better error for image format id parsing

Author: icewind1991

espflash/src/error.rs

@@ -6,7 +6,7 @@ use miette::{Diagnostic, SourceOffset, SourceSpan};
 use slip_codec::Error as SlipError;
 use std::fmt::{Display, Formatter};
 use std::io;
-use strum::AsStaticRef;
+use strum::{AsStaticRef, VariantNames};
 use thiserror::Error;
 
 #[derive(Error, Debug, Diagnostic)]
@@ -51,6 +51,12 @@ pub enum Error {
     #[error(transparent)]
     #[diagnostic(transparent)]
     UnsupportedImageFormat(#[from] UnsupportedImageFormatError),
+    #[error("Unrecognized image format {0}")]
+    #[diagnostic(
+        code(espflash::unknown_format),
+        help("The following image formats are {}", ImageFormatId::VARIANTS.join(", "))
+    )]
+    UnknownImageFormat(String),
 }
 
 #[derive(Error, Debug, Diagnostic)]

espflash/src/image_format/mod.rs

@@ -8,7 +8,9 @@ pub use esp32bootloader::*;
 pub use esp32directboot::*;
 pub use esp8266::*;
 
-use strum_macros::{AsStaticStr, Display, EnumString};
+use crate::error::Error;
+use std::str::FromStr;
+use strum_macros::{AsStaticStr, Display, EnumVariantNames};
 
 const ESP_MAGIC: u8 = 0xE9;
 const WP_PIN_DISABLED: u8 = 0xEE;
@@ -44,10 +46,21 @@ pub trait ImageFormat<'a> {
         'a: 'b;
 }
 
-#[derive(Debug, Copy, Clone, Eq, PartialEq, Display, EnumString, AsStaticStr)]
+#[derive(Debug, Copy, Clone, Eq, PartialEq, Display, AsStaticStr, EnumVariantNames)]
+#[strum(serialize_all = "kebab-case")]
 pub enum ImageFormatId {
-    #[strum(serialize = "bootloader")]
     Bootloader,
-    #[strum(serialize = "direct-boot")]
     DirectBoot,
 }
+
+impl FromStr for ImageFormatId {
+    type Err = Error;
+
+    fn from_str(s: &str) -> Result<Self, Self::Err> {
+        match s {
+            "bootloader" => Ok(Self::Bootloader),
+            "direct-boot" => Ok(Self::DirectBoot),
+            _ => Err(Error::UnknownImageFormat(s.into())),
+        }
+    }
+}

espflash/src/main.rs

@@ -90,11 +90,7 @@ fn main() -> Result<()> {
         let image_format = image_format_string
             .as_deref()
             .map(ImageFormatId::from_str)
-            .transpose()
-            .into_diagnostic()
-            .wrap_err_with(|| {
-                format!("Unrecognized image format {}", image_format_string.unwrap())
-            })?;
+            .transpose()?;
         let partition_table = partition_table_path
             .as_deref()
             .map(|path| {