Move long path recursion prevention to MemberExpression

src/ast/nodes/MemberExpression.ts

@@ -34,6 +34,9 @@ import {
 } from './shared/Expression';
 import { ExpressionNode, IncludeChildren, NodeBase } from './shared/Node';
 
+// To avoid infinite recursions
+const MAX_PATH_DEPTH = 7;
+
 function getResolvablePropertyKey(memberExpression: MemberExpression): string | null {
 	return memberExpression.computed
 		? getResolvableComputedPropertyKey(memberExpression.property)
@@ -124,7 +127,9 @@ export default class MemberExpression extends NodeBase implements DeoptimizableE
 		if (this.variable) {
 			this.variable.deoptimizePath(path);
 		} else if (!this.replacement) {
-			this.object.deoptimizePath([this.getPropertyKey(), ...path]);
+			if (path.length < MAX_PATH_DEPTH) {
+				this.object.deoptimizePath([this.getPropertyKey(), ...path]);
+			}
 		}
 	}
 
@@ -137,12 +142,16 @@ export default class MemberExpression extends NodeBase implements DeoptimizableE
 		if (this.variable) {
 			this.variable.deoptimizeThisOnEventAtPath(event, path, thisParameter, recursionTracker);
 		} else if (!this.replacement) {
-			this.object.deoptimizeThisOnEventAtPath(
-				event,
-				[this.getPropertyKey(), ...path],
-				thisParameter,
-				recursionTracker
-			);
+			if (path.length < MAX_PATH_DEPTH) {
+				this.object.deoptimizeThisOnEventAtPath(
+					event,
+					[this.getPropertyKey(), ...path],
+					thisParameter,
+					recursionTracker
+				);
+			} else {
+				thisParameter.deoptimizePath(UNKNOWN_PATH);
+			}
 		}
 	}
 
@@ -158,11 +167,14 @@ export default class MemberExpression extends NodeBase implements DeoptimizableE
 			return UnknownValue;
 		}
 		this.expressionsToBeDeoptimized.push(origin);
-		return this.object.getLiteralValueAtPath(
-			[this.getPropertyKey(), ...path],
-			recursionTracker,
-			origin
-		);
+		if (path.length < MAX_PATH_DEPTH) {
+			return this.object.getLiteralValueAtPath(
+				[this.getPropertyKey(), ...path],
+				recursionTracker,
+				origin
+			);
+		}
+		return UnknownValue;
 	}
 
 	getReturnExpressionWhenCalledAtPath(
@@ -183,12 +195,15 @@ export default class MemberExpression extends NodeBase implements DeoptimizableE
 			return UNKNOWN_EXPRESSION;
 		}
 		this.expressionsToBeDeoptimized.push(origin);
-		return this.object.getReturnExpressionWhenCalledAtPath(
-			[this.getPropertyKey(), ...path],
-			callOptions,
-			recursionTracker,
-			origin
-		);
+		if (path.length < MAX_PATH_DEPTH) {
+			return this.object.getReturnExpressionWhenCalledAtPath(
+				[this.getPropertyKey(), ...path],
+				callOptions,
+				recursionTracker,
+				origin
+			);
+		}
+		return UNKNOWN_EXPRESSION;
 	}
 
 	hasEffects(context: HasEffectsContext): boolean {
@@ -217,7 +232,10 @@ export default class MemberExpression extends NodeBase implements DeoptimizableE
 		if (this.replacement) {
 			return true;
 		}
-		return this.object.hasEffectsWhenAccessedAtPath([this.getPropertyKey(), ...path], context);
+		if (path.length < MAX_PATH_DEPTH) {
+			return this.object.hasEffectsWhenAccessedAtPath([this.getPropertyKey(), ...path], context);
+		}
+		return true;
 	}
 
 	hasEffectsWhenAssignedAtPath(path: ObjectPath, context: HasEffectsContext): boolean {
@@ -227,7 +245,10 @@ export default class MemberExpression extends NodeBase implements DeoptimizableE
 		if (this.replacement) {
 			return true;
 		}
-		return this.object.hasEffectsWhenAssignedAtPath([this.getPropertyKey(), ...path], context);
+		if (path.length < MAX_PATH_DEPTH) {
+			return this.object.hasEffectsWhenAssignedAtPath([this.getPropertyKey(), ...path], context);
+		}
+		return true;
 	}
 
