JS: Preserve information about 'defer' keyword

javascript/extractor/lib/typescript/src/main.ts

@@ -267,6 +267,7 @@ const astProperties: string[] = [
     "parameterName",
     "parameters",
     "parseDiagnostics",
+    "phaseModifier",
     "properties",
     "propertyName",
     "qualifier",

javascript/extractor/src/com/semmle/js/ast/ImportDeclaration.java

@@ -26,11 +26,11 @@ public class ImportDeclaration extends Statement implements INodeWithSymbol {
 
   private int symbol = -1;
 
-  private boolean hasTypeKeyword;
+  private ImportPhaseModifier phaseModifier;
 
   public ImportDeclaration(
       SourceLocation loc, List<ImportSpecifier> specifiers, Literal source, Expression attributes) {
-    this(loc, specifiers, source, attributes, false);
+    this(loc, specifiers, source, attributes, ImportPhaseModifier.NONE);
   }
 
   public ImportDeclaration(
@@ -38,12 +38,12 @@ public class ImportDeclaration extends Statement implements INodeWithSymbol {
       List<ImportSpecifier> specifiers,
       Literal source,
       Expression attributes,
-      boolean hasTypeKeyword) {
+      ImportPhaseModifier phaseModifier) {
     super("ImportDeclaration", loc);
     this.specifiers = specifiers;
     this.source = source;
     this.attributes = attributes;
-    this.hasTypeKeyword = hasTypeKeyword;
+    this.phaseModifier = phaseModifier;
   }
 
   public Literal getSource() {
@@ -79,6 +79,15 @@ public class ImportDeclaration extends Statement implements INodeWithSymbol {
 
   /** Returns true if this is an <code>import type</code> declaration. */
   public boolean hasTypeKeyword() {
-    return hasTypeKeyword;
+    return phaseModifier == ImportPhaseModifier.TYPE;
+  }
+
+  /** Returns true if this is an <code>import defer</code> declaration. */
+  public boolean hasDeferKeyword() {
+    return phaseModifier == ImportPhaseModifier.DEFER;
+  }
+
+  public ImportPhaseModifier getPhaseModifier() {
+    return phaseModifier;
   }
 }

javascript/extractor/src/com/semmle/js/ast/ImportPhaseModifier.java

@@ -0,0 +1,10 @@
+package com.semmle.js.ast;
+
+/**
+ * A keyword that may appear on import declarations.
+ */
+public enum ImportPhaseModifier {
+    NONE,
+    DEFER,
+    TYPE,
+}

javascript/extractor/src/com/semmle/js/ast/NodeCopier.java

@@ -564,7 +564,7 @@ public class NodeCopier implements Visitor<Void, INode> {
         copy(nd.getSpecifiers()),
         copy(nd.getSource()),
         copy(nd.getAttributes()),
-        nd.hasTypeKeyword());
+        nd.getPhaseModifier());
   }
 
   @Override

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

@@ -1833,6 +1833,9 @@ public class ASTExtractor {
       if (nd.hasTypeKeyword()) {
         trapwriter.addTuple("has_type_keyword", lbl);
       }
+      if (nd.hasDeferKeyword()) {
+        trapwriter.addTuple("has_defer_keyword", lbl);
+      }
       return lbl;
     }
 

