refactor: Replace concolor with anstream & friends

CHANGELOG.md

@@ -76,6 +76,19 @@ will become the public version at the next release._
 
   (@aljazerzen, #2605)
 
+- We've changed how we handle colors. We now use the
+  `[anstream](https://github.com/rust-cli/anstyle)` library in `prqlc` &
+  `prql-compiler`.
+
+  `Options::color` is deprecated and has no effect. Code which consumes
+  `prql_compiler::compile` should instead accept the output with colors and use
+  a library such as `anstream` to handle the presentation of colors. To ensure
+  minimal disruption, `prql_compiler` will currently strip color codes when a
+  standard environment variable such as `CLI_COLOR=0` is set or when it detects
+  `stderr` is not a TTY.
+
+  (@max-sixty, #2773)
+
 **Fixes**:
 
 **Documentation**:

bindings/prql-js/src/lib.rs

@@ -11,7 +11,7 @@ use wasm_bindgen::prelude::*;
 pub fn compile(prql_query: &str, options: Option<CompileOptions>) -> Option<String> {
     return_or_throw(
         prql_compiler::compile(prql_query, &options.map(|x| x.into()).unwrap_or_default())
-            .map_err(|e| e.composed(&prql_query.into(), false)),
+            .map_err(|e| e.composed(&prql_query.into())),
     )
 }
 

bindings/prql-lib/src/lib.rs

@@ -37,7 +37,7 @@ pub unsafe extern "C" fn compile(
                 .and_then(prql_compiler::pl_to_rq)
                 .and_then(|rq| prql_compiler::rq_to_sql(rq, &opts.unwrap_or_default()))
         })
-        .map_err(|e| e.composed(&prql_query.into(), false));
+        .map_err(|e| e.composed(&prql_query.into()));
 
     result_into_c_str(result)
 }

bindings/prql-python/src/lib.rs

@@ -15,7 +15,7 @@ pub fn compile(prql_query: &str, options: Option<CompileOptions>) -> PyResult<St
                 .and_then(prql_compiler::pl_to_rq)
                 .and_then(|rq| prql_compiler::rq_to_sql(rq, &opts.unwrap_or_default()))
         })
-        .map_err(|e| e.composed(&prql_query.into(), false))
+        .map_err(|e| e.composed(&prql_query.into()))
         .map_err(|e| (PyErr::new::<exceptions::PySyntaxError, _>(e.to_string())))
 }
 

prql-compiler/Cargo.toml

@@ -11,6 +11,7 @@ version.workspace = true
 metadata.msrv = "1.65.0"
 
 [dependencies]
+anstream = {version = "0.3.2", features = ["auto"]}
 anyhow = {version = "1.0.57", features = ["backtrace"]}
 ariadne = "0.3.0"
 csv = "1.2.0"

prql-compiler/prqlc/Cargo.toml

@@ -11,15 +11,16 @@ version.workspace = true
 metadata.msrv = "1.65.0"
 
 [target.'cfg(not(target_family="wasm"))'.dependencies]
+anstream = {version = "0.3.2", features = ["auto"]}
 anyhow = {version = "1.0.57"}
 ariadne = "0.3.0"
 atty = "0.2.14"
 clap = {version = "4.3.0", features = ["derive", "env", "wrap_help"]}
 clap_complete_command = "0.5.1"
 clio = {version = "0.2.7", features = ['clap-parse']}
 color-eyre = "0.6.1"
-concolor = "0.1.0"
-concolor-clap = {version = "0.1.0", features = ["api"]}
+colorchoice = "1.0.0"
+colorchoice-clap = "1.0.0"
 env_logger = {version = "0.10.0", features = ["color"]}
 itertools = "0.10.3"
 notify = "^6.0.0"

prql-compiler/prqlc/src/cli.rs

@@ -1,3 +1,4 @@
+use anstream::eprintln;
 use anyhow::bail;
 use anyhow::Result;
 use ariadne::Source;
@@ -22,7 +23,7 @@ pub fn main() -> color_eyre::eyre::Result<()> {
     env_logger::builder().format_timestamp(None).init();
     color_eyre::install()?;
     let mut cli = Cli::parse();
-    cli.color.apply();
+    cli.color.write_global();
 
     if let Err(error) = cli.command.run() {
         eprintln!("{error}");
@@ -33,12 +34,11 @@ pub fn main() -> color_eyre::eyre::Result<()> {
 }
 
 #[derive(Parser, Debug, Clone)]
-#[command(color = concolor_clap::color_choice())]
 struct Cli {
     #[command(subcommand)]
     command: Command,
     #[command(flatten)]
-    color: concolor_clap::Color,
+    color: colorchoice_clap::Color,
 }
 
 #[derive(Subcommand, Debug, Clone)]
@@ -170,7 +170,7 @@ impl Command {
                     }
                 };
 
