fix: improve error handling in roo-config service to only catch expected filesystem errors

- Replace broad catch-all error handling with specific error code checking
- Only catch expected errors (ENOENT, ENOTDIR, EISDIR) in filesystem operations
- Allow unexpected errors (EACCES, EIO, etc.) to propagate for proper diagnosis
- Update directoryExists(), fileExists(), and readFileIfExists() functions
- Add comprehensive test coverage for both expected and unexpected error scenarios
- Verify loadConfiguration() properly propagates errors from file operations

This prevents masking of critical system errors like permission issues, I/O failures,
and disk problems while maintaining graceful handling of expected "file not found" cases.
Improves debugging capabilities and follows error handling best practices.

Fixes potential issues where permission denied or I/O errors were silently treated
as "file doesn't exist", making troubleshooting difficult in production environments.

Author: samhvw8

src/services/roo-config/__tests__/index.spec.ts

@@ -73,13 +73,33 @@ describe("RooConfigService", () => {
 		})
 
 		it("should return false for non-existing path", async () => {
-			mockStat.mockRejectedValue(new Error("ENOENT"))
+			const error = new Error("ENOENT") as any
+			error.code = "ENOENT"
+			mockStat.mockRejectedValue(error)
 
 			const result = await directoryExists("/non/existing/path")
 
 			expect(result).toBe(false)
 		})
 
+		it("should return false for ENOTDIR error", async () => {
+			const error = new Error("ENOTDIR") as any
+			error.code = "ENOTDIR"
+			mockStat.mockRejectedValue(error)
+
+			const result = await directoryExists("/not/a/directory")
+
+			expect(result).toBe(false)
+		})
+
+		it("should throw unexpected errors", async () => {
+			const error = new Error("Permission denied") as any
+			error.code = "EACCES"
+			mockStat.mockRejectedValue(error)
+
+			await expect(directoryExists("/permission/denied")).rejects.toThrow("Permission denied")
+		})
+
 		it("should return false for files", async () => {
 			mockStat.mockResolvedValue({ isDirectory: () => false } as any)
 
@@ -100,13 +120,33 @@ describe("RooConfigService", () => {
 		})
 
 		it("should return false for non-existing file", async () => {
-			mockStat.mockRejectedValue(new Error("ENOENT"))
+			const error = new Error("ENOENT") as any
+			error.code = "ENOENT"
+			mockStat.mockRejectedValue(error)
 
 			const result = await fileExists("/non/existing/file.txt")
 
 			expect(result).toBe(false)
 		})
 
+		it("should return false for ENOTDIR error", async () => {
+			const error = new Error("ENOTDIR") as any
+			error.code = "ENOTDIR"
+			mockStat.mockRejectedValue(error)
+
+			const result = await fileExists("/not/a/directory/file.txt")
+
+			expect(result).toBe(false)
+		})
+
+		it("should throw unexpected errors", async () => {
+			const error = new Error("Permission denied") as any
+			error.code = "EACCES"
+			mockStat.mockRejectedValue(error)
+
+			await expect(fileExists("/permission/denied/file.txt")).rejects.toThrow("Permission denied")
+		})
+
 		it("should return false for directories", async () => {
 			mockStat.mockResolvedValue({ isFile: () => false } as any)
 
@@ -127,12 +167,42 @@ describe("RooConfigService", () => {
 		})
 
 		it("should return null for non-existing file", async () => {
-			mockReadFile.mockRejectedValue(new Error("ENOENT"))
+			const error = new Error("ENOENT") as any
+			error.code = "ENOENT"
+			mockReadFile.mockRejectedValue(error)
 
 			const result = await readFileIfExists("/non/existing/file.txt")
 
 			expect(result).toBe(null)
 		})
+
+		it("should return null for ENOTDIR error", async () => {
+			const error = new Error("ENOTDIR") as any
+			error.code = "ENOTDIR"
+			mockReadFile.mockRejectedValue(error)
+
+			const result = await readFileIfExists("/not/a/directory/file.txt")
+
+			expect(result).toBe(null)
+		})
+
+		it("should return null for EISDIR error", async () => {
+			const error = new Error("EISDIR") as any
+			error.code = "EISDIR"
+			mockReadFile.mockRejectedValue(error)
+
+			const result = await readFileIfExists("/is/a/directory")
+
+			expect(result).toBe(null)
+		})
+
+		it("should throw unexpected errors", async () => {
+			const error = new Error("Permission denied") as any
+			error.code = "EACCES"
+			mockReadFile.mockRejectedValue(error)
+
+			await expect(readFileIfExists("/permission/denied/file.txt")).rejects.toThrow("Permission denied")
+		})
 	})
 
