Allow matching errors and warnings by error code.

Author: Jarcho

README.md

@@ -11,16 +11,16 @@ A smaller version of compiletest-rs
 ## Supported magic comment annotations
 
 If your test tests for failure, you need to add a `//~` annotation where the error is happening
-to make sure that the test will always keep failing with a specific message at the annotated line.
+to ensure that the test will always keep failing at the annotated line. These comments can take two forms:
 
-`//~ ERROR: XXX` make sure the stderr output contains `XXX` for an error in the line where this comment is written
-
-* Also supports `HELP`, `WARN` or `NOTE` for different kind of message
-    * if one of those levels is specified explicitly, *all* diagnostics of this level or higher need an annotation. If you want to avoid this, just leave out the all caps level note entirely.
-* If the all caps note is left out, a message of any level is matched. Leaving it out is not allowed for `ERROR` levels.
-* This checks the output *before* normalization, so you can check things that get normalized away, but need to
-    be careful not to accidentally have a pattern that differs between platforms.
-* if `XXX` is of the form `/XXX/` it is treated as a regex instead of a substring and will succeed if the regex matches.
+* `//~ LEVEL: XXX` matches by error level and message text
+    * `LEVEL` can be one of the following (descending order): `ERROR`, `HELP`, `WARN` or `NOTE`
+    * If a level is specified explicitly, *all* diagnostics of that level or higher need an annotation. To avoid this see `//@require-annotations-for-level`
+    * This checks the output *before* normalization, so you can check things that get normalized away, but need to
+        be careful not to accidentally have a pattern that differs between platforms.
+    * if `XXX` is of the form `/XXX/` it is treated as a regex instead of a substring and will succeed if the regex matches.
+* `//~ CODE` matches by diagnostic code.
+    * `CODE` can take multiple forms such as: `E####`, `lint_name`, `tool::lint_name`.
 
 In order to change how a single test is tested, you can add various `//@` comments to the test.
 Any other comments will be ignored, and all `//@` comments must be formatted precisely as

src/error.rs

@@ -25,6 +25,13 @@ pub enum Error {
         /// Can be `None` when it is expected outside the current file
         expected_line: Option<NonZeroUsize>,
     },
+    /// A diagnostic code matcher was declared but had no matching error.
+    CodeNotFound {
+        /// The code that was not found, and the span of where that code was declared.
+        code: Spanned<String>,
+        /// Can be `None` when it is expected outside the current file
+        expected_line: Option<NonZeroUsize>,
+    },
     /// A ui test checking for failure does not have any failure patterns
     NoPatternsFound,
     /// A ui test checking for success has failure patterns

src/lib.rs

@@ -14,7 +14,7 @@ use color_eyre::eyre::{eyre, Result};
 use crossbeam_channel::{unbounded, Receiver, Sender};
 use dependencies::{Build, BuildManager};
 use lazy_static::lazy_static;
-use parser::{ErrorMatch, MaybeSpanned, OptWithLine, Revisioned, Spanned};
+use parser::{ErrorMatch, ErrorMatchKind, MaybeSpanned, OptWithLine, Revisioned, Spanned};
 use regex::bytes::{Captures, Regex};
 use rustc_stderr::{Level, Message, Span};
 use status_emitter::{StatusEmitter, TestStatus};
@@ -1092,35 +1092,58 @@ fn check_annotations(
     // We will ensure that *all* diagnostics of level at least `lowest_annotation_level`
     // are matched.
     let mut lowest_annotation_level = Level::Error;
-    for &ErrorMatch {
-        ref pattern,
-        level,
-        line,
-    } in comments
+    for &ErrorMatch { ref kind, line } in comments
         .for_revision(revision)
         .flat_map(|r| r.error_matches.iter())
     {
-        seen_error_match = Some(pattern.span());
-        // If we found a diagnostic with a level annotation, make sure that all
-        // diagnostics of that level have annotations, even if we don't end up finding a matching diagnostic
-        // for this pattern.
-        if lowest_annotation_level > level {
-            lowest_annotation_level = level;
+        match kind {
+            ErrorMatchKind::Code(code) => {
+                seen_error_match = Some(code.span());
+            }
+            &ErrorMatchKind::Pattern { ref pattern, level } => {
+                seen_error_match = Some(pattern.span());
+                // If we found a diagnostic with a level annotation, make sure that all
+                // diagnostics of that level have annotations, even if we don't end up finding a matching diagnostic
+                // for this pattern.
+                if lowest_annotation_level > level {
+                    lowest_annotation_level = level;
+                }
+            }
         }
 
