Rust: integrate rust code generation into //rust/codegen

rust/ast-generator/BUILD.bazel

@@ -1,3 +1,4 @@
+load("@tree_sitter_extractors_deps//:defs.bzl", "aliases", "all_crate_deps")
 load("//misc/bazel:rust.bzl", "codeql_rust_binary")
 
 codeql_rust_binary(
@@ -12,3 +13,9 @@ codeql_rust_binary(
         normal = True,
     ),
 )
+
+filegroup(
+    name = "manifest",
+    srcs = ["Cargo.toml"],
+    visibility = ["//rust:__subpackages__"],
+)

rust/ast-generator/src/codegen.rs

@@ -12,5 +12,5 @@ pub fn ensure_file_contents(
     contents: &String,
     _check: bool,
 ) {
-    std::fs::write(path, contents).expect("Unable to write file");
+    std::fs::write(path, contents).unwrap_or_else(|_| panic!("Unable to write {}", path.display()));
 }

rust/ast-generator/src/main.rs

@@ -57,7 +57,7 @@ fn write_schema(
         buf,
         "# Generated by `ast-generator`, do not edit by hand.\n"
     )?;
-    writeln!(buf, "from .prelude import *\n")?;
+    writeln!(buf, "from .prelude import *")?;
 
     for node in &grammar.enums {
         let super_classses = if let Some(cls) = super_types.get(&node.name) {
@@ -66,9 +66,13 @@ fn write_schema(
         } else {
             "AstNode".to_owned()
         };
-        writeln!(buf, "class {}({}):", class_name(&node.name), super_classses)?;
+        writeln!(
+            buf,
+            "\nclass {}({}):",
+            class_name(&node.name),
+            super_classses
+        )?;
         writeln!(buf, "   pass")?;
-        writeln!(buf)?;
     }
     for node in &grammar.nodes {
         let super_classses = if let Some(cls) = super_types.get(&node.name) {
@@ -77,7 +81,12 @@ fn write_schema(
         } else {
             "AstNode".to_owned()
         };
-        writeln!(buf, "class {}({}):", class_name(&node.name), super_classses)?;
+        writeln!(
+            buf,
+            "\nclass {}({}):",
+            class_name(&node.name),
+            super_classses
+        )?;
         let mut empty = true;
         for field in get_fields(node) {
             if field.tp == "SyntaxToken" {
@@ -111,7 +120,6 @@ fn write_schema(
         if empty {
             writeln!(buf, "   pass")?;
         }
-        writeln!(buf)?;
     }
     Ok(String::from_utf8_lossy(&buf).to_string())
 }
@@ -409,6 +417,8 @@ fn write_extractor(grammar: &AstSrc) -> std::io::Result<String> {
     writeln!(
         buf,
         "//! Generated by `ast-generator`, do not edit by hand.\n
+#![cfg_attr(any(), rustfmt::skip)]
+
 use crate::generated;
 use super::base::{{TextValue, Translator}};
 use crate::trap::{{Label, TrapId}};
@@ -548,7 +558,7 @@ fn main() -> std::io::Result<()> {
         super_class_x.cmp(&super_class_y).then(x.name.cmp(&y.name))
     });
     let schema = write_schema(&grammar, super_types)?;
-    let schema_path = PathBuf::from("../schema/ast.py");
+    let schema_path = project_root().join("schema/ast.py");
     codegen::ensure_file_contents(
         crate::flags::CodegenType::Grammar,
         &schema_path,
@@ -557,7 +567,7 @@ fn main() -> std::io::Result<()> {
     );
 
     let extractor = write_extractor(&grammar)?;
-    let extractor_path = PathBuf::from("../extractor/src/translate/generated.rs");
+    let extractor_path = project_root().join("extractor/src/translate/generated.rs");
     codegen::ensure_file_contents(
         crate::flags::CodegenType::Grammar,
         &extractor_path,