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Merge pull request #16061 from RasmusWL/js-extractor-fix
JS: More robust CommonJS/ES2015 detection logic for extractor
2 parents 116873c + 64321b3 commit 9082972

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+581
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‎javascript/extractor/src/com/semmle/js/extractor/AbstractDetector.java‎

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package com.semmle.js.extractor;
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import com.semmle.js.ast.AssignmentExpression;
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import com.semmle.js.ast.BlockStatement;
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import com.semmle.js.ast.CallExpression;
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import com.semmle.js.ast.Expression;
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import com.semmle.js.ast.ExpressionStatement;
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import com.semmle.js.ast.IFunction;
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import com.semmle.js.ast.Identifier;
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import com.semmle.js.ast.IfStatement;
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import com.semmle.js.ast.MemberExpression;
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import com.semmle.js.ast.Node;
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import com.semmle.js.ast.ParenthesizedExpression;
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import com.semmle.js.ast.Program;
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import com.semmle.js.ast.Statement;
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import com.semmle.js.ast.TryStatement;
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import com.semmle.js.ast.UnaryExpression;
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import com.semmle.js.ast.VariableDeclaration;
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import com.semmle.js.ast.VariableDeclarator;
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import java.util.List;
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/**
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* A utility base class for running detection logic on statements/expressions by
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* visiting each node. It performs recursive decent into assignment expressions and
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* callee expressions for call-expressions (to handle detection of `foo` in `foo()()`)
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* */
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public abstract class AbstractDetector {
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protected boolean programDetection(Node ast) {
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if (!(ast instanceof Program)) return false;
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return visitStatements(((Program) ast).getBody());
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}
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protected boolean visitStatements(List<Statement> stmts) {
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for (Statement stmt : stmts) if (visitStatement(stmt)) return true;
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return false;
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}
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protected boolean visitStatement(Statement stmt) {
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if (stmt instanceof ExpressionStatement) {
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Expression e = stripParens(((ExpressionStatement) stmt).getExpression());
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// check whether `e` is an iife; if so, recursively check its body
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// strip off unary operators to handle `!function(){...}()`
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if (e instanceof UnaryExpression) e = ((UnaryExpression) e).getArgument();
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if (e instanceof CallExpression && ((CallExpression) e).getArguments().isEmpty()) {
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Expression callee = stripParens(((CallExpression) e).getCallee());
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if (callee instanceof IFunction) {
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Node body = ((IFunction) callee).getBody();
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if (body instanceof BlockStatement)
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return visitStatements(((BlockStatement) body).getBody());
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}
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}
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if (visitExpression(e)) return true;
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} else if (stmt instanceof VariableDeclaration) {
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for (VariableDeclarator decl : ((VariableDeclaration) stmt).getDeclarations()) {
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Expression init = stripParens(decl.getInit());
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if (visitExpression(init)) return true;
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}
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} else if (stmt instanceof TryStatement) {
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return visitStatement(((TryStatement) stmt).getBlock());
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} else if (stmt instanceof BlockStatement) {
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return visitStatements(((BlockStatement) stmt).getBody());
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} else if (stmt instanceof IfStatement) {
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IfStatement is = (IfStatement) stmt;
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return visitStatement(is.getConsequent())
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|| visitStatement(is.getAlternate());
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}
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return false;
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}
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private static Expression stripParens(Expression e) {
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if (e instanceof ParenthesizedExpression)
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return stripParens(((ParenthesizedExpression) e).getExpression());
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return e;
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}
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/**
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* Recursively check {@code e} if it's a call or an assignment.
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*/
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protected boolean visitExpression(Expression e) {
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if (e instanceof CallExpression) {
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CallExpression call = (CallExpression) e;
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Expression callee = call.getCallee();
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// recurse, to handle things like `foo()()`
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if (visitExpression(callee)) return true;
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return false;
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} else if (e instanceof MemberExpression) {
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return visitExpression(((MemberExpression) e).getObject());
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} else if (e instanceof AssignmentExpression) {
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AssignmentExpression assgn = (AssignmentExpression) e;
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// filter out compound assignments
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if (!"=".equals(assgn.getOperator())) return false;
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return visitExpression(assgn.getRight());
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}
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return false;
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}
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/** Is {@code e} an identifier with name {@code name}? */
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protected static boolean isIdentifier(Expression e, String name) {
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return e instanceof Identifier && name.equals(((Identifier) e).getName());
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}
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}

