fn emit_diagnostic(&mut self, _db: &Diagnostic) {}
 }
 
-fn silent_emitter() -> Box<SilentEmitter> {
+fn silent_emitter() -> Box<dyn Emitter + Send> {
     Box::new(SilentEmitter {})
 }
 
@@ -769,36 +775,38 @@ fn make_parse_sess(
     ignore_path_set: Rc<IgnorePathSet>,
     can_reset: Rc<RefCell<bool>>,
 ) -> ParseSess {
-    let tty_handler = if config.hide_parse_errors() {
-        let silent_emitter = silent_emitter();
-        Handler::with_emitter(true, None, silent_emitter)
+    let supports_color = term::stderr().map_or(false, |term| term.supports_color());
+    let color_cfg = if supports_color {
+        ColorConfig::Auto
     } else {
-        let supports_color = term::stderr().map_or(false, |term| term.supports_color());
-        let color_cfg = if supports_color {
-            ColorConfig::Auto
-        } else {
-            ColorConfig::Never
-        };
+        ColorConfig::Never
+    };
 
-        let emitter_writer = EmitterWriter::stderr(
+    let emitter = if config.hide_parse_errors() {
+        silent_emitter()
+    } else {
+        Box::new(EmitterWriter::stderr(
             color_cfg,
             Some(source_map.clone()),
             false,
             false,
             None,
             false,
-        );
-        let emitter = Box::new(SilentOnIgnoredFilesEmitter {
-            has_non_ignorable_parser_errors: false,
-            ignore_path_set: ignore_path_set,
-            source_map: Rc::clone(&source_map),
-            emitter: emitter_writer,
-            can_reset,
-        });
-        Handler::with_emitter(true, None, emitter)
+        ))
     };
+    let handler = Handler::with_emitter(
+        true,
+        None,
+        Box::new(SilentOnIgnoredFilesEmitter {
+            has_non_ignorable_parser_errors: false,
+            source_map: source_map.clone(),
+            emitter,
+            ignore_path_set,
+            can_reset,
+        }),
+    );
 
-    ParseSess::with_span_handler(tty_handler, source_map)
+    ParseSess::with_span_handler(handler, source_map)
 }
 