 	describe("getRooDirectoriesForCwd", () => {
@@ -147,7 +217,9 @@ describe("RooConfigService", () => {
 
 	describe("loadConfiguration", () => {
 		it("should load global configuration only when project does not exist", async () => {
-			mockReadFile.mockResolvedValueOnce("global content").mockRejectedValueOnce(new Error("ENOENT"))
+			const error = new Error("ENOENT") as any
+			error.code = "ENOENT"
+			mockReadFile.mockResolvedValueOnce("global content").mockRejectedValueOnce(error)
 
 			const result = await loadConfiguration("rules/rules.md", "/project/path")
 
@@ -159,7 +231,9 @@ describe("RooConfigService", () => {
 		})
 
 		it("should load project configuration only when global does not exist", async () => {
-			mockReadFile.mockRejectedValueOnce(new Error("ENOENT")).mockResolvedValueOnce("project content")
+			const error = new Error("ENOENT") as any
+			error.code = "ENOENT"
+			mockReadFile.mockRejectedValueOnce(error).mockResolvedValueOnce("project content")
 
 			const result = await loadConfiguration("rules/rules.md", "/project/path")
 
@@ -183,7 +257,9 @@ describe("RooConfigService", () => {
 		})
 
 		it("should return empty merged content when neither exists", async () => {
-			mockReadFile.mockRejectedValueOnce(new Error("ENOENT")).mockRejectedValueOnce(new Error("ENOENT"))
+			const error = new Error("ENOENT") as any
+			error.code = "ENOENT"
+			mockReadFile.mockRejectedValueOnce(error).mockRejectedValueOnce(error)
 
 			const result = await loadConfiguration("rules/rules.md", "/project/path")
 
@@ -194,6 +270,25 @@ describe("RooConfigService", () => {
 			})
 		})
 
+		it("should propagate unexpected errors from global file read", async () => {
+			const error = new Error("Permission denied") as any
+			error.code = "EACCES"
+			mockReadFile.mockRejectedValueOnce(error)
+
+			await expect(loadConfiguration("rules/rules.md", "/project/path")).rejects.toThrow("Permission denied")
+		})
+
+		it("should propagate unexpected errors from project file read", async () => {
+			const globalError = new Error("ENOENT") as any
+			globalError.code = "ENOENT"
+			const projectError = new Error("Permission denied") as any
+			projectError.code = "EACCES"
+
+			mockReadFile.mockRejectedValueOnce(globalError).mockRejectedValueOnce(projectError)
+
+			await expect(loadConfiguration("rules/rules.md", "/project/path")).rejects.toThrow("Permission denied")
+		})
+
 		it("should use correct file paths", async () => {
 			mockReadFile.mockResolvedValue("content")
 

src/services/roo-config/index.ts

@@ -26,8 +26,13 @@ export async function directoryExists(dirPath: string): Promise<boolean> {
 	try {
 		const stat = await fs.stat(dirPath)
 		return stat.isDirectory()
-	} catch {
-		return false
+	} catch (error: any) {
+		// Only catch expected "not found" errors
+		if (error.code === "ENOENT" || error.code === "ENOTDIR") {
+			return false
+		}
+		// Re-throw unexpected errors (permission, I/O, etc.)
+		throw error
 	}
 }
 
@@ -38,8 +43,13 @@ export async function fileExists(filePath: string): Promise<boolean> {
 	try {
 		const stat = await fs.stat(filePath)
 		return stat.isFile()
-	} catch {
-		return false
+	} catch (error: any) {
+		// Only catch expected "not found" errors
+		if (error.code === "ENOENT" || error.code === "ENOTDIR") {
+			return false
+		}
+		// Re-throw unexpected errors (permission, I/O, etc.)
+		throw error
 	}
 }
 
@@ -49,8 +59,13 @@ export async function fileExists(filePath: string): Promise<boolean> {
 export async function readFileIfExists(filePath: string): Promise<string | null> {
 	try {
 		return await fs.readFile(filePath, "utf-8")
-	} catch {
-		return null
+	} catch (error: any) {
+		// Only catch expected "not found" errors
+		if (error.code === "ENOENT" || error.code === "ENOTDIR" || error.code === "EISDIR") {
+			return null
+		}
+		// Re-throw unexpected errors (permission, I/O, etc.)
+		throw error
 	}
 }