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Updated no-broken-super-chain rule to account for more lifecycle hooks … #94

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Updated no-broken-super-chain rule to account for more lifecycle hooks … #94

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a8b7a68
Refactored and updated the rule to account for more lifecycle hooks …
evanfarina Nov 2, 2017
abdad6d
Addressed feedback, added tests for new cases
evanfarina Nov 4, 2017
56dcd1b
Addressed feedback, added tests for new cases
evanfarina Nov 4, 2017
1a8aad3
Added more lifecycle hooks
evanfarina Nov 4, 2017
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148 changes: 81 additions & 67 deletions lib/rules/no-broken-super-chain.js
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Original file line number Diff line number Diff line change
Expand Up @@ -3,93 +3,107 @@
*/

const MESSAGES = {
noSuper: '\'this._super(...arguments)\' must be called in init()',
noThisBeforeSuper: 'Must call \'this._super(...arguments)\' before accessing `this`',
tooManySupers: 'Only call `this._super(...arguments)` once per init()'
noSuper: '`this._super(...arguments)` must be called in',
tooManySupers: 'Only call `this._super(...arguments)` once per lifecycle hook',
argsNotPassedToSuper: '...arguments need to be passed to this._super() call'
};

// TODO: Make this configurable
const EMBER_MODULES_WITH_SUPER_CHAIN = {
Component: true,
Mixin: true,
Route: true,
Controller: true,
View: true
};
const LIFECYCLE_HOOKS = ['init', 'willDestroy', 'willDestroyElement', 'destroy'];
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@rwjblue to be 100% safe, I think we should add all life cycle hooks here. Otherwise, we have no guarantee that mixins will work as expected.

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Ya, makes sense. Do we have a canonical list?

I guess we can start with the ones listed in https://guides.emberjs.com/v2.16.0/components/the-component-lifecycle/...


/**
* Determines if this is an init method in an extension of Ember[EMBER_MODULES_WITH_SUPER_CHAIN.*]
* @param {Node} node
*/
function isInit(node) {
if (node.type === 'FunctionExpression' && node.parent && node.parent.key && node.parent.key.name === 'init') {
function isExtend(node) {
return node && node.callee && node.callee.property && node.callee.property.name === 'extend';
}

function isSuperCall(lineWithinFn) {
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One more case we need to handle is:

Foo.extend({
  init() {
    return this._super(...argument);
  }
});

This ^ is valid, the linting rule should not complain about it.

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Great catch. Updated to: expression = expressionStatement.type === 'ReturnStatement' ? expressionStatement.argument : expressionStatement.expression;

if (lineWithinFn.type !== 'MemberExpression') {
return false;
}

let isSuperCall = false;

if (lineWithinFn.object.type === 'ThisExpression') {
isSuperCall = lineWithinFn.property.type === 'Identifier' && lineWithinFn.property.name === '_super';
} else if (lineWithinFn.object.type === 'MemberExpression') {
isSuperCall = lineWithinFn.object.property.name === '_super';
}

return isSuperCall;
}

if (node.parent.parent
&& node.parent.parent.parent
&& node.parent.parent.parent.callee
&& node.parent.parent.parent.callee.object
&& node.parent.parent.parent.callee.object.object
&& node.parent.parent.parent.callee.object.object.name === 'Ember') {
return (node.parent.parent.parent.callee.object.property
&& EMBER_MODULES_WITH_SUPER_CHAIN[node.parent.parent.parent.callee.object.property.name]);
}
function wereArgumentsPassedToSuper(expression) {
const callee = expression.callee;

if (!expression || callee.type !== 'MemberExpression') {
return;
}

return false;
if (callee.property.name === '_super') {
const firstArgumentToSuper = expression.arguments[0];
return firstArgumentToSuper && firstArgumentToSuper.type === 'SpreadElement' && firstArgumentToSuper.argument.name === 'arguments';
} else if (callee.property.name === 'apply') {
const args = expression.arguments;
return args.length >= 2 && args[0].type === 'ThisExpression' && args[1].name === 'arguments';
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When would args be > 2? I think we want args.length === 2...

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+1

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Yeah, not sure what I had in mind here

}
}

module.exports = {
meta: {
docs: {
description: 'Prevent the absence of `this._super(...arguments)` in `init()` calls or the use of `this` prior to `this._super()`',
description: 'Prevent the absence of `this._super(...arguments)` in calls to various lifecycle hooks or the use of `this` prior to `this._super()`',
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or the use of this prior to this._super()

I don't think we do this at the moment, do we? I don't see the code that does it at least...

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good catch, also updated file description

category: 'Best Practices',
recommended: true
},
messages: MESSAGES
},
create(context) {
let initOverride = null;

return {
onCodePathStart(codePath, node) {
if (isInit(node)) {
initOverride = {
superCalled: false,
superCalledFirst: false
};
}
},
onCodePathEnd(codePath, node) {
if (initOverride && isInit(node)) { // TODO: Maybe check against codepath.name
if (!initOverride.superCalled) {
context.report({
message: MESSAGES.noSuper,
node
});
}
CallExpression(node) {
if (isExtend(node)) {
let superCount = 0;
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Seems like this variable should be initialized from inside the extendedObjects.forEach loop (then you wouldn't need to reset it to 0 at the end of the loop).

const extendedObjects = node.arguments;

initOverride = null;
}
return;
},
'CallExpression:exit'(node) {
if (initOverride) {
const property = node.callee.property;
if (property && property.type === 'Identifier' && property.name === '_super') {
if (initOverride.superCalled) {
context.report({
message: MESSAGES.tooManySupers,
node
});
} else {
initOverride.superCalled = true;
}
}
extendedObjects.forEach(extendedObj => {
extendedObj.properties.forEach(property => {
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We need to guard for extendedObj.properties being undefined here (or filter out non ObjectExpressions before .forEaching).

