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Closure Compiler is a JavaScript optimizing compiler. It parses your
JavaScript, analyzes it, removes dead code and rewrites and minimizes
what's left. It also checks syntax, variable references, and types, and
warns about common JavaScript pitfalls. It is used in many of Google's
JavaScript apps, including Gmail, Google Web Search, Google Maps, and
Google Docs.
/*
* Copyright 2008 The Closure Compiler Authors.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package com.google.javascript.jscomp;
import static com.google.common.base.Preconditions.checkState;
import com.google.common.base.Joiner;
import com.google.common.base.Predicate;
import com.google.common.base.Predicates;
import com.google.common.base.Splitter;
import com.google.common.collect.ImmutableList;
import com.google.common.collect.Iterables;
import com.google.javascript.jscomp.NodeUtil.Visitor;
import com.google.javascript.rhino.JSDocInfo;
import com.google.javascript.rhino.JSTypeExpression;
import com.google.javascript.rhino.Node;
import java.util.HashMap;
import java.util.HashSet;
import java.util.List;
import java.util.Locale;
import java.util.Map;
import java.util.Set;
import javax.annotation.Nullable;
/**
* Walks the AST looking for usages of qualified names, and 'goog.require's of those names. Then,
* reconciles the two lists, and reports warning for any discrepancies.
*
* This pass is deprecated, and it's functionality is being moved to other passes, such as:
*
*
* - The {@link com.google.javascript.jscomp.lint.CheckExtraRequires} pass for checking extra
* requires.
*
*
* The rules on when a warning is reported are:
*
*
* - Type is referenced in code → goog.require is required (missingRequires check fails if it's
* not there)
*
- Type is referenced in an @extends or @implements → goog.require is required
* (missingRequires check fails if it's not there)
*
- Type is referenced in other JsDoc (@type etc) → goog.require is optional (don't warn,
* regardless of if it is there)
*
*/
public class CheckMissingAndExtraRequires implements HotSwapCompilerPass, NodeTraversal.Callback {
private final AbstractCompiler compiler;
private final CodingConvention codingConvention;
private static final Splitter DOT_SPLITTER = Splitter.on('.');
private static final Joiner DOT_JOINER = Joiner.on('.');
private final Set providedNames = new HashSet<>();
// Keys are the local name of a required namespace. Values are the goog.require CALL node.
private final Map requires = new HashMap<>();
// Adding an entry to usages indicates that the name is used and should be required.
private final Map usages = new HashMap<>();
// Adding an entry to weakUsages indicates that the name is used, but in a way which may not
// require a goog.require, such as in a @type annotation. If the only usages of a name are
// in weakUsages, don't give a missingRequire warning, nor an extraRequire warning.
private final Set weakUsages = new HashSet<>();
// The body of the goog.scope function, if any.
@Nullable private Node googScopeBlock;
public static final DiagnosticType MISSING_REQUIRE_WARNING =
DiagnosticType.disabled("JSC_MISSING_REQUIRE_WARNING", "missing require: ''{0}''");
static final DiagnosticType MISSING_REQUIRE_FOR_GOOG_SCOPE =
DiagnosticType.disabled("JSC_MISSING_REQUIRE_FOR_GOOG_SCOPE", "missing require: ''{0}''");
// TODO(tbreisacher): Remove this and just use MISSING_REQUIRE_WARNING.
public static final DiagnosticType MISSING_REQUIRE_STRICT_WARNING =
DiagnosticType.disabled("JSC_MISSING_REQUIRE_STRICT_WARNING", "missing require: ''{0}''");
CheckMissingAndExtraRequires(AbstractCompiler compiler) {
this.compiler = compiler;
this.codingConvention = compiler.getCodingConvention();
}
@Override
public void process(Node externs, Node root) {
reset();
NodeTraversal.traverseRoots(compiler, this, externs, root);
}
@Override
public void hotSwapScript(Node scriptRoot, Node originalRoot) {
// TODO(joeltine): Remove this and properly handle hot swap passes. See
// b/28869281 for context.
reset();
NodeTraversal.traverse(compiler, scriptRoot, this);
}
// Return true if the name is a class name (starts with an uppercase
// character, but is not in all-caps).