‎javascript/extractor/src/com/semmle/js/extractor/ES2015Detector.java‎

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package com.semmle.js.extractor;
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import com.semmle.js.ast.DynamicImport;
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import com.semmle.js.ast.ExportDeclaration;
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import com.semmle.js.ast.Expression;
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import com.semmle.js.ast.ImportDeclaration;
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import com.semmle.js.ast.Node;
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import com.semmle.js.ast.Statement;
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/** A utility class for detecting Node.js code. */
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public class ES2015Detector extends AbstractDetector {
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/**
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* Is {@code ast} a program that uses ES2015 import/export code?
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*/
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public static boolean looksLikeES2015(Node ast) {
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return new ES2015Detector().programDetection(ast);
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}
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@Override
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protected boolean visitStatement(Statement stmt) {
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if (stmt instanceof ImportDeclaration || stmt instanceof ExportDeclaration) {
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return true;
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}
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return super.visitStatement(stmt);
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}
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@Override
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protected boolean visitExpression(Expression e) {
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if (e instanceof DynamicImport) {
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return true;
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}
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return super.visitExpression(e);
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}
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}

‎javascript/extractor/src/com/semmle/js/extractor/JSExtractor.java‎

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@@ -58,6 +58,26 @@ public Pair<Label, ParseResultInfo> extract(
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JSParser.Result parserRes =
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JSParser.parse(config, sourceType, source, textualExtractor.getMetrics());
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// Check if we guessed wrong with the regex in `establishSourceType`, (which could
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// happen due to a block-comment line starting with ' import').
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if (config.getSourceType() == SourceType.AUTO && sourceType != SourceType.SCRIPT) {
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boolean wrongGuess = false;
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if (sourceType == SourceType.MODULE) {
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// check that we did see an import/export declaration
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wrongGuess = ES2015Detector.looksLikeES2015(parserRes.getAST()) == false;
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} else if (sourceType == SourceType.CLOSURE_MODULE ) {
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// TODO
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}
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if (wrongGuess) {
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sourceType = SourceType.SCRIPT;
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parserRes =
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JSParser.parse(config, sourceType, source, textualExtractor.getMetrics());
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}
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}
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return extract(textualExtractor, source, toplevelKind, scopeManager, sourceType, parserRes);
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}
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‎javascript/extractor/src/com/semmle/js/extractor/NodeJSDetector.java‎

