refactor: Move fallback extensions to supported-extensions.ts

- Consolidate fallback extensions functionality into supported-extensions.ts
- Update imports in parser.ts and test files
- Remove separate fallback-extensions.ts file
- All functionality remains the same, just better organized

Author: daniel-lxs

src/services/code-index/processors/__tests__/parser.vb.spec.ts

@@ -11,7 +11,7 @@ vi.mock("../../../../../packages/telemetry/src/TelemetryService", () => ({
 	},
 }))
 
-import { shouldUseFallbackChunking } from "../../shared/fallback-extensions"
+import { shouldUseFallbackChunking } from "../../shared/supported-extensions"
 
 describe("CodeParser - VB.NET and Fallback Extensions Support", () => {
 	let parser: CodeParser

src/services/code-index/processors/parser.ts

@@ -5,8 +5,7 @@ import { Node } from "web-tree-sitter"
 import { LanguageParser, loadRequiredLanguageParsers } from "../../tree-sitter/languageParser"
 import { parseMarkdown } from "../../tree-sitter/markdownParser"
 import { ICodeParser, CodeBlock } from "../interfaces"
-import { scannerExtensions } from "../shared/supported-extensions"
-import { shouldUseFallbackChunking } from "../shared/fallback-extensions"
+import { scannerExtensions, shouldUseFallbackChunking } from "../shared/supported-extensions"
 import { MAX_BLOCK_CHARS, MIN_BLOCK_CHARS, MIN_CHUNK_REMAINDER_CHARS, MAX_CHARS_TOLERANCE_FACTOR } from "../constants"
 import { TelemetryService } from "@roo-code/telemetry"
 import { TelemetryEventName } from "@roo-code/types"

src/services/code-index/shared/fallback-extensions.ts

@@ -2,3 +2,32 @@ import { extensions as allExtensions } from "../../tree-sitter"
 
 // Include all extensions including markdown for the scanner
 export const scannerExtensions = allExtensions
+
+/**
+ * Extensions that should always use fallback chunking instead of tree-sitter parsing.
+ * These are typically languages that don't have a proper WASM parser available
+ * or where the parser doesn't work correctly.
+ *
+ * NOTE: Only extensions that are already in the supported extensions list can be added here.
+ * To add support for new file types, they must first be added to the tree-sitter extensions list.
+ *
+ * HOW TO ADD A NEW FALLBACK EXTENSION:
+ * 1. First ensure the extension is in src/services/tree-sitter/index.ts extensions array
+ * 2. Add the extension to the fallbackExtensions array below
+ * 3. The file will automatically use length-based chunking for indexing
+ *
+ * Note: Do NOT remove parser cases from languageParser.ts as they may be used elsewhere
+ */
+export const fallbackExtensions = [
+	".vb", // Visual Basic .NET - no dedicated WASM parser
+	".scala", // Scala - uses fallback chunking instead of Lua query workaround
+]
+
+/**
+ * Check if a file extension should use fallback chunking
+ * @param extension File extension (including the dot)
+ * @returns true if the extension should use fallback chunking
+ */
+export function shouldUseFallbackChunking(extension: string): boolean {
+	return fallbackExtensions.includes(extension.toLowerCase())
+}