Move GitHub rendering to ruff_db (#20320)

## Summary

This is the GitHub analog to #20117. This PR prepares to add a GitHub
output format to ty by moving the implementation from `ruff_linter` to
`ruff_db`. Hopefully this one is a bit easier to review
commit-by-commit. Almost all of the refactoring this time is in the
first commit, then the second commit adds the new `OutputFormat` variant
and moves the file into `ruff_db`. The third commit is just a small
touch up to use a private method that accommodates ty files so that we
can run the tests and update/move the snapshots.

I had to push a fourth commit to fix and test diagnostics without a
span/file.

## Test Plan

Existing tests

crates/ruff/src/printer.rs

@@ -14,9 +14,7 @@ use ruff_db::diagnostic::{
 };
 use ruff_linter::fs::relativize_path;
 use ruff_linter::logging::LogLevel;
-use ruff_linter::message::{
-    Emitter, EmitterContext, GithubEmitter, GroupedEmitter, SarifEmitter, TextEmitter,
-};
+use ruff_linter::message::{Emitter, EmitterContext, GroupedEmitter, SarifEmitter, TextEmitter};
 use ruff_linter::notify_user;
 use ruff_linter::settings::flags::{self};
 use ruff_linter::settings::types::{OutputFormat, UnsafeFixes};
@@ -290,7 +288,11 @@ impl Printer {
                 self.write_summary_text(writer, diagnostics)?;
             }
             OutputFormat::Github => {
-                GithubEmitter.emit(writer, &diagnostics.inner, &context)?;
+                let config = DisplayDiagnosticConfig::default()
+                    .format(DiagnosticFormat::Github)
+                    .preview(preview);
+                let value = DisplayDiagnostics::new(&context, &config, &diagnostics.inner);
+                write!(writer, "{value}")?;
             }
             OutputFormat::Gitlab => {
                 let config = DisplayDiagnosticConfig::default()

crates/ruff_db/src/diagnostic/mod.rs

@@ -1447,6 +1447,11 @@ pub enum DiagnosticFormat {
     /// [Code Quality]: https://docs.gitlab.com/ci/testing/code_quality/#code-quality-report-format
     #[cfg(feature = "serde")]
     Gitlab,
+
+    /// Print diagnostics in the format used by [GitHub Actions] workflow error annotations.
+    ///
+    /// [GitHub Actions]: https://docs.github.com/en/actions/reference/workflows-and-actions/workflow-commands#setting-an-error-message
+    Github,
 }
 
 /// A representation of the kinds of messages inside a diagnostic.

crates/ruff_db/src/diagnostic/render.rs

@@ -25,11 +25,13 @@ use super::{
 
 use azure::AzureRenderer;
 use concise::ConciseRenderer;
+use github::GithubRenderer;
 use pylint::PylintRenderer;
 
 mod azure;
 mod concise;
 mod full;
+mod github;
 #[cfg(feature = "serde")]
 mod gitlab;
 #[cfg(feature = "serde")]
@@ -142,6 +144,9 @@ impl std::fmt::Display for DisplayDiagnostics<'_> {
             DiagnosticFormat::Gitlab => {
                 gitlab::GitlabRenderer::new(self.resolver).render(f, self.diagnostics)?;
             }
+            DiagnosticFormat::Github => {
+                GithubRenderer::new(self.resolver).render(f, self.diagnostics)?;
+            }
         }
 
