fix(graphical): fix nested error wrapping (#358)

Fixes: #333

src/eyreish/wrapper.rs

@@ -6,35 +6,9 @@ use crate::{Diagnostic, LabeledSpan, Report, SourceCode};
 
 use crate as miette;
 
-#[repr(transparent)]
-pub(crate) struct DisplayError<M>(pub(crate) M);
-
 #[repr(transparent)]
 pub(crate) struct MessageError<M>(pub(crate) M);
 
-pub(crate) struct NoneError;
-
-impl<M> Debug for DisplayError<M>
-where
-    M: Display,
-{
-    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
-        Display::fmt(&self.0, f)
-    }
-}
-
-impl<M> Display for DisplayError<M>
-where
-    M: Display,
-{
-    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
-        Display::fmt(&self.0, f)
-    }
-}
-
-impl<M> StdError for DisplayError<M> where M: Display + 'static {}
-impl<M> Diagnostic for DisplayError<M> where M: Display + 'static {}
-
 impl<M> Debug for MessageError<M>
 where
     M: Display + Debug,
@@ -56,21 +30,6 @@ where
 impl<M> StdError for MessageError<M> where M: Display + Debug + 'static {}
 impl<M> Diagnostic for MessageError<M> where M: Display + Debug + 'static {}
 
-impl Debug for NoneError {
-    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
-        Debug::fmt("Option was None", f)
-    }
-}
-
-impl Display for NoneError {
-    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
-        Display::fmt("Option was None", f)
-    }
-}
-
-impl StdError for NoneError {}
-impl Diagnostic for NoneError {}
-
 #[repr(transparent)]
 pub(crate) struct BoxedError(pub(crate) Box<dyn Diagnostic + Send + Sync>);
 

src/handlers/graphical.rs

@@ -1,7 +1,7 @@
 use std::fmt::{self, Write};
 
 use owo_colors::{OwoColorize, Style, StyledList};
-use unicode_width::UnicodeWidthChar;
+use unicode_width::{UnicodeWidthChar, UnicodeWidthStr};
 
 use crate::diagnostic_chain::{DiagnosticChain, ErrorKind};
 use crate::handlers::theme::*;
@@ -225,7 +225,7 @@ impl GraphicalReportHandler {
         self.render_related(f, diagnostic, src)?;
         if let Some(footer) = &self.footer {
             writeln!(f)?;
-            let width = self.termwidth.saturating_sub(4);
+            let width = self.termwidth.saturating_sub(2);
             let mut opts = textwrap::Options::new(width)
                 .initial_indent("  ")
                 .subsequent_indent("  ")
@@ -265,16 +265,15 @@ impl GraphicalReportHandler {
             );
             write!(header, "{}", link)?;
             writeln!(f, "{}", header)?;
-            writeln!(f)?;
         } else if let Some(code) = diagnostic.code() {
             write!(header, "{}", code.style(severity_style),)?;
             if self.links == LinkStyle::Text && diagnostic.url().is_some() {
                 let url = diagnostic.url().unwrap(); // safe
                 write!(header, " ({})", url.style(self.theme.styles.link))?;
             }
             writeln!(f, "{}", header)?;
-            writeln!(f)?;
         }
+        writeln!(f)?;
         Ok(())
     }
 
@@ -354,8 +353,12 @@ impl GraphicalReportHandler {
                         inner_renderer.footer = None;
                         // Cause chains are already flattened, so don't double-print the nested error
                         inner_renderer.with_cause_chain = false;
+                        // Since everything from here on is indented, shrink the virtual terminal
+                        inner_renderer.termwidth -= rest_indent.width();
                         inner_renderer.render_report(&mut inner, diag)?;
 
+                        // If there was no header, remove the leading newline
+                        let inner = inner.trim_start_matches('\n');
                         writeln!(f, "{}", self.wrap(&inner, opts))?;
                     }
                     ErrorKind::StdError(err) => {
@@ -370,7 +373,7 @@ impl GraphicalReportHandler {
 
     fn render_footer(&self, f: &mut impl fmt::Write, diagnostic: &(dyn Diagnostic)) -> fmt::Result {
         if let Some(help) = diagnostic.help() {
-            let width = self.termwidth.saturating_sub(4);
+            let width = self.termwidth.saturating_sub(2);
             let initial_indent = "  help: ".style(self.theme.styles.help).to_string();
             let mut opts = textwrap::Options::new(width)
                 .initial_indent(&initial_indent)
@@ -398,8 +401,8 @@ impl GraphicalReportHandler {
             let mut inner_renderer = self.clone();
             // Re-enable the printing of nested cause chains for related errors
             inner_renderer.with_cause_chain = true;
-            writeln!(f)?;
             for rel in related {
+                writeln!(f)?;
                 match rel.severity() {
                     Some(Severity::Error) | None => write!(f, "Error: ")?,
                     Some(Severity::Warning) => write!(f, "Warning: ")?,

tests/derive.rs

@@ -6,12 +6,14 @@ fn related() {
     #[derive(Error, Debug, Diagnostic)]
     #[error("welp")]
     #[diagnostic(code(foo::bar::baz))]
+    #[allow(dead_code)]
     struct Foo {
         #[related]
         related: Vec<Baz>,
     }
 
     #[derive(Error, Debug, Diagnostic)]
+    #[allow(dead_code)]
     enum Bar {
         #[error("variant1")]
         #[diagnostic(code(foo::bar::baz))]
@@ -29,6 +31,7 @@ fn related() {
 
     #[derive(Error, Debug, Diagnostic)]
     #[error("welp2")]
+    #[allow(dead_code)]
     struct Baz;
 }
 
@@ -37,6 +40,7 @@ fn related_report() {
     #[derive(Error, Debug, Diagnostic)]
     #[error("welp")]
     #[diagnostic(code(foo::bar::baz))]
+    #[allow(dead_code)]
     struct Foo {
         #[related]
         related: Vec<Report>,
@@ -288,6 +292,7 @@ fn test_snippet_named_struct() {
     #[derive(Debug, Diagnostic, Error)]
     #[error("welp")]
     #[diagnostic(code(foo::bar::baz))]
+    #[allow(dead_code)]
     struct Foo<'a> {
         #[source_code]
         src: &'a str,
@@ -310,6 +315,7 @@ fn test_snippet_unnamed_struct() {
     #[derive(Debug, Diagnostic, Error)]
     #[error("welp")]
     #[diagnostic(code(foo::bar::baz))]
+    #[allow(dead_code)]
     struct Foo<'a>(
         #[source_code] &'a str,
         #[label("{0}")] SourceSpan,