Auto merge of #147207 - Muscraft:anstyle-anstream, r=davidtwco

refactor: Move to anstream + anstyle for styling

`rustc` uses [`termcolor`](https://crates.io/crates/termcolor) for styling and writing, while `annotate-snippets` uses [`anstyle`](https://crates.io/crates/anstyle) for styling and currently writes directly to a `String`. When rendering directly to a terminal, there isn't/shouldn't be any differences. Still, there are differences in the escape sequences, which leads to slightly different output in JSON and SVG tests. As part of my work to have `rustc` use `annotate-snippets`, and to reduce the test differences between the two, I switched `rustc` to use `anstlye` and [`anstream`](https://crates.io/crates/anstream) for styling and writing.

The first commit migrates to `anstyle` and `anstream` and notably does not change the output. This is because it includes extra formatting to ensure that `anstyle` + `anstream` match the current output exactly. Most of this code is unnecessary, as it adds redundant resets or uses 256-color (8-bit) when it could be using 4-bit color. The subsequent commits remove this extra formatting while maintaining the correct output when rendered.

[Zulip discussion](https://rust-lang.zulipchat.com/#narrow/channel/147480-t-compiler.2Fdiagnostics/topic/annotate-snippets.20hurdles)

Author: bors

Cargo.lock

@@ -95,9 +95,9 @@ dependencies = [
 
 [[package]]
 name = "anstyle"
-version = "1.0.11"
+version = "1.0.13"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "862ed96ca487e809f1c8e5a8447f6ee2cf102f846893800b20cebdf541fc6bbd"
+checksum = "5192cca8006f1fd4f7237516f40fa183bb07f8fbdfedaa0036de5ea9b0b45e78"
 
 [[package]]
 name = "anstyle-lossy"
@@ -3757,6 +3757,8 @@ name = "rustc_errors"
 version = "0.0.0"
 dependencies = [
  "annotate-snippets 0.11.5",
+ "anstream",
+ "anstyle",
  "derive_setters",
  "rustc_abi",
  "rustc_ast",
@@ -3773,7 +3775,6 @@ dependencies = [
  "rustc_span",
  "serde",
  "serde_json",
- "termcolor",
  "termize",
  "tracing",
  "windows 0.61.3",
@@ -4327,7 +4328,6 @@ dependencies = [
  "rustc_macros",
  "rustc_session",
  "rustc_span",
- "termcolor",
  "thin-vec",
  "tracing",
  "unicode-normalization",

compiler/rustc_driver_impl/src/lib.rs

@@ -520,11 +520,11 @@ fn show_md_content_with_pager(content: &str, color: ColorConfig) {
     };
 
     // Try to prettify the raw markdown text. The result can be used by the pager or on stdout.
-    let pretty_data = {
+    let mut pretty_data = {
         let mdstream = markdown::MdStream::parse_str(content);
         let bufwtr = markdown::create_stdout_bufwtr();
-        let mut mdbuf = bufwtr.buffer();
-        if mdstream.write_termcolor_buf(&mut mdbuf).is_ok() { Some((bufwtr, mdbuf)) } else { None }
+        let mut mdbuf = Vec::new();
+        if mdstream.write_anstream_buf(&mut mdbuf).is_ok() { Some((bufwtr, mdbuf)) } else { None }
     };
 
     // Try to print via the pager, pretty output if possible.
@@ -545,8 +545,8 @@ fn show_md_content_with_pager(content: &str, color: ColorConfig) {
     }
 
