Bug 215353 – [ macOS iOS ] svg/animations/smil-leak-element-instances-noBaseValRef.svg is a flaky failure

• Component: New Bugs
• Status: RESOLVED FIXED

[Hector Lopez]

svg/animations/smil-leak-element-instances-noBaseValRef.svg

Test is a flaky failure on macOS wk 2 Release and iOS wk2 Debug according to history. First occurrence of failure on macOS appears at r254248. First occurrence of failure on iOS appears at r259172.

History:
https://results.webkit.org/?suite=layout-tests&test=svg%2Fanimations%2Fsmil-leak-element-instances-noBaseValRef.svg&platform=ios&platform=mac&limit=50000

Diff:
--- /Volumes/Data/slave/catalina-release-tests-wk2/build/layout-test-results/svg/animations/smil-leak-element-instances-noBaseValRef-expected.txt
+++ /Volumes/Data/slave/catalina-release-tests-wk2/build/layout-test-results/svg/animations/smil-leak-element-instances-noBaseValRef-actual.txt
@@ -1 +1 @@
-PASS
+FAIL: 3 extra live node(s)

[Radar WebKit Bug Importer]

<rdar://problem/66810097>

[Hector Lopez]

Test expectations while investigated:

https://trac.webkit.org/changeset/265484/webkit

[Said Abou-Hallawa]

Here is the history of this test:

r115518     Added smil-leak* tests
r155648     Changed the smil-leak* tests by moving garbage collection to the next run-loop after touching the nodes
r155882     Changed the smil-leak* tests by trying garbage collection mutiple times
r155890     Changed the smil-leak* tests by changing settimeout(, 0) to settimeout(, 100)
r155897     Changed platform/mac/TestExpectations - marked smil-leak* tests flaky on mac ports only
r181345     Caused smil-leak* tests to be more flaky
r181401     Changed platform/mac/TestExpectations- unmarked smil-leak* tests flaky on mac ports
r181401     Changed TestExpectations - marked smil-leak* tests flaky on all ports
r196268     Changed TestExpectations - unmarked smil-leak* tests un-flaky on all ports
r226187     Changed platform/mac-wk1/TestExpectations - marked smil-leak-element-instances-noBaseValRef.svg flaky on mac-wk1
r234441     Changed platform/mac-wk1/TestExpectations - unmarked smil-leak-element-instances-noBaseValRef.svg un-flaky on mac-wk1
r265484     Changed platform/ios-wk2/TestExpectations - marked smil-leak-element-instances-noBaseValRef.svg falky on ios-wk2
r265484     Changed platform/mac-wk2/TestExpectations - marked smil-leak-element-instances-noBaseValRef.svg falky on mac-wk2

[Said Abou-Hallawa]

From the history of this test and from other tests, I think the flakiness is in GCController.collect(). Calling this function from JS does not guarantee the memory of all the deallocated objects is garbage-collected. Multiple calls to GCController.collect() may be invoked to overcome this problem. Putting idle time before requesting the numberOfLiveNodes() might be need as well.

This is a stress test. It adds 100 <use> elements. In each one of them an <animate> element is added. So these objects are allocated then deallocated:

1. <use> elements, each with animated properties.
2. Shadow trees in which there is a <rect> element is created with its animated properties 
3. <animate> elements
4. SVGAnimators for the <animate> elements
5. Renderers for all the <use> and the <rect> elements in the shadow trees.

Since the GCController.collect() is flaky, I think we have to make the number of elements small such that there is kind of guarantee all the deallocated memory will be garbage collected during the test trials. I think adding three <use> elements should be enough to test the SVG animated properties do not leak. And allocating and freeing this number of objects should not exercise the flakiness of GCController.collect().

[Said Abou-Hallawa]

Created attachment 406502 [details]
Patch

[EWS]

Tools/Scripts/svn-apply failed to apply attachment 406502 [details] to trunk.
Please resolve the conflicts and upload a new patch.

[Said Abou-Hallawa]

Created attachment 406749 [details]
Patch

[EWS]

Committed r265780: <https://trac.webkit.org/changeset/265780>

All reviewed patches have been landed. Closing bug and clearing flags on attachment 406749 [details].

[Said Abou-Hallawa]

Reopening to attach new patch.

[Said Abou-Hallawa]

Created attachment 408244 [details]
Patch

[Said Abou-Hallawa]

After r265780, bots still show flakiness. Although the flakiness became very rare but it still exists.

[Geoffrey Garen]

Comment on attachment 408244 [details]
Patch

r=me

[EWS]

Committed r266765: <https://trac.webkit.org/changeset/266765>

All reviewed patches have been landed. Closing bug and clearing flags on attachment 408244 [details].