         if let Some(msgs) = messages.get_mut(line.get()) {
-            let found = msgs
-                .iter()
-                .position(|msg| pattern.matches(&msg.message) && msg.level == level);
-            if let Some(found) = found {
-                msgs.remove(found);
-                continue;
+            match kind {
+                &ErrorMatchKind::Pattern { ref pattern, level } => {
+                    let found = msgs
+                        .iter()
+                        .position(|msg| pattern.matches(&msg.message) && msg.level == level);
+                    if let Some(found) = found {
+                        msgs.remove(found);
+                        continue;
+                    }
+                }
+                ErrorMatchKind::Code(code) => {
+                    let found = msgs.iter().position(|msg| {
+                        msg.level >= Level::Warn
+                            && msg.code.as_ref().is_some_and(|msg| *msg == **code)
+                    });
+                    if let Some(found) = found {
+                        msgs.remove(found);
+                        continue;
+                    }
+                }
             }
         }
 
-        errors.push(Error::PatternNotFound {
-            pattern: pattern.clone(),
-            expected_line: Some(line),
+        errors.push(match kind {
+            ErrorMatchKind::Pattern { pattern, .. } => Error::PatternNotFound {
+                pattern: pattern.clone(),
+                expected_line: Some(line),
+            },
+            ErrorMatchKind::Code(code) => Error::CodeNotFound {
+                code: code.clone(),
+                expected_line: Some(line),
+            },
         });
     }
 

src/parser.rs

@@ -178,10 +178,20 @@ pub enum Pattern {
     Regex(Regex),
 }
 
+#[derive(Debug, Clone)]
+pub(crate) enum ErrorMatchKind {
+    /// A level and pattern pair parsed from a `//~ LEVEL: Message` comment.
+    Pattern {
+        pattern: Spanned<Pattern>,
+        level: Level,
+    },
+    /// An error code parsed from a `//~ error_code` comment.
+    Code(Spanned<String>),
+}
+
 #[derive(Debug)]
 pub(crate) struct ErrorMatch {
-    pub pattern: Spanned<Pattern>,
-    pub level: Level,
+    pub(crate) kind: ErrorMatchKind,
     /// The line this pattern is expecting to find a message in.
     pub line: NonZeroUsize,
 }
@@ -260,6 +270,7 @@ impl Comments {
                 }
             }
         }
+
         if parser.errors.is_empty() {
             Ok(parser.comments)
         } else {
@@ -707,7 +718,10 @@ impl<CommentsType> CommentParser<CommentsType> {
 }
 
 impl CommentParser<&mut Revisioned> {
-    // parse something like (\[[a-z]+(,[a-z]+)*\])?(?P<offset>\||[\^]+)? *(?P<level>ERROR|HELP|WARN|NOTE): (?P<text>.*)
+    // parse something like:
+    // (\[[a-z]+(,[a-z]+)*\])?
+    // (?P<offset>\||[\^]+)? *
+    // ((?P<level>ERROR|HELP|WARN|NOTE): (?P<text>.*))|(?P<code>[a-z0-9_:]+)
     fn parse_pattern(&mut self, pattern: Spanned<&str>, fallthrough_to: &mut Option<NonZeroUsize>) {
         let (match_line, pattern) = match pattern.chars().next() {
             Some('|') => (
@@ -750,43 +764,52 @@ impl CommentParser<&mut Revisioned> {
         };
 
         let pattern = pattern.trim_start();
-        let offset = match pattern.chars().position(|c| !c.is_ascii_alphabetic()) {
-            Some(offset) => offset,
-            None => {
-                self.error(pattern.span(), "pattern without level");
-                return;
-            }
-        };
+        let offset = pattern
+            .bytes()
+            .position(|c| !(c.is_ascii_alphanumeric() || c == b'_' || c == b':'))
+            .unwrap_or(pattern.len());
+
+        let (level_or_code, pattern) = pattern.split_at(offset);
+        if let Some(level) = level_or_code.strip_suffix(":") {
+            let level = match (*level).parse() {
+                Ok(level) => level,
+                Err(msg) => {
+                    self.error(level.span(), msg);
+                    return;
+                }
+            };
 
-        let (level, pattern) = pattern.split_at(offset);
-        let level = match (*level).parse() {
-            Ok(level) => level,
-            Err(msg) => {
-                self.error(level.span(), msg);
-                return;
-            }
-        };
-        let pattern = match pattern.strip_prefix(":") {
-            Some(offset) => offset,
-            None => {
-                self.error(pattern.span(), "no `:` after level found");
-                return;
-            }
-        };
+            let pattern = pattern.trim();
 
