Fix unwraps in connection module when probing a loopback port (#954)

* Fix unwraps in connection module when probing a loopback port

* Changelog

* Fix rustfmt check fail

Author: nullstalgia

CHANGELOG.md

@@ -13,6 +13,8 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 ### Fixed
 
+- Fix a crash with Connection module when connecting to a loopback serial port (#954)
+
 ### Removed
 
 ## [4.1.0] - 2025-09-18

espflash/src/connection/mod.rs

@@ -397,31 +397,24 @@ impl Connection {
 
                 let value = match response.len() {
                     10 | 12 => CommandResponseValue::ValueU32(u32::from_le_bytes(
-                        response[4..][..4].try_into().unwrap(),
+                        response[4..][..4].try_into()?,
+                    )),
+                    // MD5 is in ASCII
+                    44 => CommandResponseValue::ValueU128(u128::from_str_radix(
+                        std::str::from_utf8(&response[8..][..32])?,
+                        16,
+                    )?),
+                    // MD5 is BE bytes
+                    26 => CommandResponseValue::ValueU128(u128::from_be_bytes(
+                        response[8..][..16].try_into()?,
                     )),
-                    44 => {
-                        // MD5 is in ASCII
-                        CommandResponseValue::ValueU128(
-                            u128::from_str_radix(
-                                std::str::from_utf8(&response[8..][..32]).unwrap(),
-                                16,
-                            )
-                            .unwrap(),
-                        )
-                    }
-                    26 => {
-                        // MD5 is BE bytes
-                        CommandResponseValue::ValueU128(u128::from_be_bytes(
-                            response[8..][..16].try_into().unwrap(),
-                        ))
-                    }
                     _ => CommandResponseValue::Vector(response.clone()),
                 };
 
                 let header = CommandResponse {
                     resp: response[0],
                     return_op: response[1],
-                    return_length: u16::from_le_bytes(response[2..][..2].try_into().unwrap()),
+                    return_length: u16::from_le_bytes(response[2..][..2].try_into()?),
                     value,
                     error: response[response.len() - status_len + 1],
                     status: response[response.len() - status_len],

espflash/src/error.rs

@@ -2,7 +2,7 @@
 
 #[cfg(feature = "serialport")]
 use std::fmt::{Display, Formatter};
-use std::{array::TryFromSliceError, io};
+use std::{array::TryFromSliceError, io, num::ParseIntError, str::Utf8Error};
 
 use miette::Diagnostic;
 #[cfg(feature = "serialport")]
@@ -294,6 +294,14 @@ pub enum Error {
     #[error(transparent)]
     TryFromSlice(CoreError),
 
+    /// Error while trying to parse int from text
+    #[error(transparent)]
+    ParseIntError(CoreError),
+
+    /// Error while trying to parse UTF-8 from bytes
+    #[error(transparent)]
+    Utf8Error(CoreError),
+
     /// Failed to open file
     #[error("Failed to open file: {0}")]
     FileOpenError(String, #[source] io::Error),
@@ -380,6 +388,18 @@ impl From<TryFromSliceError> for Error {
     }
 }
 
+impl From<ParseIntError> for Error {
+    fn from(err: ParseIntError) -> Self {
+        Self::ParseIntError(Box::new(err))
+    }
+}
+
+impl From<Utf8Error> for Error {
+    fn from(err: Utf8Error) -> Self {
+        Self::Utf8Error(Box::new(err))
+    }
+}
+
 impl From<object::Error> for Error {
     fn from(err: object::Error) -> Self {
         Self::InvalidElf(err.into())

espflash/src/flasher/mod.rs

@@ -1051,8 +1051,8 @@ impl Flasher {
         {
             let metadata = image_format.metadata();
             if metadata.contains_key("app_size") && metadata.contains_key("part_size") {
-                let app_size = metadata["app_size"].parse::<u32>().unwrap();
-                let part_size = metadata["part_size"].parse::<u32>().unwrap();
+                let app_size = metadata["app_size"].parse::<u32>()?;
+                let part_size = metadata["part_size"].parse::<u32>()?;
 
                 crate::cli::display_image_size(app_size, Some(part_size));
             }