yeast: Integrate yeast with shared tree-sitter extractor

extract() gains a rules parameter. When empty, uses tree-sitter native
traversal (no behavior change). When non-empty, runs yeast desugaring
and extracts via traverse_yeast.

Adds AstNode trait abstracting over tree_sitter::Node and yeast::Node,
with minimal changes to existing Visitor methods (Node -> &N in 6
signatures).

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

Author: tausbn

ruby/extractor/src/extractor.rs

@@ -123,6 +123,8 @@ pub fn run(options: Options) -> std::io::Result<()> {
                     &path,
                     &source,
                     &[],
+                    vec![],
+                    None,
                 );
 
                 let (ranges, line_breaks) = scan_erb(
@@ -211,6 +213,8 @@ pub fn run(options: Options) -> std::io::Result<()> {
                 &path,
                 &source,
                 &code_ranges,
+                vec![],
+                None,
             );
             std::fs::create_dir_all(src_archive_file.parent().unwrap())?;
             if needs_conversion {

shared/tree-sitter-extractor/Cargo.toml

@@ -20,6 +20,7 @@ serde_json = "1.0"
 chrono = { version = "0.4.42", features = ["serde"] }
 num_cpus = "1.17.0"
 zstd = "0.13.3"
+yeast = { path = "../yeast" }
 
 [dev-dependencies]
 tree-sitter-ql = "0.23.1"

shared/tree-sitter-extractor/src/extractor/mod.rs

@@ -18,6 +18,45 @@ use tree_sitter::{Language, Node, Parser, Range, Tree};
 
 pub mod simple;
 
+/// Trait abstracting over tree-sitter and yeast node types for extraction.
+trait AstNode {
+    fn kind(&self) -> &str;
+    fn is_named(&self) -> bool;
+    fn is_missing(&self) -> bool;
+    fn is_error(&self) -> bool;
+    fn is_extra(&self) -> bool;
+    fn start_position(&self) -> tree_sitter::Point;
+    fn end_position(&self) -> tree_sitter::Point;
+    fn byte_range(&self) -> std::ops::Range<usize>;
+    fn start_byte(&self) -> usize { self.byte_range().start }
+    fn end_byte(&self) -> usize { self.byte_range().end }
+    /// For yeast nodes with synthetic content, return it. Otherwise None.
+    fn opt_string_content(&self) -> Option<String> { None }
+}
+
+impl<'a> AstNode for Node<'a> {
+    fn kind(&self) -> &str { Node::kind(self) }
+    fn is_named(&self) -> bool { Node::is_named(self) }
+    fn is_missing(&self) -> bool { Node::is_missing(self) }
+    fn is_error(&self) -> bool { Node::is_error(self) }
+    fn is_extra(&self) -> bool { Node::is_extra(self) }
+    fn start_position(&self) -> tree_sitter::Point { Node::start_position(self) }
+    fn end_position(&self) -> tree_sitter::Point { Node::end_position(self) }
+    fn byte_range(&self) -> std::ops::Range<usize> { Node::byte_range(self) }
+}
+
+impl AstNode for yeast::Node {
+    fn kind(&self) -> &str { yeast::Node::kind(self) }
+    fn is_named(&self) -> bool { yeast::Node::is_named(self) }
+    fn is_missing(&self) -> bool { yeast::Node::is_missing(self) }
+    fn is_error(&self) -> bool { yeast::Node::is_error(self) }
+    fn is_extra(&self) -> bool { yeast::Node::is_extra(self) }
+    fn start_position(&self) -> tree_sitter::Point { yeast::Node::start_position(self) }
+    fn end_position(&self) -> tree_sitter::Point { yeast::Node::end_position(self) }
+    fn byte_range(&self) -> std::ops::Range<usize> { yeast::Node::byte_range(self) }
+    fn opt_string_content(&self) -> Option<String> { yeast::Node::opt_string_content(self) }
+}
+
 /// Sets the tracing level based on the environment variables
 /// `RUST_LOG` and `CODEQL_VERBOSITY` (prioritized in that order),
 /// falling back to `warn` if neither is set.
@@ -204,6 +243,9 @@ pub fn location_label(writer: &mut trap::Writer, location: trap::Location) -> tr
 }
 
