feat(collection): allow LabeledSpan in label collections

To allow customization of the text for each label in a collection, add
support for using LabeledSpan in collections instead of just regular
spans

README.md

@@ -697,6 +697,32 @@ let report: miette::Report = MyError {
 println!("{:?}", report.with_source_code("About something or another or yet another ...".to_string()));
 ```
 
+A collection can also be of `LabeledSpan` if you want to have different text
+for different labels. Labels with no text will use the one from the `label`
+attribute
+
+```rust
+#[derive(Debug, Diagnostic, Error)]
+#[error("oops!")]
+struct MyError {
+    #[label("main issue")]
+    primary_span: SourceSpan,
+
+    #[label(collection, "related to this")]
+    other_spans: Vec<LabeledSpan>, // LabeledSpan
+}
+
+let report: miette::Report = MyError {
+    primary_span: (6, 9).into(),
+    other_spans: vec![
+        LabeledSpan::new(None, 19, 7), // Use default text `related to this`
+        LabeledSpan::new(Some("and also this".to_string()), 30, 11), // Use specific text
+    ],
+}.into();
+
+println!("{:?}", report.with_source_code("About something or another or yet another ...".to_string()));
+```
+
 ### MSRV
 
 This crate requires rustc 1.70.0 or later.

miette-derive/src/label.rs

@@ -212,15 +212,17 @@ impl Labels {
             };
             Some(quote! {
                 let display = #display;
-                #labels_gen_var.extend(
-                    self.#span.iter().map(|label| {
-                        miette::macro_helpers::OptionalWrapper::<#ty>::new().to_option(label)
-                            .map(|span| miette::LabeledSpan::new_with_span(
-                                #display,
-                                span.clone(),
-                            ))
-                    })
-                );
+                #labels_gen_var.extend(self.#span.iter().map(|label| {
+                    miette::macro_helpers::OptionalWrapper::<#ty>::new().to_option(label)
+                        .map(|span| {
+                            use miette::macro_helpers::{ToLabelSpanWrapper,ToLabeledSpan};
+                            let mut labeled_span = ToLabelSpanWrapper::to_labeled_span(span.clone());
+                            if #display.is_some() && labeled_span.label().is_none() {
+                                labeled_span.set_label(#display)
+                            }
+                            labeled_span
+                        })
+                }));
             })
         });
 
@@ -299,15 +301,17 @@ impl Labels {
                         };
                         Some(quote! {
                             let display = #display;
-                            #labels_gen_var.extend(
-                                #field.iter().map(|label| {
-                                    miette::macro_helpers::OptionalWrapper::<#ty>::new().to_option(label)
-                                                                .map(|span| miette::LabeledSpan::new_with_span(
-                                                                    #display,
-                                                                    span.clone(),
-                                                                ))
-                                })
-                            );
+                            #labels_gen_var.extend(#field.iter().map(|label| {
+                                miette::macro_helpers::OptionalWrapper::<#ty>::new().to_option(label)
+                                    .map(|span| {
+                                        use miette::macro_helpers::{ToLabelSpanWrapper,ToLabeledSpan};
+                                        let mut labeled_span = ToLabelSpanWrapper::to_labeled_span(span.clone());
+                                        if #display.is_some() && labeled_span.label().is_none() {
+                                            labeled_span.set_label(#display)
+                                        }
+                                        labeled_span
+                                    })