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@@ -1,132 +1,30 @@
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package com.semmle.js.extractor;
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import com.semmle.js.ast.AssignmentExpression;
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import com.semmle.js.ast.BlockStatement;
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import com.semmle.js.ast.CallExpression;
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import com.semmle.js.ast.Expression;
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import com.semmle.js.ast.ExpressionStatement;
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import com.semmle.js.ast.IFunction;
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import com.semmle.js.ast.Identifier;
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import com.semmle.js.ast.IfStatement;
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import com.semmle.js.ast.MemberExpression;
127
import com.semmle.js.ast.Node;
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import com.semmle.js.ast.ParenthesizedExpression;
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import com.semmle.js.ast.Program;
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import com.semmle.js.ast.Statement;
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import com.semmle.js.ast.TryStatement;
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import com.semmle.js.ast.UnaryExpression;
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import com.semmle.js.ast.VariableDeclaration;
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import com.semmle.js.ast.VariableDeclarator;
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import java.util.List;
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/** A utility class for detecting Node.js code. */
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public class NodeJSDetector {
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public class NodeJSDetector extends AbstractDetector {
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/**
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* Is {@code ast} a program that looks like Node.js code, that is, does it contain a top-level
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* {@code require} or an export?
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* {@code require} or an {@code module.exports = ...}/{@code exports = ...}?
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*/
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public static boolean looksLikeNodeJS(Node ast) {
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if (!(ast instanceof Program)) return false;
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return hasToplevelRequireOrExport(((Program) ast).getBody());
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}
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/**
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* Does this program contain a statement that looks like a Node.js {@code require} or an export?
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*
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* <p>We recursively traverse argument-less immediately invoked function expressions (i.e., no UMD
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* modules), but not loops or if statements.
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*/
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private static boolean hasToplevelRequireOrExport(List<Statement> stmts) {
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for (Statement stmt : stmts) if (hasToplevelRequireOrExport(stmt)) return true;
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return false;
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return new NodeJSDetector().programDetection(ast);
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}
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private static boolean hasToplevelRequireOrExport(Statement stmt) {
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if (stmt instanceof ExpressionStatement) {
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Expression e = stripParens(((ExpressionStatement) stmt).getExpression());
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// check whether `e` is an iife; if so, recursively check its body
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// strip off unary operators to handle `!function(){...}()`
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if (e instanceof UnaryExpression) e = ((UnaryExpression) e).getArgument();
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if (e instanceof CallExpression && ((CallExpression) e).getArguments().isEmpty()) {
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Expression callee = stripParens(((CallExpression) e).getCallee());
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if (callee instanceof IFunction) {
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Node body = ((IFunction) callee).getBody();
58-
if (body instanceof BlockStatement)
59-
return hasToplevelRequireOrExport(((BlockStatement) body).getBody());
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}
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}
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if (isRequireCall(e) || isExport(e)) return true;
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} else if (stmt instanceof VariableDeclaration) {
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for (VariableDeclarator decl : ((VariableDeclaration) stmt).getDeclarations()) {
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Expression init = stripParens(decl.getInit());
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if (isRequireCall(init) || isExport(init)) return true;
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}
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} else if (stmt instanceof TryStatement) {
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return hasToplevelRequireOrExport(((TryStatement) stmt).getBlock());
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} else if (stmt instanceof BlockStatement) {
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return hasToplevelRequireOrExport(((BlockStatement) stmt).getBody());
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} else if (stmt instanceof IfStatement) {
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IfStatement is = (IfStatement) stmt;
79-
return hasToplevelRequireOrExport(is.getConsequent())
80-
|| hasToplevelRequireOrExport(is.getAlternate());
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}
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return false;
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}
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private static Expression stripParens(Expression e) {
87-
if (e instanceof ParenthesizedExpression)
88-
return stripParens(((ParenthesizedExpression) e).getExpression());
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return e;
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}
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/**
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* Is {@code e} a call to a function named {@code require} with one argument, or an assignment
94-
* whose right hand side is the result of such a call?
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*/
96-
private static boolean isRequireCall(Expression e) {
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@Override
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protected boolean visitExpression(Expression e) {
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// require('...')
9722
if (e instanceof CallExpression) {
9823
CallExpression call = (CallExpression) e;
9924
Expression callee = call.getCallee();
10025
if (isIdentifier(callee, "require") && call.getArguments().size() == 1) return true;
101-
if (isRequireCall(callee)) return true;
102-
return false;
103-
} else if (e instanceof MemberExpression) {
104-
return isRequireCall(((MemberExpression) e).getObject());
105-
} else if (e instanceof AssignmentExpression) {
106-
AssignmentExpression assgn = (AssignmentExpression) e;
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// filter out compound assignments
109-
if (!"=".equals(assgn.getOperator())) return false;
110-
111-
return isRequireCall(assgn.getRight());
11226
}
113-
return false;
114-
}
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/**
117-
* Does {@code e} look like a Node.js export?
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*
119-
* <p>Currently, three kinds of exports are recognised:
120-
*
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* <ul>
122-
* <li><code>exports.foo = ...</code>
123-
* <li><code>module.exports = ...</code>
124-
* <li><code>module.exports.foo = ...</code>
125-
* </ul>
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*
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* Detection is done recursively, so <code>foo = exports.foo = ...</code> is handled correctly.
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*/
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private static boolean isExport(Expression e) {
13028
if (e instanceof AssignmentExpression) {
13129
AssignmentExpression assgn = (AssignmentExpression) e;
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14947
if (isModuleExports(targetBase)) return true;
15048
}
15149
}
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153-
// recursively check right hand side
154-
return isExport(assgn.getRight());
15550
}
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157-
return false;
52+
return super.visitExpression(e);
15853
}
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/** Is {@code me} a member expression {@code module.exports}? */
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16358
&& isIdentifier(me.getObject(), "module")
16459
&& isIdentifier(me.getProperty(), "exports");
16560
}
166-
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/** Is {@code e} an identifier with name {@code name}? */
168-
private static boolean isIdentifier(Expression e, String name) {
169-
return e instanceof Identifier && name.equals(((Identifier) e).getName());
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}
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}

‎javascript/extractor/test/com/semmle/js/extractor/test/AllTests.java‎

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@SuiteClasses({
1919
JSXTests.class,
2020
NodeJSDetectorTests.class,
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ES2015DetectorTests.class,
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TrapTests.class,
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ObjectRestSpreadTests.class,
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ClassPropertiesTests.class,

‎javascript/extractor/test/com/semmle/js/extractor/test/BUILD.bazel‎

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"TS_WRAPPER_ZIP": "$(rlocationpath //javascript/extractor/lib/typescript)",
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},
1414
test_class = "com.semmle.js.extractor.test.AllTests",
15+
# To use `replaceExpectedOutput` you need to uncomment the following line
16+
# (to be allowed to override the .trap files on disk)
17+
# tags = ["no-sandbox"],
1518
deps = [
1619
"//javascript/extractor",
1720
"//javascript/extractor:deps",

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