feat(report): add debug report as default, instead of narrated one

src/eyreish/mod.rs

@@ -30,7 +30,7 @@ use crate::Diagnostic;
 #[cfg(feature = "fancy")]
 use crate::MietteHandler;
 #[cfg(not(feature = "fancy"))]
-use crate::NarratableReportHandler;
+use crate::DebugReportHandler;
 
 use error::ErrorImpl;
 
@@ -95,7 +95,7 @@ fn get_default_printer(_err: &(dyn Diagnostic + 'static)) -> Box<dyn ReportHandl
     #[cfg(feature = "fancy")]
     return Box::new(MietteHandler::new());
     #[cfg(not(feature = "fancy"))]
-    return Box::new(NarratableReportHandler::new());
+    return Box::new(DebugReportHandler::new());
 }
 
 impl dyn ReportHandler {

src/handlers/debug.rs

@@ -0,0 +1,69 @@
+use std::fmt;
+
+use crate::{protocol::Diagnostic, ReportHandler};
+
+/**
+[ReportHandler] that renders plain text and avoids extraneous graphics.
+It's optimized for screen readers and braille users, but is also used in any
+non-graphical environments, such as non-TTY output.
+*/
+#[derive(Debug, Clone)]
+pub struct DebugReportHandler;
+
+impl DebugReportHandler {
+    /// Create a new [NarratableReportHandler]. There are no customization
+    /// options.
+    pub fn new() -> Self {
+        Self
+    }
+}
+
+impl Default for DebugReportHandler {
+    fn default() -> Self {
+        Self::new()
+    }
+}
+
+impl DebugReportHandler {
+    /// Render a [Diagnostic]. This function is mostly internal and meant to
+    /// be called by the toplevel [ReportHandler] handler, but is
+    /// made public to make it easier (possible) to test in isolation from
+    /// global state.
+    pub fn render_report(
+        &self,
+        f: &mut fmt::Formatter<'_>,
+        diagnostic: &(dyn Diagnostic),
+    ) -> fmt::Result {
+        let mut diag = f.debug_struct("Diagnostic");
+        diag.field("message", &format!("{}", diagnostic));
+        if let Some(code) = diagnostic.code() {
+            diag.field("code", &code.to_string());
+        }
+        if let Some(severity) = diagnostic.severity() {
+            diag.field("severity", &format!("{:?}", severity));
+        }
+        if let Some(url) = diagnostic.url() {
+            diag.field("url", &url.to_string());
+        }
+        if let Some(help) = diagnostic.help() {
+            diag.field("help", &help.to_string());
+        }
+        if let Some(snippets) = diagnostic.snippets() {
+            let snippets: Vec<_> = snippets.collect();
+            diag.field("snippets", &format!("{:?}", snippets));
+        }
+        diag.finish()?;
+        writeln!(f)?;
+        writeln!(f, "NOTE: If you're looking for the fancy error reports, install miette with the `fancy` feature, or write your own and hook it up with miette::set_hook().")
+    }
+}
+
+impl ReportHandler for DebugReportHandler {
+    fn debug(&self, diagnostic: &(dyn Diagnostic), f: &mut fmt::Formatter<'_>) -> fmt::Result {
+        if f.alternate() {
+            return fmt::Debug::fmt(diagnostic, f);
+        }
+
+        self.render_report(f, diagnostic)
+    }
+}

src/handlers/mod.rs

@@ -2,6 +2,8 @@
 Reporters included with `miette`.
 */
 
+#[allow(unreachable_pub)]
+pub use debug::*;
 #[allow(unreachable_pub)]
 #[cfg(feature = "fancy")]
 pub use graphical::*;
@@ -11,6 +13,7 @@ pub use narratable::*;
 #[cfg(feature = "fancy")]
 pub use theme::*;
 
+mod debug;
 #[cfg(feature = "fancy")]
 mod graphical;
 mod narratable;