Correction of string read

Cargo.toml

@@ -4,8 +4,8 @@ workspace = { members = ["macros"] }
 name = "vaultwarden"
 version = "1.0.0"
 authors = ["Daniel García <dani-garcia@users.noreply.github.com>"]
-edition = "2021"
-rust-version = "1.83.0"
+edition = "2024"
+rust-version = "1.85.0"
 resolver = "2"
 
 repository = "https://github.com/dani-garcia/vaultwarden"

rust-toolchain.toml

@@ -1,4 +1,4 @@
 [toolchain]
-channel = "1.84.1"
+channel = "1.85"
 components = [ "rustfmt", "clippy" ]
 profile = "minimal"

rustfmt.toml

@@ -1,4 +1,4 @@
-edition = "2021"
+edition = "2024"
 max_width = 120
 newline_style = "Unix"
 use_small_heuristics = "Off"

src/mail.rs

@@ -10,7 +10,7 @@ use lettre::{
     Address, AsyncSendmailTransport, AsyncSmtpTransport, AsyncTransport, Tokio1Executor,
 };
 use percent_encoding::{percent_encode, NON_ALPHANUMERIC};
-use std::{env::consts::EXE_SUFFIX, io::Read, str::FromStr};
+use std::{env::consts::EXE_SUFFIX, fs, str::FromStr};
 
 use crate::{
     api::EmptyResult,
@@ -650,14 +650,12 @@ async fn send_email(address: &str, subject: &str, body_html: String, body_text:
                     Some(true) => DkimSigningAlgorithm::Rsa,
                     _ => DkimSigningAlgorithm::Ed25519,
                 };
-                let mut key = String::with_capacity(4096);
-                let sig = match std::fs::File::open(sig) {
-                    Ok(mut f) => {
-                        if let Err(e) = f.read_to_string(&mut key) {
-                            debug!("Cannot read DKIM file. Err is {:?}", e);
+                let sig = match fs::read_to_string(sig) {
+                    Err(e) => {
+                        debug!("Cannot read DKIM file. Err is {:?}", e);
                             None
-                        } else {
-                            key.shrink_to_fit();
+                    },
+                    Ok(key) => {
                             match DkimSigningKey::new(&key, algo) {
                                 Ok(d) => Some(d),
                                 Err(e) => {
@@ -666,11 +664,6 @@ async fn send_email(address: &str, subject: &str, body_html: String, body_text:
                                 }
                             }
                         }
-                    },
-                    Err(e) => {
-                        debug!("Cannot read DKIM file. Err is {:?}", e);
-                        None
-                    }
                 };
                 match (sig, infos.split(':').collect::<Vec<&str>>()) {
                     (Some(sig), split2) if split2.len() == 2 => {