fix(diagnostics): skip minified fallback for single-line reporters

apps/oxlint/src/output_formatter/github.rs

@@ -26,6 +26,10 @@ impl DiagnosticReporter for GithubReporter {
         Some(get_diagnostic_result_output(result))
     }
 
+    fn supports_minified_file_fallback(&self) -> bool {
+        false
+    }
+
     fn render_error(&mut self, error: Error) -> Option<String> {
         Some(format_github(&error))
     }
@@ -83,7 +87,7 @@ fn escape_property(value: &str) -> String {
 #[cfg(test)]
 mod test {
     use oxc_diagnostics::{
-        NamedSource, OxcDiagnostic,
+        DiagnosticService, NamedSource, OxcDiagnostic,
         reporter::{DiagnosticReporter, DiagnosticResult},
     };
     use oxc_span::Span;
@@ -123,4 +127,25 @@ mod test {
             "::warning file=file%3A//test.ts,line=1,endLine=1,col=1,endColumn=9,title=oxlint::error message\n"
         );
     }
+
+    #[test]
+    fn reporter_does_not_use_minified_fallback_for_long_annotations() {
+        let source_text = format!("{}\n", "a".repeat(1300));
+        let diagnostic = OxcDiagnostic::warn("error message")
+            .with_label(Span::new(0, 1300))
+            .with_source_code(NamedSource::new("file://test.ts", source_text));
+
+        let (mut service, sender) = DiagnosticService::new(Box::new(GithubReporter));
+        sender.send(vec![diagnostic]).unwrap();
+        drop(sender);
+
+        let mut output = Vec::new();
+        service.run(&mut output);
+        let output = String::from_utf8(output).unwrap();
+
+        assert!(output.starts_with("::warning file=file%3A//test.ts,line=1,endLine=1,col=1,"));
+        assert!(output.contains("title=oxlint::error message"));
+        assert!(!output.contains("File is too long to fit on the screen"));
+        assert!(!output.contains("file=,line=0,endLine=0,col=0,endColumn=0"));
+    }
 }

apps/oxlint/src/output_formatter/unix.rs

@@ -33,6 +33,10 @@ impl DiagnosticReporter for UnixReporter {
         None
     }
 
+    fn supports_minified_file_fallback(&self) -> bool {
+        false
+    }
+
     fn render_error(&mut self, error: Error) -> Option<String> {
         self.total += 1;
         Some(format_unix(&error))

apps/oxlint/test/fixtures/github_report_long_message/.oxlintrc.json

@@ -0,0 +1,7 @@
+{
+  "jsPlugins": ["./plugin.ts"],
+  "categories": { "correctness": "off" },
+  "rules": {
+    "plugin/long-message": "error"
+  }
+}

apps/oxlint/test/fixtures/github_report_long_message/files/index.ts

@@ -0,0 +1 @@
+export function test() {}

apps/oxlint/test/fixtures/github_report_long_message/options.json

@@ -0,0 +1,3 @@
+{
+  "args": ["--format", "github"]
+}

apps/oxlint/test/fixtures/github_report_long_message/output.snap.md

@@ -0,0 +1,13 @@
+# Exit code
+1
+
+# stdout
+```
+::error file=files/index.ts,line=1,endLine=2,col=1,endColumn=1,title=plugin(long-message)::This is a very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very very long message
+
+Found 0 warnings and 1 error.
+```
+
+# stderr
+```
+```

apps/oxlint/test/fixtures/github_report_long_message/plugin.ts

@@ -0,0 +1,25 @@
+import type { Plugin, Rule } from "#oxlint/plugins";
+
+const rule: Rule = {
+  create(context) {
+    return {
+      Program(node) {
+        context.report({
+          message: `This is a ${Array.from({ length: 240 }, () => "very").join(" ")} long message`,
+          node,
+        });
+      },
+    };
+  },
+};
+
+const plugin: Plugin = {
+  meta: {
+    name: "plugin",
+  },
+  rules: {
+    "long-message": rule,
+  },
+};
+
+export default plugin;

crates/oxc_diagnostics/src/reporter.rs

@@ -47,6 +47,15 @@ pub trait DiagnosticReporter {
     /// upheld in Oxc's API. Do not rely on this behavior.
     fn finish(&mut self, result: &DiagnosticResult) -> Option<String>;
 
