perf(linter/plugins): lazy deserialize comments array

apps/oxlint/src-js/generated/deserialize.js

@@ -1,7 +1,7 @@
 // Auto-generated code, DO NOT EDIT DIRECTLY!
 // To edit this generated file you have to edit `tasks/ast_tools/src/generators/raw_transfer.rs`.
 
-let uint8, uint32, float64, sourceText, sourceIsAscii, sourceByteLen, parent = null, getLoc;
+let uint8, uint32, float64, sourceText, sourceIsAscii, sourceByteLen, astId = 0, parent = null, getLoc;
 
 const textDecoder = new TextDecoder('utf-8', { ignoreBOM: true }),
   decodeStr = textDecoder.decode.bind(textDecoder),
@@ -38,13 +38,33 @@ function deserializeWith(buffer, sourceTextInput, sourceByteLenInput, getLocInpu
 
 function deserializeProgram(pos) {
   let end = deserializeU32(pos + 4),
+    ref_uint32 = uint32,
+    ref_uint8 = uint8,
+    ref_sourceText = sourceText,
+    localAstId = ++astId,
     program = parent = {
       __proto__: NodeProto,
       type: 'Program',
       body: null,
       sourceType: deserializeModuleKind(pos + 125),
       hashbang: null,
-      comments: deserializeVecComment(pos + 24),
+      get comments() {
+        if (localAstId !== astId) {throw Error(
+            'The AST being accessed has already been cleaned up. Please ensure that the plugin works synchronously.',
+          );}
+        // restore buffers
+        uint32 = ref_uint32;
+        uint8 = ref_uint8;
+        sourceText = ref_sourceText;
+        // deserialize the comments
+        let c = deserializeVecComment(pos + 24);
+        // drop the references
+        ref_uint32 = void 0;
+        ref_uint8 = void 0;
+        ref_sourceText = void 0;
+        Object.defineProperty(this, 'comments', { value: c });
+        return c;
+      },
       start: 0,
       end,
       range: [0, end],

crates/oxc_ast/src/serialize/mod.rs

@@ -124,12 +124,38 @@ impl Program<'_> {
     const start = IS_TS ? 0 : DESER[u32](POS_OFFSET.span.start),
         end = DESER[u32](POS_OFFSET.span.end);
 
+
+    /* IF LINTER */
+    // Buffers will be cleaned up after the main program is deserialized.
+    // We hold references here in case the comments need to be later accessed.
+    let ref_uint32 = uint32;
+    let ref_uint8 = uint8;
+    let ref_sourceText = sourceText;
+    const localAstId = ++astId;
+    /* END_IF */
+
     const program = parent = {
         type: 'Program',
         body: null,
         sourceType: DESER[ModuleKind](POS_OFFSET.source_type.module_kind),
         hashbang: null,
-        ...(COMMENTS && { comments: DESER[Vec<Comment>](POS_OFFSET.comments) }),
+        /* IF LINTER */
+        get comments() {
+            if (localAstId !== astId) throw new Error(`The AST being accessed has already been cleaned up. Please ensure that the plugin works synchronously.`);
+            // restore buffers
+            uint32 = ref_uint32;
+            uint8 = ref_uint8;
+            sourceText = ref_sourceText;
+            // deserialize the comments
+            const c = DESER[Vec<Comment>](POS_OFFSET.comments);
+            // drop the references
+            ref_uint32 = undefined;
+            ref_uint8 = undefined;
+            ref_sourceText = undefined;
+            Object.defineProperty(this, 'comments', { value: c });
+            return c;
+        },
+        /* END_IF */
         start,
         end,
         ...(RANGE && { range: [start, end] }),

tasks/ast_tools/src/generators/raw_transfer.rs

@@ -136,6 +136,7 @@ fn generate_deserializers(
     let mut code = format!("
         let uint8, uint32, float64, sourceText, sourceIsAscii, sourceByteLen;
 
+        let astId = 0;
         let parent = null;
         let getLoc;
 
@@ -221,7 +222,7 @@ fn generate_deserializers(
     }
 
     impl VariantGenerator<7> for VariantGen {
-        const FLAG_NAMES: [&str; 7] =
+        const FLAG_NAMES: [&str;7] =
             ["IS_TS", "RANGE", "LOC", "PARENT", "PRESERVE_PARENS", "COMMENTS", "LINTER"];
 
         fn variants(&mut self) -> Vec<[bool; 7]> {
@@ -240,8 +241,7 @@ fn generate_deserializers(
 
                         variants.push([
                             is_ts, range, /* loc */ false, parent,
-                            /* preserve_parens */ true, /* comments */ false,
-                            /* linter */ false,
+                            /* preserve_parens */ true, /* comments */ false, /* linter */ false,
                         ]);
                     }
                 }
@@ -251,8 +251,7 @@ fn generate_deserializers(
             self.variant_paths.push(format!("{OXLINT_APP_PATH}/src-js/generated/deserialize.js"));
             variants.push([
                 /* is_ts */ true, /* range */ true, /* loc */ true,
-                /* parent */ true, /* preserve_parens */ false, /* comments */ true,
-                /* linter */ true,
+                /* parent */ true, /* preserve_parens */ false, /* comments */ true, /* linter */ true,
             ]);
 
             variants