feat(report): add `with_source_code`

Fixes #64

src/eyreish/error.rs

@@ -7,7 +7,8 @@ use std::error::Error as StdError;
 use super::Report;
 use super::ReportHandler;
 use crate::chain::Chain;
-use crate::Diagnostic;
+use crate::eyreish::wrapper::WithSourceCode;
+use crate::{Diagnostic, SourceCode};
 use core::ops::{Deref, DerefMut};
 
 impl Report {
@@ -386,6 +387,15 @@ impl Report {
     pub fn handler_mut(&mut self) -> &mut dyn ReportHandler {
         self.inner.handler.as_mut().unwrap().as_mut()
     }
+
+    /// Provide source code for this error
+    pub fn with_source_code(self, source_code: impl SourceCode + Send + Sync + 'static) -> Report {
+        WithSourceCode {
+            source_code,
+            error: self,
+        }
+        .into()
+    }
 }
 
 impl<E> From<E> for Report

src/eyreish/wrapper.rs

@@ -2,7 +2,7 @@ use core::fmt::{self, Debug, Display};
 
 use std::error::Error as StdError;
 
-use crate::{Diagnostic, LabeledSpan};
+use crate::{Diagnostic, LabeledSpan, Report, SourceCode};
 
 use crate as miette;
 
@@ -117,3 +117,92 @@ impl Display for BoxedError {
 }
 
 impl StdError for BoxedError {}
+
+pub(crate) struct WithSourceCode<E, C> {
+    pub(crate) error: E,
+    pub(crate) source_code: C,
+}
+
+impl<E: Diagnostic, C: SourceCode> Diagnostic for WithSourceCode<E, C> {
+    fn code<'a>(&'a self) -> Option<Box<dyn Display + 'a>> {
+        self.error.code()
+    }
+
+    fn severity(&self) -> Option<miette::Severity> {
+        self.error.severity()
+    }
+
+    fn help<'a>(&'a self) -> Option<Box<dyn Display + 'a>> {
+        self.error.help()
+    }
+
+    fn url<'a>(&'a self) -> Option<Box<dyn Display + 'a>> {
+        self.error.url()
+    }
+
+    fn labels<'a>(&'a self) -> Option<Box<dyn Iterator<Item = LabeledSpan> + 'a>> {
+        self.error.labels()
+    }
+
+    fn source_code(&self) -> Option<&dyn miette::SourceCode> {
+        Some(&self.source_code)
+    }
+
+    fn related<'a>(&'a self) -> Option<Box<dyn Iterator<Item = &'a dyn Diagnostic> + 'a>> {
+        self.error.related()
+    }
+}
+
+impl<C: SourceCode> Diagnostic for WithSourceCode<Report, C> {
+    fn code<'a>(&'a self) -> Option<Box<dyn Display + 'a>> {
+        self.error.code()
+    }
+
+    fn severity(&self) -> Option<miette::Severity> {
+        self.error.severity()
+    }
+
+    fn help<'a>(&'a self) -> Option<Box<dyn Display + 'a>> {
+        self.error.help()
+    }
+
+    fn url<'a>(&'a self) -> Option<Box<dyn Display + 'a>> {
+        self.error.url()
+    }
+
+    fn labels<'a>(&'a self) -> Option<Box<dyn Iterator<Item = LabeledSpan> + 'a>> {
+        self.error.labels()
+    }
+
+    fn source_code(&self) -> Option<&dyn miette::SourceCode> {
+        Some(&self.source_code)
+    }
+
+    fn related<'a>(&'a self) -> Option<Box<dyn Iterator<Item = &'a dyn Diagnostic> + 'a>> {
+        self.error.related()
+    }
+}
+
+impl<E: Debug, C> Debug for WithSourceCode<E, C> {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+        Debug::fmt(&self.error, f)
+    }
+}
+
+impl<E: Display, C> Display for WithSourceCode<E, C> {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+        Display::fmt(&self.error, f)
+    }
+}
+
+impl<E: StdError, C> StdError for WithSourceCode<E, C> {
+    fn source(&self) -> Option<&(dyn StdError + 'static)> {
+        self.error.source()
+    }
+}
+
+impl<C> StdError for WithSourceCode<Report, C> {
+    fn source(&self) -> Option<&(dyn StdError + 'static)> {
+        self.error.source()
+    }
+}

tests/graphical.rs

@@ -186,6 +186,41 @@ fn single_line_highlight() -> Result<(), MietteError> {
     Ok(())
 }
 
+#[test]
+fn external_source() -> Result<(), MietteError> {
+    #[derive(Debug, Diagnostic, Error)]
+    #[error("oops!")]
+    #[diagnostic(code(oops::my::bad), help("try doing it better next time?"))]
+    struct MyBad {
+        #[label("this bit here")]
+        highlight: SourceSpan,
+    }
+
+    let src = "source\n  text\n    here".to_string();
+    let err = Report::from(MyBad {
+        highlight: (9, 4).into(),
+    })
+    .with_source_code(NamedSource::new("bad_file.rs", src));
+    let out = fmt_report(err);
+    println!("Error: {}", out);
+    let expected = r#"oops::my::bad
+
+  × oops!
+   ╭─[bad_file.rs:1:1]
+ 1 │ source
+ 2 │   text
+   ·   ──┬─
+   ·     ╰── this bit here
+ 3 │     here
+   ╰────
+  help: try doing it better next time?
+"#
+    .trim_start()
+    .to_string();
+    assert_eq!(expected, out);
+    Ok(())
+}
+
 #[test]
 fn single_line_highlight_offset_zero() -> Result<(), MietteError> {
     #[derive(Debug, Diagnostic, Error)]