From cf55ade92a5c0388663742880280191956ee16a8 Mon Sep 17 00:00:00 2001
From: Greg Joseph <grjoseph+odspmdb@microsoft.com>
Date: Tue, 30 Jun 2026 11:45:03 -0700
Subject: [PATCH] fix(validation): launch sample processes via executable shim
 on Windows

Resolve-CommandPath returned the highest-precedence Get-Command match,
which on Windows is the PowerShell script shim (e.g. npx.ps1). Start-
LoggedProcess passes that path to Start-Process with output redirection,
forcing the CreateProcess code path -- which cannot execute .ps1 (or the
extensionless npm/npx) shims. Every Windows runtime/browser smoke step
therefore failed immediately with "%1 is not a valid Win32 application".

Resolve a directly executable form (.cmd/.exe/...) when one exists, while
falling back to the Application command form for Linux/macOS, where the
shebang executable can be exec'd directly. The call operator path
(Invoke-ExternalCommand) is unaffected since it runs .cmd shims fine too.

Verified on Windows (pwsh 7.4): Resolve-CommandPath now returns npx.cmd /
npm.cmd / node.exe; Start-LoggedProcess launches with redirection without
error; and project-management/validate-sample.ps1 reaches and passes the
preview-server startup it previously crashed on (exit code 0).

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>
---
 Tools/powershell/SampleValidation.ps1 | 33 +++++++++++++++++++++++----
 1 file changed, 29 insertions(+), 4 deletions(-)

diff --git a/Tools/powershell/SampleValidation.ps1 b/Tools/powershell/SampleValidation.ps1
index f215afa..127abe8 100644
--- a/Tools/powershell/SampleValidation.ps1
+++ b/Tools/powershell/SampleValidation.ps1
@@ -30,12 +30,37 @@ function Resolve-CommandPath {
         return $Name
     }
 
-    $command = Get-Command $Name -ErrorAction Stop
-    if ($null -ne $command.Source -and $command.Source.Length -gt 0) {
-        return $command.Source
+    $commands = @(Get-Command $Name -All -ErrorAction Stop)
+
+    # Start-LoggedProcess launches commands through Start-Process, which (when output is
+    # redirected) uses the OS CreateProcess API. CreateProcess cannot execute PowerShell
+    # script shims (.ps1) and, on Windows, cannot execute the extensionless shell-script
+    # shims that npm/npx ship. Get-Command returns the .ps1 shim first by precedence, so
+    # prefer a directly executable form (.cmd/.exe/...) that both the call operator and
+    # Start-Process can launch.
+    $executableExtensions = @('.exe', '.cmd', '.bat', '.com')
+
+    $preferred = $commands | Where-Object {
+        $_.CommandType -eq 'Application' -and
+        $_.Source -and
+        $executableExtensions -contains [System.IO.Path]::GetExtension($_.Source).ToLowerInvariant()
+    } | Select-Object -First 1
+
+    if ($null -eq $preferred) {
+        # On non-Windows platforms the Application form is typically an extensionless
+        # executable or a shebang script that CreateProcess can exec directly.
+        $preferred = $commands | Where-Object { $_.CommandType -eq 'Application' } | Select-Object -First 1
     }
 
-    return $command.Name
+    if ($null -eq $preferred) {
+        $preferred = $commands | Select-Object -First 1
+    }
+
+    if ($null -ne $preferred.Source -and $preferred.Source.Length -gt 0) {
+        return $preferred.Source
+    }
+
+    return $preferred.Name
 }
 
 function Invoke-ExternalCommand {