     // The pager failed. Try to print pretty output to stdout.
-    if let Some((bufwtr, mdbuf)) = &pretty_data
-        && bufwtr.print(mdbuf).is_ok()
+    if let Some((bufwtr, mdbuf)) = &mut pretty_data
+        && bufwtr.write_all(&mdbuf).is_ok()
     {
         return;
     }

compiler/rustc_errors/Cargo.toml

@@ -6,6 +6,8 @@ edition = "2024"
 [dependencies]
 # tidy-alphabetical-start
 annotate-snippets = "0.11"
+anstream = "0.6.20"
+anstyle = "1.0.13"
 derive_setters = "0.1.6"
 rustc_abi = { path = "../rustc_abi" }
 rustc_ast = { path = "../rustc_ast" }
@@ -22,7 +24,6 @@ rustc_serialize = { path = "../rustc_serialize" }
 rustc_span = { path = "../rustc_span" }
 serde = { version = "1.0.125", features = ["derive"] }
 serde_json = "1.0.59"
-termcolor = "1.2.0"
 termize = "0.2"
 tracing = "0.1"
 # tidy-alphabetical-end

compiler/rustc_errors/src/emitter.rs

@@ -16,6 +16,8 @@ use std::iter;
 use std::path::Path;
 use std::sync::Arc;
 
+use anstream::{AutoStream, ColorChoice};
+use anstyle::{AnsiColor, Effects};
 use derive_setters::Setters;
 use rustc_data_structures::fx::{FxIndexMap, FxIndexSet};
 use rustc_data_structures::sync::{DynSend, IntoDynSyncSend};
@@ -25,7 +27,6 @@ use rustc_lint_defs::pluralize;
 use rustc_span::hygiene::{ExpnKind, MacroKind};
 use rustc_span::source_map::SourceMap;
 use rustc_span::{FileLines, FileName, SourceFile, Span, char_width, str_width};
-use termcolor::{Buffer, BufferWriter, Color, ColorChoice, ColorSpec, StandardStream, WriteColor};
 use tracing::{debug, instrument, trace, warn};
 
 use crate::registry::Registry;
@@ -525,10 +526,6 @@ impl Emitter for HumanEmitter {
         !self.short_message
     }
 
-    fn supports_color(&self) -> bool {
-        self.dst.supports_color()
-    }
-
     fn translator(&self) -> &Translator {
         &self.translator
     }
@@ -1701,7 +1698,6 @@ impl HumanEmitter {
             } else {
                 col_sep_before_no_show_source = true;
             }
-
             // print out the span location and spacer before we print the annotated source
             // to do this, we need to know if this span will be primary
             let is_primary = primary_lo.file.name == annotated_file.file.name;
@@ -3127,7 +3123,6 @@ impl FileWithAnnotatedLines {
                 multiline_depth: 0,
             });
         }
-
         let mut output = vec![];
         let mut multiline_annotations = vec![];
 
@@ -3361,7 +3356,7 @@ const OUTPUT_REPLACEMENTS: &[(char, &str)] = &[
     ('\u{2069}', "�"),
 ];
 
-fn normalize_whitespace(s: &str) -> String {
+pub(crate) fn normalize_whitespace(s: &str) -> String {
     const {
         let mut i = 1;
         while i < OUTPUT_REPLACEMENTS.len() {
@@ -3406,7 +3401,7 @@ fn overlaps(a1: &Annotation, a2: &Annotation, padding: usize) -> bool {
     )
 }
 
-fn emit_to_destination(
+pub(crate) fn emit_to_destination(
     rendered_buffer: &[Vec<StyledString>],
     lvl: &Level,
     dst: &mut Destination,
@@ -3429,10 +3424,8 @@ fn emit_to_destination(
     let _buffer_lock = lock::acquire_global_lock("rustc_errors");
     for (pos, line) in rendered_buffer.iter().enumerate() {
         for part in line {
-            let style = part.style.color_spec(*lvl);
-            dst.set_color(&style)?;
-            write!(dst, "{}", part.text)?;
-            dst.reset()?;
+            let style = part.style.anstyle(*lvl);
+            write!(dst, "{style}{}{style:#}", part.text)?;
         }
         if !short_message && (!lvl.is_failure_note() || pos != rendered_buffer.len() - 1) {
             writeln!(dst)?;
@@ -3442,11 +3435,11 @@ fn emit_to_destination(
     Ok(())
 }
 
