fix: properly implement UTF-8 support for Windows terminals

- Add LANG and LC_ALL environment variables for UTF-8 encoding
- Prepend 'chcp 65001' command on Windows to set code page to UTF-8
- Handle both PowerShell and CMD syntax for code page switching
- Remove incorrect CHCP environment variable approach
- Update tests to reflect the corrected implementation

This properly fixes non-ASCII characters (Cyrillic, Chinese, Hindi, etc.)
being displayed as '?' or diamond symbols in terminal output on Windows.

Fixes #8530

src/integrations/terminal/Terminal.ts

@@ -165,11 +165,6 @@ export class Terminal extends BaseTerminal {
 			LC_ALL: "en_US.UTF-8",
 		}
 
-		// On Windows, set the code page to UTF-8 (65001) for proper Unicode support
-		if (process.platform === "win32") {
-			env.CHCP = "65001"
-		}
-
 		// Set Oh My Zsh shell integration if enabled
 		if (Terminal.getTerminalZshOhMy()) {
 			env.ITERM_SHELL_INTEGRATION_INSTALLED = "Yes"

src/integrations/terminal/TerminalProcess.ts

@@ -114,9 +114,21 @@ export class TerminalProcess extends BaseTerminalProcess {
 			(defaultWindowsShellProfile === null ||
 				(defaultWindowsShellProfile as string)?.toLowerCase().includes("powershell"))
 
-		if (isPowerShell) {
-			let commandToExecute = command
+		let commandToExecute = command
 
+		// On Windows, prepend chcp 65001 to set UTF-8 code page for proper Unicode support
+		// This fixes issues with non-ASCII characters being displayed as "?" or diamond symbols
+		if (process.platform === "win32") {
+			if (isPowerShell) {
+				// PowerShell syntax: use semicolon to chain commands and redirect output to null
+				commandToExecute = `chcp 65001 > $null ; ${command}`
+			} else {
+				// CMD syntax: use && to chain commands and redirect output to nul
+				commandToExecute = `chcp 65001 > nul && ${command}`
+			}
+		}
+
+		if (isPowerShell) {
 			// Only add the PowerShell counter workaround if enabled
 			if (Terminal.getPowershellCounter()) {
 				commandToExecute += ` ; "(Roo/PS Workaround: ${this.terminal.cmdCounter++})" > $null`
@@ -126,12 +138,10 @@ export class TerminalProcess extends BaseTerminalProcess {
 			if (Terminal.getCommandDelay() > 0) {
 				commandToExecute += ` ; start-sleep -milliseconds ${Terminal.getCommandDelay()}`
 			}
-
-			terminal.shellIntegration.executeCommand(commandToExecute)
-		} else {
-			terminal.shellIntegration.executeCommand(command)
 		}
 
+		terminal.shellIntegration.executeCommand(commandToExecute)
+
 		this.isHot = true
 
 		// Wait for stream to be available

src/integrations/terminal/__tests__/TerminalRegistry.spec.ts

@@ -126,40 +126,5 @@ describe("TerminalRegistry", () => {
 				Terminal.setTerminalZshP10k(false)
 			}
 		})
-
-		it("adds CHCP=65001 on Windows for UTF-8 support", () => {
-			// Mock platform as Windows
-			const originalPlatform = process.platform
-			Object.defineProperty(process, "platform", {
-				value: "win32",
-				writable: true,
-				configurable: true,
-			})
-
-			try {
-				TerminalRegistry.createTerminal("/test/path", "vscode")
-
-				expect(mockCreateTerminal).toHaveBeenCalledWith({
-					cwd: "/test/path",
-					name: "Roo Code",
-					iconPath: expect.any(Object),
-					env: {
-						PAGER: "",
-						VTE_VERSION: "0",
-						PROMPT_EOL_MARK: "",
-						LANG: "en_US.UTF-8",
-						LC_ALL: "en_US.UTF-8",
-						CHCP: "65001",
-					},
-				})
-			} finally {
-				// Restore original platform
-				Object.defineProperty(process, "platform", {
-					value: originalPlatform,
-					writable: true,
-					configurable: true,
-				})
-			}
-		})
 	})
 })