Refactor DOM attribute code (take two) (#11815)

* Harden tests around init/addition/update/removal of aliased attributes

I noticed some patterns weren't being tested.

* Call setValueForProperty() for null and undefined

The branching before the call is unnecessary because setValueForProperty() already
has an internal branch that delegates to deleteValueForProperty() for null and
undefined through the shouldIgnoreValue() check.

The goal is to start unifying these methods because their separation doesn't
reflect the current behavior (e.g. for unknown properties) anymore, and obscures
what actually happens with different inputs.

* Inline deleteValueForProperty() into setValueForProperty()

Now we don't read propertyInfo twice in this case.

I also dropped a few early returns. I added them a while ago when we had
Stack-only tracking of DOM operations, and some operations were being
counted twice because of how this code is structured. This isn't a problem
anymore (both because we don't track operations, and because I've just
inlined this method call).

* Inline deleteValueForAttribute() into setValueForAttribute()

The special cases for null and undefined already exist in setValueForAttribute().

* Delete some dead code

* Make setValueForAttribute() a branch of setValueForProperty()

Their naming is pretty confusing by now. For example setValueForProperty()
calls setValueForAttribute() when shouldSetAttribute() is false (!). I want
to refactor (as in, inline and then maybe factor it out differently) the relation
between them. For now, I'm consolidating the callers to use setValueForProperty().

* Make it more obvious where we skip and when we reset attributes

The naming of these methods is still very vague and conflicting in some cases.
Will need further work.

* Rewrite setValueForProperty() with early exits

This makes the flow clearer in my opinion.

* Move shouldIgnoreValue() into DOMProperty

It was previously duplicated.

It's also suspiciously similar in purpose to shouldTreatAttributeValueAsNull()
so I want to see if there is a way to unify them.

* Use more specific methods for testing validity

* Unify shouldTreatAttributeValueAsNull() and shouldIgnoreValue()

* Remove shouldSetAttribute()

Its naming was confusing and it was used all over the place instead of more specific checks.
Now that we only have one call site, we might as well inline and get rid of it.

* Remove unnecessary condition

* Remove another unnecessary condition

* Add Flow coverage

* Oops

* Fix lint (ESLint complains about Flow suppression)

* Fix treatment of Symbol/Function values on boolean attributes

They weren't being properly skipped because of the early return.
I added tests for this case.

* Avoid getPropertyInfo() calls

I think this PR looks worse on benchmarks because we have to read propertyInfo in different places.
Originally I tried to get rid of propertyInfo, but looks like it's important for performance after all.

So now I'm going into the opposite direction, and precompute propertyInfo as early as possible, and then just pass it around.
This way we can avoid extra lookups but keep functions nice and modular.

* Pass propertyInfo as argument to getValueForProperty()

It always exists because this function is only called for known properties.

* Make it clearer this branch is boolean-specific

I wrote this and then got confused myself.

* Memoize whether propertyInfo accepts boolean value

Since we run these checks for all booleans, might as well remember it.

* Fix a crash when numeric property is given a Symbol

* Record attribute table

The changes reflect that SSR doesn't crash with symbols anymore (and just warns, consistently with the client).

* Refactor attribute initialization

Instead of using flags, explicitly group similar attributes/properties.

* Optimization: we know built-in attributes are never invalid

* Use strict comparison

* Rename methods for clarity

* Lint nit

* Minor tweaks

* Document all the different attribute types

Author: gaearon

fixtures/attribute-behavior/AttributeTableSnapshot.md

@@ -442,6 +442,97 @@ describe('ReactDOMComponent', () => {
       expect(container.firstChild.className).toEqual('');
     });
 