-pub type Destination = Box<dyn WriteColor + Send>;
+pub type Destination = AutoStream<Box<dyn Write + Send>>;
 
 struct Buffy {
-    buffer_writer: BufferWriter,
-    buffer: Buffer,
+    buffer_writer: std::io::Stderr,
+    buffer: Vec<u8>,
 }
 
 impl Write for Buffy {
@@ -3455,7 +3448,7 @@ impl Write for Buffy {
     }
 
     fn flush(&mut self) -> io::Result<()> {
-        self.buffer_writer.print(&self.buffer)?;
+        self.buffer_writer.write_all(&self.buffer)?;
         self.buffer.clear();
         Ok(())
     }
@@ -3470,83 +3463,59 @@ impl Drop for Buffy {
     }
 }
 
-impl WriteColor for Buffy {
-    fn supports_color(&self) -> bool {
-        self.buffer.supports_color()
-    }
-
-    fn set_color(&mut self, spec: &ColorSpec) -> io::Result<()> {
-        self.buffer.set_color(spec)
-    }
-
-    fn reset(&mut self) -> io::Result<()> {
-        self.buffer.reset()
-    }
-}
-
 pub fn stderr_destination(color: ColorConfig) -> Destination {
+    let buffer_writer = std::io::stderr();
     let choice = color.to_color_choice();
+    // We need to resolve `ColorChoice::Auto` before `Box`ing since
+    // `ColorChoice::Auto` on `dyn Write` will always resolve to `Never`
+    let choice = if matches!(choice, ColorChoice::Auto) {
+        AutoStream::choice(&buffer_writer)
+    } else {
+        choice
+    };
     // On Windows we'll be performing global synchronization on the entire
     // system for emitting rustc errors, so there's no need to buffer
     // anything.
     //
     // On non-Windows we rely on the atomicity of `write` to ensure errors
     // don't get all jumbled up.
     if cfg!(windows) {
-        Box::new(StandardStream::stderr(choice))
+        AutoStream::new(Box::new(buffer_writer), choice)
     } else {
-        let buffer_writer = BufferWriter::stderr(choice);
-        let buffer = buffer_writer.buffer();
-        Box::new(Buffy { buffer_writer, buffer })
+        let buffer = Vec::new();
+        AutoStream::new(Box::new(Buffy { buffer_writer, buffer }), choice)
     }
 }
 
 /// On Windows, BRIGHT_BLUE is hard to read on black. Use cyan instead.
 ///
 /// See #36178.
-const BRIGHT_BLUE: Color = if cfg!(windows) { Color::Cyan } else { Color::Blue };
+const BRIGHT_BLUE: anstyle::Style = if cfg!(windows) {
+    AnsiColor::BrightCyan.on_default()
+} else {
+    AnsiColor::BrightBlue.on_default()
+};
 