I believe the following test should be added (which will fail ATM but pass if we filtered non ObjectExpressions):

Foo.extend(SomeMixin, {
  init() {
    this._super(...arguments);
  }
});

I'd suggest either of the following:

extendedObjects = node.arguments.filter(arg => arg.type === 'ObjectExpression');

// or

extendedObjects.forEach(extendedObj => {
  if (extendedObj.type !== 'ObjectExpression') { return; }

  // ...snip...
});

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I would also suggest adding a test case for this.

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Updated, and added test.

if (LIFECYCLE_HOOKS.includes(property.key.name)) {
const propertyFnBody = property.value.body;

if (propertyFnBody && propertyFnBody.body) {
let expression;
property.value.body.body.forEach(fnBody => {
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This should likely use propertyFnBody.body instead of property.value.body.body.forEach

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Can you rename fnBody to expressionStatement?

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  1. Correct. 2. Gladly

expression = fnBody.expression;
if (expression.type === 'CallExpression') {
const line = expression.callee;
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line isn't super descriptive, maybe call this callee?

if (isSuperCall(line)) {
if (!wereArgumentsPassedToSuper(expression)) {
context.report({
node: fnBody,
message: context.meta.messages.argsNotPassedToSuper
});
}
superCount++;
}
}
});

if (superCount === 0) {
context.report({
node: property,
message: `${context.meta.messages.noSuper} ${property.key.name}`
});
} else if (superCount > 1) {
context.report({
node: property,
message: context.meta.messages.tooManySupers
});
}

superCount = 0;
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This shouldn't be needed, we should initialize superCount inside the loop...

}
}
});
});
}
},
'Program:exit'() {
initOverride = null;
}
};
}
};
};
119 changes: 84 additions & 35 deletions tests/lib/rules/no-broken-super-chain.js
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Original file line number Diff line number Diff line change
@@ -1,7 +1,7 @@
const rule = require('../../../lib/rules/no-broken-super-chain');
const RuleTester = require('eslint').RuleTester;

const { noSuper, tooManySupers } = rule.meta.messages;
const { noSuper, tooManySupers, argsNotPassedToSuper } = rule.meta.messages;
const ruleTester = new RuleTester({
parserOptions: {
ecmaVersion: 6,
Expand All @@ -23,6 +23,15 @@ ruleTester.run('no-broken-super-chain', rule, {
}
});`
},
{
code: `
export default Ember.Component.extend({
init() {
this._super.apply(this, arguments);
this.alias = this.concrete;
},
});`
},
{
code: `
export default Ember.Route.extend({
Expand All @@ -47,14 +56,6 @@ ruleTester.run('no-broken-super-chain', rule, {
}
});`
},
{
code: `
export default Ember.Service.extend({
init() {
this.alias = this.concrete;
}
});`
},
{
code: `
export default Ember.Component.extend({
Expand Down Expand Up @@ -85,6 +86,17 @@ ruleTester.run('no-broken-super-chain', rule, {
}
],
invalid: [
{
code: `
export default Ember.Service.extend({
init() {
this.alias = this.concrete;
}
});`,
errors: [{
message: `${noSuper} init`
}]
},
{
code: `
export default Ember.Component.extend({
Expand All @@ -93,7 +105,40 @@ ruleTester.run('no-broken-super-chain', rule, {
}
});`,
errors: [{
message: noSuper
message: `${noSuper} init`
}]
},
{
code: `
export default Ember.Component.extend({
destroy() {
this.alias = this.concrete;
}
});`,
errors: [{
message: `${noSuper} destroy`
}]
},
{
code: `
export default Ember.Component.extend({
willDestroy() {
this.alias = this.concrete;
}
});`,
errors: [{
message: `${noSuper} willDestroy`
}]
},
{
code: `
export default Ember.Component.extend({
willDestroyElement() {
this.alias = this.concrete;
}
});`,
errors: [{
message: `${noSuper} willDestroyElement`
}]
},
{
Expand All @@ -104,32 +149,36 @@ ruleTester.run('no-broken-super-chain', rule, {
}
});`,
errors: [{
message: noSuper
message: `${noSuper} init`
}]
},
// TODO
// {
// code: `
// export default Ember.Component.extend({
// init() {
// this._super(); // missing '...arguments'
// this.alias = this.concrete;
// }
// });`,
// },
// TODO
// {
// code: `
// export default Ember.Component.extend({
// init() {
// this.alias = this.concrete;
// this._super(...arguments);
// }
// });`,
// errors: [{
// message: noThisBeforeSuper
// }]
// },
{
code: `
export default Ember.Component.extend({
init() {
this._super(); // missing '...arguments'
this.alias = this.concrete;
}
});`,
errors: [{
message: argsNotPassedToSuper
}]
},
/**
TODO
{
code: `
export default Ember.Component.extend({
init() {
this.alias = this.concrete;
this._super(...arguments);
}
});`,
errors: [{
message: noThisBeforeSuper
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Let’s remove this TODO commented test.

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When we add a rule about no this before super we will probably make it a new more focused rule anyways.

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Removed TODO

}]
},
*/
{
code: `
export default Ember.Component.extend({
Expand All @@ -156,4 +205,4 @@ ruleTester.run('no-broken-super-chain', rule, {
// }]
// }
]
});
});