feat: Only send needed data to task runner (no-changelog) (#11487)

packages/@n8n/task-runner/src/js-task-runner/built-ins-parser/built-ins-parser.ts

@@ -0,0 +1,142 @@
+import type { CallExpression, Identifier, Node, Program } from 'acorn';
+import { parse } from 'acorn';
+import { ancestor } from 'acorn-walk';
+import type { Result } from 'n8n-workflow';
+import { toResult } from 'n8n-workflow';
+
+import {
+	isAssignmentExpression,
+	isIdentifier,
+	isLiteral,
+	isMemberExpression,
+	isVariableDeclarator,
+} from './acorn-helpers';
+import { BuiltInsParserState } from './built-ins-parser-state';
+
+/**
+ * Class for parsing Code Node code to identify which built-in variables
+ * are accessed
+ */
+export class BuiltInsParser {
+	/**
+	 * Parses which built-in variables are accessed in the given code
+	 */
+	public parseUsedBuiltIns(code: string): Result<BuiltInsParserState, Error> {
+		return toResult(() => {
+			const wrappedCode = `async function VmCodeWrapper() { ${code} }`;
+			const ast = parse(wrappedCode, { ecmaVersion: 2025, sourceType: 'module' });
+
+			return this.identifyBuiltInsByWalkingAst(ast);
+		});
+	}
+
+	/** Traverse the AST of the script and mark any data needed for it to run. */
+	private identifyBuiltInsByWalkingAst(ast: Program) {
+		const accessedBuiltIns = new BuiltInsParserState();
+
+		ancestor(
+			ast,
+			{
+				CallExpression: this.visitCallExpression,
+				Identifier: this.visitIdentifier,
+			},
+			undefined,
+			accessedBuiltIns,
+		);
+
+		return accessedBuiltIns;
+	}
+
+	private visitCallExpression = (
+		node: CallExpression,
+		state: BuiltInsParserState,
+		ancestors: Node[],
+	) => {
+		// $(...)
+		const isDollar = node.callee.type === 'Identifier' && node.callee.name === '$';
+		if (!isDollar) return;
+
+		// $(): This is not valid, ignore
+		if (node.arguments.length === 0) {
+			return;
+		}
+
+		const firstArg = node.arguments[0];
+		if (!isLiteral(firstArg)) {
+			// $(variable): Can't easily determine statically, mark all nodes as needed
+			state.markNeedsAllNodes();
+			return;
+		}
+
+		if (typeof firstArg.value !== 'string') {
+			// $(123): Static value, but not a string --> invalid code --> ignore
+			return;
+		}
+
+		// $("node"): Static value, mark 'nodeName' as needed
+		state.markNodeAsNeeded(firstArg.value);
+
+		// Determine how $("node") is used
+		this.handlePrevNodeCall(node, state, ancestors);
+	};
+
+	private handlePrevNodeCall(_node: CallExpression, state: BuiltInsParserState, ancestors: Node[]) {
+		// $("node").item, .pairedItem or .itemMatching: In a case like this, the execution
+		// engine will traverse back from current node (i.e. the Code Node) to
+		// the "node" node and use `pairedItem`s to find which item is linked
+		// to the current item. So, we need to mark all nodes as needed.
+		// TODO: We could also mark all the nodes between the current node and
+		// the "node" node as needed, but that would require more complex logic.
+		const directParent = ancestors[ancestors.length - 2];
+		if (isMemberExpression(directParent)) {
+			const accessedProperty = directParent.property;
+
+			if (directParent.computed) {
+				// $("node")["item"], ["pairedItem"] or ["itemMatching"]
+				if (isLiteral(accessedProperty)) {
+					if (this.isPairedItemProperty(accessedProperty.value)) {
+						state.markNeedsAllNodes();
+					}
+					// Else: $("node")[123]: Static value, but not any of the ones above --> ignore
+				}
+				// $("node")[variable]
+				else if (isIdentifier(accessedProperty)) {
+					state.markNeedsAllNodes();
+				}
+			}
+			// $("node").item, .pairedItem or .itemMatching
+			else if (isIdentifier(accessedProperty) && this.isPairedItemProperty(accessedProperty.name)) {
+				state.markNeedsAllNodes();
+			}
+		} else if (isVariableDeclarator(directParent) || isAssignmentExpression(directParent)) {
+			// const variable = $("node") or variable = $("node"):
+			// In this case we would need to track down all the possible use sites
+			// of 'variable' and determine if `.item` is accessed on it. This is
+			// more complex and skipped for now.
+			// TODO: Optimize for this case
+			state.markNeedsAllNodes();
+		} else {
+			// Something else than the cases above. Mark all nodes as needed as it
+			// could be a dynamic access.
+			state.markNeedsAllNodes();
+		}
+	}
+
+	private visitIdentifier = (node: Identifier, state: BuiltInsParserState) => {
+		if (node.name === '$env') {
+			state.markEnvAsNeeded();
+		} else if (node.name === '$input' || node.name === '$json') {
+			state.markInputAsNeeded();
+		} else if (node.name === '$execution') {
+			state.markExecutionAsNeeded();
+		} else if (node.name === '$prevNode') {
+			state.markPrevNodeAsNeeded();
+		}
+	};
+
+	private isPairedItemProperty(
+		property?: string | boolean | null | number | RegExp | bigint,
+	): boolean {
+		return property === 'item' || property === 'pairedItem' || property === 'itemMatching';
+	}
+}