 /// Extracts the source file at `path`, which is assumed to be canonicalized.
+/// When `rules` is non-empty, the parsed tree is first transformed through
+/// yeast before TRAP extraction. If `output_schema` is provided, it is used
+/// by the yeast runner to resolve output-only node kinds and fields.
 pub fn extract(
     language: &Language,
     language_prefix: &str,
@@ -214,6 +256,8 @@ pub fn extract(
     path: &Path,
     source: &[u8],
     ranges: &[Range],
+    rules: Vec<yeast::Rule>,
+    output_schema: Option<yeast::schema::Schema>,
 ) {
     let path_str = file_paths::normalize_and_transform_path(path, transformer);
     let span = tracing::span!(
@@ -236,13 +280,24 @@ pub fn extract(
         source,
         diagnostics_writer,
         trap_writer,
-        // TODO: should we handle path strings that are not valid UTF8 better?
         &path_str,
         file_label,
         language_prefix,
         schema,
     );
-    traverse(&tree, &mut visitor);
+
+    if rules.is_empty() {
+        traverse(&tree, &mut visitor);
+    } else {
+        let runner = match output_schema {
+            Some(schema) => yeast::Runner::with_schema(language.clone(), schema, rules),
+            None => yeast::Runner::new(language.clone(), rules),
+        };
+        let ast = runner
+            .run_from_tree(&tree)
+            .unwrap_or_else(|e| panic!("Desugaring failed for {path_str}: {e}"));
+        traverse_yeast(&ast, &mut visitor);
+    }
 
     parser.reset();
 }
@@ -329,11 +384,11 @@ impl<'a> Visitor<'a> {
         );
     }
 
-    fn record_parse_error_for_node(
+    fn record_parse_error_for_node<N: AstNode>(
         &mut self,
         message: &str,
         args: &[diagnostics::MessageArg],
-        node: Node,
+        node: &N,
         status_page: bool,
     ) {
         let loc = location_for(self, self.file_label, node);
@@ -357,7 +412,7 @@ impl<'a> Visitor<'a> {
         self.record_parse_error(loc_label, &mesg);
     }
 
-    fn enter_node(&mut self, node: Node) -> bool {
+    fn enter_node<N: AstNode>(&mut self, node: &N) -> bool {
         if node.is_missing() {
             self.record_parse_error_for_node(
                 "A parse error occurred (expected {} symbol). Check the syntax of the file. If the file is invalid, correct the error or {} the file from analysis.",
@@ -383,7 +438,7 @@ impl<'a> Visitor<'a> {
         true
     }
 
-    fn leave_node(&mut self, field_name: Option<&'static str>, node: Node) {
+    fn leave_node<N: AstNode>(&mut self, field_name: Option<&'static str>, node: &N) {
         if node.is_error() || node.is_missing() {
             return;
         }
@@ -434,7 +489,7 @@ impl<'a> Visitor<'a> {
                 fields,
                 name: table_name,
             } => {
-                if let Some(args) = self.complex_node(&node, fields, &child_nodes, id) {
+                if let Some(args) = self.complex_node(node, fields, &child_nodes, id) {
                     self.trap_writer.add_tuple(
                         &self.ast_node_location_table_name,
                         vec![trap::Arg::Label(id), trap::Arg::Label(loc_label)],
@@ -495,9 +550,9 @@ impl<'a> Visitor<'a> {
         }
     }
 
-    fn complex_node(
+    fn complex_node<N: AstNode>(
         &mut self,
-        node: &Node,
+        node: &N,
         fields: &[Field],
         child_nodes: &[ChildNode],
         parent_id: trap::Label,
@@ -529,7 +584,7 @@ impl<'a> Visitor<'a> {
                             diagnostics::MessageArg::Code(&format!("{:?}", child_node.type_name)),
                             diagnostics::MessageArg::Code(&format!("{:?}", field.type_info)),
                         ],
-                        *node,
+                        node,
                         false,
                     );
                 }
@@ -541,7 +596,7 @@ impl<'a> Visitor<'a> {
                         diagnostics::MessageArg::Code(child_node.field_name.unwrap_or("child")),
                         diagnostics::MessageArg::Code(&format!("{:?}", child_node.type_name)),
                     ],
-                    *node,
+                    node,
                     false,
                 );
             }
@@ -566,7 +621,7 @@ impl<'a> Visitor<'a> {
                             node.kind(),
                             column_name
                         );
-                        self.record_parse_error_for_node(&error_message, &[], *node, false);
+                        self.record_parse_error_for_node(&error_message, &[], node, false);
                     }
                 }
                 Storage::Table {
@@ -582,7 +637,7 @@ impl<'a> Visitor<'a> {
                                     diagnostics::MessageArg::Code(node.kind()),
                                     diagnostics::MessageArg::Code(table_name),
                                 ],
-                                *node,
+                                node,
                                 false,
                             );
                             break;
@@ -639,15 +694,17 @@ impl<'a> Visitor<'a> {
 }
 
