fix: enhance error handling in github-sync-main.ps1

Added error handling for git commands in the sync process to ensure that failures during 'git switch', 'git pull', and 'git push' are logged and the script exits gracefully. This improves the robustness of the synchronization script.

Author: omalleyandy

scripts/github-sync-main.ps1

@@ -7,6 +7,7 @@ param(
 )
 
 $ErrorActionPreference = "Stop"
+# $ErrorActionPreference does not apply to external commands (e.g. git). We check $LASTEXITCODE after each git call in the -Sync block.
 $repoRoot = (Get-Item $PSScriptRoot).Parent.FullName
 Set-Location $repoRoot
 
@@ -30,13 +31,34 @@ $out += ""
 if ($Sync) {
     $out += "=== Syncing main ==="
     git switch main 2>&1 | ForEach-Object { $out += $_ }
+    if ($LASTEXITCODE -ne 0) {
+        $out += "ERROR: git switch main failed (exit $LASTEXITCODE). Sync aborted to avoid running pull/push on current branch."
+        $text = $out -join "`r`n"
+        $text | Out-File -FilePath $logPath -Encoding utf8
+        Write-Host $text
+        exit $LASTEXITCODE
+    }
     git pull origin main --rebase 2>&1 | ForEach-Object { $out += $_ }
+    if ($LASTEXITCODE -ne 0) {
+        $out += "ERROR: git pull failed (exit $LASTEXITCODE)."
+        $text = $out -join "`r`n"
+        $text | Out-File -FilePath $logPath -Encoding utf8
+        Write-Host $text
+        exit $LASTEXITCODE
+    }
     git push origin main 2>&1 | ForEach-Object { $out += $_ }
+    if ($LASTEXITCODE -ne 0) {
+        $out += "ERROR: git push failed (exit $LASTEXITCODE)."
+        $text = $out -join "`r`n"
+        $text | Out-File -FilePath $logPath -Encoding utf8
+        Write-Host $text
+        exit $LASTEXITCODE
+    }
     $out += "Done."
 } else {
     $out += "To sync main (pull + push), run: .\scripts\github-sync-main.ps1 -Sync"
 }
 
 $text = $out -join "`r`n"
 $text | Out-File -FilePath $logPath -Encoding utf8
-Write-Host $text
+Write-Host $text