AutoSaveIT#autoSavesOnlyOnceWhenTwoClientsEdit is flickering

The functional test org.xwiki.blocknote.test.ui.AllIT$NestedAutoSaveIT#autoSavesOnlyOnceWhenTwoClientsEdit fails intermittently on the CI, on both master and stable-18.8.x.

The test opens the same page in two tabs, each with its own auto-saver, and asserts that only the client that wins the save election writes a version. The failure is the second half of that check:

org.opentest4j.AssertionFailedError: A second client saved the same changes.

It is not random: it only happens on MySQL

Over the last 28 days, Develocity records 4 failures in 42 executions (9.5%), and the failure group happens only with database = mysql latest (17% of runs, p=0.0003):

• master / chrome / mysql latest / tomcat 11-jdk25 — 2/4 (50.0%)
• stable-18.8.x / chrome / mysql latest / tomcat 11-jdk25 — 2/3 (66.7%)

The other 8 configurations it runs in have never failed. A save election whose outcome depends on how long the save itself takes is the shape that turns on with a slower database, so the suspicion is the width of the election window rather than the editor.

First seen 2026-09-17, last seen 2026-09-20.

Evidence

• Build scans: https://community.develocity.cloud/s/nk6emdybvtfkw and https://community.develocity.cloud/s/woxyveug3k3vg
• CI build: https://ci.xwiki.org/job/XWiki%20Environment%20Tests/job/xwiki-platform/job/master/1379

Affected tests

• org.xwiki.blocknote.test.ui.AllIT$NestedAutoSaveIT#autoSavesOnlyOnceWhenTwoClientsEdit

Affected branches: master, stable-18.8.x.

Verifying a fix

At the 57% failure rate seen in the affected configurations, about 4 consecutive clean runs there are enough to conclude the failure stopped — but they must be on chrome / mysql latest / tomcat 11-jdk25, not on the default configuration, where this test has never failed.

Filed automatically by the daily CI check. If this is wrong or already covered by another issue, just close it.