 fn should_emit_verbose<F>(is_stdin: bool, config: &Config, f: F)
@@ -809,3 +817,174 @@ where
         f();
     }
 }
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    mod emitter {
+        use super::*;
+        use crate::config::IgnoreList;
+        use crate::is_nightly_channel;
+        use crate::utils::mk_sp;
+        use rustc_span::{BytePos, FileName as SourceMapFileName, MultiSpan, DUMMY_SP};
+        use std::path::{Path, PathBuf};
+
+        struct TestEmitter {
+            num_emitted_errors: Rc<RefCell<u32>>,
+        }
+
+        impl Emitter for TestEmitter {
+            fn source_map(&self) -> Option<&Lrc<SourceMap>> {
+                None
+            }
+            fn emit_diagnostic(&mut self, _db: &Diagnostic) {
+                *self.num_emitted_errors.borrow_mut() += 1;
+            }
+        }
+
+        fn build_diagnostic(level: DiagnosticLevel, span: Option<MultiSpan>) -> Diagnostic {
+            Diagnostic {
+                level,
+                code: None,
+                message: vec![],
+                children: vec![],
+                suggestions: vec![],
+                span: span.unwrap_or_else(MultiSpan::new),
+                sort_span: DUMMY_SP,
+            }
+        }
+
+        fn build_emitter(
+            num_emitted_errors: Rc<RefCell<u32>>,
+            can_reset: Rc<RefCell<bool>>,
+            source_map: Option<Rc<SourceMap>>,
+            ignore_list: Option<IgnoreList>,
+        ) -> SilentOnIgnoredFilesEmitter {
+            let emitter_writer = TestEmitter { num_emitted_errors };
+            let source_map =
+                source_map.unwrap_or_else(|| Rc::new(SourceMap::new(FilePathMapping::empty())));
+            let ignore_path_set =
+                Rc::new(IgnorePathSet::from_ignore_list(&ignore_list.unwrap_or_default()).unwrap());
+            SilentOnIgnoredFilesEmitter {
+                has_non_ignorable_parser_errors: false,
+                source_map,
+                emitter: Box::new(emitter_writer),
+                ignore_path_set,
+                can_reset,
+            }
+        }
+
+        fn get_ignore_list(config: &str) -> IgnoreList {
+            Config::from_toml(config, Path::new("")).unwrap().ignore()
+        }
+
+        #[test]
+        fn handles_fatal_parse_error_in_ignored_file() {
+            let num_emitted_errors = Rc::new(RefCell::new(0));
+            let can_reset_errors = Rc::new(RefCell::new(false));
+            let ignore_list = get_ignore_list(r#"ignore = ["foo.rs"]"#);
+            let source_map = Rc::new(SourceMap::new(FilePathMapping::empty()));
+            let source =
+                String::from(r#"extern "system" fn jni_symbol!( funcName ) ( ... ) -> {} "#);
+            source_map.new_source_file(SourceMapFileName::Real(PathBuf::from("foo.rs")), source);
+            let mut emitter = build_emitter(
+                Rc::clone(&num_emitted_errors),
+                Rc::clone(&can_reset_errors),
+                Some(Rc::clone(&source_map)),
+                Some(ignore_list),
+            );
+            let span = MultiSpan::from_span(mk_sp(BytePos(0), BytePos(1)));
+            let fatal_diagnostic = build_diagnostic(DiagnosticLevel::Fatal, Some(span));
+            emitter.emit_diagnostic(&fatal_diagnostic);
+            assert_eq!(*num_emitted_errors.borrow(), 1);
+            assert_eq!(*can_reset_errors.borrow(), false);
+        }
+
+        #[test]
+        fn handles_recoverable_parse_error_in_ignored_file() {
+            if !is_nightly_channel!() {
+                return;
+            }
+            let num_emitted_errors = Rc::new(RefCell::new(0));
+            let can_reset_errors = Rc::new(RefCell::new(false));
+            let ignore_list = get_ignore_list(r#"ignore = ["foo.rs"]"#);
+            let source_map = Rc::new(SourceMap::new(FilePathMapping::empty()));
+            let source = String::from(r#"pub fn bar() { 1x; }"#);
+            source_map.new_source_file(SourceMapFileName::Real(PathBuf::from("foo.rs")), source);
+            let mut emitter = build_emitter(
+                Rc::clone(&num_emitted_errors),
+                Rc::clone(&can_reset_errors),
+                Some(Rc::clone(&source_map)),
+                Some(ignore_list),
+            );
+            let span = MultiSpan::from_span(mk_sp(BytePos(0), BytePos(1)));
+            let non_fatal_diagnostic = build_diagnostic(DiagnosticLevel::Warning, Some(span));
+            emitter.emit_diagnostic(&non_fatal_diagnostic);
+            assert_eq!(*num_emitted_errors.borrow(), 0);
+            assert_eq!(*can_reset_errors.borrow(), true);
+        }
+
+        #[test]
+        fn handles_recoverable_parse_error_in_non_ignored_file() {
+            if !is_nightly_channel!() {
+                return;
+            }
+            let num_emitted_errors = Rc::new(RefCell::new(0));
+            let can_reset_errors = Rc::new(RefCell::new(false));
+            let source_map = Rc::new(SourceMap::new(FilePathMapping::empty()));
+            let source = String::from(r#"pub fn bar() { 1x; }"#);
+            source_map.new_source_file(SourceMapFileName::Real(PathBuf::from("foo.rs")), source);
+            let mut emitter = build_emitter(
+                Rc::clone(&num_emitted_errors),
+                Rc::clone(&can_reset_errors),
+                Some(Rc::clone(&source_map)),
+                None,
+            );
+            let span = MultiSpan::from_span(mk_sp(BytePos(0), BytePos(1)));
+            let non_fatal_diagnostic = build_diagnostic(DiagnosticLevel::Warning, Some(span));
+            emitter.emit_diagnostic(&non_fatal_diagnostic);
+            assert_eq!(*num_emitted_errors.borrow(), 1);
+            assert_eq!(*can_reset_errors.borrow(), false);
+        }
+
+        #[test]
+        fn handles_mix_of_recoverable_parse_error() {
+            if !is_nightly_channel!() {
+                return;
+            }
+            let num_emitted_errors = Rc::new(RefCell::new(0));
+            let can_reset_errors = Rc::new(RefCell::new(false));
+            let source_map = Rc::new(SourceMap::new(FilePathMapping::empty()));
+            let ignore_list = get_ignore_list(r#"ignore = ["foo.rs"]"#);
+            let bar_source = String::from(r#"pub fn bar() { 1x; }"#);
+            let foo_source = String::from(r#"pub fn foo() { 1x; }"#);
+            let fatal_source =
+                String::from(r#"extern "system" fn jni_symbol!( funcName ) ( ... ) -> {} "#);
+            source_map
+                .new_source_file(SourceMapFileName::Real(PathBuf::from("bar.rs")), bar_source);
+            source_map
+                .new_source_file(SourceMapFileName::Real(PathBuf::from("foo.rs")), foo_source);
+            source_map.new_source_file(
+                SourceMapFileName::Real(PathBuf::from("fatal.rs")),
+                fatal_source,
+            );
+            let mut emitter = build_emitter(
+                Rc::clone(&num_emitted_errors),
+                Rc::clone(&can_reset_errors),
+                Some(Rc::clone(&source_map)),
+                Some(ignore_list),
+            );
+            let bar_span = MultiSpan::from_span(mk_sp(BytePos(0), BytePos(1)));
+            let foo_span = MultiSpan::from_span(mk_sp(BytePos(21), BytePos(22)));
+            let bar_diagnostic = build_diagnostic(DiagnosticLevel::Warning, Some(bar_span));
+            let foo_diagnostic = build_diagnostic(DiagnosticLevel::Warning, Some(foo_span));
+            let fatal_diagnostic = build_diagnostic(DiagnosticLevel::Fatal, None);
+            emitter.emit_diagnostic(&bar_diagnostic);
+            emitter.emit_diagnostic(&foo_diagnostic);
+            emitter.emit_diagnostic(&fatal_diagnostic);
+            assert_eq!(*num_emitted_errors.borrow(), 2);
+            assert_eq!(*can_reset_errors.borrow(), false);
+        }
+    }
+}