fix: provider cache path handling in Windows

docs/src/data/changelog/unreleased.mdx → docs/src/data/changelog/v1.0.1.mdx

@@ -1,5 +1,5 @@
 ---
-version: "Unreleased"
+version: "v1.0.1"
 ---
 
 ### 🧪 Experiments Added
@@ -43,6 +43,10 @@ A regression introduced in v0.99.4 caused `read_terragrunt_config()` to fail to
 
 Chaining dependencies with exposed includes no longer produces a spurious "Could not convert include to the execution ctx to evaluate additional locals" error during partial parsing.
 
+#### Provider cache fixed on Windows for remote URLs
+
+The provider cache failed on Windows with `CreateFile https://...: The filename, directory name, or volume label syntax is incorrect` because remote download URLs were passed to `os.Stat`, and the colon in `https:` is invalid Windows path syntax. The fix skips the filesystem existence check when the download URL is a remote URL (`://`), going directly to the download path.
+
 ### ⚙️ Process Updates
 
 ---

internal/tf/cache/services/provider_cache.go

@@ -13,6 +13,7 @@ import (
 	"path"
 	"path/filepath"
 	"slices"
+	"strings"
 	"sync"
 	"time"
 
@@ -318,12 +319,12 @@ func (cache *ProviderCache) warmUp(ctx context.Context) error {
 		return errors.Errorf("not found provider download url")
 	}
 
-	downloadURLExists, err := vfs.FileExists(fs, cache.DownloadURL)
+	downloadURLIsLocalFile, err := cache.isLocalFile(fs, cache.DownloadURL)
 	if err != nil {
 		return errors.New(err)
 	}
 
-	if downloadURLExists {
+	if downloadURLIsLocalFile {
 		cache.archivePath = cache.DownloadURL
 	} else {
 		if err := util.DoWithRetry(ctx, fmt.Sprintf("Fetching provider %s", cache.Provider), maxRetriesFetchFile, retryDelayFetchFile, cache.logger, log.DebugLevel, func(ctx context.Context) error {
@@ -404,6 +405,17 @@ func (cache *ProviderCache) removeArchive() error {
 	return nil
 }
 
+// isLocalFile checks whether the given path refers to an existing local file.
+// Remote URLs (containing "://") are never checked against the filesystem because
+// on Windows the colon in "https:" is invalid path syntax and causes an error.
+func (cache *ProviderCache) isLocalFile(fs vfs.FS, path string) (bool, error) {
+	if strings.Contains(path, "://") {
+		return false, nil
+	}
+
+	return vfs.FileExists(fs, path)
+}
+
 func (cache *ProviderCache) acquireLockFile(ctx context.Context) (*util.Lockfile, error) {
 	lockfile := util.NewLockfile(cache.lockfilePath)
 
@@ -670,8 +682,10 @@ func (service *ProviderService) startProviderCaching(ctx context.Context, cache
 			service.logger.Warnf("Failed to clean up package dir %q: %v", cache.packageDir, err)
 		}
 
-		if err := service.FS().Remove(cache.archivePath); err != nil {
-			service.logger.Warnf("Failed to clean up archive %q: %v", cache.archivePath, err)
+		if cache.archiveCached {
+			if err := service.FS().Remove(cache.archivePath); err != nil {
+				service.logger.Warnf("Failed to clean up archive %q: %v", cache.archivePath, err)
+			}
 		}
 
 		return cache.err

test/fixtures/provider-cache/windows-remote-url/main.tf

@@ -0,0 +1,10 @@
+terraform {
+  required_providers {
+    null = {
+      source  = "hashicorp/null"
+      version = "3.2.4"
+    }
+  }
+}
+
+resource "null_resource" "example" {}

test/fixtures/provider-cache/windows-remote-url/terragrunt.hcl

@@ -0,0 +1 @@
+# Intentionally empty

test/integration_windows_test.go

@@ -23,6 +23,7 @@ const (
 	testFixtureLocalRelativeArgsWindowsDownloadPath = "fixtures/download/local-windows"
 	testFixtureManifestRemoval                      = "fixtures/manifest-removal"
 	testFixtureTflintNoIssuesFound                  = "fixtures/tflint/no-issues-found"
+	testFixtureProviderCacheWindowsRemoteURL        = "fixtures/provider-cache/windows-remote-url"
 
 	tempDir = `C:\tmp`
 )
@@ -228,6 +229,27 @@ func TestWindowsScaffoldRef(t *testing.T) {
 	assert.NoError(t, err)
 }
 
+// TestWindowsProviderCacheWithRemoteURL verifies that provider caching works on Windows
+// when providers are fetched from remote URLs. Previously, passing a URL like
+// "https://github.com/..." to os.Stat caused a "syntax is incorrect" error on Windows
+// because the colon in "https:" is invalid Windows path syntax.
+func TestWindowsProviderCacheWithRemoteURL(t *testing.T) {
+	t.Parallel()
+
+	helpers.CleanupTerraformFolder(t, testFixtureProviderCacheWindowsRemoteURL)
+	tmpEnvPath := helpers.CopyEnvironment(t, testFixtureProviderCacheWindowsRemoteURL)
+	rootPath := filepath.Join(tmpEnvPath, testFixtureProviderCacheWindowsRemoteURL)
+
+	providerCacheDir := filepath.Join(t.TempDir(), "provider-cache-windows-test")
+
+	helpers.RunTerragrunt(t, fmt.Sprintf("terragrunt run init --provider-cache --provider-cache-dir %s --non-interactive --working-dir %s", providerCacheDir, rootPath))
+
+	// Verify the provider was cached
+	entries, err := os.ReadDir(providerCacheDir)
+	require.NoError(t, err)
+	assert.NotEmpty(t, entries, "provider cache dir should not be empty after init")
+}
+
 func CopyEnvironmentToPath(t *testing.T, environmentPath, targetPath string) {
 	if err := os.MkdirAll(targetPath, 0777); err != nil {
 		t.Fatalf("Failed to create temp dir %s due to error %v", targetPath, err)