displaying diagnostic count on all open buffers in bufferline and for all buffers with diagnostics in the picker in addition with a red highlight

helix-term/src/commands.rs

@@ -10,6 +10,7 @@ pub use typed::*;
 
 use helix_core::{
     char_idx_at_visual_offset, comment,
+    diagnostic::{Diagnostic, Severity::*},
     doc_formatter::TextFormat,
     encoding, find_first_non_whitespace_char, find_root, graphemes,
     history::UndoKind,
@@ -2440,12 +2441,13 @@ fn buffer_picker(cx: &mut Context) {
         path: Option<PathBuf>,
         is_modified: bool,
         is_current: bool,
+        diagnostics: Vec<Diagnostic>,
     }
 
     impl ui::menu::Item for BufferMeta {
-        type Data = ();
+        type Data = (helix_view::graphics::Style, helix_view::graphics::Style);
 
-        fn format(&self, _data: &Self::Data) -> Row {
+        fn format(&self, data: &Self::Data) -> Row {
             let path = self
                 .path
                 .as_deref()
@@ -2455,15 +2457,61 @@ fn buffer_picker(cx: &mut Context) {
                 None => SCRATCH_BUFFER_NAME,
             };
 
-            let mut flags = String::new();
+            let mut flags = Vec::new();
+
+            let diagnostics = &self.diagnostics;
+
+            let (hint, info, warning, error) =
+                diagnostics
+                    .iter()
+                    .filter_map(|d| d.severity)
+                    .fold((0, 0, 0, 0), |mut acc, s| {
+                        match s {
+                            Hint => acc.0 += 1,
+                            Info => acc.1 += 1,
+                            Warning => acc.2 += 1,
+                            Error => acc.3 += 1,
+                        }
+
+                        acc
+                    });
+
+            if !diagnostics.is_empty() {
+                flags.push("!");
+            }
             if self.is_modified {
                 flags.push('+');
             }
             if self.is_current {
                 flags.push('*');
             }
 
-            Row::new([self.id.to_string(), flags, path.to_string()])
+            let flag = if flags.is_empty() {
+                "".into()
+            } else {
+                format!(" ({})", flags.join(""))
+            };
+
+            let (diag, text) = data;
+
+            Row::new(vec![
+                self.id.to_string(),
+                path.to_string(),
+                flag,
+                if !diagnostics.is_empty() {
+                    format!(
+                        " | {} error(s), {} warning(s), {} info, {} hint(s)",
+                        error, warning, info, hint
+                    )
+                } else {
+                    String::new()
+                },
+            ])
+            .style(if !diagnostics.is_empty() {
+                *diag
+            } else {
+                *text
+            })
         }
     }
 
@@ -2472,6 +2520,7 @@ fn buffer_picker(cx: &mut Context) {
         path: doc.path().cloned(),
         is_modified: doc.is_modified(),
         is_current: doc.id() == current,
+        diagnostics: doc.diagnostics().to_vec(),
     };
 
     let picker = FilePicker::new(
@@ -2480,7 +2529,7 @@ fn buffer_picker(cx: &mut Context) {
             .values()
             .map(|doc| new_meta(doc))
             .collect(),
-        (),
+        (cx.editor.theme.get("error"), cx.editor.theme.get("text")),
         |cx, meta, action| {
             cx.editor.switch(meta.id, action);
         },

helix-term/src/ui/editor.rs

@@ -561,13 +561,43 @@ impl EditorView {
                 bufferline_inactive
             };
 
-            let text = format!(" {}{} ", fname, if doc.is_modified() { "[+]" } else { "" });
+            let diagnostic_count = doc.diagnostics().len();
+
+            let text = format!(
+                " {}{}{} ",
+                fname,
+                if diagnostic_count > 9 {
+                    String::from(" 9+")
+                } else if diagnostic_count > 0 {
+                    format!(" {}", diagnostic_count)
+                } else {
+                    String::new()
+                },
+                if doc.is_modified() && diagnostic_count > 0 {
+                    " [+]"
+                } else if doc.is_modified() {
+                    "[+]"
+                } else {
+                    ""
+                }
+            );
+
             let used_width = viewport.x.saturating_sub(x);
             let rem_width = surface.area.width.saturating_sub(used_width);
 
-            x = surface
-                .set_stringn(x, viewport.y, text, rem_width as usize, style)
-                .0;
+            x = if diagnostic_count > 0 {
+                let background_style = editor.theme.get("ui.background");
+                let error_style = editor.theme.get("error");
+                let diagnostic_style = Style::reset().patch(background_style).patch(error_style);
+
+                surface
+                    .set_stringn(x, viewport.y, text, rem_width as usize, diagnostic_style)
+                    .0
+            } else {
+                surface
+                    .set_stringn(x, viewport.y, text, rem_width as usize, style)
+                    .0
+            };
 
             if x >= surface.area.right() {
                 break;