         Ok(())

crates/ruff_db/src/diagnostic/render/github.rs

@@ -0,0 +1,109 @@
+use crate::diagnostic::{Diagnostic, FileResolver};
+
+pub(super) struct GithubRenderer<'a> {
+    resolver: &'a dyn FileResolver,
+}
+
+impl<'a> GithubRenderer<'a> {
+    pub(super) fn new(resolver: &'a dyn FileResolver) -> Self {
+        Self { resolver }
+    }
+
+    pub(super) fn render(
+        &self,
+        f: &mut std::fmt::Formatter,
+        diagnostics: &[Diagnostic],
+    ) -> std::fmt::Result {
+        for diagnostic in diagnostics {
+            write!(
+                f,
+                "::error title=Ruff ({code})",
+                code = diagnostic.secondary_code_or_id()
+            )?;
+
+            if let Some(span) = diagnostic.primary_span() {
+                let file = span.file();
+                write!(f, ",file={file}", file = file.path(self.resolver))?;
+
+                let (start_location, end_location) = if self.resolver.is_notebook(file) {
+                    // We can't give a reasonable location for the structured formats,
+                    // so we show one that's clearly a fallback
+                    None
+                } else {
+                    let diagnostic_source = file.diagnostic_source(self.resolver);
+                    let source_code = diagnostic_source.as_source_code();
+
+                    span.range().map(|range| {
+                        (
+                            source_code.line_column(range.start()),
+                            source_code.line_column(range.end()),
+                        )
+                    })
+                }
+                .unwrap_or_default();
+
+                write!(
+                    f,
+                    ",line={row},col={column},endLine={end_row},endColumn={end_column}::",
+                    row = start_location.line,
+                    column = start_location.column,
+                    end_row = end_location.line,
+                    end_column = end_location.column,
+                )?;
+
+                write!(
+                    f,
+                    "{path}:{row}:{column}: ",
+                    path = file.relative_path(self.resolver).display(),
+                    row = start_location.line,
+                    column = start_location.column,
+                )?;
+            } else {
+                write!(f, "::")?;
+            }
+
+            if let Some(code) = diagnostic.secondary_code() {
+                write!(f, "{code}")?;
+            } else {
+                write!(f, "{id}:", id = diagnostic.id())?;
+            }
+
+            writeln!(f, " {}", diagnostic.body())?;
+        }
+
+        Ok(())
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use crate::diagnostic::{
+        DiagnosticFormat,
+        render::tests::{TestEnvironment, create_diagnostics, create_syntax_error_diagnostics},
+    };
+
+    #[test]
+    fn output() {
+        let (env, diagnostics) = create_diagnostics(DiagnosticFormat::Github);
+        insta::assert_snapshot!(env.render_diagnostics(&diagnostics));
+    }
+
+    #[test]
+    fn syntax_errors() {
+        let (env, diagnostics) = create_syntax_error_diagnostics(DiagnosticFormat::Github);
+        insta::assert_snapshot!(env.render_diagnostics(&diagnostics));
+    }
+
+    #[test]
+    fn missing_file() {
+        let mut env = TestEnvironment::new();
+        env.format(DiagnosticFormat::Github);
+
+        let diag = env.err().build();
+
+        insta::assert_snapshot!(
+            env.render(&diag),
+            @"::error title=Ruff (test-diagnostic)::test-diagnostic: main diagnostic message",
+        );
+    }
+}

crates/ruff_db/src/diagnostic/render/snapshots/ruff_db__diagnostic__render__github__tests__output.snap

@@ -1,7 +1,6 @@
 ---
-source: crates/ruff_linter/src/message/github.rs
-expression: content
-snapshot_kind: text
+source: crates/ruff_db/src/diagnostic/render/github.rs
+expression: env.render_diagnostics(&diagnostics)
 ---
 ::error title=Ruff (F401),file=fib.py,line=1,col=8,endLine=1,endColumn=10::fib.py:1:8: F401 `os` imported but unused
 ::error title=Ruff (F841),file=fib.py,line=6,col=5,endLine=6,endColumn=6::fib.py:6:5: F841 Local variable `x` is assigned to but never used

crates/ruff_db/src/diagnostic/render/snapshots/ruff_db__diagnostic__render__github__tests__syntax_errors.snap