javascript/extractor/src/com/semmle/ts/extractor/TypeScriptASTConverter.java

@@ -52,6 +52,7 @@ import com.semmle.js.ast.IfStatement;
 import com.semmle.js.ast.ImportDeclaration;
 import com.semmle.js.ast.ImportDefaultSpecifier;
 import com.semmle.js.ast.ImportNamespaceSpecifier;
+import com.semmle.js.ast.ImportPhaseModifier;
 import com.semmle.js.ast.ImportSpecifier;
 import com.semmle.js.ast.InvokeExpression;
 import com.semmle.js.ast.LabeledStatement;
@@ -1404,7 +1405,7 @@ public class TypeScriptASTConverter {
     Literal src = tryConvertChild(node, "moduleSpecifier", Literal.class);
     Expression attributes = convertChild(node, "attributes");
     List<ImportSpecifier> specifiers = new ArrayList<>();
-    boolean hasTypeKeyword = false;
+    ImportPhaseModifier phaseModifier = ImportPhaseModifier.NONE;
     if (hasChild(node, "importClause")) {
       JsonObject importClause = node.get("importClause").getAsJsonObject();
       if (hasChild(importClause, "name")) {
@@ -1418,10 +1419,22 @@ public class TypeScriptASTConverter {
           specifiers.addAll(convertChildren(namedBindings, "elements"));
         }
       }
-      hasTypeKeyword = importClause.get("isTypeOnly").getAsBoolean();
+      if (hasChild(importClause, "phaseModifier")) {
+        String name = metadata.getSyntaxKindName(importClause.get("phaseModifier").getAsInt());
+        switch (name) {
+          case "DeferKeyword": {
+            phaseModifier = ImportPhaseModifier.DEFER;
+            break;
+          }
+          case "TypeKeyword": {
+            phaseModifier = ImportPhaseModifier.TYPE;
+            break;
+          }
+        }
+      }
     }
     ImportDeclaration importDecl =
-        new ImportDeclaration(loc, specifiers, src, attributes, hasTypeKeyword);
+        new ImportDeclaration(loc, specifiers, src, attributes, phaseModifier);
     attachSymbolInformation(importDecl, node);
     return importDecl;
   }

javascript/ql/lib/semmle/javascript/ES2015Modules.qll

@@ -151,6 +151,14 @@ class ImportDeclaration extends Stmt, Import, @import_declaration {
   /** Holds if this is declared with the `type` keyword, so it only imports types. */
   predicate isTypeOnly() { has_type_keyword(this) }
 
+  /**
+   * Holds if this is declared with the `defer` keyword, for example:
+   * ```ts
+   * import defer * as f from "somewhere";
+   * ```
+   */
+  predicate isDeferredImport() { has_defer_keyword(this) }
+
   override string getAPrimaryQlClass() { result = "ImportDeclaration" }
 }
 

javascript/ql/lib/semmlecode.javascript.dbscheme

@@ -516,6 +516,7 @@ has_private_keyword (int id: @property ref);
 has_protected_keyword (int id: @property ref);
 has_readonly_keyword (int id: @property ref);
 has_type_keyword (int id: @type_keyword_operand ref);
+has_defer_keyword (int id: @import_declaration ref);
 is_optional_member (int id: @property ref);
 has_definite_assignment_assertion (int id: @field_or_vardeclarator ref);
 is_optional_parameter_declaration (unique int parameter: @pattern ref);

javascript/ql/lib/semmlecode.javascript.dbscheme.stats

@@ -4319,6 +4319,17 @@
 <dependencies/>
 </relation>
 <relation>
+<name>has_defer_keyword</name>
+<cardinality>1000</cardinality>
+<columnsizes>
+<e>
+<k>id</k>
+<v>1000</v>
+</e>
+</columnsizes>
+<dependencies/>
+</relation>
+<relation>
 <name>is_optional_member</name>
 <cardinality>3668</cardinality>
 <columnsizes>

javascript/ql/test/library-tests/TypeScript/ImportDefer/test.expected

@@ -1 +1 @@
-| tst.ts:1:1:1:31 | import  ... m "fs"; |
+| tst.ts:1:1:1:44 | import  ... where"; |

javascript/ql/test/library-tests/TypeScript/ImportDefer/test.ql

@@ -1,5 +1,3 @@
 import javascript
 
-from ImportDeclaration decl
-select decl
-
+query predicate deferredImports(ImportDeclaration decl) { decl.isDeferredImport() }

javascript/ql/test/library-tests/TypeScript/ImportDefer/tst.ts

@@ -1 +1,4 @@
-import defer * as fs from "fs";
+import defer * as deferred from "somewhere";
+import type * as t from "somewhere";
+import * as normal from "somewhere";
+import defer from "somewhere";