com.google.javascript.jscomp.CheckGlobalNames Maven / Gradle / Ivy
/*
* 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.checkArgument;
import static com.google.common.base.Preconditions.checkNotNull;
import static com.google.common.base.Preconditions.checkState;
import com.google.javascript.jscomp.GlobalNamespace.Name;
import com.google.javascript.jscomp.GlobalNamespace.Ref;
import com.google.javascript.rhino.JSDocInfo;
import com.google.javascript.rhino.Node;
import java.util.HashSet;
import java.util.Set;
/**
* Checks references to undefined properties of global variables.
*
* @author [email protected] (Nick Santos)
*/
class CheckGlobalNames implements CompilerPass {
private final AbstractCompiler compiler;
private final CodingConvention convention;
private final CheckLevel level;
private GlobalNamespace namespace = null;
private final Set objectPrototypeProps = new HashSet<>();
private final Set functionPrototypeProps = new HashSet<>();
// Warnings
static final DiagnosticType UNDEFINED_NAME_WARNING = DiagnosticType.warning(
"JSC_UNDEFINED_NAME",
"{0} is never defined");
static final DiagnosticType NAME_DEFINED_LATE_WARNING =
DiagnosticType.warning(
"JSC_NAME_DEFINED_LATE",
"{0} defined before its owner. {1} is defined at {2}:{3}");
static final DiagnosticType STRICT_MODULE_DEP_QNAME =
DiagnosticType.disabled(
"JSC_STRICT_MODULE_DEP_QNAME",
// The newline below causes the JS compiler not to complain when the
// referenced module's name changes because, for example, it's a
// synthetic module.
"cannot reference {2} because of a missing module dependency\n"
+ "defined in module {1}, referenced from module {0}");
/**
* Creates a pass to check global name references at the given warning level.
*/
CheckGlobalNames(AbstractCompiler compiler, CheckLevel level) {
this.compiler = compiler;
this.convention = compiler.getCodingConvention();
this.level = level;
}
/**
* Injects a pre-computed global namespace, so that the same namespace
* can be re-used for multiple check passes. Returns this for easy chaining.
*/
CheckGlobalNames injectNamespace(GlobalNamespace namespace) {
checkArgument(namespace.hasExternsRoot());
this.namespace = namespace;
return this;
}
@Override
public void process(Node externs, Node root) {
if (namespace == null) {
namespace = new GlobalNamespace(compiler, externs, root);
}
// Find prototype properties that will affect our analysis.
checkState(namespace.hasExternsRoot());
findPrototypeProps("Object", objectPrototypeProps);
findPrototypeProps("Function", functionPrototypeProps);
objectPrototypeProps.addAll(
convention.getIndirectlyDeclaredProperties());
for (Name name : namespace.getNameForest()) {
// Skip extern names. Externs are often not runnable as real code,
// and will do things like:
// var x;
// x.method;
// which this check forbids.
if (name.getSourceKind() != GlobalNamespace.SourceKind.CODE) {
continue;
}
checkDescendantNames(name, name.getGlobalSets() + name.getLocalSets() > 0);
}
}
private void findPrototypeProps(String type, Set props) {
Name slot = namespace.getSlot(type);
if (slot != null) {
for (Ref ref : slot.getRefs()) {
if (ref.type == Ref.Type.PROTOTYPE_GET) {
Node fullName = ref.getNode().getGrandparent();
if (fullName.isGetProp()) {
props.add(fullName.getLastChild().getString());
}
}
}
}
}
/**
* Checks to make sure all the descendants of a name are defined if they
* are referenced.
*
* @param name A global name.
* @param nameIsDefined If true, {@code name} is defined. Otherwise, it's
* undefined, and any references to descendant names should emit warnings.
*/
private void checkDescendantNames(Name name, boolean nameIsDefined) {
if (name.props != null) {
for (Name prop : name.props) {
// if the ancestor of a property is not defined, then we should emit
// warnings for all references to the property.
boolean propIsDefined = false;
if (nameIsDefined) {
// if the ancestor of a property is defined, then let's check that
// the property is also explicitly defined if it needs to be.
propIsDefined =
(!propertyMustBeInitializedByFullName(prop)
|| prop.getGlobalSets() + prop.getLocalSets() > 0);
}
validateName(prop, propIsDefined);
checkDescendantNames(prop, propIsDefined);
}
}
}
private void validateName(Name name, boolean isDefined) {
// If the name is not defined, emit warnings for each reference. While
// we're looking through each reference, check all the module dependencies.
Name parent = name.getParent();
boolean isTypedef = isTypedef(name);
for (Ref ref : name.getRefs()) {
// Don't worry about global exprs.
boolean isGlobalExpr = ref.getNode().getParent().isExprResult();
if (!isDefined && !isTypedef) {
if (!isGlobalExpr) {
reportRefToUndefinedName(name, ref);
}
} else if (checkForBadModuleReference(name, ref)) {
reportBadModuleReference(name, ref);
} else {
// Check for late references.
if (ref.scope.getClosestHoistScope().isGlobal()) {
// Prototype references are special, because in our reference graph,
// A.prototype counts as a reference to A.
boolean isPrototypeGet = (ref.type == Ref.Type.PROTOTYPE_GET);
Name owner = isPrototypeGet ? name : parent;
boolean singleGlobalParentDecl =
owner != null && owner.getDeclaration() != null && owner.getLocalSets() == 0;
if (singleGlobalParentDecl &&
owner.getDeclaration().preOrderIndex > ref.preOrderIndex) {
String refName = isPrototypeGet
? name.getFullName() + ".prototype"
: name.getFullName();
compiler.report(
JSError.make(
ref.getNode(),
NAME_DEFINED_LATE_WARNING,
refName,
owner.getFullName(),
owner.getDeclaration().getSourceFile().getName(),
String.valueOf(owner.getDeclaration().getNode().getLineno())));
}
}
}
}
}
private static boolean isTypedef(Name name) {
if (name.getDeclaration() != null) {
// typedefs don't have 'declarations' because you can't assign to them
return false;
}
for (Ref ref : name.getRefs()) {
// If this is an annotated EXPR-GET, don't do anything.
