| | 1 | = What is an abandoned document? = |
| | 2 | |
| | 3 | Abandoned documents are effectively leaked: they are Document objects which have never been destroyed, and persist after loading about:blank and clearing caches. This is probably because there's some object that is holding a reference to the Document object, possibly in the GC heap, or via a retain cycle (often involving Nodes in the document). |
| | 4 | |
| | 5 | All documents are referenced by Document::allDocumentsMap(), so they are not leaked in the sense that the 'leaks' tool doesn't show them. |
| | 6 | |
| | 7 | = Why are layout test results showing me a list of abandoned documents? = |
| | 8 | |
| | 9 | Because leaked documents usually entrain a lot of other objects, which can use lots of memory (e.g. via entries in the memory cache). Leaking documents is bad because it will cause ever-increasing memory use as the user browses. See [https://bugs.webkit.org/show_bug.cgi?id=186214] |
| | 10 | |
| | 11 | = What should I do if see a new case of document abandonment? = |
| | 12 | |
| | 13 | If you made a code change that is causing a test to newly show that a document is leaked, it probably means you have a coding bug that is triggered a leak or (more likely) a reference cycle. You need to resolve this before committing. |