private static boolean isClassName(String name) {
return isClassOrConstantName(name) && !name.equals(name.toUpperCase(Locale.ROOT));
}
// Return true if the name looks like a class name or a constant name.
private static boolean isClassOrConstantName(String name) {
return name != null && name.length() > 1 && Character.isUpperCase(name.charAt(0));
}
// Return the shortest prefix of the className that refers to a class,
// or null if no part refers to a class.
private static ImmutableList getClassNames(String qualifiedName) {
ImmutableList.Builder classNames = ImmutableList.builder();
List parts = DOT_SPLITTER.splitToList(qualifiedName);
for (int i = 0; i < parts.size(); i++) {
String part = parts.get(i);
if (isClassOrConstantName(part)) {
classNames.add(DOT_JOINER.join(parts.subList(0, i + 1)));
}
}
return classNames.build();
}
// TODO(tbreisacher): Update CodingConvention.extractClassNameIf{Require,Provide} to match this.
private String extractNamespace(Node call, String... primitiveNames) {
Node callee = call.getFirstChild();
if (!callee.isGetProp()) {
return null;
}
for (String primitiveName : primitiveNames) {
if (callee.matchesQualifiedName(primitiveName)) {
Node target = callee.getNext();
if (target != null && target.isString()) {
return target.getString();
}
}
}
return null;
}
private String extractNamespaceIfRequire(Node call) {
return extractNamespace(call, "goog.require", "goog.requireType");
}
private String extractNamespaceIfProvide(Node call) {
return extractNamespace(call, "goog.provide");
}
@Override
public boolean shouldTraverse(NodeTraversal t, Node n, Node parent) {
if (n.isCall() && n.getFirstChild().matchesQualifiedName("goog.scope")) {
Node function = n.getSecondChild();
if (function.isFunction()) {
googScopeBlock = NodeUtil.getFunctionBody(function);
}
}
return parent == null || !parent.isScript() || !t.getInput().isExtern();
}
@Override
public void visit(NodeTraversal t, Node n, Node parent) {
maybeAddJsDocUsages(t, n);
switch (n.getToken()) {
case ASSIGN:
maybeAddProvidedName(n);
break;
case VAR:
case LET:
case CONST:
maybeAddProvidedName(n);
maybeAddGoogScopeUsage(t, n, parent);
break;
case FUNCTION:
// Exclude function expressions.
if (NodeUtil.isStatement(n)) {
maybeAddProvidedName(n);
}
break;
case NAME:
if (!NodeUtil.isLValue(n) && !parent.isGetProp() && !parent.isImportSpec()) {
visitQualifiedName(n);
}
break;
case GETPROP:
// If parent is a GETPROP, they will handle the weak usages.
if (!parent.isGetProp() && n.isQualifiedName()) {
visitQualifiedName(n);
}
break;
case CALL:
visitCallNode(t, n, parent);
break;
case SCRIPT:
visitScriptNode();
reset();
break;
case NEW:
visitNewNode(t, n);
break;
case CLASS:
visitClassNode(t, n);
break;
case IMPORT:
visitImportNode(n);
break;
default:
break;
}
}
private void reset() {
this.usages.clear();
this.weakUsages.clear();
this.requires.clear();
this.providedNames.clear();
this.googScopeBlock = null;
}
private void visitScriptNode() {
Set namespaces = new HashSet<>();
// For every usage, check that there is a goog.require, and warn if not.
for (Map.Entry entry : usages.entrySet()) {
String namespace = entry.getKey();
Node node = entry.getValue();
boolean isMissing = isMissingRequire(namespace, node);
if (isMissing
&& (namespace.endsWith(".call")
|| namespace.endsWith(".apply")
|| namespace.endsWith(".bind"))) {
// assume that the user is calling the corresponding built in function and only look for
// imports 'above' it.
String namespaceMinusApply = namespace.substring(0, namespace.lastIndexOf('.'));
isMissing = isMissingRequire(namespaceMinusApply, node);
}
if (isMissing && !namespaces.contains(namespace)) {
// TODO(mknichel): If the symbol is not explicitly provided, find the next best
// symbol from the provides in the same file.
if (node.isCall()) {
String defaultName =
namespace.lastIndexOf('.') > 0
? namespace.substring(0, namespace.lastIndexOf('.'))
