warn if a catchall config option (unknown config option) exists

a longer way of saying: warn if a config key is unknown

Signed-off-by: strawberry <strawberry@puppygock.gay>

src/config/mod.rs

@@ -11,7 +11,7 @@ use itertools::Itertools;
 use regex::RegexSet;
 use ruma::{OwnedServerName, RoomVersionId};
 use serde::{de::IgnoredAny, Deserialize};
-use tracing::{error, warn};
+use tracing::{debug, error, warn};
 
 mod proxy;
 
@@ -157,6 +157,7 @@ const DEPRECATED_KEYS: &[&str] = &["cache_capacity"];
 impl Config {
     /// Iterates over all the keys in the config file and warns if there is a deprecated key specified
     pub fn warn_deprecated(&self) {
+        debug!("Checking for deprecated config keys");
         let mut was_deprecated = false;
         for key in self
             .catchall
@@ -172,6 +173,14 @@ impl Config {
         }
     }
 
+    /// iterates over all the catchall keys (unknown config options) and warns if there are any.
+    pub fn warn_unknown_key(&self) {
+        debug!("Checking for unknown config keys");
+        for key in self.catchall.keys() {
+            warn!("Config parameter \"{}\" is unknown to conduwuit.", key);
+        }
+    }
+
     /// Checks the presence of the `address` and `unix_socket_path` keys in the raw_config, exiting the process if both keys were detected.
     pub fn is_dual_listening(&self, raw_config: Figment) -> bool {
         let check_address = raw_config.find_value("address");

src/main.rs

@@ -136,6 +136,9 @@ async fn main() {
     maximize_fd_limit().expect("Unable to increase maximum soft and hard file descriptor limit");
 
     config.warn_deprecated();
+    config.warn_unknown_key();
+
+    // don't start if we're listening on both UNIX sockets and TCP at same time
     if config.is_dual_listening(raw_config) {
         return;
     };