+    /// Whether [`DiagnosticService`](crate::service::DiagnosticService) should replace very long
+    /// rendered lines with the synthetic "minified file" warning.
+    ///
+    /// Human-readable reporters generally want this behavior to avoid dumping unreadable output.
+    /// Machine-readable or intentionally single-line reporters should disable it.
+    fn supports_minified_file_fallback(&self) -> bool {
+        true
+    }
+
     /// Render a diagnostic into this reporter's desired format. For example, a JSONLinesReporter
     /// might return a stringified JSON object on a single line. Returns [`None`] to skip reporting
     /// of this diagnostic.

crates/oxc_diagnostics/src/service.rs

@@ -154,6 +154,7 @@ impl DiagnosticService {
     pub fn run(&mut self, writer: &mut dyn Write) -> DiagnosticResult {
         let mut warnings_count: usize = 0;
         let mut errors_count: usize = 0;
+        let supports_minified_file_fallback = self.reporter.supports_minified_file_fallback();
 
         while let Ok(diagnostics) = self.receiver.recv() {
             let mut is_minified = false;
@@ -187,7 +188,9 @@ impl DiagnosticService {
                 if let Some(err_str) = self.reporter.render_error(diagnostic) {
                     // Skip large output and print only once.
                     // Setting to 1200 because graphical output may contain ansi escape codes and other decorations.
-                    if err_str.lines().any(|line| line.len() >= 1200) {
+                    if supports_minified_file_fallback
+                        && err_str.lines().any(|line| line.len() >= 1200)
+                    {
                         let mut diagnostic =
                             OxcDiagnostic::warn("File is too long to fit on the screen");
                         if let Some(path) = path {
@@ -339,9 +342,16 @@ fn strict_canonicalize<P: AsRef<Path>>(path: P) -> std::io::Result<PathBuf> {
 
 #[cfg(test)]
 mod tests {
-    use crate::service::from_file_path;
     use std::path::PathBuf;
 
+    use crate::{
+        Error, OxcDiagnostic,
+        reporter::{DiagnosticReporter, DiagnosticResult},
+        service::from_file_path,
+    };
+
+    use super::DiagnosticService;
+
     fn with_schema(path: &str) -> String {
         const EXPECTED_SCHEMA: &str = if cfg!(windows) { "file:///" } else { "file://" };
         format!("{EXPECTED_SCHEMA}{path}")
@@ -407,4 +417,41 @@ mod tests {
             assert_eq!(uri, expected);
         }
     }
+
+    #[test]
+    fn preserves_long_lines_for_single_line_reporters() {
+        #[derive(Default)]
+        struct LongLineReporter {
+            fallback_enabled: bool,
+        }
+
+        impl DiagnosticReporter for LongLineReporter {
+            fn finish(&mut self, _result: &DiagnosticResult) -> Option<String> {
+                None
+            }
+
+            fn supports_minified_file_fallback(&self) -> bool {
+                self.fallback_enabled
+            }
+
+            fn render_error(&mut self, error: Error) -> Option<String> {
+                let message = error.to_string();
+                if message == "original diagnostic" {
+                    Some(format!("{}\n", "x".repeat(1200)))
+                } else {
+                    Some(format!("{message}\n"))
+                }
+            }
+        }
+        let (mut service, sender) =
+            DiagnosticService::new(Box::new(LongLineReporter { fallback_enabled: false }));
+        sender.send(vec![Error::new(OxcDiagnostic::warn("original diagnostic"))]).unwrap();
+        drop(sender);
+
+        let mut output = Vec::new();
+        service.run(&mut output);
+        let output = String::from_utf8(output).unwrap();
+
+        assert_eq!(output, format!("{}\n", "x".repeat(1200)));
+    }
 }