Move diagnostics to a separate library

This will make it possible to share it across crates.

Author: ehuss

Cargo.lock

@@ -10,3 +10,6 @@ resolver = "2"
 [workspace.package]
 edition = "2024"
 license = "MIT OR Apache-2.0"
+
+[workspace.dependencies]
+diagnostics = { path = "tools/diagnostics" }

Cargo.toml

@@ -0,0 +1,6 @@
+[package]
+name = "diagnostics"
+edition.workspace = true
+license.workspace = true
+
+[dependencies]

tools/diagnostics/Cargo.toml

@@ -0,0 +1,52 @@
+//! Very basic diagnostics output support.
+
+use std::fmt;
+
+/// Handler for errors and warnings.
+pub struct Diagnostics {
+    /// Whether or not warnings should be errors (set by SPEC_DENY_WARNINGS
+    /// environment variable).
+    pub deny_warnings: bool,
+    /// Number of messages generated.
+    pub count: u32,
+}
+
+impl Diagnostics {
+    pub fn new() -> Diagnostics {
+        let deny_warnings = std::env::var("SPEC_DENY_WARNINGS").as_deref() == Ok("1");
+        Diagnostics {
+            deny_warnings,
+            count: 0,
+        }
+    }
+
+    /// Displays a warning or error (depending on whether warnings are denied).
+    ///
+    /// Usually you want the [`warn_or_err!`] macro.
+    pub fn warn_or_err(&mut self, args: fmt::Arguments<'_>) {
+        if self.deny_warnings {
+            eprintln!("error: {args}");
+        } else {
+            eprintln!("warning: {args}");
+        }
+        self.count += 1;
+    }
+}
+
+/// Displays a warning or error (depending on whether warnings are denied).
+#[macro_export]
+macro_rules! warn_or_err {
+    ($diag:expr, $($arg:tt)*) => {
+        $diag.warn_or_err(format_args!($($arg)*));
+    };
+}
+
+/// Displays a message for an internal error, and immediately exits.
+#[macro_export]
+macro_rules! bug {
+    ($($arg:tt)*) => {
+        eprintln!("mdbook-spec internal error: {}", format_args!($($arg)*));
+        std::process::exit(1);
+    };
+}
+

tools/diagnostics/src/lib.rs

@@ -10,6 +10,7 @@ default-run = "mdbook-spec"
 
 [dependencies]
 anyhow = "1.0.79"
+diagnostics.workspace = true
 mdbook-markdown = "0.5.1"
 mdbook-preprocessor = "0.5.1"
 once_cell = "1.19.0"

tools/mdbook-spec/Cargo.toml

@@ -2,14 +2,10 @@
 
 use crate::rules::Rules;
 use anyhow::{Context, Result, bail};
-use mdbook_preprocessor::book::BookItem;
-use mdbook_preprocessor::book::{Book, Chapter};
-use mdbook_preprocessor::errors::Error;
-use mdbook_preprocessor::{Preprocessor, PreprocessorContext};
+use diagnostics::{Diagnostics, warn_or_err};
 use once_cell::sync::Lazy;
 use regex::{Captures, Regex};
 use semver::{Version, VersionReq};
-use std::fmt;
 use std::io;
 use std::ops::Range;
 use std::path::PathBuf;
@@ -47,54 +43,6 @@ pub fn handle_preprocessing() -> Result<(), Error> {
     Ok(())
 }
 
-/// Handler for errors and warnings.
-pub struct Diagnostics {
-    /// Whether or not warnings should be errors (set by SPEC_DENY_WARNINGS
-    /// environment variable).
-    deny_warnings: bool,
-    /// Number of messages generated.
-    count: u32,
-}
-
-impl Diagnostics {
-    fn new() -> Diagnostics {
-        let deny_warnings = std::env::var("SPEC_DENY_WARNINGS").as_deref() == Ok("1");
-        Diagnostics {
-            deny_warnings,
-            count: 0,
-        }
-    }
-
-    /// Displays a warning or error (depending on whether warnings are denied).
-    ///
-    /// Usually you want the [`warn_or_err!`] macro.
-    fn warn_or_err(&mut self, args: fmt::Arguments<'_>) {
-        if self.deny_warnings {
-            eprintln!("error: {args}");
-        } else {
-            eprintln!("warning: {args}");
-        }
-        self.count += 1;
-    }
-}
-
-/// Displays a warning or error (depending on whether warnings are denied).
-#[macro_export]
-macro_rules! warn_or_err {
-    ($diag:expr, $($arg:tt)*) => {
-        $diag.warn_or_err(format_args!($($arg)*));
-    };
-}
-
-/// Displays a message for an internal error, and immediately exits.
-#[macro_export]
-macro_rules! bug {
-    ($($arg:tt)*) => {
-        eprintln!("mdbook-spec internal error: {}", format_args!($($arg)*));
-        std::process::exit(1);
-    };
-}
-
 pub struct Spec {
     /// Path to the rust-lang/rust git repository (set by SPEC_RUST_ROOT
     /// environment variable).

tools/mdbook-spec/src/lib.rs

@@ -1,7 +1,7 @@
 //! Support for translating links to the standard library.
 
-use crate::{Diagnostics, bug, warn_or_err};
 use anyhow::{Result, bail};
+use diagnostics::{Diagnostics, bug, warn_or_err};
 use mdbook_markdown::pulldown_cmark::{BrokenLink, CowStr, Event, LinkType, Options, Parser, Tag};
 use mdbook_preprocessor::book::BookItem;
 use mdbook_preprocessor::book::{Book, Chapter};