[autoroller] Log an error when # of checks is different than expected #

This is to let us know whenever the number of checks change till there
is a better solution hopefully soon.

Change-Id: I0c98d104599e5a2923484b55edc2991cd174b293
Reviewed-on: https://skia-review.googlesource.com/c/buildbot/+/252180
Reviewed-by: Eric Boren <borenet@google.com>
Commit-Queue: Ravi Mistry <rmistry@google.com>
diff --git a/autoroll/go/codereview/roll.go b/autoroll/go/codereview/roll.go
index 2e64e99..59fc31f 100644
--- a/autoroll/go/codereview/roll.go
+++ b/autoroll/go/codereview/roll.go
@@ -421,6 +421,10 @@
 			return nil, fmt.Errorf("Could not merge pull request %d: %s", a.Issue, err)
 		}
 		pullRequestModified = true
+
+		if len(tryResults) != checksNum {
+			sklog.Errorf("The PR %d landed with different number of checks (%d) than what was expected (%d). Check to see if this number should be updated in the roller config.", a.Issue, len(tryResults), checksNum)
+		}
 	}
 
 	if pullRequestModified {