@@ -1,6 +1,6 @@
 ---
-source: crates/ruff_linter/src/message/github.rs
-expression: content
+source: crates/ruff_db/src/diagnostic/render/github.rs
+expression: env.render_diagnostics(&diagnostics)
 ---
 ::error title=Ruff (invalid-syntax),file=syntax_errors.py,line=1,col=15,endLine=2,endColumn=1::syntax_errors.py:1:15: invalid-syntax: Expected one or more symbol names after import
 ::error title=Ruff (invalid-syntax),file=syntax_errors.py,line=3,col=12,endLine=4,endColumn=1::syntax_errors.py:3:12: invalid-syntax: Expected ')', found newline

crates/ruff_linter/src/message/github.rs

@@ -1,90 +0,0 @@
-use std::io::Write;
-
-use ruff_db::diagnostic::Diagnostic;
-use ruff_source_file::LineColumn;
-
-use crate::fs::relativize_path;
-use crate::message::{Emitter, EmitterContext};
-
-/// Generate error workflow command in GitHub Actions format.
-/// See: [GitHub documentation](https://docs.github.com/en/actions/reference/workflow-commands-for-github-actions#setting-an-error-message)
-#[derive(Default)]
-pub struct GithubEmitter;
-
-impl Emitter for GithubEmitter {
-    fn emit(
-        &mut self,
-        writer: &mut dyn Write,
-        diagnostics: &[Diagnostic],
-        context: &EmitterContext,
-    ) -> anyhow::Result<()> {
-        for diagnostic in diagnostics {
-            let source_location = diagnostic.ruff_start_location().unwrap_or_default();
-            let filename = diagnostic.expect_ruff_filename();
-            let location = if context.is_notebook(&filename) {
-                // We can't give a reasonable location for the structured formats,
-                // so we show one that's clearly a fallback
-                LineColumn::default()
-            } else {
-                source_location
-            };
-
-            let end_location = diagnostic.ruff_end_location().unwrap_or_default();
-
-            write!(
-                writer,
-                "::error title=Ruff ({code}),file={file},line={row},col={column},endLine={end_row},endColumn={end_column}::",
-                code = diagnostic.secondary_code_or_id(),
-                file = filename,
-                row = source_location.line,
-                column = source_location.column,
-                end_row = end_location.line,
-                end_column = end_location.column,
-            )?;
-
-            write!(
-                writer,
-                "{path}:{row}:{column}:",
-                path = relativize_path(&filename),
-                row = location.line,
-                column = location.column,
-            )?;
-
-            if let Some(code) = diagnostic.secondary_code() {
-                write!(writer, " {code}")?;
-            } else {
-                write!(writer, " {id}:", id = diagnostic.id())?;
-            }
-
-            writeln!(writer, " {}", diagnostic.body())?;
-        }
-
-        Ok(())
-    }
-}
-
-#[cfg(test)]
-mod tests {
-    use insta::assert_snapshot;
-
-    use crate::message::GithubEmitter;
-    use crate::message::tests::{
-        capture_emitter_output, create_diagnostics, create_syntax_error_diagnostics,
-    };
-
-    #[test]
-    fn output() {
-        let mut emitter = GithubEmitter;
-        let content = capture_emitter_output(&mut emitter, &create_diagnostics());
-
-        assert_snapshot!(content);
-    }
-
-    #[test]
-    fn syntax_errors() {
-        let mut emitter = GithubEmitter;
-        let content = capture_emitter_output(&mut emitter, &create_syntax_error_diagnostics());
-
-        assert_snapshot!(content);
-    }
-}

crates/ruff_linter/src/message/mod.rs

@@ -9,7 +9,6 @@ use ruff_db::diagnostic::{
 };
 use ruff_db::files::File;
 
-pub use github::GithubEmitter;
 pub use grouped::GroupedEmitter;
 use ruff_notebook::NotebookIndex;
 use ruff_source_file::SourceFile;
@@ -20,7 +19,6 @@ pub use text::TextEmitter;
 use crate::Fix;
 use crate::registry::Rule;
 
-mod github;
 mod grouped;
 mod sarif;
 mod text;