 // Emit a slice of a source file as an Arg.
-fn sliced_source_arg(source: &[u8], n: Node) -> trap::Arg {
-    let range = n.byte_range();
-    trap::Arg::String(String::from_utf8_lossy(&source[range.start..range.end]).into_owned())
+fn sliced_source_arg<N: AstNode>(source: &[u8], n: &N) -> trap::Arg {
+    trap::Arg::String(n.opt_string_content().unwrap_or_else(|| {
+        let range = n.byte_range();
+        String::from_utf8_lossy(&source[range.start..range.end]).into_owned()
+    }))
 }
 
 // Emit a pair of `TrapEntry`s for the provided node, appropriately calibrated.
 // The first is the location and label definition, and the second is the
 // 'Located' entry.
-fn location_for(visitor: &mut Visitor, file_label: trap::Label, n: Node) -> trap::Location {
+fn location_for<N: AstNode>(visitor: &mut Visitor, file_label: trap::Label, n: &N) -> trap::Location {
     // Tree-sitter row, column values are 0-based while CodeQL starts
     // counting at 1. In addition Tree-sitter's row and column for the
     // end position are exclusive while CodeQL's end positions are inclusive.
@@ -715,6 +772,28 @@ fn location_for(visitor: &mut Visitor, file_label: trap::Label, n: Node) -> trap
 
 fn traverse(tree: &Tree, visitor: &mut Visitor) {
     let cursor = &mut tree.walk();
+    visitor.enter_node(&cursor.node());
+    let mut recurse = true;
+    loop {
+        if recurse && cursor.goto_first_child() {
+            recurse = visitor.enter_node(&cursor.node());
+        } else {
+            visitor.leave_node(cursor.field_name(), &cursor.node());
+
+            if cursor.goto_next_sibling() {
+                recurse = visitor.enter_node(&cursor.node());
+            } else if cursor.goto_parent() {
+                recurse = false;
+            } else {
+                break;
+            }
+        }
+    }
+}
+
+fn traverse_yeast(tree: &yeast::Ast, visitor: &mut Visitor) {
+    use yeast::Cursor;
+    let mut cursor = tree.walk();
     visitor.enter_node(cursor.node());
     let mut recurse = true;
     loop {

shared/tree-sitter-extractor/src/extractor/simple.rs

@@ -12,6 +12,10 @@ pub struct LanguageSpec {
     pub prefix: &'static str,
     pub ts_language: tree_sitter::Language,
     pub node_types: &'static str,
+    /// If set, the extractor validates TRAP output against these node types
+    /// instead of `node_types`. Use when desugaring produces an AST that
+    /// differs from the tree-sitter grammar.
+    pub output_node_types: Option<&'static str>,
     pub file_globs: Vec<String>,
 }
 
@@ -86,7 +90,8 @@ impl Extractor {
 
         let mut schemas = vec![];
         for lang in &self.languages {
-            let schema = node_types::read_node_types_str(lang.prefix, lang.node_types)?;
+            let effective_node_types = lang.output_node_types.unwrap_or(lang.node_types);
+            let schema = node_types::read_node_types_str(lang.prefix, effective_node_types)?;
             schemas.push(schema);
         }
 
@@ -162,6 +167,8 @@ impl Extractor {
                                     &path,
                                     &source,
                                     &[],
+                                    vec![],
+                                    None,
                                 );
                                 std::fs::create_dir_all(src_archive_file.parent().unwrap())?;
                                 std::fs::copy(&path, &src_archive_file)?;

shared/tree-sitter-extractor/tests/integration_test.rs

@@ -13,6 +13,7 @@ fn simple_extractor() {
         prefix: "ql",
         ts_language: tree_sitter_ql::LANGUAGE.into(),
         node_types: tree_sitter_ql::NODE_TYPES,
+        output_node_types: None,
         file_globs: vec!["*.qll".into()],
     };
 

shared/tree-sitter-extractor/tests/multiple_languages.rs

@@ -13,12 +13,14 @@ fn multiple_language_extractor() {
         prefix: "ql",
         ts_language: tree_sitter_ql::LANGUAGE.into(),
         node_types: tree_sitter_ql::NODE_TYPES,
+        output_node_types: None,
         file_globs: vec!["*.qll".into()],
     };
     let lang_json = simple::LanguageSpec {
         prefix: "json",
         ts_language: tree_sitter_json::LANGUAGE.into(),
         node_types: tree_sitter_json::NODE_TYPES,
+        output_node_types: None,
         file_globs: vec!["*.json".into(), "*Jsonfile".into()],
     };