+    it('should not set null/undefined attributes', () => {
+      var container = document.createElement('div');
+      // Initial render.
+      ReactDOM.render(<img src={null} data-foo={undefined} />, container);
+      var node = container.firstChild;
+      expect(node.hasAttribute('src')).toBe(false);
+      expect(node.hasAttribute('data-foo')).toBe(false);
+      // Update in one direction.
+      ReactDOM.render(<img src={undefined} data-foo={null} />, container);
+      expect(node.hasAttribute('src')).toBe(false);
+      expect(node.hasAttribute('data-foo')).toBe(false);
+      // Update in another direction.
+      ReactDOM.render(<img src={null} data-foo={undefined} />, container);
+      expect(node.hasAttribute('src')).toBe(false);
+      expect(node.hasAttribute('data-foo')).toBe(false);
+      // Removal.
+      ReactDOM.render(<img />, container);
+      expect(node.hasAttribute('src')).toBe(false);
+      expect(node.hasAttribute('data-foo')).toBe(false);
+      // Addition.
+      ReactDOM.render(<img src={undefined} data-foo={null} />, container);
+      expect(node.hasAttribute('src')).toBe(false);
+      expect(node.hasAttribute('data-foo')).toBe(false);
+    });
+
+    it('should apply React-specific aliases to HTML elements', () => {
+      var container = document.createElement('div');
+      ReactDOM.render(<form acceptCharset="foo" />, container);
+      var node = container.firstChild;
+      // Test attribute initialization.
+      expect(node.getAttribute('accept-charset')).toBe('foo');
+      expect(node.hasAttribute('acceptCharset')).toBe(false);
+      // Test attribute update.
+      ReactDOM.render(<form acceptCharset="boo" />, container);
+      expect(node.getAttribute('accept-charset')).toBe('boo');
+      expect(node.hasAttribute('acceptCharset')).toBe(false);
+      // Test attribute removal by setting to null.
+      ReactDOM.render(<form acceptCharset={null} />, container);
+      expect(node.hasAttribute('accept-charset')).toBe(false);
+      expect(node.hasAttribute('acceptCharset')).toBe(false);
+      // Restore.
+      ReactDOM.render(<form acceptCharset="foo" />, container);
+      expect(node.getAttribute('accept-charset')).toBe('foo');
+      expect(node.hasAttribute('acceptCharset')).toBe(false);
+      // Test attribute removal by setting to undefined.
+      ReactDOM.render(<form acceptCharset={undefined} />, container);
+      expect(node.hasAttribute('accept-charset')).toBe(false);
+      expect(node.hasAttribute('acceptCharset')).toBe(false);
+      // Restore.
+      ReactDOM.render(<form acceptCharset="foo" />, container);
+      expect(node.getAttribute('accept-charset')).toBe('foo');
+      expect(node.hasAttribute('acceptCharset')).toBe(false);
+      // Test attribute removal.
+      ReactDOM.render(<form />, container);
+      expect(node.hasAttribute('accept-charset')).toBe(false);
+      expect(node.hasAttribute('acceptCharset')).toBe(false);
+    });
+
+    it('should apply React-specific aliases to SVG elements', () => {
+      var container = document.createElement('div');
+      ReactDOM.render(<svg arabicForm="foo" />, container);
+      var node = container.firstChild;
+      // Test attribute initialization.
+      expect(node.getAttribute('arabic-form')).toBe('foo');
+      expect(node.hasAttribute('arabicForm')).toBe(false);
+      // Test attribute update.
+      ReactDOM.render(<svg arabicForm="boo" />, container);
+      expect(node.getAttribute('arabic-form')).toBe('boo');
+      expect(node.hasAttribute('arabicForm')).toBe(false);
+      // Test attribute removal by setting to null.
+      ReactDOM.render(<svg arabicForm={null} />, container);
+      expect(node.hasAttribute('arabic-form')).toBe(false);
+      expect(node.hasAttribute('arabicForm')).toBe(false);
+      // Restore.
+      ReactDOM.render(<svg arabicForm="foo" />, container);
+      expect(node.getAttribute('arabic-form')).toBe('foo');
+      expect(node.hasAttribute('arabicForm')).toBe(false);
+      // Test attribute removal by setting to undefined.
+      ReactDOM.render(<svg arabicForm={undefined} />, container);
+      expect(node.hasAttribute('arabic-form')).toBe(false);
+      expect(node.hasAttribute('arabicForm')).toBe(false);
+      // Restore.
+      ReactDOM.render(<svg arabicForm="foo" />, container);
+      expect(node.getAttribute('arabic-form')).toBe('foo');
+      expect(node.hasAttribute('arabicForm')).toBe(false);
+      // Test attribute removal.
+      ReactDOM.render(<svg />, container);
+      expect(node.hasAttribute('arabic-form')).toBe(false);
+      expect(node.hasAttribute('arabicForm')).toBe(false);
+    });
+
     it('should properly update custom attributes on custom elements', () => {
       const container = document.createElement('div');
       ReactDOM.render(<some-custom-element foo="bar" />, container);
@@ -451,6 +542,25 @@ describe('ReactDOMComponent', () => {
       expect(node.getAttribute('bar')).toBe('buzz');
     });
 
