Improve compiletest expected/not found formatting

src/tools/compiletest/src/errors.rs

@@ -57,6 +57,18 @@ pub struct Error {
     pub msg: String,
 }
 
+impl Error {
+    pub fn render_for_expected(&self) -> String {
+        use colored::Colorize;
+        format!(
+            "{: <10}line {: >3}: {}",
+            self.kind.map(|kind| kind.to_string()).unwrap_or_default().to_uppercase(),
+            self.line_num,
+            self.msg.cyan(),
+        )
+    }
+}
+
 #[derive(PartialEq, Debug)]
 enum WhichLine {
     ThisLine,

src/tools/compiletest/src/main.rs

@@ -1,10 +1,18 @@
-use std::{env, sync::Arc};
+use std::{env, io::IsTerminal, sync::Arc};
 
 use compiletest::{common::Mode, log_config, parse_config, run_tests};
 
 fn main() {
     tracing_subscriber::fmt::init();
 
+    // colored checks stdout by default, but for some reason only stderr is a terminal.
+    // compiletest *does* print many things to stdout, but it doesn't really matter.
+    if std::io::stderr().is_terminal()
+        && matches!(std::env::var("NO_COLOR").as_deref(), Err(_) | Ok("0"))
+    {
+        colored::control::set_override(true);
+    }
+
     let config = Arc::new(parse_config(env::args().collect()));
 
     if config.valgrind_path.is_none() && config.force_valgrind {

src/tools/compiletest/src/runtest.rs

@@ -17,10 +17,10 @@ use crate::json;
 use crate::read2::{read2_abbreviated, Truncated};
 use crate::util::{add_dylib_path, dylib_env_var, logv, PathBufExt};
 use crate::ColorConfig;
+use colored::Colorize;
 use miropt_test_tools::{files_for_miropt_test, MiroptTest, MiroptTestFile};
 use regex::{Captures, Regex};
 use rustfix::{apply_suggestions, get_suggestions_from_json, Filter};
-
 use std::collections::{HashMap, HashSet};
 use std::env;
 use std::ffi::{OsStr, OsString};
@@ -1493,14 +1493,22 @@ impl<'test> TestCx<'test> {
                 unexpected.len(),
                 not_found.len()
             ));
-            println!("status: {}\ncommand: {}", proc_res.status, proc_res.cmdline);
+            println!("status: {}\ncommand: {}\n", proc_res.status, proc_res.cmdline);
             if !unexpected.is_empty() {
-                println!("unexpected errors (from JSON output): {:#?}\n", unexpected);
+                println!("{}", "--- unexpected errors (from JSON output) ---".green());
+                for error in &unexpected {
+                    println!("{}", error.render_for_expected());
+                }
+                println!("{}", "---".green());
             }
             if !not_found.is_empty() {
-                println!("not found errors (from test file): {:#?}\n", not_found);
+                println!("{}", "--- not found errors (from test file) ---".red());
+                for error in &not_found {
+                    println!("{}", error.render_for_expected());
+                }
+                println!("{}", "---\n".red());
             }
-            panic!();
+            panic!("errors differ from expected");
         }
     }