 	hasEffectsWhenCalledAtPath(
@@ -241,11 +262,14 @@ export default class MemberExpression extends NodeBase implements DeoptimizableE
 		if (this.replacement) {
 			return true;
 		}
-		return this.object.hasEffectsWhenCalledAtPath(
-			[this.getPropertyKey(), ...path],
-			callOptions,
-			context
-		);
+		if (path.length < MAX_PATH_DEPTH) {
+			return this.object.hasEffectsWhenCalledAtPath(
+				[this.getPropertyKey(), ...path],
+				callOptions,
+				context
+			);
+		}
+		return true;
 	}
 
 	include(context: InclusionContext, includeChildrenRecursively: IncludeChildren): void {

src/ast/nodes/shared/ObjectMember.ts

@@ -20,7 +20,12 @@ export class ObjectMember extends ExpressionEntity {
 		thisParameter: ExpressionEntity,
 		recursionTracker: PathTracker
 	): void {
-		this.object.deoptimizeThisOnEventAtPath(event, path, thisParameter, recursionTracker);
+		this.object.deoptimizeThisOnEventAtPath(
+			event,
+			[this.key, ...path],
+			thisParameter,
+			recursionTracker
+		);
 	}
 
 	getLiteralValueAtPath(

src/ast/variables/LocalVariable.ts

@@ -17,9 +17,6 @@ import { ExpressionNode, Node } from '../nodes/shared/Node';
 import { ObjectPath, PathTracker, UNKNOWN_PATH } from '../utils/PathTracker';
 import Variable from './Variable';
 
-// To avoid infinite recursions
-const MAX_PATH_DEPTH = 7;
-
 export default class LocalVariable extends Variable {
 	calledFromTryStatement = false;
 	declarations: (Identifier | ExportDefaultDeclaration)[];
@@ -64,7 +61,6 @@ export default class LocalVariable extends Variable {
 
 	deoptimizePath(path: ObjectPath): void {
 		if (
-			path.length > MAX_PATH_DEPTH ||
 			this.isReassigned ||
 			this.deoptimizationTracker.trackEntityAtPathAndGetIfTracked(path, this)
 		) {
@@ -91,7 +87,7 @@ export default class LocalVariable extends Variable {
 		thisParameter: ExpressionEntity,
 		recursionTracker: PathTracker
 	): void {
-		if (this.isReassigned || !this.init || path.length > MAX_PATH_DEPTH) {
+		if (this.isReassigned || !this.init) {
 			return thisParameter.deoptimizePath(UNKNOWN_PATH);
 		}
 		recursionTracker.withTrackedEntityAtPath(
@@ -107,7 +103,7 @@ export default class LocalVariable extends Variable {
 		recursionTracker: PathTracker,
 		origin: DeoptimizableEntity
 	): LiteralValueOrUnknown {
-		if (this.isReassigned || !this.init || path.length > MAX_PATH_DEPTH) {
+		if (this.isReassigned || !this.init) {
 			return UnknownValue;
 		}
 		return recursionTracker.withTrackedEntityAtPath(
@@ -127,7 +123,7 @@ export default class LocalVariable extends Variable {
 		recursionTracker: PathTracker,
 		origin: DeoptimizableEntity
 	): ExpressionEntity {
-		if (this.isReassigned || !this.init || path.length > MAX_PATH_DEPTH) {
+		if (this.isReassigned || !this.init) {
 			return UNKNOWN_EXPRESSION;
 		}
 		return recursionTracker.withTrackedEntityAtPath(
@@ -147,14 +143,14 @@ export default class LocalVariable extends Variable {
 	}
 
 	hasEffectsWhenAccessedAtPath(path: ObjectPath, context: HasEffectsContext): boolean {
-		if (this.isReassigned || path.length > MAX_PATH_DEPTH) return true;
+		if (this.isReassigned) return true;
 		return (this.init &&
 			!context.accessed.trackEntityAtPathAndGetIfTracked(path, this) &&
 			this.init.hasEffectsWhenAccessedAtPath(path, context))!;
 	}
 