 impl Style {
-    fn color_spec(&self, lvl: Level) -> ColorSpec {
-        let mut spec = ColorSpec::new();
+    pub(crate) fn anstyle(&self, lvl: Level) -> anstyle::Style {
         match self {
-            Style::Addition => {
-                spec.set_fg(Some(Color::Green)).set_intense(true);
-            }
-            Style::Removal => {
-                spec.set_fg(Some(Color::Red)).set_intense(true);
-            }
-            Style::LineAndColumn => {}
-            Style::LineNumber => {
-                spec.set_bold(true);
-                spec.set_intense(true);
-                spec.set_fg(Some(BRIGHT_BLUE));
-            }
-            Style::Quotation => {}
-            Style::MainHeaderMsg => {
-                spec.set_bold(true);
-                if cfg!(windows) {
-                    spec.set_intense(true).set_fg(Some(Color::White));
-                }
-            }
-            Style::UnderlinePrimary | Style::LabelPrimary => {
-                spec = lvl.color();
-                spec.set_bold(true);
-            }
-            Style::UnderlineSecondary | Style::LabelSecondary => {
-                spec.set_bold(true).set_intense(true);
-                spec.set_fg(Some(BRIGHT_BLUE));
-            }
-            Style::HeaderMsg | Style::NoStyle => {}
-            Style::Level(lvl) => {
-                spec = lvl.color();
-                spec.set_bold(true);
-            }
-            Style::Highlight => {
-                spec.set_bold(true).set_fg(Some(Color::Magenta));
+            Style::Addition => AnsiColor::BrightGreen.on_default(),
+            Style::Removal => AnsiColor::BrightRed.on_default(),
+            Style::LineAndColumn => anstyle::Style::new(),
+            Style::LineNumber => BRIGHT_BLUE.effects(Effects::BOLD),
+            Style::Quotation => anstyle::Style::new(),
+            Style::MainHeaderMsg => if cfg!(windows) {
+                AnsiColor::BrightWhite.on_default()
+            } else {
+                anstyle::Style::new()
             }
+            .effects(Effects::BOLD),
+            Style::UnderlinePrimary | Style::LabelPrimary => lvl.color().effects(Effects::BOLD),
+            Style::UnderlineSecondary | Style::LabelSecondary => BRIGHT_BLUE.effects(Effects::BOLD),
+            Style::HeaderMsg | Style::NoStyle => anstyle::Style::new(),
+            Style::Level(lvl) => lvl.color().effects(Effects::BOLD),
+            Style::Highlight => AnsiColor::Magenta.on_default().effects(Effects::BOLD),
         }
-        spec
     }
 }
 

compiler/rustc_errors/src/json.rs

@@ -15,6 +15,7 @@ use std::path::Path;
 use std::sync::{Arc, Mutex};
 use std::vec;
 
+use anstream::{AutoStream, ColorChoice};
 use derive_setters::Setters;
 use rustc_data_structures::sync::IntoDynSyncSend;
 use rustc_error_messages::FluentArgs;
@@ -23,7 +24,6 @@ use rustc_span::Span;
 use rustc_span::hygiene::ExpnData;
 use rustc_span::source_map::{FilePathMapping, SourceMap};
 use serde::Serialize;
-use termcolor::{ColorSpec, WriteColor};
 
 use crate::diagnostic::IsLint;
 use crate::emitter::{
@@ -333,7 +333,7 @@ impl Diagnostic {
         // generate regular command line output and store it in the json
 
         // A threadsafe buffer for writing.
-        #[derive(Default, Clone)]
+        #[derive(Clone)]
         struct BufWriter(Arc<Mutex<Vec<u8>>>);
 
         impl Write for BufWriter {
@@ -344,19 +344,6 @@ impl Diagnostic {
                 self.0.lock().unwrap().flush()
             }
         }
-        impl WriteColor for BufWriter {
-            fn supports_color(&self) -> bool {
-                false
-            }
-
-            fn set_color(&mut self, _spec: &ColorSpec) -> io::Result<()> {
-                Ok(())
-            }
-
-            fn reset(&mut self) -> io::Result<()> {
-                Ok(())
-            }
-        }
 
         let translated_message = je.translator.translate_messages(&diag.messages, &args);
 
@@ -382,13 +369,15 @@ impl Diagnostic {
             children
                 .insert(0, Diagnostic::from_sub_diagnostic(&diag.emitted_at_sub_diag(), &args, je));
         }
-        let buf = BufWriter::default();
-        let mut dst: Destination = Box::new(buf.clone());
+        let buf = BufWriter(Arc::new(Mutex::new(Vec::new())));
         let short = je.json_rendered.short();
-        match je.color_config {
-            ColorConfig::Always | ColorConfig::Auto => dst = Box::new(termcolor::Ansi::new(dst)),
-            ColorConfig::Never => {}
-        }
+        let dst: Destination = AutoStream::new(
+            Box::new(buf.clone()),
+            match je.color_config.to_color_choice() {
+                ColorChoice::Auto => ColorChoice::Always,
+                choice => choice,
+            },
+        );
         HumanEmitter::new(dst, je.translator.clone())
             .short_message(short)
             .sm(je.sm.clone())