Remove source from default Display implementation

Closes #356
shepmaster · Nov 28, 2023 · 5987482 · 5987482
1 parent e4c84fb
commit 5987482
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Showing 9 changed files with 24 additions and 29 deletions.
diff --git a/README.md b/README.md
@@ -15,10 +15,10 @@ use std::{fs, io, path::PathBuf};
 
 #[derive(Debug, Snafu)]
 enum Error {
-    #[snafu(display("Unable to read configuration from {}: {}", path.display(), source))]
+    #[snafu(display("Unable to read configuration from {}", path.display()))]
     ReadConfiguration { source: io::Error, path: PathBuf },
 
-    #[snafu(display("Unable to write result to {}: {}", path.display(), source))]
+    #[snafu(display("Unable to write result to {}", path.display()))]
     WriteResult { source: io::Error, path: PathBuf },
 }
 

diff --git a/snafu-derive/src/shared.rs b/snafu-derive/src/shared.rs
@@ -545,23 +545,19 @@ pub mod display {
             let mut shorthand_names = &BTreeSet::new();
             let mut assigned_names = &BTreeSet::new();
 
-            let format = match (display_format, doc_comment, source_field) {
-                (Some(v), _, _) => {
+            let format = match (display_format, doc_comment) {
+                (Some(v), _) => {
                     let exprs = &v.exprs;
                     shorthand_names = &v.shorthand_names;
                     assigned_names = &v.assigned_names;
                     quote! { #(#exprs),* }
                 }
-                (_, Some(d), _) => {
+                (_, Some(d)) => {
                     let content = &d.content;
                     shorthand_names = &d.shorthand_names;
                     quote! { #content }
                 }
-                (_, _, Some(f)) => {
-                    let field_name = &f.name;
-                    quote! { concat!(stringify!(#default_name), ": {}"), #field_name }
-                }
-                _ => quote! { stringify!(#default_name)},
+                _ => quote! { stringify!(#default_name) },
             };
 
             let field_names = super::AllFieldNames(field_container).field_names();

diff --git a/src/Snafu.md b/src/Snafu.md
@@ -32,17 +32,17 @@ it is valid. Detailed information on each attribute is below.
 
 ### Enum variant or struct
 
-| Option (inside `#[snafu(...)]`) | Description                                                                                                                                                                                     |
-|---------------------------------|-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
-| `display("{field:?}: {}", foo)` | Sets the display implementation for this error variant using `format_args!` syntax. If this is omitted, the default is `"VariantName: {source}"` if there is a source or `"VariantName"` if not |
-| `context(false)`                | Skips creation of the context selector, implements `From` for the mandatory source error                                                                                                        |
-| `context(suffix(N))`            | Changes the suffix of the generated context selector to `N`                                                                                                                                     |
-| `context(suffix(false))`        | No suffix for the generated context selector                                                                                                                                                    |
-| `transparent`                   | Delegates `Display` and `Error::source` to this error's source, implies `context(false)`                                                                                                        |
-| `visibility(v)`                 | Sets the visibility of the generated context selector to `v` (e.g. `pub`)                                                                                                                       |
-| `visibility`                    | Resets visibility back to private                                                                                                                                                               |
-| `provide(flags, type => expr)`  | Provides the type using the `expr` with the optional flags                                                                                                                                      |
-| `whatever`                      | Stringly-typed error. Message field must be called `message`. Source optional, but if present must be of a specific [format](#controlling-stringly-typed-errors)                                |
+| Option (inside `#[snafu(...)]`) | Description                                                                                                                                                      |
+|---------------------------------|------------------------------------------------------------------------------------------------------------------------------------------------------------------|
+| `display("{field:?}: {}", foo)` | Sets the display implementation for this error variant using `format_args!` syntax. If this is omitted, the default is `"VariantName"                            |
+| `context(false)`                | Skips creation of the context selector, implements `From` for the mandatory source error                                                                         |
+| `context(suffix(N))`            | Changes the suffix of the generated context selector to `N`                                                                                                      |
+| `context(suffix(false))`        | No suffix for the generated context selector                                                                                                                     |
+| `transparent`                   | Delegates `Display` and `Error::source` to this error's source, implies `context(false)`                                                                         |
+| `visibility(v)`                 | Sets the visibility of the generated context selector to `v` (e.g. `pub`)                                                                                        |
+| `visibility`                    | Resets visibility back to private                                                                                                                                |
+| `provide(flags, type => expr)`  | Provides the type using the `expr` with the optional flags                                                                                                       |
+| `whatever`                      | Stringly-typed error. Message field must be called `message`. Source optional, but if present must be of a specific [format](#controlling-stringly-typed-errors) |
 
 ### Context fields
 

diff --git a/src/guide/comparison/failure.md b/src/guide/comparison/failure.md
@@ -76,13 +76,13 @@ use std::num::ParseIntError;
 
 #[derive(Debug, Snafu)]
 enum Error {
-    #[snafu(display(r#"Could not parse the area code from "{value}": {source}"#))]
+    #[snafu(display(r#"Could not parse the area code from "{value}""#))]
     AreaCodeInvalid {
         value: String,
         source: ParseIntError,
     },
 
-    #[snafu(display(r#"Could not parse the phone exchange from "{value}": {source}"#))]
+    #[snafu(display(r#"Could not parse the phone exchange from "{value}""#))]
     PhoneExchangeInvalid {
         value: String,
         source: ParseIntError,

diff --git a/src/guide/troubleshooting/missing_field_source.md b/src/guide/troubleshooting/missing_field_source.md
@@ -14,7 +14,7 @@ use std::io;
 #[derive(Debug, Snafu)]
 #[snafu(visibility(pub(crate)))]
 pub enum ProjectError {
-    #[snafu(display("Unable to read configuration from {path}: {source}"))]
+    #[snafu(display("Unable to read configuration from {path}"))]
     IOConfigError {
         path: &'static str,
         source: io::Error,

diff --git a/src/guide/what_code_is_generated.md b/src/guide/what_code_is_generated.md
@@ -156,8 +156,7 @@ impl std::fmt::Display for Error {
 ```
 
 If no display format is specified, the variant's name will be used
-by default. If the field is an underlying error, that error's
-`Display` implementation will also be included.
+by default.
 
 #### `ErrorCompat`
 

diff --git a/tests/basic.rs b/tests/basic.rs
@@ -6,7 +6,7 @@ use std::{
 
 #[derive(Debug, Snafu)]
 enum Error {
-    #[snafu(display("Could not open config file at {}: {}", filename.display(), source))]
+    #[snafu(display("Could not open config file at {}", filename.display()))]
     OpenConfig {
         filename: PathBuf,
         source: io::Error,

diff --git a/tests/default_error_display.rs b/tests/default_error_display.rs
@@ -17,5 +17,5 @@ fn default_error_display() {
         .fail::<()>()
         .context(NoDisplaySnafu)
         .unwrap_err();
-    assert_eq!(format!("{}", err), "NoDisplay: inner error",);
+    assert_eq!(err.to_string(), "NoDisplay");
 }
diff --git a/tests/transparent.rs b/tests/transparent.rs
@@ -48,7 +48,7 @@ fn implements_error() {
 fn implements_display() {
     let error = example().unwrap_err();
     // no `Beta: ` prefix
-    assert_eq!(error.to_string(), "BetaError: AlphaError");
+    assert_eq!(error.to_string(), "BetaError");
 }
 
 mod with_backtraces {