YEAST: fix one-shot rules for unnamed nodes and self-captures

One-shot desugaring rules now skip unnamed nodes (punctuation, keywords,
etc.) since rules are intended to target named nodes only.

Also prevent infinite recursion when a capture refers to the root node of
the matched tree (e.g. an @_ capture on the pattern root).

Additionally fix the swift.rs add_phase call to match the updated 3-arg
signature introduced by the one-shot phase kind commit.

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

Author: asgerf

shared/yeast/src/lib.rs

@@ -703,6 +703,7 @@ fn apply_one_shot_rules_inner(
     fresh: &tree_builder::FreshScope,
     rewrite_depth: usize,
 ) -> Result<Vec<Id>, String> {
+
     if rewrite_depth > MAX_REWRITE_DEPTH {
         return Err(format!(
             "Desugaring exceeded maximum rewrite depth ({MAX_REWRITE_DEPTH}). \
@@ -711,13 +712,29 @@ fn apply_one_shot_rules_inner(
     }
 
     let node_kind = ast.get_node(id).map(|n| n.kind()).unwrap_or("");
+
+    // Don't rewrite unnamed nodes (punctuation, keywords, etc.); leave them
+    // as-is. Rules target named nodes only.
+    if let Some(node) = ast.get_node(id) {
+        if !node.is_named() {
+            return Ok(vec![id]);
+        }
+    }
+
     for rule in index.rules_for_kind(node_kind) {
         if let Some(mut captures) = rule.try_match(ast, id)? {
             // Recursively translate every captured node before invoking the
             // transform. The transform's output uses output-schema kinds, so
             // we must translate captured input-schema nodes to their
             // output-schema equivalents first.
             captures.try_map_all_captures(|captured_id| {
+                // Avoid infinite recursion when a capture refers to the root
+                // node of the matched tree (e.g. an `@_` capture on the
+                // pattern root): re-analyzing it would match the same rule
+                // again indefinitely.
+                if captured_id == id {
+                    return Ok(captured_id);
+                }
                 let result =
                     apply_one_shot_rules_inner(index, ast, captured_id, fresh, rewrite_depth + 1)?;
                 if result.len() != 1 {

unified/extractor/src/languages/swift/swift.rs

@@ -1,5 +1,5 @@
 use codeql_extractor::extractor::simple;
-use yeast::{rule, DesugaringConfig};
+use yeast::{rule, DesugaringConfig, PhaseKind};
 
 fn desugaring_rules() -> Vec<yeast::Rule> {
     vec![
@@ -12,7 +12,7 @@ fn desugaring_rules() -> Vec<yeast::Rule> {
 }
 
 pub fn language_spec() -> simple::LanguageSpec {
-    let desugar = DesugaringConfig::new().add_phase("desugar", desugaring_rules());
+    let desugar = DesugaringConfig::new().add_phase("desugar", PhaseKind::Repeating, desugaring_rules());
     simple::LanguageSpec {
         prefix: "swift",
         ts_language: tree_sitter_swift::LANGUAGE.into(),