Fix bug on old terragrunt version on arm64 (M1 darwin) arch

lib/install.go

@@ -140,7 +140,7 @@ func GetRecentVersions() ([]string, error) {
 	return nil, nil
 }
 
-//CreateRecentFile : create a recent file
+// CreateRecentFile : create a recent file
 func CreateRecentFile(requestedVersion string) {
 
 	installLocation = GetInstallLocation()
@@ -168,7 +168,7 @@ func ValidVersionFormat(version string) bool {
 	return semverRegex.MatchString(version)
 }
 
-//Install : Install the provided version in the argument
+// Install : Install the provided version in the argument
 func Install(tgversion string, usrBinPath string, mirrorURL string) string {
 	/* Check to see if user has permission to the default bin location which is  "/usr/local/bin/terragrunt"
 	 * If user does not have permission to default bin location, proceed to create $HOME/bin and install the tgswitch there
@@ -183,6 +183,17 @@ func Install(tgversion string, usrBinPath string, mirrorURL string) string {
 	goarch := runtime.GOARCH
 	goos := runtime.GOOS
 
+	checkDarwinArm64Constraint, err := CheckDarwinArm64VersionConstraint(tgversion, goarch, goos)
+
+	if err != nil {
+		log.Println(err)
+	}
+
+	if checkDarwinArm64Constraint {
+		fmt.Printf("%s satisfies Darwin arm64 constraints for tg version < 0.28.12. Switching arch to amd64 \n", tgversion)
+		goarch = "amd64"
+	}
+
 	/* check if selected version already downloaded */
 	installFileVersionPath := ConvertExecutableExt(filepath.Join(installLocation, installVersion+tgversion))
 	fileExist := CheckFileExist(installLocation + installVersion + tgversion)
@@ -225,7 +236,7 @@ func Install(tgversion string, usrBinPath string, mirrorURL string) string {
 	/* rename unzipped file to terragrunt version name - terraform_x.x.x */
 	RenameFile(downloadedFile, installFileVersionPath)
 
-	err := os.Chmod(installFileVersionPath, 0755)
+	err = os.Chmod(installFileVersionPath, 0755)
 	if err != nil {
 		log.Println(err)
 	}
@@ -244,9 +255,9 @@ func Install(tgversion string, usrBinPath string, mirrorURL string) string {
 	return ""
 }
 
-//InstallableBinLocation : Checks if terragrunt is installable in the location provided by the user.
-//If not, create $HOME/bin. Ask users to add  $HOME/bin to $PATH
-//Return $HOME/bin as install location
+// InstallableBinLocation : Checks if terragrunt is installable in the location provided by the user.
+// If not, create $HOME/bin. Ask users to add  $HOME/bin to $PATH
+// Return $HOME/bin as install location
 func InstallableBinLocation(userBinPath string) string {
 
 	usr, errCurr := user.Current()
@@ -294,7 +305,7 @@ func PrintCreateDirStmt(unableDir string, writable string) {
 	fmt.Printf("RUN `export PATH=$PATH:%s` to append bin to $PATH\n", writable)
 }
 
-//ConvertExecutableExt : convert excutable with local OS extension
+// ConvertExecutableExt : convert excutable with local OS extension
 func ConvertExecutableExt(fpath string) string {
 	switch runtime.GOOS {
 	case "windows":

lib/semver.go

@@ -53,3 +53,12 @@ func SemVerParser(tfconstraint *string, tflist []string) (string, error) {
 func PrintInvalidTFVersion() {
 	fmt.Println("Version does not exist or invalid terraform version format.\n Format should be #.#.# or #.#.#-@# where # are numbers and @ are word characters.\n For example, 0.11.7 and 0.11.9-beta1 are valid versions")
 }
+
+// Function that check constraint for darwin M1. Terragrunt started release arm64 versions for linux and darwin OS from version 0.28.12 included.
+// However, amd64 versions work on darwin arm64. To be tested on linux platforms.
+func CheckDarwinArm64VersionConstraint(tgversion string, goarch string, goos string) (bool, error) {
+	version, err := semver.NewVersion(tgversion)
+	darwinM1constraint, err := semver.NewConstraint("< 0.28.12")
+
+	return darwinM1constraint.Check(version) && goarch == "arm64" && goos == "darwin", err
+}

test-data/test_terragrunt-version_m1/.terragrunt-version

@@ -0,0 +1 @@
+0.26.7

test-data/test_terragrunt_hcl_m1/terragrunt.hcl

@@ -0,0 +1,16 @@
+include {
+  path = "${find_in_parent_folders()}"
+}
+
+terraform {
+  source = "..."
+
+  extra_arguments "variables" {
+    commands = get_terraform_commands_that_need_vars()
+  }
+}
+  inputs = merge(
+    jsondecode(file("${find_in_parent_folders("general.tfvars")}"))
+)
+
+terragrunt_version_constraint=">= 0.28, < 0.28.1"

test-data/test_tgswitchrc_m1/.tgswitchrc

@@ -0,0 +1 @@
+0.28.0

test-data/test_tgswitchtoml_m1/.tgswitch.toml

@@ -0,0 +1,2 @@
+bin = "/usr/local/bin/terragrunt"
+version = "0.26.7"

test-tgswitch.sh

@@ -82,3 +82,12 @@ runtestdir "tgswitchrc" "test_tgswitchrc" "v0.33.0"
 runtestdir ".toml" "test_tgswitchtoml" "v0.34.0"
 runtestenv "env variable" "0.37.1" "v0.37.1"
 runtestarg "passing argument" "0.36.1" "v0.36.1"
+# M1 darwin arm64 test versions < 0.28.12
+runtestdir "terragrunt version" "test_terragrunt-version_m1" "v0.26.7"
+runtestdir "terragrunt hcl" "test_terragrunt_hcl_m1" "v0.28.0"
+runtestdir "tgswitchrc" "test_tgswitchrc_m1" "v0.28.0"
+runtestdir ".toml" "test_tgswitchtoml_m1" "v0.26.7"
+runtestenv "env variable" "0.26.7" "v0.26.7"
+runtestarg "passing argument" "0.26.7" "v0.26.7"
+# Edge case
+runtestarg "passing argument" "0.28.12" "v0.28.12"