Retry installing Visual Studio Build Tools on failure

.github/workflows/scripts/windows/install-vsb.ps1

@@ -9,13 +9,36 @@
 ## See https://swift.org/CONTRIBUTORS.txt for the list of Swift project authors
 ##
 ##===----------------------------------------------------------------------===##
+
 $VSB='https://download.visualstudio.microsoft.com/download/pr/5536698c-711c-4834-876f-2817d31a2ef2/c792bdb0fd46155de19955269cac85d52c4c63c23db2cf43d96b9390146f9390/vs_BuildTools.exe'
 $VSB_SHA256='C792BDB0FD46155DE19955269CAC85D52C4C63C23DB2CF43D96B9390146F9390'
 Set-Variable ErrorActionPreference Stop
 Set-Variable ProgressPreference SilentlyContinue
 Write-Host -NoNewLine ('Downloading {0} ... ' -f ${VSB})
-Invoke-WebRequest -Uri $VSB -OutFile $env:TEMP\vs_buildtools.exe
-Write-Host 'SUCCESS'
+try {
+    # Use curl with retry logic (10 retries with exponential backoff starting at 1 second)
+    # --retry-all-errors ensures we retry on transfer failures (e.g., exit code 18)
+    # -C - enables resume for partial downloads
+    $exitCode = (Start-Process -FilePath "curl" -ArgumentList @(
+        "--retry", "10",
+        "--retry-delay", "1",
+        "--retry-all-errors",
+        "--retry-max-time", "300",
+        "--location",
+        "-C", "-",
+        "--output", "$env:TEMP\vs_buildtools.exe",
+        $VSB
+    ) -Wait -PassThru -NoNewWindow).ExitCode
+
+    if ($exitCode -ne 0) {
+        throw "curl failed with exit code $exitCode"
+    }
+    Write-Host 'SUCCESS'
+}
+catch {
+    Write-Host "FAILED: $($_.Exception.Message)"
+    exit 1
+}
 Write-Host -NoNewLine ('Verifying SHA256 ({0}) ... ' -f $VSB_SHA256)
 $Hash = Get-FileHash $env:TEMP\vs_buildtools.exe -Algorithm sha256
 if ($Hash.Hash -eq $VSB_SHA256) {

.github/workflows/scripts/windows/swift/install-swift.ps1

@@ -9,6 +9,7 @@
 ## See https://swift.org/CONTRIBUTORS.txt for the list of Swift project authors
 ##
 ##===----------------------------------------------------------------------===##
+
 function Install-Swift {
     param (
         [string]$Url,
@@ -17,8 +18,30 @@ function Install-Swift {
     Set-Variable ErrorActionPreference Stop
     Set-Variable ProgressPreference SilentlyContinue
     Write-Host -NoNewLine ('Downloading {0} ... ' -f $url)
-    Invoke-WebRequest -Uri $url -OutFile installer.exe
-    Write-Host 'SUCCESS'
+    try {
+        # Use curl with retry logic (10 retries with exponential backoff starting at 1 second)
+        # --retry-all-errors ensures we retry on transfer failures (e.g., exit code 18)
+        # -C - enables resume for partial downloads
+        $exitCode = (Start-Process -FilePath "curl" -ArgumentList @(
+            "--retry", "10",
+            "--retry-delay", "1",
+            "--retry-all-errors",
+            "--retry-max-time", "300",
+            "--location",
+            "-C", "-",
+            "--output", "installer.exe",
+            $url
+        ) -Wait -PassThru -NoNewWindow).ExitCode
+
+        if ($exitCode -ne 0) {
+            throw "curl failed with exit code $exitCode"
+        }
+        Write-Host 'SUCCESS'
+    }
+    catch {
+        Write-Host "FAILED: $($_.Exception.Message)"
+        exit 1
+    }
     Write-Host -NoNewLine ('Verifying SHA256 ({0}) ... ' -f $Sha256)
     $Hash = Get-FileHash installer.exe -Algorithm sha256
     if ($Hash.Hash -eq $Sha256 -or $Sha256 -eq "") {