fix: handle non-file URI schemes gracefully in shellcheck linting

When opening files via virtual filesystems (WebDAV, kio-fuse, etc.),
the document URI may not use the file: scheme. Previously, calling
fileURLToPath() on such URIs would throw ERR_INVALID_URL_SCHEME.

This change adds a safeFileURLToPath helper that:
- Returns the file path for valid file: URIs
- Returns null for non-file URIs or invalid URIs
- Allows linting to proceed without the document directory in source paths

Closes #1370

Author: taronsung

server/src/shellcheck/__tests__/index.test.ts

@@ -295,4 +295,22 @@ describe('linter', () => {
       diagnostics: [],
     })
   })
+
+  it('should handle non-file URI schemes gracefully', async () => {
+    const shell = [
+      '#!/bin/bash',
+      'echo "hello"',
+    ].join('\n')
+
+    const nonFileUri = 'webdav://example.com/path/to/script.sh'
+    const document = TextDocument.create(nonFileUri, 'bash', 0, shell)
+
+    const [result] = await getLintingResult({
+      document,
+      sourcePaths: [],
+    })
+
+    expect(result.diagnostics).toEqual([])
+    expect(result.codeActions).toEqual({})
+  })
 })

server/src/shellcheck/index.ts

@@ -1,5 +1,5 @@
 import { dirname } from 'node:path'
-import { fileURLToPath } from 'node:url'
+import { fileURLToPath, URL } from 'node:url'
 
 import { spawn } from 'child_process'
 import * as LSP from 'vscode-languageserver/node'
@@ -17,6 +17,19 @@ import {
 } from './types'
 
 const DEBOUNCE_MS = 500
+
+function safeFileURLToPath(uri: string): string | null {
+  try {
+    const url = new URL(uri)
+    if (url.protocol !== 'file:') {
+      return null
+    }
+    return fileURLToPath(uri)
+  } catch {
+    return null
+  }
+}
+
 type LinterOptions = {
   executablePath: string
   cwd?: string
@@ -91,10 +104,15 @@ export class Linter {
       return { diagnostics: [], codeActions: {} }
     }
 
+    const documentPath = safeFileURLToPath(document.uri)
+    const effectiveSourcePaths = documentPath
+      ? [...sourcePaths, dirname(documentPath)]
+      : sourcePaths
+
     const result = await this.runShellCheck(
       documentText,
       shellName,
-      [...sourcePaths, dirname(fileURLToPath(document.uri))],
+      effectiveSourcePaths,
       additionalShellCheckArguments,
     )