+                            }));
                         })
                     });
                     let variant_name = ident.clone();

src/macro_helpers.rs

@@ -1,3 +1,5 @@
+use crate::protocol::{LabeledSpan, SourceSpan};
+
 // Huge thanks to @jam1gamer for this hack:
 // https://twitter.com/jam1garner/status/1515887996444323840
 
@@ -36,3 +38,24 @@ impl<T> ToOption for &OptionalWrapper<T> {
         Some(value)
     }
 }
+
+#[doc(hidden)]
+#[derive(Debug)]
+pub struct ToLabelSpanWrapper {}
+pub trait ToLabeledSpan<T> {
+    #[doc(hidden)]
+    fn to_labeled_span(span: T) -> LabeledSpan;
+}
+impl ToLabeledSpan<LabeledSpan> for ToLabelSpanWrapper {
+    fn to_labeled_span(span: LabeledSpan) -> LabeledSpan {
+        span
+    }
+}
+impl<T> ToLabeledSpan<T> for ToLabelSpanWrapper
+where
+    T: Into<SourceSpan>,
+{
+    fn to_labeled_span(span: T) -> LabeledSpan {
+        LabeledSpan::new_with_span(None, span.into())
+    }
+}

src/protocol.rs

@@ -293,6 +293,11 @@ impl LabeledSpan {
         }
     }
 
+    /// Change the text of the label
+    pub fn set_label(&mut self, label: Option<String>) {
+        self.label = label;
+    }
+
     /// Makes a new label at specified span
     ///
     /// # Examples

tests/test_derive_collection.rs

@@ -195,6 +195,76 @@ fn attr_collection_of_range() {
     assert_eq!(err_span, expectation);
 }
 
+#[test]
+fn attr_collection_of_labeled_span_in_struct() {
+    #[derive(Debug, Diagnostic, Error)]
+    #[error("oops!")]
+    struct MyBad {
+        #[source_code]
+        src: NamedSource<String>,
+        #[label("this bit here")]
+        highlight: SourceSpan,
+        #[label(collection, "then there")]
+        highlight2: Vec<LabeledSpan>,
+    }
+
+    let src = "source\n  text\n    here".to_string();
+    let err = MyBad {
+        src: NamedSource::new("bad_file.rs", src),
+        highlight: (9, 4).into(),
+        highlight2: vec![
+            LabeledSpan::new_with_span(Some("continuing here".to_string()), (1, 2)),
+            LabeledSpan::new_with_span(None, (3, 4)),
+        ],
+    };
+    let mut label_iter = err.labels().unwrap();
+    let err_span = label_iter.next().unwrap();
+    let expectation = LabeledSpan::new(Some("this bit here".into()), 9usize, 4usize);
+    assert_eq!(err_span, expectation);
+    let err_span = label_iter.next().unwrap();
+    let expectation = LabeledSpan::new(Some("continuing here".into()), 1usize, 2usize);
+    assert_eq!(err_span, expectation);
+    let err_span = label_iter.next().unwrap();
+    let expectation = LabeledSpan::new(Some("then there".into()), 3usize, 4usize);
+    assert_eq!(err_span, expectation);
+}
+
+#[test]
+fn attr_collection_of_labeled_span_in_enum() {
+    #[derive(Debug, Diagnostic, Error)]
+    #[error("oops!")]
+    enum MyBad {
+        Only {
+            #[source_code]
+            src: NamedSource<String>,
+            #[label("this bit here")]
+            highlight: SourceSpan,
+            #[label(collection, "then there")]
+            highlight2: Vec<LabeledSpan>,
+        },
+    }
+
+    let src = "source\n  text\n    here".to_string();
+    let err = MyBad::Only {
+        src: NamedSource::new("bad_file.rs", src),
+        highlight: (9, 4).into(),
+        highlight2: vec![
+            LabeledSpan::new_with_span(Some("continuing here".to_string()), (1, 2)),
+            LabeledSpan::new_with_span(None, (3, 4)),
+        ],
+    };
+    let mut label_iter = err.labels().unwrap();
+    let err_span = label_iter.next().unwrap();
+    let expectation = LabeledSpan::new(Some("this bit here".into()), 9usize, 4usize);
+    assert_eq!(err_span, expectation);
+    let err_span = label_iter.next().unwrap();
+    let expectation = LabeledSpan::new(Some("continuing here".into()), 1usize, 2usize);
+    assert_eq!(err_span, expectation);
+    let err_span = label_iter.next().unwrap();
+    let expectation = LabeledSpan::new(Some("then there".into()), 3usize, 4usize);
+    assert_eq!(err_span, expectation);
+}
+
 #[test]
 fn attr_collection_multi() {
     #[derive(Debug, Diagnostic, Error)]