Defer username default

Author: sfackler

postgres/src/config.rs

@@ -158,12 +158,8 @@ impl Config {
         self
     }
 
-    /// Gets the user to authenticate with.
-    ///
-    /// If no user has been configured with the [`user`](Config::user) method,
-    /// then this defaults to the user executing this process. It always
-    /// returns `Some`.
-    // FIXME remove option
+    /// Gets the user to authenticate with, if one has been configured with
+    /// the `user` method.
     pub fn get_user(&self) -> Option<&str> {
         self.config.get_user()
     }

tokio-postgres/src/config.rs

@@ -190,7 +190,7 @@ pub enum Host {
 /// ```
 #[derive(Clone, PartialEq, Eq)]
 pub struct Config {
-    pub(crate) user: String,
+    pub(crate) user: Option<String>,
     pub(crate) password: Option<Vec<u8>>,
     pub(crate) dbname: Option<String>,
     pub(crate) options: Option<String>,
@@ -219,7 +219,7 @@ impl Config {
     /// Creates a new configuration.
     pub fn new() -> Config {
         Config {
-            user: whoami::username(),
+            user: None,
             password: None,
             dbname: None,
             options: None,
@@ -247,18 +247,14 @@ impl Config {
     ///
     /// Defaults to the user executing this process.
     pub fn user(&mut self, user: &str) -> &mut Config {
-        self.user = user.to_string();
+        self.user = Some(user.to_string());
         self
     }
 
-    /// Gets the user to authenticate with.
-    ///
-    /// If no user has been configured with the [`user`](Config::user) method,
-    /// then this defaults to the user executing this process. It always
-    /// returns `Some`.
-    // FIXME remove option
+    /// Gets the user to authenticate with, if one has been configured with
+    /// the `user` method.
     pub fn get_user(&self) -> Option<&str> {
-        Some(&self.user)
+        self.user.as_deref()
     }
 
     /// Sets the password to authenticate with.

tokio-postgres/src/connect_raw.rs

@@ -96,8 +96,10 @@ where
         delayed: VecDeque::new(),
     };
 
-    startup(&mut stream, config).await?;
-    authenticate(&mut stream, config).await?;
+    let user = config.user.clone().unwrap_or_else(whoami::username);
+
+    startup(&mut stream, config, &user).await?;
+    authenticate(&mut stream, config, &user).await?;
     let (process_id, secret_key, parameters) = read_info(&mut stream).await?;
 
     let (sender, receiver) = mpsc::unbounded();
@@ -107,13 +109,17 @@ where
     Ok((client, connection))
 }
 
-async fn startup<S, T>(stream: &mut StartupStream<S, T>, config: &Config) -> Result<(), Error>
+async fn startup<S, T>(
+    stream: &mut StartupStream<S, T>,
+    config: &Config,
+    user: &str,
+) -> Result<(), Error>
 where
     S: AsyncRead + AsyncWrite + Unpin,
     T: AsyncRead + AsyncWrite + Unpin,
 {
     let mut params = vec![("client_encoding", "UTF8")];
-    params.push(("user", &config.user));
+    params.push(("user", user));
     if let Some(dbname) = &config.dbname {
         params.push(("database", &**dbname));
     }
@@ -133,7 +139,11 @@ where
         .map_err(Error::io)
 }
 
-async fn authenticate<S, T>(stream: &mut StartupStream<S, T>, config: &Config) -> Result<(), Error>
+async fn authenticate<S, T>(
+    stream: &mut StartupStream<S, T>,
+    config: &Config,
+    user: &str,
+) -> Result<(), Error>
 where
     S: AsyncRead + AsyncWrite + Unpin,
     T: TlsStream + Unpin,
@@ -156,7 +166,6 @@ where
         Some(Message::AuthenticationMd5Password(body)) => {
             can_skip_channel_binding(config)?;
 
-            let user = &config.user;
             let pass = config
                 .password
                 .as_ref()