Node parent = ref.getNode().getParent();
if (parent.isExprResult()) {
JSDocInfo info = ref.getNode().getJSDocInfo();
if (info != null && info.hasTypedefType()) {
return true;
}
}
}
return false;
}
/**
* Returns true if this name is potentially referenced before being defined in a different module
*
* For example:
*
*
* - Module B depends on Module A. name is set in Module A and referenced in Module B. this is
* fine, and this method returns false.
*
- Module A and Module B are unrelated. name is set in Module A and referenced in Module B.
* this is an error, and this method returns true.
*
- name is referenced in Module A, and never set globally. This warning is not specific to
* modules, so is emitted elsewhere.
*
*/
private boolean checkForBadModuleReference(Name name, Ref ref) {
JSModuleGraph moduleGraph = compiler.getModuleGraph();
if (name.getGlobalSets() == 0 || ref.type == Ref.Type.SET_FROM_GLOBAL) {
// Back off if either 1) this name was never set, or 2) this reference /is/ a set.
return false;
}
if (name.getGlobalSets() == 1) {
// there is only one global set - it should be set as name.declaration
// just look at that declaration instead of iterating through every single reference.
Ref declaration = checkNotNull(name.getDeclaration());
return !isSetFromPrecedingModule(ref, declaration, moduleGraph);
}
// there are multiple sets, so check if any of them happens in this module or a module earlier
// in the dependency chain.
for (Ref set : name.getRefs()) {
if (isSetFromPrecedingModule(ref, set, moduleGraph)) {
return false;
}
}
return true;
}
/** Whether the set is in the global scope and occurs in a module the original ref depends on */
private static boolean isSetFromPrecedingModule(
Ref originalRef, Ref set, JSModuleGraph moduleGraph) {
return set.type == Ref.Type.SET_FROM_GLOBAL
&& (originalRef.getModule() == set.getModule()
|| moduleGraph.dependsOn(originalRef.getModule(), set.getModule()));
}
private void reportBadModuleReference(Name name, Ref ref) {
compiler.report(
JSError.make(
ref.getNode(),
STRICT_MODULE_DEP_QNAME,
ref.getModule().getName(),
name.getDeclaration().getModule().getName(),
name.getFullName()));
}
private void reportRefToUndefinedName(Name name, Ref ref) {
// grab the highest undefined ancestor to output in the warning message.
while (name.getParent() != null
&& name.getParent().getGlobalSets() + name.getParent().getLocalSets() == 0) {
name = name.getParent();
}
compiler.report(JSError.make(ref.getNode(), level, UNDEFINED_NAME_WARNING, name.getFullName()));
}
/**
* The input name is a property. Check whether this property
* must be initialized with its full qualified name.
*/
private boolean propertyMustBeInitializedByFullName(Name name) {
// If an object or function literal in the global namespace is never
// aliased, then its properties can only come from one of 2 places:
// 1) From its prototype chain, or
// 2) From an assignment to its fully qualified name.
// If we assume #1 is not the case, then #2 implies that its
// properties must all be modeled in the GlobalNamespace as well.
//
// We assume that for global object literals and types (constructors and
// interfaces), we can find all the properties inherited from the prototype
// chain of functions and objects.
if (name.getParent() == null) {
return false;
}
if (isNameUnsafelyAliased(name.getParent())) {
// e.g. if we have `const ns = {}; escape(ns); alert(ns.a.b);`
// we don't expect ns.a.b to be defined somewhere because `ns` has escaped
return false;
}
if (objectPrototypeProps.contains(name.getBaseName())) {
// checks for things on Object.prototype, e.g. a call to
// something.hasOwnProperty('a');
return false;
}
if (name.getParent().isObjectLiteral()) {
// if this is a property on an object literal, always expect an initialization somewhere
return true;
}
if (name.getParent().isClass()) {
// only warn on class properties if there is no superclass, because we don't handle
// class side inheritance here very well yet.
return !hasSuperclass(name.getParent());
}
// warn on remaining names if they are on a constructor and are not a Function.prototype
// property (e.g. f.call(1);)
return name.getParent().isFunction()
&& name.getParent().isDeclaredType()
&& !functionPrototypeProps.contains(name.getBaseName());
}
/** Returns whether the given ES6 class extends something. */
private boolean hasSuperclass(Name es6Class) {
Node decl = es6Class.getDeclaration().getNode();
Node classNode = NodeUtil.getRValueOfLValue(decl);
checkState(classNode.isClass(), classNode);
Node superclass = classNode.getSecondChild();
return !superclass.isEmpty();
}
private boolean isNameUnsafelyAliased(Name name) {
if (name.getAliasingGets() > 0) {
for (Ref ref : name.getRefs()) {
if (ref.type == Ref.Type.ALIASING_GET) {
Node aliaser = ref.getNode().getParent();
// We don't need to worry about known aliased, because
// they're already covered by the getIndirectlyDeclaredProperties
// call at the top.
boolean isKnownAlias =
aliaser.isCall()
&& (convention.getClassesDefinedByCall(aliaser) != null
|| convention.getSingletonGetterClassName(aliaser) != null);
if (!isKnownAlias) {
return true;
}
}
}
}
return name.getParent() != null && isNameUnsafelyAliased(name.getParent());
}
}