I wanted to land some CLs this weekend and found the tree was closed. I retried the failing build on https://build.chromium.org/p/chromium.infra/builders/infra-continuous-win-64/builds/5045 as https://build.chromium.org/p/chromium.infra/builders/infra-continuous-win-64/builds/5046 and it then succeeded.

Unfortunately https://uberchromegw.corp.google.com/i/chromium.infra/builders/infra-continuous-xenial-64/builds/2585 failed on the first retry (same revision), but then I forced a new build and it went green.

Same thing with https://uberchromegw.corp.google.com/i/chromium.infra/builders/infra-continuous-precise-64/builds/5116 which succeeded in the following build.

I'm not sure what's causing the flakiness but I could see Vadim had been reopening several times already at https://infra-status.appspot.com/

All these failures seems to be like: 
.......x......
Failures:

  * E:/b/rr/tmptcfj_l/w/infra/go/src/infra/monitoring/analyzer/step/test_step_test.go 
  Line 355:
  Expected: '[]messages.ReasonRaw{(*step.testFailure){TestNames:[]string{"...... too many results, data snipped....", "test_a", "test_b"}, StepName:"something_tests", Tests:[]step.testWithResult{step.testWithResult{TestName:"test_a", IsFlaky:false, SuspectedCLs:[]messages.SuspectCL{messages.SuspectCL{RepoName:"repo", Revision:"deadbeef", CommitPosition:1234, Confidence:0, AnalysisApproach:""}}}, step.testWithResult{TestName:"test_b", IsFlaky:false, SuspectedCLs:[]messages.SuspectCL{messages.SuspectCL{RepoName:"repo", Revision:"deadbeef", CommitPosition:1234, Confidence:0, AnalysisApproach:""}}}, step.testWithResult{TestName:"...... too many results, data snipped....", IsFlaky:false, SuspectedCLs:[]messages.SuspectCL(nil)}}}}'
  Actual:   '[]messages.ReasonRaw{(*step.testFailure){TestNames:[]string{"...... too many results, data snipped....", "test_b", "test_c"}, StepName:"something_tests", Tests:[]step.testWithResult{step.testWithResult{TestName:"test_b", IsFlaky:false, SuspectedCLs:[]messages.SuspectCL{messages.SuspectCL{RepoName:"repo", Revision:"deadbeef", CommitPosition:1234, Confidence:0, AnalysisApproach:""}}}, step.testWithResult{TestName:"test_c", IsFlaky:false, SuspectedCLs:[]messages.SuspectCL(nil)}, step.testWithResult{TestName:"...... too many results, data snipped....", IsFlaky:false, SuspectedCLs:[]messages.SuspectCL(nil)}}}}'
  (Should resemble)!