: namespace;
String nameToReport = Iterables.getFirst(getClassNames(namespace), defaultName);
compiler.report(JSError.make(node, MISSING_REQUIRE_STRICT_WARNING, nameToReport));
} else if (node.getParent().isName()
&& node.getParent().getGrandparent() == googScopeBlock) {
compiler.report(JSError.make(node, MISSING_REQUIRE_FOR_GOOG_SCOPE, namespace));
} else {
if (node.isGetProp() && !node.getParent().isClass()) {
compiler.report(JSError.make(node, MISSING_REQUIRE_STRICT_WARNING, namespace));
} else {
compiler.report(JSError.make(node, MISSING_REQUIRE_WARNING, namespace));
}
}
namespaces.add(namespace);
}
}
}
/** Returns true if the given namespace is not satisfied by any {@code goog.provide}. */
private boolean isMissingRequire(String namespace, Node node) {
if (namespace.startsWith("goog.global.")
// Most functions in base.js are goog.someName, but
// goog.module.{get,declareLegacyNamespace} are the exceptions, so just
// check for them explicitly.
|| namespace.equals("goog.module.get")
|| namespace.equals("goog.module.declareLegacyNamespace")) {
return false;
}
JSDocInfo info = NodeUtil.getBestJSDocInfo(NodeUtil.getEnclosingStatement(node));
if (info != null && info.getSuppressions().contains("missingRequire")) {
return false;
}
List classNames = getClassNames(namespace);
// The parent namespace of the outermost class is also checked, so that classes
// used by goog.module are still checked properly. This may cause missing requires
// to be missed but in practice that should happen rarely.
String nonNullClassName = Iterables.getFirst(classNames, namespace);
String parentNamespace = null;
int separatorIndex = nonNullClassName.lastIndexOf('.');
if (separatorIndex > 0) {
parentNamespace = nonNullClassName.substring(0, separatorIndex);
}
if ("goog".equals(parentNamespace)
&& !isClassName(nonNullClassName.substring(separatorIndex + 1))) {
// This is probably something provided in Closure's base.js so it doesn't need
// to be required.
return false;
}
boolean providedByConstructors =
providedNames.contains(namespace) || providedNames.contains(parentNamespace);
boolean providedByRequires =
requires.containsKey(namespace) || requires.containsKey(parentNamespace);
for (String className : classNames) {
if (providedNames.contains(className)) {
providedByConstructors = true;
break;
}
if (requires.containsKey(className)) {
providedByRequires = true;
break;
}
}
return !providedByRequires && !providedByConstructors;
}
/**
* @param localName The name that should be used in this file.
*
* Require style | localName
* -------------------------------------|----------
* goog.require('foo.bar'); | foo.bar
* var bar = goog.require('foo.bar'); | bar
* var {qux} = goog.require('foo.bar'); | qux
* import {qux} from 'foo.bar'; | qux
*
*/
private void visitRequire(String localName, Node node) {
if (!requires.containsKey(localName)) {
requires.put(localName, node);
}
// For goog.require('example.Outer.Inner'), add example.Outer as well.
