From 5b984bffae779511ddc189d7a5ce088fd5ecd022 Mon Sep 17 00:00:00 2001
From: Christian Gunderman <gundermanc@google.com>
Date: Mon, 2 Feb 2026 11:41:58 -0800
Subject: [PATCH] Fix powershell encoding.

---
 packages/core/src/utils/shell-utils.test.ts | 30 +++++++++++++++++----
 packages/core/src/utils/shell-utils.ts      | 12 +++++++--
 2 files changed, 35 insertions(+), 7 deletions(-)

diff --git a/packages/core/src/utils/shell-utils.test.ts b/packages/core/src/utils/shell-utils.test.ts
index 81b43abf50..a4e7bf6f8f 100644
--- a/packages/core/src/utils/shell-utils.test.ts
+++ b/packages/core/src/utils/shell-utils.test.ts
@@ -429,7 +429,11 @@ describe('getShellConfiguration', () => {
       delete process.env['ComSpec'];
       const config = getShellConfiguration();
       expect(config.executable).toBe('powershell.exe');
-      expect(config.argsPrefix).toEqual(['-NoProfile', '-Command']);
+      expect(config.argsPrefix).toEqual([
+        '-NoProfile',
+        '-Command',
+        '$OutputEncoding = [Console]::InputEncoding = [Console]::OutputEncoding = [System.Text.Encoding]::UTF8;',
+      ]);
       expect(config.shell).toBe('powershell');
     });
 
@@ -438,7 +442,11 @@ describe('getShellConfiguration', () => {
       process.env['ComSpec'] = cmdPath;
       const config = getShellConfiguration();
       expect(config.executable).toBe('powershell.exe');
-      expect(config.argsPrefix).toEqual(['-NoProfile', '-Command']);
+      expect(config.argsPrefix).toEqual([
+        '-NoProfile',
+        '-Command',
+        '$OutputEncoding = [Console]::InputEncoding = [Console]::OutputEncoding = [System.Text.Encoding]::UTF8;',
+      ]);
       expect(config.shell).toBe('powershell');
     });
 
@@ -448,7 +456,11 @@ describe('getShellConfiguration', () => {
       process.env['ComSpec'] = psPath;
       const config = getShellConfiguration();
       expect(config.executable).toBe(psPath);
-      expect(config.argsPrefix).toEqual(['-NoProfile', '-Command']);
+      expect(config.argsPrefix).toEqual([
+        '-NoProfile',
+        '-Command',
+        '$OutputEncoding = [Console]::InputEncoding = [Console]::OutputEncoding = [System.Text.Encoding]::UTF8;',
+      ]);
       expect(config.shell).toBe('powershell');
     });
 
@@ -457,7 +469,11 @@ describe('getShellConfiguration', () => {
       process.env['ComSpec'] = pwshPath;
       const config = getShellConfiguration();
       expect(config.executable).toBe(pwshPath);
-      expect(config.argsPrefix).toEqual(['-NoProfile', '-Command']);
+      expect(config.argsPrefix).toEqual([
+        '-NoProfile',
+        '-Command',
+        '$OutputEncoding = [Console]::InputEncoding = [Console]::OutputEncoding = [System.Text.Encoding]::UTF8;',
+      ]);
       expect(config.shell).toBe('powershell');
     });
 
@@ -465,7 +481,11 @@ describe('getShellConfiguration', () => {
       process.env['ComSpec'] = 'C:\\Path\\To\\POWERSHELL.EXE';
       const config = getShellConfiguration();
       expect(config.executable).toBe('C:\\Path\\To\\POWERSHELL.EXE');
-      expect(config.argsPrefix).toEqual(['-NoProfile', '-Command']);
+      expect(config.argsPrefix).toEqual([
+        '-NoProfile',
+        '-Command',
+        '$OutputEncoding = [Console]::InputEncoding = [Console]::OutputEncoding = [System.Text.Encoding]::UTF8;',
+      ]);
       expect(config.shell).toBe('powershell');
     });
   });
diff --git a/packages/core/src/utils/shell-utils.ts b/packages/core/src/utils/shell-utils.ts
index 3a002f2895..edb65ba02f 100644
--- a/packages/core/src/utils/shell-utils.ts
+++ b/packages/core/src/utils/shell-utils.ts
@@ -552,7 +552,11 @@ export function getShellConfiguration(): ShellConfiguration {
       ) {
         return {
           executable: comSpec,
-          argsPrefix: ['-NoProfile', '-Command'],
+          argsPrefix: [
+            '-NoProfile',
+            '-Command',
+            '$OutputEncoding = [Console]::InputEncoding = [Console]::OutputEncoding = [System.Text.Encoding]::UTF8;',
+          ],
           shell: 'powershell',
         };
       }
@@ -561,7 +565,11 @@ export function getShellConfiguration(): ShellConfiguration {
     // Default to PowerShell for all other Windows configurations.
     return {
       executable: 'powershell.exe',
-      argsPrefix: ['-NoProfile', '-Command'],
+      argsPrefix: [
+        '-NoProfile',
+        '-Command',
+        '$OutputEncoding = [Console]::InputEncoding = [Console]::OutputEncoding = [System.Text.Encoding]::UTF8;',
+      ],
       shell: 'powershell',
     };
   }