chore: disallow self-install/upgrade (#61)

Author: marwanhawari

constants/constants.go

@@ -45,3 +45,9 @@ var RegexGithubSearch = `(?i)^[A-Za-z0-9\_\.\-\/\:]+$`
 
 // RegexURL is a regular express for valid URLs
 var RegexURL = `(http|ftp|https):\/\/([\w_-]+(?:(?:\.[\w_-]+)+))([\w.,@?^=%&:\/~+#-]*[\w@?^=%&\/~+#-])`
+
+// StewOwner is the username of the stew github repo owner
+var StewOwner = `marwanhawari`
+
+// StewRepo is the name of the stew github repo
+var StewRepo = `stew`

lib/errors.go

@@ -163,10 +163,19 @@ func (e InvalidGithubSearchQueryError) Error() string {
 	return fmt.Sprintf("%v The search query %v contains invalid characters", constants.RedColor("Error:"), constants.RedColor(e.SearchQuery))
 }
 
+// BinaryMismatchError occurs if the downloaded binary hash doesn't match the hash in the lockfile
 type BinaryMismatchError struct {
 	BinaryName string
 }
 
 func (e BinaryMismatchError) Error() string {
 	return fmt.Sprintf("%v The hash for the downloaded binary %v does not match the hash in the lockfile", constants.RedColor("Error:"), constants.RedColor(e.BinaryName))
 }
+
+// SelfInstallError occurs when attempting to install or upgrade stew using stew
+type SelfInstallError struct {
+}
+
+func (e SelfInstallError) Error() string {
+	return fmt.Sprintf("%v Stew cannot self-install/self-upgrade. You should upgrade stew with the original install method, whether it was manually or through a package manager", constants.RedColor("Error:"))
+}

lib/github.go

@@ -56,6 +56,10 @@ func getGithubJSON(owner, repo string) (string, error) {
 
 // NewGithubProject creates a new instance of the GithubProject struct
 func NewGithubProject(owner, repo string) (GithubProject, error) {
+	if owner == constants.StewOwner && repo == constants.StewRepo {
+		return GithubProject{}, SelfInstallError{}
+	}
+
 	ghJSON, err := getGithubJSON(owner, repo)
 	if err != nil {
 		return GithubProject{}, err