-                output.write_all(pl_to_prql(ast)?.as_bytes())?;
+                output.write_all(&pl_to_prql(ast)?.into_bytes())?;
                 Ok(())
             }
             Command::ShellCompletion { shell } => {
@@ -223,7 +223,7 @@ impl Command {
 
                 let context = semantic::resolve(stmts, Default::default())
                     .map_err(prql_compiler::downcast)
-                    .map_err(|e| e.composed(sources, true))?;
+                    .map_err(|e| e.composed(sources))?;
 
                 let mut out = Vec::new();
                 for (source_id, source) in &sources.sources {
@@ -284,13 +284,12 @@ impl Command {
 
                 let opts = Options::default()
                     .with_target(Target::from_str(target).map_err(|e| downcast(e.into()))?)
-                    .with_color(concolor::get(concolor::Stream::Stdout).ansi_color())
                     .with_signature_comment(*hide_signature_comment);
 
                 prql_to_pl_tree(sources)
                     .and_then(|pl| pl_to_rq_tree(pl, &main_path))
                     .and_then(|rq| rq_to_sql(rq, &opts))
-                    .map_err(|e| e.composed(sources, opts.color))?
+                    .map_err(|e| e.composed(sources))?
                     .as_bytes()
                     .to_vec()
             }
@@ -646,15 +645,12 @@ group a_column (take 10 | sort b_column | derive {the_number = rank, last = lag
         "###);
     }
 
+    /// Check we get an error on a bad input
     #[test]
     fn compile() {
-        // Check we get an error on a bad input
         // Disable colors (would be better if this were a proper CLI test and
         // passed in `--color=never`)
-        concolor_clap::Color {
-            color: concolor_clap::ColorChoice::Never,
-        }
-        .apply();
+        anstream::ColorChoice::Never.write_global();
 
         let result = Command::execute(
             &Command::SQLCompile {
@@ -665,7 +661,8 @@ group a_column (take 10 | sort b_column | derive {the_number = rank, last = lag
             &mut "asdf".into(),
             "",
         );
-        assert_display_snapshot!(result.unwrap_err(), @r###"
+
+        assert_display_snapshot!(&result.unwrap_err().to_string(), @r###"
         Error:
            ╭─[:1:1]
            │

prql-compiler/src/error.rs

@@ -1,14 +1,15 @@
+use anstream::adapter::strip_str;
 pub use anyhow::Result;
 
 use ariadne::{Cache, Config, Label, Report, ReportKind, Source};
 use serde::de::Visitor;
 use serde::{Deserialize, Serialize};
 
-use std::collections::HashMap;
 use std::error::Error as StdError;
 use std::fmt::{self, Debug, Display, Formatter};
 use std::ops::{Add, Range};
 use std::path::PathBuf;
+use std::{collections::HashMap, io::stderr};
 
 use crate::SourceTree;
 
@@ -258,7 +259,7 @@ impl ErrorMessages {
     }
 
     /// Computes message location and builds the pretty display.
-    pub fn composed(mut self, sources: &SourceTree, color: bool) -> Self {
+    pub fn composed(mut self, sources: &SourceTree) -> Self {
         let mut cache = FileTreeCache::new(sources);
 
         for e in &mut self.inner {
@@ -274,20 +275,16 @@ impl ErrorMessages {
             };
             e.location = e.compose_location(source);
 
-            e.display = e.compose_display(source_path.clone(), &mut cache, color);
+            e.display = e.compose_display(source_path.clone(), &mut cache);
         }
         self
     }
 }
 
 impl ErrorMessage {
-    fn compose_display(
-        &self,
-        source_path: PathBuf,
-        cache: &mut FileTreeCache,
-        color: bool,
-    ) -> Option<String> {
-        let config = Config::default().with_color(color);
+    fn compose_display(&self, source_path: PathBuf, cache: &mut FileTreeCache) -> Option<String> {
+        // We always pass color to ariadne as true, and then (currently) strip later.
+        let config = Config::default().with_color(true);
 
         let span = Range::from(self.span?);
 
@@ -312,7 +309,19 @@ impl ErrorMessage {
 
         let mut out = Vec::new();
         report.finish().write(cache, &mut out).ok()?;
-        String::from_utf8(out).ok()
+
+        // Strip colors, for external libraries which don't yet strip
+        // themselves, and for insta snapshot tests. This will respond to
+        // environment variables such as `CLI_COLOR`. Eventually we can remove
+        // this, always pass colors back, and the consuming library can strip
+        // (including insta https://github.com/mitsuhiko/insta/issues/378).
+        String::from_utf8(out).ok().map(|x| {
+            if !should_use_color() {
+                strip_str(&x).to_string()
+            } else {
+                x
+            }
+        })
     }
 
     fn compose_location(&self, source: &Source) -> Option<SourceLocation> {
@@ -327,6 +336,15 @@ impl ErrorMessage {
     }
 }
 
+fn should_use_color() -> bool {
+    match anstream::AutoStream::choice(&stderr()) {
+        anstream::ColorChoice::Auto => true,
+        anstream::ColorChoice::Always => true,
+        anstream::ColorChoice::AlwaysAnsi => true,
+        anstream::ColorChoice::Never => false,
+    }
+}
+
 struct FileTreeCache<'a> {
     file_tree: &'a SourceTree,
     cache: HashMap<PathBuf, Source>,