feat: Improve handling of ExcludeFromCopy configuration in Terragrunt

cli/commands/terraform/download_source.go

@@ -211,14 +211,14 @@ func readVersionFile(terraformSource *terraform.Source) (string, error) {
 	return util.ReadFileAsString(terraformSource.VersionFile)
 }
 
-// updateGetters returns the customized go-getter interfaces that Terragrunt relies on. Specifically:
+// UpdateGetters returns the customized go-getter interfaces that Terragrunt relies on. Specifically:
 //   - Local file path getter is updated to copy the files instead of creating symlinks, which is what go-getter defaults
 //     to.
 //   - Include the customized getter for fetching sources from the Terraform Registry.
 //
 // This creates a closure that returns a function so that we have access to the terragrunt configuration, which is
 // necessary for customizing the behavior of the file getter.
-func updateGetters(terragruntOptions *options.TerragruntOptions, terragruntConfig *config.TerragruntConfig) func(*getter.Client) error {
+func UpdateGetters(terragruntOptions *options.TerragruntOptions, terragruntConfig *config.TerragruntConfig) func(*getter.Client) error {
 	return func(client *getter.Client) error {
 		// We copy all the default getters from the go-getter library, but replace the "file" getter. We shallow clone the
 		// getter map here rather than using getter.Getters directly because (a) we shouldn't change the original,
@@ -270,7 +270,7 @@ func downloadSource(terraformSource *terraform.Source, terragruntOptions *option
 		canonicalSourceURL,
 		terraformSource.DownloadDir)
 
-	if err := getter.GetAny(terraformSource.DownloadDir, terraformSource.CanonicalSourceURL.String(), updateGetters(terragruntOptions, terragruntConfig)); err != nil {
+	if err := getter.GetAny(terraformSource.DownloadDir, terraformSource.CanonicalSourceURL.String(), UpdateGetters(terragruntOptions, terragruntConfig)); err != nil {
 		return errors.New(err)
 	}
 

cli/commands/terraform/download_source_test.go

@@ -24,6 +24,7 @@ import (
 	"github.com/gruntwork-io/terragrunt/config"
 	"github.com/gruntwork-io/terragrunt/options"
 	"github.com/gruntwork-io/terragrunt/util"
+	"github.com/hashicorp/go-getter"
 )
 
 func TestAlreadyHaveLatestCodeLocalFilePathWithNoModifiedFiles(t *testing.T) {
@@ -502,3 +503,57 @@ func copyFolder(t *testing.T, src string, dest string) {
 	err := util.CopyFolderContents(logger, filepath.FromSlash(src), filepath.FromSlash(dest), ".terragrunt-test", nil, nil)
 	require.NoError(t, err)
 }
+
+// TestUpdateGettersExcludeFromCopy verifies the correct behavior of updateGetters with ExcludeFromCopy configuration
+func TestUpdateGettersExcludeFromCopy(t *testing.T) {
+	t.Parallel()
+
+	testCases := []struct {
+		name                 string
+		terragruntConfig     *config.TerragruntConfig
+		expectedExcludeFiles []string
+	}{
+		{
+			name: "Nil ExcludeFromCopy",
+			terragruntConfig: &config.TerragruntConfig{
+				Terraform: &config.TerraformConfig{
+					ExcludeFromCopy: nil,
+				},
+			},
+			expectedExcludeFiles: nil,
+		},
+		{
+			name: "Non-Nil ExcludeFromCopy",
+			terragruntConfig: &config.TerragruntConfig{
+				Terraform: &config.TerraformConfig{
+					ExcludeFromCopy: &[]string{"*.tfstate", "excluded_dir/"},
+				},
+			},
+			expectedExcludeFiles: []string{"*.tfstate", "excluded_dir/"},
+		},
+	}
+
+	for _, tc := range testCases {
+		t.Run(tc.name, func(t *testing.T) {
+			t.Parallel()
+
+			terragruntOptions, err := options.NewTerragruntOptionsForTest("./test")
+			require.NoError(t, err)
+
+			client := &getter.Client{}
+
+			// Call updateGetters
+			updateGettersFunc := terraform.UpdateGetters(terragruntOptions, tc.terragruntConfig)
+			err = updateGettersFunc(client)
+			require.NoError(t, err)
+
+			// Find the file getter
+			fileGetter, ok := client.Getters["file"].(*terraform.FileCopyGetter)
+			require.True(t, ok, "File getter should be of type FileCopyGetter")
+
+			// Verify ExcludeFromCopy
+			assert.Equal(t, tc.expectedExcludeFiles, fileGetter.ExcludeFromCopy,
+				"ExcludeFromCopy should match expected value")
+		})
+	}
+}