 	hasEffectsWhenAssignedAtPath(path: ObjectPath, context: HasEffectsContext): boolean {
-		if (this.included || path.length > MAX_PATH_DEPTH) return true;
+		if (this.included) return true;
 		if (path.length === 0) return false;
 		if (this.isReassigned) return true;
 		return (this.init &&
@@ -167,7 +163,7 @@ export default class LocalVariable extends Variable {
 		callOptions: CallOptions,
 		context: HasEffectsContext
 	): boolean {
-		if (path.length > MAX_PATH_DEPTH || this.isReassigned) return true;
+		if (this.isReassigned) return true;
 		return (this.init &&
 			!(
 				callOptions.withNew ? context.instantiated : context.called

test/form/samples/deep-properties-access/_config.js

@@ -0,0 +1,3 @@
+module.exports = {
+	description: 'handles deeply nested property accesses'
+};

test/form/samples/deep-properties-access/_expected.js

@@ -0,0 +1,2 @@
+var obj = { obj: {obj: {obj: {obj: {obj: {obj: {obj: {obj: {obj: {obj: {}}}}}}}}}}};
+console.log(obj.obj.obj.obj.obj.obj.obj.obj.obj.foo);

test/form/samples/deep-properties-access/main.js

@@ -0,0 +1,2 @@
+var obj = { obj: {obj: {obj: {obj: {obj: {obj: {obj: {obj: {obj: {obj: {}}}}}}}}}}};
+console.log(obj.obj.obj.obj.obj.obj.obj.obj.obj.foo);

test/form/samples/deep-properties/_config.js

@@ -0,0 +1,6 @@
+module.exports = {
+	description: 'handles deeply nested properties',
+	options: {
+		treeshake: { propertyReadSideEffects: false }
+	}
+};

test/form/samples/deep-properties/_expected.js

@@ -0,0 +1,11 @@
+var obj1 = obj1;
+console.log(obj1.foo());
+
+var obj2 = { obj: {obj: {obj: {obj: {obj: {obj: {obj: {obj: {obj: {obj: {}}}}}}}}}}};
+obj2.obj.obj.obj.obj.obj.obj.obj.foo();
+
+var obj3 = { obj: {obj: {obj: {obj: {obj: {obj: {obj: {obj: {obj: {obj: {}}}}}}}}}}};
+if (obj3.obj.obj.obj.obj.obj.obj.obj.obj.foo) console.log('nested');
+
+var obj4 = { obj: {obj: {obj: {obj: {obj: {obj: {obj: {obj: {obj: {obj: {}}}}}}}}}}};
+obj4.obj.obj.obj.obj.obj.obj.obj.foo = 'nested';

test/form/samples/deep-properties/main.js

@@ -0,0 +1,11 @@
+var obj1 = obj1;
+console.log(obj1.foo());
+
+var obj2 = { obj: {obj: {obj: {obj: {obj: {obj: {obj: {obj: {obj: {obj: {}}}}}}}}}}};
+obj2.obj.obj.obj.obj.obj.obj.obj.foo();
+
+var obj3 = { obj: {obj: {obj: {obj: {obj: {obj: {obj: {obj: {obj: {obj: {}}}}}}}}}}};
+if (obj3.obj.obj.obj.obj.obj.obj.obj.obj.foo) console.log('nested');
+
+var obj4 = { obj: {obj: {obj: {obj: {obj: {obj: {obj: {obj: {obj: {obj: {}}}}}}}}}}};
+obj4.obj.obj.obj.obj.obj.obj.obj.foo = 'nested';

test/form/samples/static-method-deoptimization/_config.js

@@ -0,0 +1,3 @@
+module.exports = {
+	description: 'avoids infinite recursions when deoptimizing "this" context'
+};

test/form/samples/static-method-deoptimization/_expected.js

@@ -0,0 +1,13 @@
+class Foo {
+	static echo(message) {
+		this.prototype.echo(message);
+	}
+	echo(message) {
+		console.log(message);
+	}
+}
+
+class Bar extends Foo {}
+
+global.baz = 'PASS';
+Bar.echo(baz);

test/form/samples/static-method-deoptimization/main.js

@@ -0,0 +1,13 @@
+class Foo {
+	static echo(message) {
+		this.prototype.echo(message);
+	}
+	echo(message) {
+		console.log(message);
+	}
+}
+
+class Bar extends Foo {}
+
+global.baz = 'PASS';
+Bar.echo(baz);