Only free elements that the DOMElementPool created

spec/dom-element-pool-spec.js

@@ -51,29 +51,44 @@ describe('DOMElementPool', function () {
     expect(domElementPool.buildElement('div')).not.toBe(div)
   })
 
+  it('does not attempt to free nodes that were not created by the pool', () => {
+    let assertionFailure
+    atom.onDidFailAssertion((error) => assertionFailure = error)
+
+    const foreignDiv = document.createElement('div')
+    const div = domElementPool.buildElement('div')
+    div.appendChild(foreignDiv)
+    domElementPool.freeElementAndDescendants(div)
+    const span = domElementPool.buildElement('span')
+    span.appendChild(foreignDiv)
+    domElementPool.freeElementAndDescendants(span)
+
+    expect(assertionFailure).toBeUndefined()
+  })
+
   it('fails an assertion when freeing the same element twice', function () {
-    let failure
-    atom.onDidFailAssertion((error) => failure = error)
+    let assertionFailure
+    atom.onDidFailAssertion((error) => assertionFailure = error)
 
     const div = domElementPool.buildElement('div')
     div.textContent = 'testing'
     domElementPool.freeElementAndDescendants(div)
-    expect(failure).toBeUndefined()
+    expect(assertionFailure).toBeUndefined()
     domElementPool.freeElementAndDescendants(div)
-    expect(failure.message).toBe('Assertion failed: The element has already been freed!')
-    expect(failure.metadata.content).toBe('<div>testing</div>')
+    expect(assertionFailure.message).toBe('Assertion failed: The element has already been freed!')
+    expect(assertionFailure.metadata.content).toBe('<div>testing</div>')
   })
 
   it('fails an assertion when freeing the same text node twice', function () {
-    let failure
-    atom.onDidFailAssertion((error) => failure = error)
+    let assertionFailure
+    atom.onDidFailAssertion((error) => assertionFailure = error)
 
     const node = domElementPool.buildText('testing')
     domElementPool.freeElementAndDescendants(node)
-    expect(failure).toBeUndefined()
+    expect(assertionFailure).toBeUndefined()
     domElementPool.freeElementAndDescendants(node)
-    expect(failure.message).toBe('Assertion failed: The element has already been freed!')
-    expect(failure.metadata.content).toBe('testing')
+    expect(assertionFailure.message).toBe('Assertion failed: The element has already been freed!')
+    expect(assertionFailure.metadata.content).toBe('testing')
   })
 
   it('throws an error when trying to free an invalid element', function () {

src/dom-element-pool.js

@@ -1,11 +1,13 @@
 module.exports =
 class DOMElementPool {
   constructor () {
+    this.managedElements = new Set()
     this.freeElementsByTagName = new Map()
     this.freedElements = new Set()
   }
 
   clear () {
+    this.managedElements.clear()
     this.freedElements.clear()
     this.freeElementsByTagName.clear()
   }
@@ -27,6 +29,7 @@ class DOMElementPool {
       this.freedElements.delete(element)
     } else {
       element = document.createElement(tagName)
+      this.managedElements.add(element)
     }
     return element
   }
@@ -39,6 +42,7 @@ class DOMElementPool {
       this.freedElements.delete(element)
     } else {
       element = document.createTextNode(textContent)
+      this.managedElements.add(element)
     }
     return element
   }
@@ -50,6 +54,7 @@ class DOMElementPool {
 
   free (element) {
     if (element == null) { throw new Error('The element cannot be null or undefined.') }
+    if (!this.managedElements.has(element)) return
     if (this.freedElements.has(element)) {
       atom.assert(false, 'The element has already been freed!', {
         content: element instanceof Text ? element.textContent : element.outerHTML.toString()