for (String className : getClassNames(localName)) {
requires.put(className, node);
}
}
private void visitImportNode(Node importNode) {
Node defaultImport = importNode.getFirstChild();
if (defaultImport.isName()) {
visitRequire(defaultImport.getString(), importNode);
}
Node namedImports = defaultImport.getNext();
if (namedImports.isImportSpecs()) {
for (Node importSpec : namedImports.children()) {
visitRequire(importSpec.getLastChild().getString(), importNode);
}
}
}
private void visitGoogRequire(String namespace, Node googRequireCall, Node parent) {
if (parent.isName()) {
visitRequire(parent.getString(), googRequireCall);
} else if (parent.isDestructuringLhs() && parent.getFirstChild().isObjectPattern()) {
if (parent.getFirstChild().hasChildren()) {
for (Node stringKey : parent.getFirstChild().children()) {
Node importName = stringKey.getFirstChild();
if (!importName.isName()) {
// invalid reported elsewhere
continue;
}
visitRequire(importName.getString(), importName);
}
} else {
visitRequire(namespace, googRequireCall);
}
} else {
visitRequire(namespace, googRequireCall);
}
}
private void visitCallNode(NodeTraversal t, Node call, Node parent) {
String required = extractNamespaceIfRequire(call);
if (required != null) {
visitGoogRequire(required, call, parent);
return;
}
String provided = extractNamespaceIfProvide(call);
if (provided != null) {
providedNames.add(provided);
return;
}
Node callee = call.getFirstChild();
if (callee.matchesQualifiedName("goog.module.get") && call.getSecondChild().isString()) {
weakUsages.add(call.getSecondChild().getString());
}
if (codingConvention.isClassFactoryCall(call)) {
if (parent.isName()) {
providedNames.add(parent.getString());
} else if (parent.isAssign()) {
providedNames.add(parent.getFirstChild().getQualifiedName());
}
}
if (callee.isName()) {
weakUsages.add(callee.getString());
} else if (callee.isQualifiedName()) {
Node root = NodeUtil.getRootOfQualifiedName(callee);
if (root.isName()) {
Var var = t.getScope().getVar(root.getString());
if (var == null || (!var.isExtern() && var.isGlobal())) {
usages.put(callee.getQualifiedName(), call);
}
}
}
}
private void addWeakUsagesOfAllPrefixes(String qualifiedName) {
// For "foo.bar.baz.qux" add weak usages for "foo.bar.baz.qux", "foo.bar.baz",
// "foo.bar", and "foo" because those might all be goog.provide'd in different files,
// so it doesn't make sense to require the user to goog.require all of them.
for (int i = qualifiedName.indexOf('.'); i != -1; i = qualifiedName.indexOf('.', i + 1)) {
String prefix = qualifiedName.substring(0, i);
weakUsages.add(prefix);
}
weakUsages.add(qualifiedName);
}
private void visitQualifiedName(Node n) {
checkState(n.isName() || n.isGetProp() || n.isStringKey(), n);
String qualifiedName = n.isStringKey() ? n.getString() : n.getQualifiedName();
addWeakUsagesOfAllPrefixes(qualifiedName);
}
private void visitNewNode(NodeTraversal t, Node newNode) {
Node qNameNode = newNode.getFirstChild();
// If the ctor is something other than a qualified name, ignore it.
if (!qNameNode.isQualifiedName()) {
return;
}
// Grab the root ctor namespace.
Node root = NodeUtil.getRootOfQualifiedName(qNameNode);
// We only consider programmer-defined constructors that are
// global variables, or are defined on global variables.
if (!root.isName()) {
return;
}
String name = root.getString();
Var var = t.getScope().getVar(name);
if (var != null && (var.isExtern() || var.getSourceFile() == newNode.getStaticSourceFile())) {
return;
}
usages.put(qNameNode.getQualifiedName(), newNode);
// for "new foo.bar.Baz.Qux" add weak usages for "foo.bar.Baz", "foo.bar", and "foo"
// because those might be goog.provide'd from a different file than foo.bar.Baz.Qux,
// so it doesn't make sense to require the user to goog.require all of them.
for (; qNameNode != null; qNameNode = qNameNode.getFirstChild()) {
weakUsages.add(qNameNode.getQualifiedName());
}
}
private void visitClassNode(NodeTraversal t, Node classNode) {
String name = NodeUtil.getName(classNode);
if (name != null) {
providedNames.add(name);
}
Node extendClass = classNode.getSecondChild();
// If the superclass is something other than a qualified name, ignore it.
if (!extendClass.isQualifiedName()) {
return;
}
Node root = NodeUtil.getRootOfQualifiedName(extendClass);
// It should always be a name. Extending this.something or
// super.something is unlikely.
// We only consider programmer-defined superclasses that are
// global variables, or are defined on global variables.
if (root.isName()) {
String rootName = root.getString();
Var var = t.getScope().getVar(rootName);
if (var != null && (var.isLocal() || var.isExtern())) {
// "require" not needed for these
} else {
List classNames = getClassNames(extendClass.getQualifiedName());
String outermostClassName = Iterables.getFirst(classNames, extendClass.getQualifiedName());
usages.put(outermostClassName, extendClass);
}
}
}
private void maybeAddProvidedName(Node n) {
Node name = n.getFirstChild();
if (name.isQualifiedName()) {
providedNames.add(name.getQualifiedName());
}
}
/**
* "var Dog = some.cute.Dog;" counts as a usage of some.cute.Dog, if it's immediately inside a
* goog.scope function.
