Tidy up error implementations

graphql_client_cli/src/error.rs

@@ -1,5 +1,3 @@
-use std::fmt::{Debug, Display};
-
 pub struct Error {
     source: Option<Box<dyn std::error::Error + Send + Sync + 'static>>,
     message: Option<String>,
@@ -28,25 +26,16 @@ impl Error {
 }
 
 // This is the impl that shows up when the error bubbles up to `main()`.
-impl Debug for Error {
+impl std::fmt::Debug for Error {
     fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
-        if let Some(msg) = &self.message {
-            f.write_str(msg)?;
-            f.write_str("\n")?;
-        }
-
-        if self.source.is_some() && self.message.is_some() {
-            f.write_str("Cause: ")?;
+        match (&self.message, &self.source) {
+            (Some(msg), Some(source)) => {
+                write!(f, "{msg}\nCause: {source}\nLocation: {}", self.location)
+            }
+            (Some(msg), None) => write!(f, "{msg}\nLocation: {}", self.location),
+            (None, Some(source)) => write!(f, "{source}\nLocation: {}", self.location),
+            (None, None) => write!(f, "\nLocation: {}", self.location),
         }
-
-        if let Some(source) = self.source.as_ref() {
-            Display::fmt(source, f)?;
-        }
-
-        f.write_str("\nLocation: ")?;
-        Display::fmt(self.location, f)?;
-
-        Ok(())
     }
 }
 

graphql_client_codegen/Cargo.toml

@@ -17,3 +17,4 @@ quote = "^1.0"
 serde_json = "1.0"
 serde = { version = "^1.0", features = ["derive"] }
 syn = "^1.0"
+thiserror = "2.0.11"

graphql_client_codegen/src/generated_module.rs

@@ -6,23 +6,13 @@ use crate::{
 use heck::*;
 use proc_macro2::{Ident, Span, TokenStream};
 use quote::quote;
-use std::{error::Error, fmt::Display};
 
-#[derive(Debug)]
+#[derive(Debug, thiserror::Error)]
+#[error("Could not find an operation named {operation_name} in the query document.")]
 struct OperationNotFound {
     operation_name: String,
 }
 
-impl Display for OperationNotFound {
-    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
-        f.write_str("Could not find an operation named ")?;
-        f.write_str(&self.operation_name)?;
-        f.write_str(" in the query document.")
-    }
-}
-
-impl Error for OperationNotFound {}
-
 /// This struct contains the parameters necessary to generate code for a given operation.
 pub(crate) struct GeneratedModule<'a> {
     pub operation: &'a str,

graphql_client_codegen/src/lib.rs

@@ -28,19 +28,12 @@ mod tests;
 
 pub use crate::codegen_options::{CodegenMode, GraphQLClientCodegenOptions};
 
-use std::{collections::BTreeMap, fmt::Display, io};
+use std::{collections::BTreeMap, io};
 
-#[derive(Debug)]
+#[derive(Debug, thiserror::Error)]
+#[error("{0}")]
 struct GeneralError(String);
 
-impl Display for GeneralError {
-    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
-        f.write_str(&self.0)
-    }
-}
-
-impl std::error::Error for GeneralError {}
-
 type BoxError = Box<dyn std::error::Error + Send + Sync + 'static>;
 type CacheMap<T> = std::sync::Mutex<BTreeMap<std::path::PathBuf, T>>;
 type QueryDocument = graphql_parser::query::Document<'static, String>;
@@ -169,34 +162,20 @@ fn generate_module_token_stream_inner(
     Ok(modules)
 }
 
-#[derive(Debug)]
+#[derive(Debug, thiserror::Error)]
 enum ReadFileError {
-    FileNotFound { path: String, io_error: io::Error },
-    ReadError { path: String, io_error: io::Error },
-}
-
-impl Display for ReadFileError {
-    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
-        match self {
-            ReadFileError::FileNotFound { path, .. } => {
-                write!(f, "Could not find file with path: {}\n
-                Hint: file paths in the GraphQLQuery attribute are relative to the project root (location of the Cargo.toml). Example: query_path = \"src/my_query.graphql\".", path)
-            }
-            ReadFileError::ReadError { path, .. } => {
-                f.write_str("Error reading file at: ")?;
-                f.write_str(path)
-            }
-        }
-    }
-}
-
-impl std::error::Error for ReadFileError {
-    fn source(&self) -> Option<&(dyn std::error::Error + 'static)> {
-        match self {
-            ReadFileError::FileNotFound { io_error, .. }
-            | ReadFileError::ReadError { io_error, .. } => Some(io_error),
-        }
-    }
+    #[error("Could not find file with path: {path}\nHint: file paths in the GraphQLQuery attribute are relative to the project root (location of the Cargo.toml). Example: query_path = \"src/my_query.graphql\".")]
+    FileNotFound {
+        path: String,
+        #[source]
+        io_error: io::Error,
+    },
+    #[error("Error reading file at: {path}")]
+    ReadError {
+        path: String,
+        #[source]
+        io_error: io::Error,
+    },
 }
 
 fn read_file(path: &std::path::Path) -> Result<String, ReadFileError> {

graphql_client_codegen/src/query.rs

@@ -18,24 +18,14 @@ use crate::{
         StoredInputType, StoredScalar, TypeId, UnionId,
     },
 };
-use std::{
-    collections::{BTreeMap, BTreeSet},
-    fmt::Display,
-};
+use std::collections::{BTreeMap, BTreeSet};
 
-#[derive(Debug)]
+#[derive(Debug, thiserror::Error)]
+#[error("{message}")]
 pub(crate) struct QueryValidationError {
     message: String,
 }
 
-impl Display for QueryValidationError {
-    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
-        f.write_str(&self.message)
-    }
-}
-
-impl std::error::Error for QueryValidationError {}
-
 impl QueryValidationError {
     pub(crate) fn new(message: String) -> Self {
         QueryValidationError { message }