+    it('should not apply React-specific aliases to custom elements', () => {
+      var container = document.createElement('div');
+      ReactDOM.render(<some-custom-element arabicForm="foo" />, container);
+      var node = container.firstChild;
+      // Should not get transformed to arabic-form as SVG would be.
+      expect(node.getAttribute('arabicForm')).toBe('foo');
+      expect(node.hasAttribute('arabic-form')).toBe(false);
+      // Test attribute update.
+      ReactDOM.render(<some-custom-element arabicForm="boo" />, container);
+      expect(node.getAttribute('arabicForm')).toBe('boo');
+      // Test attribute removal and addition.
+      ReactDOM.render(<some-custom-element acceptCharset="buzz" />, container);
+      // Verify the previous attribute was removed.
+      expect(node.hasAttribute('arabicForm')).toBe(false);
+      // Should not get transformed to accept-charset as HTML would be.
+      expect(node.getAttribute('acceptCharset')).toBe('buzz');
+      expect(node.hasAttribute('accept-charset')).toBe(false);
+    });
+
     it('should clear a single style prop when changing `style`', () => {
       let styles = {display: 'none', color: 'red'};
       const container = document.createElement('div');

packages/react-dom/src/__tests__/ReactDOMComponent-test.js

@@ -62,6 +62,16 @@ describe('ReactDOMServerIntegration', () => {
         const e = await render(<div width={null} />);
         expect(e.hasAttribute('width')).toBe(false);
       });
+
+      itRenders('no string prop with function value', async render => {
+        const e = await render(<div width={function() {}} />, 1);
+        expect(e.hasAttribute('width')).toBe(false);
+      });
+
+      itRenders('no string prop with symbol value', async render => {
+        const e = await render(<div width={Symbol('foo')} />, 1);
+        expect(e.hasAttribute('width')).toBe(false);
+      });
     });
 
     describe('boolean properties', function() {
@@ -122,6 +132,16 @@ describe('ReactDOMServerIntegration', () => {
         const e = await render(<div hidden={null} />);
         expect(e.hasAttribute('hidden')).toBe(false);
       });
+
+      itRenders('no boolean prop with function value', async render => {
+        const e = await render(<div hidden={function() {}} />, 1);
+        expect(e.hasAttribute('hidden')).toBe(false);
+      });
+
+      itRenders('no boolean prop with symbol value', async render => {
+        const e = await render(<div hidden={Symbol('foo')} />, 1);
+        expect(e.hasAttribute('hidden')).toBe(false);
+      });
     });
 
     describe('download property (combined boolean/string attribute)', function() {
@@ -164,6 +184,16 @@ describe('ReactDOMServerIntegration', () => {
         const e = await render(<div download={undefined} />);
         expect(e.hasAttribute('download')).toBe(false);
       });
+
+      itRenders('no download prop with function value', async render => {
+        const e = await render(<div download={function() {}} />, 1);
+        expect(e.hasAttribute('download')).toBe(false);
+      });
+
+      itRenders('no download prop with symbol value', async render => {
+        const e = await render(<div download={Symbol('foo')} />, 1);
+        expect(e.hasAttribute('download')).toBe(false);
+      });
     });
 
     describe('className property', function() {
@@ -257,6 +287,11 @@ describe('ReactDOMServerIntegration', () => {
         },
       );
 
+      itRenders('numeric property with zero value', async render => {
+        const e = await render(<ol start={0} />);
+        expect(e.getAttribute('start')).toBe('0');
+      });
+
       itRenders(
         'no positive numeric property with zero value',
         async render => {
@@ -265,9 +300,27 @@ describe('ReactDOMServerIntegration', () => {
         },
       );
 
-      itRenders('numeric property with zero value', async render => {
-        const e = await render(<ol start={0} />);
-        expect(e.getAttribute('start')).toBe('0');
+      itRenders('no numeric prop with function value', async render => {
+        const e = await render(<ol start={function() {}} />, 1);
+        expect(e.hasAttribute('start')).toBe(false);
+      });
+
+      itRenders('no numeric prop with symbol value', async render => {
+        const e = await render(<ol start={Symbol('foo')} />, 1);
+        expect(e.hasAttribute('start')).toBe(false);
+      });
+
+      itRenders(
+        'no positive numeric prop with function value',
+        async render => {
+          const e = await render(<input size={function() {}} />, 1);
+          expect(e.hasAttribute('size')).toBe(false);
+        },
+      );
+
+      itRenders('no positive numeric prop with symbol value', async render => {
+        const e = await render(<input size={Symbol('foo')} />, 1);
+        expect(e.hasAttribute('size')).toBe(false);
       });
     });