Don't update non editable fields from the API

src/api/admin.rs

@@ -747,7 +747,7 @@ fn get_diagnostics_http(code: u16, _token: AdminToken) -> EmptyResult {
 #[post("/config", data = "<data>")]
 fn post_config(data: Json<ConfigBuilder>, _token: AdminToken) -> EmptyResult {
     let data: ConfigBuilder = data.into_inner();
-    if let Err(e) = CONFIG.update_config(data) {
+    if let Err(e) = CONFIG.update_config(data, true) {
         err!(format!("Unable to save config: {e:?}"))
     }
     Ok(())

src/config.rs

@@ -114,6 +114,14 @@ macro_rules! make_config {
                 serde_json::from_str(&config_str).map_err(Into::into)
             }
 
+            fn clear_non_editable(&mut self) {
+                $($(
+                    if !$editable {
+                        self.$name = None;
+                    }
+                )+)+
+            }
+
             /// Merges the values of both builders into a new builder.
             /// If both have the same element, `other` wins.
             fn merge(&self, other: &Self, show_overrides: bool, overrides: &mut Vec<String>) -> Self {
@@ -677,7 +685,7 @@ make_config! {
         /// Use Sendmail |> Whether to send mail via the `sendmail` command
         use_sendmail:                  bool,   true,   def,     false;
         /// Sendmail Command |> Which sendmail command to use. The one found in the $PATH is used if not specified.
-        sendmail_command:              String, true,   option;
+        sendmail_command:              String, false,   option;
         /// Host
         smtp_host:                     String, true,   option;
         /// DEPRECATED smtp_ssl |> DEPRECATED - Please use SMTP_SECURITY
@@ -1146,12 +1154,17 @@ impl Config {
         })
     }
 
-    pub fn update_config(&self, other: ConfigBuilder) -> Result<(), Error> {
+    pub fn update_config(&self, other: ConfigBuilder, ignore_non_editable: bool) -> Result<(), Error> {
         // Remove default values
         //let builder = other.remove(&self.inner.read().unwrap()._env);
 
         // TODO: Remove values that are defaults, above only checks those set by env and not the defaults
-        let builder = other;
+        let mut builder = other;
+
+        // Remove values that are not editable
+        if ignore_non_editable {
+            builder.clear_non_editable();
+        }
 
         // Serialize now before we consume the builder
         let config_str = serde_json::to_string_pretty(&builder)?;
@@ -1186,7 +1199,7 @@ impl Config {
             let mut _overrides = Vec::new();
             usr.merge(&other, false, &mut _overrides)
         };
-        self.update_config(builder)
+        self.update_config(builder, false)
     }
 
     /// Tests whether an email's domain is allowed. A domain is allowed if it