RUST-847 Redact Credential Debug output (#366)

Author: patrickfreed

src/client/auth/mod.rs

@@ -10,7 +10,7 @@ mod scram;
 mod test;
 mod x509;
 
-use std::{borrow::Cow, str::FromStr};
+use std::{borrow::Cow, fmt::Debug, str::FromStr};
 
 use hmac::{Mac, NewMac};
 use rand::Rng;
@@ -324,7 +324,7 @@ impl FromStr for AuthMechanism {
 ///
 /// Some fields (mechanism and source) may be omitted and will either be negotiated or assigned a
 /// default value, depending on the values of other fields in the credential.
-#[derive(Clone, Debug, Default, Deserialize, TypedBuilder, PartialEq)]
+#[derive(Clone, Default, Deserialize, TypedBuilder, PartialEq)]
 #[builder(field_defaults(default, setter(strip_option)))]
 #[non_exhaustive]
 pub struct Credential {
@@ -433,6 +433,14 @@ impl Credential {
     }
 }
 
+impl Debug for Credential {
+    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
+        f.debug_tuple("Credential")
+            .field(&"REDACTED".to_string())
+            .finish()
+    }
+}
+
 /// Contains the first client message sent as part of the authentication handshake.
 pub(crate) enum ClientFirst {
     Scram(ScramVersion, scram::ClientFirst),