-        let pattern = pattern.trim();
+            self.check(pattern.span(), !pattern.is_empty(), "no pattern specified");
 
-        self.check(pattern.span(), !pattern.is_empty(), "no pattern specified");
+            let pattern = self.parse_error_pattern(pattern);
 
-        let pattern = self.parse_error_pattern(pattern);
+            self.error_matches.push(ErrorMatch {
+                kind: ErrorMatchKind::Pattern { pattern, level },
+                line: match_line,
+            });
+        } else if (*level_or_code).parse::<Level>().is_ok() {
+            // Shouldn't conflict with any real diagnostic code
+            self.error(pattern.span(), "no `:` after level found");
+            return;
+        } else if !pattern.trim_start().is_empty() {
+            self.error(
+                pattern.span(),
+                format!("text found after error code `{}`", *level_or_code),
+            );
+            return;
+        } else {
+            self.error_matches.push(ErrorMatch {
+                kind: ErrorMatchKind::Code(Spanned::new(
+                    level_or_code.to_string(),
+                    level_or_code.span(),
+                )),
+                line: match_line,
+            });
+        };
 
         *fallthrough_to = Some(match_line);
-
-        self.error_matches.push(ErrorMatch {
-            pattern,
-            level,
-            line: match_line,
-        });
     }
 }
 

src/parser/tests.rs

@@ -1,5 +1,5 @@
 use crate::{
-    parser::{Condition, Pattern},
+    parser::{Condition, ErrorMatchKind, Pattern},
     Error,
 };
 
@@ -18,8 +18,11 @@ fn main() {
     println!("parsed comments: {:#?}", comments);
     assert_eq!(comments.revisioned.len(), 1);
     let revisioned = &comments.revisioned[&vec![]];
-    assert_eq!(revisioned.error_matches[0].pattern.line().get(), 5);
-    match &*revisioned.error_matches[0].pattern {
+    let ErrorMatchKind::Pattern { pattern, .. } = &revisioned.error_matches[0].kind else {
+        panic!("expected pattern matcher");
+    };
+    assert_eq!(pattern.line().get(), 5);
+    match &**pattern {
         Pattern::SubString(s) => {
             assert_eq!(
                 s,
@@ -30,6 +33,24 @@ fn main() {
     }
 }
 
+#[test]
+fn parse_error_code_comment() {
+    let s = r"
+fn main() {
+    let _x: i32 = 0u32; //~ E0308
+}
+    ";
+    let comments = Comments::parse(s).unwrap();
+    println!("parsed comments: {:#?}", comments);
+    assert_eq!(comments.revisioned.len(), 1);
+    let revisioned = &comments.revisioned[&vec![]];
+    let ErrorMatchKind::Code(code) = &revisioned.error_matches[0].kind else {
+        panic!("expected diagnostic code matcher");
+    };
+    assert_eq!(code.line().get(), 3);
+    assert_eq!(**code, "E0308");
+}
+
 #[test]
 fn parse_missing_level() {
     let s = r"
@@ -44,7 +65,7 @@ fn main() {
     assert_eq!(errors.len(), 1);
     match &errors[0] {
         Error::InvalidComment { msg, span } if span.line_start.get() == 5 => {
-            assert_eq!(msg, "unknown level `encountered`")
+            assert_eq!(msg, "text found after error code `encountered`")
         }
         _ => unreachable!(),
     }

src/rustc_stderr.rs

@@ -5,13 +5,19 @@ use std::{
     path::{Path, PathBuf},
 };
 
+#[derive(serde::Deserialize, Debug)]
+struct RustcDiagnosticCode {
+    code: String,
+}
+
 #[derive(serde::Deserialize, Debug)]
 struct RustcMessage {
     rendered: Option<String>,
     spans: Vec<RustcSpan>,
     level: String,
     message: String,
     children: Vec<RustcMessage>,
+    code: Option<RustcDiagnosticCode>,
 }
 
 #[derive(Copy, Clone, Debug, PartialOrd, Ord, PartialEq, Eq)]
@@ -31,6 +37,7 @@ pub struct Message {
     pub(crate) level: Level,
     pub(crate) message: String,
     pub(crate) line_col: Option<Span>,
+    pub(crate) code: Option<String>,
 }
 
 /// Information about macro expansion.
@@ -126,6 +133,7 @@ impl RustcMessage {
             level: self.level.parse().unwrap(),
             message: self.message,
             line_col: line,
+            code: self.code.map(|x| x.code),
         };
         if let Some(line) = line {
             if messages.len() <= line.line_start.get() {