Add no-self-update config and flag (#388)

config.example.toml

@@ -50,6 +50,9 @@
 # Skip the preamble displayed when topgrade is run
 #display_preamble = false
 
+# Whether to self update (this is ignored if the binary has been built without self update support, available also via setting the environment variable TOPGRADE_NO_SELF_UPGRADE)
+#no_self_update = true
+
 [git]
 #max_concurrency = 5
 # Additional git repositories to pull

src/config.rs

@@ -336,6 +336,7 @@ pub struct ConfigFile {
     vagrant: Option<Vagrant>,
     flatpak: Option<Flatpak>,
     distrobox: Option<Distrobox>,
+    no_self_update: Option<bool>,
 }
 
 fn config_directory(base_dirs: &BaseDirs) -> PathBuf {
@@ -522,6 +523,10 @@ pub struct CommandLineArgs {
     /// Print roff manpage and exit
     #[clap(long, hide = true)]
     pub gen_manpage: bool,
+
+    /// Don't update Topgrade
+    #[clap(long = "no-self-update")]
+    pub no_self_update: bool,
 }
 
 impl CommandLineArgs {
@@ -645,6 +650,11 @@ impl Config {
         enabled_steps
     }
 
+    /// Tell whether we should run a self update.
+    pub fn no_self_update(&self) -> bool {
+        self.opt.no_self_update || self.config_file.no_self_update.unwrap_or(false)
+    }
+
     /// Tell whether we should run in tmux.
     pub fn run_in_tmux(&self) -> bool {
         self.opt.run_in_tmux || self.config_file.run_in_tmux.unwrap_or(false)

src/main.rs

@@ -116,7 +116,9 @@ For more information about this issue see https://askubuntu.com/questions/110969
 
     #[cfg(feature = "self-update")]
     {
-        if !run_type.dry() && env::var("TOPGRADE_NO_SELF_UPGRADE").is_err() {
+        let config_self_upgrade = env::var("TOPGRADE_NO_SELF_UPGRADE").is_err() && !config.no_self_update();
+
+        if !run_type.dry() && config_self_upgrade {
             let result = self_update::self_update();
 
             if let Err(e) = &result {