show error diagnostics for invalid rules

.github/CODEOWNERS

@@ -22,7 +22,7 @@
 # be identified in the format @org/team-name. Teams must have
 # explicit write access to the repository. In this example,
 # the octocats team in the octo-org organization owns all .txt files.
-*.txt @octo-org/octocats
+*.txt @octo-org/@test_one/octocats
 
 # In this example, @doctocat owns any files in the build/logs
 # directory at the root of the repository and any of its

CHANGELOG.md

@@ -7,6 +7,12 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 ## [Unreleased]
 
+## 4.2.0 - 2026-03-14
+
+### Added
+
+- Show error diagnostics for invalid CODEOWNERS patterns (#34).
+
 ## 4.1.0 - 2024-04-13
 
 ### Changed

package.json

@@ -4,7 +4,7 @@
   "description": "Quickly see GitHub Code Owners for the current file. Add syntax highlighting for CODEOWNERS files.",
   "publisher": "chdsbd",
   "license": "SEE LICENSE IN LICENSE",
-  "version": "4.1.0",
+  "version": "4.2.0",
   "icon": "images/logo256.png",
   "homepage": "https://github.com/chdsbd/vscode-github-code-owners/blob/master/README.md",
   "keywords": [
@@ -229,7 +229,7 @@
     "typescript": "^4.9.5"
   },
   "dependencies": {
-    "@snyk/github-codeowners": "github:chdsbd/github-codeowners#chris/line-number-information",
+    "@snyk/github-codeowners": "github:chdsbd/github-codeowners#da8b03fa3cb4de086f3a564f1af03cc44288e43c",
     "lodash": "^4.17.21"
   },
   "volta": {

src/codeowners-diagnostic-provider.ts

@@ -0,0 +1,49 @@
+import vscode from "vscode"
+import { OwnershipEngine } from "@snyk/github-codeowners/dist/lib/ownership"
+
+function updateDiagnostics(
+  document: vscode.TextDocument,
+  collection: vscode.DiagnosticCollection,
+): void {
+  if (document.languageId !== "codeowners") {
+    return
+  }
+
+  const engine = OwnershipEngine.FromCodeownersFile(document.uri.fsPath)
+
+  const diagnostics = engine.errors.map((err) => {
+    const line = document.lineAt(err.lineno)
+    return new vscode.Diagnostic(line.range, err.message, vscode.DiagnosticSeverity.Error)
+  })
+
+  collection.set(document.uri, diagnostics)
+}
+
+export function registerCodeownersDiagnostics(
+  context: vscode.ExtensionContext,
+): void {
+  const collection = vscode.languages.createDiagnosticCollection("codeowners")
+  context.subscriptions.push(collection)
+
+  vscode.workspace.textDocuments.forEach((doc) =>
+    updateDiagnostics(doc, collection),
+  )
+
+  vscode.workspace.onDidOpenTextDocument(
+    (doc) => updateDiagnostics(doc, collection),
+    null,
+    context.subscriptions,
+  )
+
+  vscode.workspace.onDidChangeTextDocument(
+    (e) => updateDiagnostics(e.document, collection),
+    null,
+    context.subscriptions,
+  )
+
+  vscode.workspace.onDidCloseTextDocument(
+    (doc) => collection.delete(doc.uri),
+    null,
+    context.subscriptions,
+  )
+}

src/extension.ts

@@ -7,6 +7,7 @@ import { showOwnersCommandHandler } from "./show-owners-command"
 import { CodeownersHoverProvider } from "./codeowners-hover-provider"
 import { statusBarTextEditorListener } from "./status-bar-text-editor-listener"
 import { AlignOwnersFormattingProvider } from "./align-codeowners"
+import { registerCodeownersDiagnostics } from "./codeowners-diagnostic-provider"
 
 const COMMAND_ID = "github-code-owners.show-owners"
 
@@ -74,6 +75,8 @@ export function activate(context: vscode.ExtensionContext) {
     ),
   )
 
+  registerCodeownersDiagnostics(context)
+
   vscode.workspace.onDidChangeConfiguration(() => {
     outputChannel.appendLine("Configuration changed: Reloading link provider")
     handles.linkProvider.dispose()