feat(cli): implement --format unix (#3039)

closes #1462

crates/oxc_cli/src/command/lint.rs

@@ -144,6 +144,7 @@ pub struct OutputOptions {
 pub enum OutputFormat {
     Default,
     Json,
+    Unix,
 }
 
 impl FromStr for OutputFormat {
@@ -152,6 +153,7 @@ impl FromStr for OutputFormat {
         match s {
             "json" => Ok(Self::Json),
             "default" => Ok(Self::Default),
+            "unix" => Ok(Self::Unix),
             _ => Err(format!("'{s}' is not a known format")),
         }
     }

crates/oxc_cli/src/lint/mod.rs

@@ -163,6 +163,7 @@ impl LintRunner {
         match output_options.format {
             OutputFormat::Default => {}
             OutputFormat::Json => diagnostic_service.set_json_reporter(),
+            OutputFormat::Unix => diagnostic_service.set_unix_reporter(),
         }
 
         diagnostic_service

crates/oxc_diagnostics/src/reporter.rs

@@ -2,31 +2,37 @@ use std::io::{BufWriter, Stdout, Write};
 
 use crate::{
     miette::{Error, JSONReportHandler},
-    GraphicalReportHandler,
+    GraphicalReportHandler, Severity,
 };
 
+/// stdio is blocked by LineWriter, use a BufWriter to reduce syscalls.
+/// See `https://github.com/rust-lang/rust/issues/60673`.
+fn writer() -> BufWriter<Stdout> {
+    BufWriter::new(std::io::stdout())
+}
+
 #[allow(clippy::large_enum_variant)] // Lerge size is fine because this is a singleton
 #[derive(Debug)]
 #[non_exhaustive]
 pub enum DiagnosticReporter {
-    // stdio is blocked by LineWriter, use a BufWriter to reduce syscalls.
-    // See `https://github.com/rust-lang/rust/issues/60673`.
     Graphical { handler: GraphicalReportHandler, writer: BufWriter<Stdout> },
     Json { diagnostics: Vec<Error> },
+    Unix { total: usize, writer: BufWriter<Stdout> },
 }
 
 impl DiagnosticReporter {
     pub fn new_graphical() -> Self {
-        Self::Graphical {
-            handler: GraphicalReportHandler::new(),
-            writer: BufWriter::new(std::io::stdout()),
-        }
+        Self::Graphical { handler: GraphicalReportHandler::new(), writer: writer() }
     }
 
     pub fn new_json() -> Self {
         Self::Json { diagnostics: vec![] }
     }
 
+    pub fn new_unix() -> Self {
+        Self::Unix { total: 0, writer: writer() }
+    }
+
     pub fn finish(&mut self) {
         match self {
             Self::Graphical { writer, .. } => {
@@ -35,24 +41,21 @@ impl DiagnosticReporter {
             // NOTE: this output does not conform to eslint json format yet
             // https://eslint.org/docs/latest/use/formatters/#json
             Self::Json { diagnostics } => {
-                let handler = JSONReportHandler::new();
-                let messages = diagnostics
-                    .drain(..)
-                    .map(|error| {
-                        let mut output = String::from("\t");
-                        handler.render_report(&mut output, error.as_ref()).unwrap();
-                        output
-                    })
-                    .collect::<Vec<_>>()
-                    .join(",\n");
-                println!("[\n{messages}\n]");
+                format_json(diagnostics);
+            }
+            Self::Unix { total, writer } => {
+                if *total > 0 {
+                    let line = format!("\n{total} problem{}\n", if *total > 1 { "s" } else { "" });
+                    writer.write_all(line.as_bytes()).unwrap();
+                }
+                writer.flush().unwrap();
             }
         }
     }
 
     pub fn render_diagnostics(&mut self, s: &[u8]) {
         match self {
-            Self::Graphical { writer, .. } => {
+            Self::Graphical { writer, .. } | Self::Unix { writer, .. } => {
                 writer.write_all(s).unwrap();
             }
             Self::Json { .. } => {}
@@ -70,6 +73,58 @@ impl DiagnosticReporter {
                 diagnostics.push(error);
                 None
             }
+            Self::Unix { total: count, .. } => {
+                *count += 1;
+                Some(format_unix(&error))
+            }
         }
     }
 }
+
+/// <https://github.com/fregante/eslint-formatters/tree/main/packages/eslint-formatter-json>
+fn format_json(diagnostics: &mut Vec<Error>) {
+    let handler = JSONReportHandler::new();
+    let messages = diagnostics
+        .drain(..)
+        .map(|error| {
+            let mut output = String::from("\t");
+            handler.render_report(&mut output, error.as_ref()).unwrap();
+            output
+        })
+        .collect::<Vec<_>>()
+        .join(",\n");
+    println!("[\n{messages}\n]");
+}
+
+/// <https://github.com/fregante/eslint-formatters/tree/main/packages/eslint-formatter-unix>
+fn format_unix(diagnostic: &Error) -> String {
+    let mut line = 0;
+    let mut column = 0;
+    let mut filename = String::new();
+    let mut message = String::new();
+    let mut severity = "Warning";
+    let mut rule_id = String::new();
+    if let Some(mut labels) = diagnostic.labels() {
+        if let Some(source) = diagnostic.source_code() {
+            if let Some(label) = labels.next() {
+                if let Ok(span_content) = source.read_span(label.inner(), 0, 0) {
+                    line = span_content.line() + 1;
+                    column = span_content.column() + 1;
+                    if let Some(name) = span_content.name() {
+                        filename = name.to_string();
+                    };
+                    if matches!(diagnostic.severity(), Some(Severity::Error)) {
+                        severity = "Warning";
+                    }
+                    let msg = diagnostic.to_string();
+                    // Our messages usually comes with `eslint(rule): message`
+                    (rule_id, message) = msg.split_once(':').map_or_else(
+                        || (String::new(), msg.to_string()),
+                        |(id, msg)| (id.to_string(), msg.trim().to_string()),
+                    );
+                }
+            }
+        }
+    }
+    format!("{filename}:{line}:{column}: {message} [{severity}/{rule_id}]\n")
+}

crates/oxc_diagnostics/src/service.rs

@@ -52,6 +52,10 @@ impl DiagnosticService {
         self.reporter = DiagnosticReporter::new_json();
     }
 
+    pub fn set_unix_reporter(&mut self) {
+        self.reporter = DiagnosticReporter::new_unix();
+    }
+
     pub fn is_graphical_output(&self) -> bool {
         matches!(self.reporter, DiagnosticReporter::Graphical { .. })
     }