Retry interrupted PostgreSQL release downloads

packaging/download_postgres.ps1

@@ -12,6 +12,7 @@ $url = "https://get.enterprisedb.com/postgresql/postgresql-$ver-windows-x64-bina
 
 $cache = if ($OutDir) { $OutDir } else { Join-Path $PSScriptRoot "cache" }
 $zipPath = Join-Path $cache "postgresql-$ver-windows-x64-binaries.zip"
+$partialPath = "$zipPath.partial"
 $extractRoot = Join-Path $cache "pgsql-$ver"
 $destPgsql = Join-Path $PSScriptRoot "postgres\pgsql"
 
@@ -22,7 +23,31 @@ if (-not (Test-Path $cache)) {
 Write-Host "==> PostgreSQL binaries URL: $url"
 if (-not (Test-Path $zipPath)) {
     Write-Host "==> Downloading (large; may take several minutes)..."
-    Invoke-WebRequest -Uri $url -OutFile $zipPath -UseBasicParsing
+    $curl = Get-Command curl.exe -ErrorAction SilentlyContinue
+    if ($curl) {
+        # PostgreSQL's archive is several hundred MB. Resume interrupted transfers
+        # instead of restarting the entire download when the CDN drops a connection.
+        & $curl.Source --fail --location --retry 8 --retry-all-errors --retry-delay 3 `
+            --connect-timeout 30 --continue-at - --output $partialPath $url
+        if ($LASTEXITCODE -ne 0) {
+            throw "postgres_download_failed: curl exit $LASTEXITCODE (partial file kept at $partialPath)"
+        }
+        Move-Item -LiteralPath $partialPath -Destination $zipPath -Force
+    } else {
+        # Fallback for environments without curl; retry from scratch on transient errors.
+        $downloaded = $false
+        for ($attempt = 1; $attempt -le 3 -and -not $downloaded; $attempt++) {
+            try {
+                Invoke-WebRequest -Uri $url -OutFile $partialPath -UseBasicParsing
+                Move-Item -LiteralPath $partialPath -Destination $zipPath -Force
+                $downloaded = $true
+            } catch {
+                if ($attempt -eq 3) { throw }
+                Remove-Item -LiteralPath $partialPath -Force -ErrorAction SilentlyContinue
+                Start-Sleep -Seconds (5 * $attempt)
+            }
+        }
+    }
 } else {
     Write-Host "==> Using cached zip: $zipPath"
 }