Merge pull request #275 from xiemaisi/js/workaround-for-nested-imports

Approved by asger-semmle

javascript/ql/src/semmle/javascript/CFG.qll

@@ -281,7 +281,7 @@ import javascript
  */
 class ControlFlowNode extends @cfg_node, Locatable {
   /** Gets a node succeeding this node in the CFG. */
-  ControlFlowNode getASuccessor() {
+  cached ControlFlowNode getASuccessor() {
     successor(this, result)
   }
 
@@ -457,3 +457,47 @@ class ConcreteControlFlowNode extends ControlFlowNode {
     not this instanceof SyntheticControlFlowNode
   }
 }
+
+/**
+ * A CFG node corresponding to a nested (that is, non-toplevel) import declaration.
+ *
+ * This is a non-standard language feature that is not currently supported very well
+ * by the extractor, in particular such imports do not appear in the control flow graph
+ * generated by the extractor. We patch them in by overriding `getASuccessor`; once an
+ * extractor fix becomes available, this class can be removed.
+ */
+private class NestedImportDeclaration extends ImportDeclaration {
+  NestedImportDeclaration() {
+    exists (ASTNode p | p = getParent() |
+      not p instanceof TopLevel
+    ) and
+    // if there are no specifiers, the default control flow graph is fine
+    exists(getASpecifier())
+  }
+
+  override ControlFlowNode getASuccessor() {
+    result = getSpecifier(0).getFirstControlFlowNode()
+  }
+}
+
+/**
+ * A CFG node corresponding to an import specifier in a nested import declaration.
+ *
+ * As for `NestedImportDeclaration` above, this is a temporary workaround that will be
+ * removed once extractor support for this non-standard language feature becomes available.
+ */
+private class NestedImportSpecifier extends ImportSpecifier {
+  NestedImportDeclaration decl;
+  int i;
+
+  NestedImportSpecifier() {
+    this = decl.getSpecifier(i)
+  }
+
+  override ControlFlowNode getASuccessor() {
+    result = decl.getSpecifier(i+1).getFirstControlFlowNode()
+    or
+    not exists(decl.getSpecifier(i+1)) and
+    successor(decl, result)
+  }
+}

javascript/ql/src/semmle/javascript/ES2015Modules.qll

@@ -27,7 +27,7 @@ class ES2015Module extends Module {
 
   /** Gets an export declaration in this module. */
   ExportDeclaration getAnExport() {
-    result.getContainer() = this
+    result.getTopLevel() = this
   }
 
   override Module getAnImportedModule() {
@@ -55,7 +55,7 @@ class ES2015Module extends Module {
 /** An import declaration. */
 class ImportDeclaration extends Stmt, Import, @importdeclaration {
   override ES2015Module getEnclosingModule() {
-    result = getContainer()
+    result = getTopLevel()
   }
 
   override PathExprInModule getImportedPath() {
@@ -254,7 +254,7 @@ class BulkReExportDeclaration extends ReExportDeclaration, @exportalldeclaration
   * but we ignore this subtlety.
   */
 private predicate isShadowedFromBulkExport(BulkReExportDeclaration reExport, string name) {
-  exists (ExportNamedDeclaration other | other.getContainer() = reExport.getEnclosingModule() |
+  exists (ExportNamedDeclaration other | other.getTopLevel() = reExport.getEnclosingModule() |
     other.getAnExportedDecl().getName() = name
     or
     other.getASpecifier().getExportedName() = name)

javascript/ql/src/semmle/javascript/dataflow/internal/InterModuleTypeInference.qll

@@ -301,7 +301,7 @@ private class AnalyzedExportAssign extends AnalyzedPropertyWrite, DataFlow::Valu
   }
 
   override predicate writes(AbstractValue baseVal, string propName, DataFlow::AnalyzedNode source) {
-    baseVal = TAbstractModuleObject(exportAssign.getContainer()) and
+    baseVal = TAbstractModuleObject(exportAssign.getTopLevel()) and
     propName = "exports" and
     source = this
   }