feat(transport-smtp): Allow building without tls support

.github/workflows/test.yml

@@ -29,6 +29,11 @@ jobs:
       - uses: actions-rs/cargo@v1
         with:
           command: test
+      - run: rm target/debug/deps/liblettre-*
+      - uses: actions-rs/cargo@v1
+        with:
+          command: test
+          args: --no-default-features --features=builder,smtp-transport,file-transport,sendmail-transport
 
   check:
     name: Check

Cargo.toml

@@ -51,7 +51,7 @@ name = "transport_smtp"
 
 [features]
 builder = ["mime", "base64", "hyperx", "textnonce", "quoted_printable"]
-default = ["file-transport", "smtp-transport", "hostname", "sendmail-transport", "rustls-tls", "builder", "r2d2"]
+default = ["file-transport", "smtp-transport", "hostname", "sendmail-transport",  "builder", "r2d2"]
 file-transport = ["serde", "serde_json"]
 rustls-tls = ["webpki", "webpki-roots", "rustls"]
 sendmail-transport = []

src/transport/smtp/client/mod.rs

@@ -186,6 +186,7 @@ impl SmtpConnection {
             && self.server_info.supports_feature(Extension::StartTls)
     }
 
+    #[allow(unused_variables)]
     pub fn starttls(
         &mut self,
         tls_parameters: &TlsParameters,

src/transport/smtp/client/net.rs

@@ -114,10 +114,13 @@ impl NetworkStream {
                     tcp_stream,
                 ))))
             }
+            #[cfg(not(any(feature = "native-tls", feature = "rustls")))]
+            Some(_) => panic!("TLS configuration without support"),
             None => Ok(NetworkStream::Tcp(tcp_stream)),
         }
     }
 
+    #[allow(unused_variables, unreachable_code)]
     pub fn upgrade_tls(&mut self, tls_parameters: &TlsParameters) -> Result<(), Error> {
         *self = match *self {
             #[cfg(feature = "native-tls")]
@@ -137,7 +140,11 @@ impl NetworkStream {
                     stream.try_clone().unwrap(),
                 )))
             }
-            NetworkStream::Tls(_) | NetworkStream::Mock(_) => return Ok(()),
+            #[cfg(not(any(feature = "native-tls", feature = "rustls")))]
+            NetworkStream::Tcp(_) => panic!("STARTTLS without TLS support"),
+            #[cfg(any(feature = "native-tls", feature = "rustls"))]
+            NetworkStream::Tls(_) => return Ok(()),
+            NetworkStream::Mock(_) => return Ok(()),
         };
 
         Ok(())
@@ -146,6 +153,7 @@ impl NetworkStream {
     pub fn is_encrypted(&self) -> bool {
         match *self {
             NetworkStream::Tcp(_) | NetworkStream::Mock(_) => false,
+            #[cfg(any(feature = "native-tls", feature = "rustls"))]
             NetworkStream::Tls(_) => true,
         }
     }
@@ -153,6 +161,7 @@ impl NetworkStream {
     pub fn set_read_timeout(&mut self, duration: Option<Duration>) -> io::Result<()> {
         match *self {
             NetworkStream::Tcp(ref mut stream) => stream.set_read_timeout(duration),
+            #[cfg(any(feature = "native-tls", feature = "rustls"))]
             NetworkStream::Tls(ref mut stream) => stream.get_ref().set_read_timeout(duration),
             NetworkStream::Mock(_) => Ok(()),
         }
@@ -162,6 +171,7 @@ impl NetworkStream {
     pub fn set_write_timeout(&mut self, duration: Option<Duration>) -> io::Result<()> {
         match *self {
             NetworkStream::Tcp(ref mut stream) => stream.set_write_timeout(duration),
+            #[cfg(any(feature = "native-tls", feature = "rustls"))]
             NetworkStream::Tls(ref mut stream) => stream.get_ref().set_write_timeout(duration),
             NetworkStream::Mock(_) => Ok(()),
         }

src/transport/smtp/commands.rs

@@ -169,7 +169,6 @@ pub struct Vrfy {
 
 impl Display for Vrfy {
     fn fmt(&self, f: &mut Formatter) -> fmt::Result {
-        #[allow(clippy::write_with_newline)]
         write!(f, "VRFY {}\r\n", self.argument)
     }
 }
@@ -190,7 +189,6 @@ pub struct Expn {
 
 impl Display for Expn {
     fn fmt(&self, f: &mut Formatter) -> fmt::Result {
-        #[allow(clippy::write_with_newline)]
         write!(f, "EXPN {}\r\n", self.argument)
     }
 }

src/transport/smtp/mod.rs

@@ -12,10 +12,12 @@
 //! * STARTTLS ([RFC 2487](http://tools.ietf.org/html/rfc2487))
 //!
 
+#[cfg(any(feature = "native-tls", feature = "rustls"))]
+use crate::transport::smtp::net::TlsParameters;
 use crate::{
     transport::smtp::{
         authentication::{Credentials, Mechanism, DEFAULT_MECHANISMS},
-        client::{net::TlsParameters, SmtpConnection},
+        client::SmtpConnection,
         error::{Error, SmtpResult},
         extension::ClientId,
     },
@@ -61,7 +63,7 @@ const DEFAULT_TLS_MIN_PROTOCOL: Protocol = Protocol::Tlsv12;
 
 /// How to apply TLS to a client connection
 #[derive(Clone)]
-#[allow(missing_debug_implementations)]
+#[allow(missing_debug_implementations, missing_copy_implementations)]
 pub enum Tls {
     /// Insecure connection only (for testing purposes)
     None,
@@ -128,6 +130,7 @@ impl SmtpTransport {
     /// Simple and secure transport, should be used when possible.
     /// Creates an encrypted transport over submissions port, using the provided domain
     /// to validate TLS certificates.
+    #[cfg(any(feature = "native-tls", feature = "rustls"))]
     pub fn relay(relay: &str) -> Result<Self, Error> {
         #[cfg(feature = "native-tls")]
         let mut tls_builder = TlsConnector::builder();
@@ -193,6 +196,7 @@ impl SmtpTransport {
     }
 
     /// Set the TLS settings to use
+    #[cfg(any(feature = "native-tls", feature = "rustls"))]
     pub fn tls(mut self, tls: Tls) -> Self {
         self.tls = tls;
         self
@@ -214,6 +218,7 @@ impl SmtpTransport {
             self.timeout,
             &self.hello_name,
             match self.tls {
+                #[cfg(any(feature = "native-tls", feature = "rustls"))]
                 Tls::Wrapper(ref tls_parameters) => Some(tls_parameters),
                 _ => None,
             },