Merge pull request #241 from teloxide/download_error_and_from

Implement `From<_> for RequestError` for more types

CHANGELOG.md

@@ -7,6 +7,12 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 ## unreleased
 
+### Added
+
+- `From<ApiError>`, `From<DownloadError>` and `From<std::io::Error>` impls for `RequestError` ([#241][pr241])
+
+[pr241]: https://github.com/teloxide/teloxide-core/pull/241
+
 ## 0.7.0 - 2022-07-19
 
 ### Added
@@ -451,7 +457,7 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 ### Changed
 
- - `NonStrictVec` -> `SemiparsedVec`.
+- `NonStrictVec` -> `SemiparsedVec`.
 
 ## 0.1.1 - 2020-02-17
 
@@ -523,8 +529,7 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
   - Make `net` module public
   - Move `Bot::download_file{,_stream}` methods to a new `Download` trait
     - Impl `Download` for all bot adaptors & the `Bot` itself
-  - Change return type of `download_file_stream` — return `Stream<Result<Bytes>>``,
-    instead of `Future<Result<Stream<Result<Bytes>>>>``
+  - Change return type of `download_file_stream` — return ` Stream<Result<Bytes>>``, instead of  `Future<Result<Stream<Result<Bytes>>>>``
   - Add `api_url` param to standalone versions of `download_file{,_stream}`
   - Make `net::{TELEGRAM_API_URL, download_file{,_stream}}` pub
 - Refactor `Bot` ([#29][pr29]):
@@ -565,7 +570,5 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 [pr4]: https://github.com/teloxide/teloxide-core/pull/4
 [pr44]: https://github.com/teloxide/teloxide-core/pull/44
-  
-
 [`teloxide`]: https://github.com/teloxide/teloxide
-[`CHANGELOG.md`]: https://github.com/teloxide/teloxide/blob/master/CHANGELOG.md
+[`changelog.md`]: https://github.com/teloxide/teloxide/blob/master/CHANGELOG.md

src/errors.rs

@@ -12,7 +12,7 @@ use crate::types::ResponseParameters;
 pub enum RequestError {
     /// A Telegram API error.
     #[error("A Telegram's error: {0}")]
-    Api(#[source] ApiError),
+    Api(#[from] ApiError),
 
     /// The group has been migrated to a supergroup with the specified
     /// identifier.
@@ -26,7 +26,7 @@ pub enum RequestError {
 
     /// Network error while sending a request to Telegram.
     #[error("A network error: {0}")]
-    // NOTE: this variant must not be created by anything except the From impl
+    // NOTE: this variant must not be created by anything except the explicit From impl
     Network(#[source] reqwest::Error),
 
     /// Error while parsing a response from Telegram.
@@ -45,7 +45,7 @@ pub enum RequestError {
 
     /// Occurs when trying to send a file to Telegram.
     #[error("An I/O error: {0}")]
-    Io(#[source] io::Error),
+    Io(#[from] io::Error),
 }
 
 /// An error caused by downloading a file.
@@ -53,7 +53,7 @@ pub enum RequestError {
 pub enum DownloadError {
     /// A network error while downloading a file from Telegram.
     #[error("A network error: {0}")]
-    // NOTE: this variant must not be created by anything except the From impl
+    // NOTE: this variant must not be created by anything except the explicit From impl
     Network(#[source] reqwest::Error),
 
     /// An I/O error while writing a file to destination.
@@ -762,6 +762,32 @@ pub enum ApiError {
     Unknown(String),
 }
 
+/// This impl allows to use `?` to propagate [`DownloadError`]s in function
+/// returning [`RequestError`]s. For example:
+///
+/// ```rust
+/// # use teloxide_core::errors::{DownloadError, RequestError};
+///
+/// async fn handler() -> Result<(), RequestError> {
+///     download_file().await?; // `?` just works
+///
+///     Ok(())
+/// }
+///
+/// async fn download_file() -> Result<(), DownloadError> {
+///     /* download file here */
+///     Ok(())
+/// }
+/// ```
+impl From<DownloadError> for RequestError {
+    fn from(download_err: DownloadError) -> Self {
+        match download_err {
+            DownloadError::Network(err) => RequestError::Network(err),
+            DownloadError::Io(err) => RequestError::Io(err),
+        }
+    }
+}
+
 impl From<reqwest::Error> for DownloadError {
     fn from(error: reqwest::Error) -> Self {
         DownloadError::Network(hide_token(error))