*/
private void maybeAddGoogScopeUsage(NodeTraversal t, Node n, Node parent) {
checkState(NodeUtil.isNameDeclaration(n));
if (n.hasOneChild() && parent == googScopeBlock) {
Node rhs = n.getFirstFirstChild();
if (rhs != null && rhs.isQualifiedName()) {
Node root = NodeUtil.getRootOfQualifiedName(rhs);
if (root.isName()) {
Var var = t.getScope().getVar(root.getString());
if (var == null || (var.isGlobal() && !var.isExtern())) {
usages.put(rhs.getQualifiedName(), rhs);
}
}
}
}
}
/**
* If this returns true, check for @extends and @implements annotations on this node. Otherwise,
* it's probably an alias for an existing class, so skip those annotations.
*
* @return Whether the given node declares a function. True for the following forms:
*
* function foo() {}
*
* var foo = function() {};
*
* foo.bar = function() {};
*/
private boolean declaresFunctionOrClass(Node n) {
if (n.isFunction() || n.isClass()) {
return true;
}
if (n.isAssign() && (n.getLastChild().isFunction() || n.getLastChild().isClass())) {
return true;
}
if (NodeUtil.isNameDeclaration(n)
&& n.getFirstChild().hasChildren()
&& (n.getFirstFirstChild().isFunction() || n.getFirstFirstChild().isClass())) {
return true;
}
return false;
}
private void maybeAddJsDocUsages(NodeTraversal t, Node n) {
JSDocInfo info = n.getJSDocInfo();
if (info == null) {
return;
}
if (declaresFunctionOrClass(n)) {
for (JSTypeExpression expr : info.getImplementedInterfaces()) {
maybeAddUsage(t, n, expr);
}
if (info.getBaseType() != null) {
maybeAddUsage(t, n, info.getBaseType());
}
for (JSTypeExpression extendedInterface : info.getExtendedInterfaces()) {
maybeAddUsage(t, n, extendedInterface);
}
}
for (Node typeNode : info.getTypeNodes()) {
maybeAddWeakUsage(t, n, typeNode);
}
}
/**
* Adds a weak usage for the given type expression (unless it references a variable that is
* defined in the externs, in which case no goog.require() is needed). When a "weak usage" is
* added, it means that a goog.require for that type is optional: No warning is given whether the
* require is there or not.
*/
private void maybeAddWeakUsage(NodeTraversal t, Node n, Node typeNode) {
maybeAddUsage(t, n, typeNode, false, Predicates.alwaysTrue());
}
/**
* Adds a usage for the given type expression (unless it references a variable that is defined in
* the externs, in which case no goog.require() is needed). When a usage is added, it means that
* there should be a goog.require for that type.
*/
private void maybeAddUsage(NodeTraversal t, Node n, final JSTypeExpression expr) {
// Just look at the root node, don't traverse.
Predicate pred =
new Predicate() {
@Override
public boolean apply(Node n) {
return n == expr.getRoot();
}
};
maybeAddUsage(t, n, expr.getRoot(), true, pred);
}
private void maybeAddUsage(
final NodeTraversal t,
final Node n,
Node rootTypeNode,
final boolean markStrongUsages,
Predicate pred) {
Visitor visitor =
new Visitor() {
@Override
public void visit(Node typeNode) {
if (typeNode.isString()) {
String typeString = typeNode.getString();
String rootName = Splitter.on('.').split(typeString).iterator().next();
Var var = t.getScope().getVar(rootName);
if (var == null || (var.isGlobal() && !var.isExtern())) {
if (markStrongUsages) {
usages.put(typeString, n);
} else {
// If we're not adding strong usages here, add weak usages for the prefixes of the
// namespace, like we do for GETPROP nodes. Otherwise we get an extra require
// warning for cases like:
//
// goog.require('foo.bar.SomeService');
//
// /** @constructor @extends {foo.bar.SomeService.Handler} */
// var MyHandler = function() {};
addWeakUsagesOfAllPrefixes(typeString);
}
} else {
// Even if the root namespace is in externs, add weak usages because the full
// namespace may still be goog.provided.
addWeakUsagesOfAllPrefixes(typeString);
}
}
}
};
NodeUtil.visitPreOrder(rootTypeNode, visitor, pred);
}
}