Show error and warning indicators in project panel items (#18182)

Closes #5016

Release Notes:

- Add setting to display error and warning indicators in project panel
items.


https://github.com/user-attachments/assets/8f8031e6-ca47-42bf-a7eb-718eb1067f36

---------

Co-authored-by: Thorsten Ball <[email protected]>
Co-authored-by: Danilo Leal <[email protected]>

assets/settings/default.json

@@ -383,6 +383,16 @@
       ///    "never"
       "show": null
     },
+    /// Which files containing diagnostic errors/warnings to mark in the project panel.
+    /// This setting can take the following three values:
+    ///
+    /// 1. Do not mark any files:
+    ///    "off"
+    /// 2. Only mark files with errors:
+    ///    "errors"
+    /// 3. Mark files with errors and warnings:
+    ///    "all"
+    "show_diagnostics": "all",
     // Settings related to indent guides in the project panel.
     "indent_guides": {
       // When to show indent guides in the project panel.

crates/editor/src/items.rs

@@ -18,6 +18,7 @@ use gpui::{
 use language::{
     proto::serialize_anchor as serialize_text_anchor, Bias, Buffer, CharKind, Point, SelectionGoal,
 };
+use lsp::DiagnosticSeverity;
 use multi_buffer::AnchorRangeExt;
 use project::{
     lsp_store::FormatTrigger, project_settings::ProjectSettings, search::SearchQuery, Item as _,
@@ -39,7 +40,7 @@ use std::{
 };
 use text::{BufferId, Selection};
 use theme::{Theme, ThemeSettings};
-use ui::{h_flex, prelude::*, Label};
+use ui::{h_flex, prelude::*, IconDecorationKind, Label};
 use util::{paths::PathExt, ResultExt, TryFutureExt};
 use workspace::item::{BreadcrumbText, FollowEvent};
 use workspace::{
@@ -1515,6 +1516,26 @@ pub fn entry_label_color(selected: bool) -> Color {
     }
 }
 
+pub fn entry_diagnostic_aware_icon_name_and_color(
+    diagnostic_severity: Option<DiagnosticSeverity>,
+) -> Option<(IconName, Color)> {
+    match diagnostic_severity {
+        Some(DiagnosticSeverity::ERROR) => Some((IconName::X, Color::Error)),
+        Some(DiagnosticSeverity::WARNING) => Some((IconName::Triangle, Color::Warning)),
+        _ => None,
+    }
+}
+
+pub fn entry_diagnostic_aware_icon_decoration_and_color(
+    diagnostic_severity: Option<DiagnosticSeverity>,
+) -> Option<(IconDecorationKind, Color)> {
+    match diagnostic_severity {
+        Some(DiagnosticSeverity::ERROR) => Some((IconDecorationKind::X, Color::Error)),
+        Some(DiagnosticSeverity::WARNING) => Some((IconDecorationKind::Triangle, Color::Warning)),
+        _ => None,
+    }
+}
+
 pub fn entry_git_aware_label_color(
     git_status: Option<GitFileStatus>,
     ignored: bool,

crates/project_panel/Cargo.toml

@@ -37,6 +37,7 @@ util.workspace = true
 client.workspace = true
 worktree.workspace = true
 workspace.workspace = true
+language.workspace = true
 
 [dev-dependencies]
 client = { workspace = true, features = ["test-support"] }