fix(runtime): resolve memory leak caused by global content ref (#5266)

tanner-reits · web-flow · commit fb1b3f5a5bf1 · 2024-01-17T18:58:05.000Z
* fix(runtime): resolve memory leak caused by global content ref

This commit resolves a memory leak in the runtime related to a global reference that existed in the vDOM algorithm. The content ref would get set when entering the render cycle for a component, but was never cleared so the reference would exist after execution

STENCIL-1072

* resolve SNC
diff --git a/src/runtime/vdom/vdom-render.ts b/src/runtime/vdom/vdom-render.ts
@@ -16,7 +16,7 @@ import { h, isHost, newVNode } from './h';
 import { updateElement } from './update-element';
 
 let scopeId: string;
-let contentRef: d.RenderNode;
+let contentRef: d.RenderNode | undefined;
 let hostTagName: string;
 let useNativeShadowDom = false;
 let checkSlotFallbackVisibility = false;
@@ -1127,6 +1127,9 @@ render() {
       }
     }
   }
+
+  // Clear the content ref so we don't create a memory leak
+  contentRef = undefined;
 };
 
 // slot comment debug nodes only created with the `--debug` flag

Original file line number	Diff line number	Diff line change
`@@ -16,7 +16,7 @@ import { h, isHost, newVNode } from './h';`
`16`	`16`	`import { updateElement } from './update-element';`
`17`	`17`
`18`	`18`	`let scopeId: string;`
`19`		`-let contentRef: d.RenderNode;`
	`19`	`+let contentRef: d.RenderNode \| undefined;`
`20`	`20`	`let hostTagName: string;`
`21`	`21`	`let useNativeShadowDom = false;`
`22`	`22`	`let checkSlotFallbackVisibility = false;`
`@@ -1127,6 +1127,9 @@ render() {`
`1127`	`1127`	`}`
`1128`	`1128`	`}`
`1129`	`1129`	`}`
	`1130`	`+`
	`1131`	`+ // Clear the content ref so we don't create a memory leak`
	`1132`	`+ contentRef = undefined;`
`1130`	`1133`	`};`
`1131`	`1134`
`1132`	`1135`	// slot comment debug nodes only created with the `--debug` flag