Fix CEL cost handling of zero length replacement strings

[jpbetz]

What type of PR is this?

/kind bug

What this PR does / why we need it:

Which issue(s) this PR fixes:

Fixes issues found in ppc64le tests of CEL estimated cost for the replace() function: #119800 (comment)

The difference in cost was caused by ppc64le calculating this expression differently than amd64:

uint64(math.Ceil(float64(sz.Max)/float64(toReplaceSz.Min))) * replaceWithSz.Max

https://gist.github.com/jpbetz/032b54ce4ef8f5427c4812c023f6c693 shows the exact difference, which is that uint64(+Inf) results in 9223372036854775808 for amd64 but 18446744073709551615 for ppc64le (and arm64?).

The fix is to avoid the divide the creates the +Inf by handling the cost edge cases for replace(). I've verified this fix works on both architectures.

Special notes for your reviewer:

Does this PR introduce a user-facing change?

Fixed CEL estimated cost of `replace()` to handle a zero length replacement string correctly.
Previously this would cause the estimated cost to be higher than it should be.

/sig api-machinery

[jpbetz]

/cc @Rajalakshmi-Girish
/assign @liggitt

[Rajalakshmi-Girish]

/lgtm
It fixes the failure on ppc64le

[root@raji-workspace2 kubernetes]# uname -m
ppc64le
[root@raji-workspace2 kubernetes]#
[root@raji-workspace2 fix]# git clone https://github.com/jpbetz/kubernetes
Cloning into 'kubernetes'...
remote: Enumerating objects: 1418172, done.
remote: Counting objects: 100% (201/201), done.
remote: Compressing objects: 100% (111/111), done.
remote: Total 1418172 (delta 101), reused 123 (delta 85), pack-reused 1417971
Receiving objects: 100% (1418172/1418172), 979.50 MiB | 16.09 MiB/s, done.
Resolving deltas: 100% (1040719/1040719), done.
Updating files: 100% (23557/23557), done.
[root@raji-workspace2 fix]# cd kubernetes/
[root@raji-workspace2 kubernetes]# go test -v -timeout 30s -run ^TestCostEstimation/extended_library_replace$ k8s.io/apiextensions-apiserver/pkg/apiserver/schema/cel
=== RUN   TestCostEstimation
=== RUN   TestCostEstimation/extended_library_replace
=== RUN   TestCostEstimation/extended_library_replace/calc_maxLength
=== RUN   TestCostEstimation/extended_library_replace/set_maxLength
--- PASS: TestCostEstimation (0.01s)
    --- PASS: TestCostEstimation/extended_library_replace (0.01s)
        --- PASS: TestCostEstimation/extended_library_replace/calc_maxLength (0.01s)
        --- PASS: TestCostEstimation/extended_library_replace/set_maxLength (0.00s)
PASS
ok      k8s.io/apiextensions-apiserver/pkg/apiserver/schema/cel 0.022s
[root@raji-workspace2 kubernetes]# git checkout fix-ppc64le
Updating files: 100% (15550/15550), done.
branch 'fix-ppc64le' set up to track 'origin/fix-ppc64le'.
Switched to a new branch 'fix-ppc64le'
[root@raji-workspace2 kubernetes]# go test -v -timeout 30s -run ^TestCostEstimation/extended_library_replace$ k8s.io/apiextensions-apiserver/pkg/apiserver/schema/cel
=== RUN   TestCostEstimation
=== RUN   TestCostEstimation/extended_library_replace
=== RUN   TestCostEstimation/extended_library_replace/calc_maxLength
=== RUN   TestCostEstimation/extended_library_replace/set_maxLength
--- PASS: TestCostEstimation (0.01s)
    --- PASS: TestCostEstimation/extended_library_replace (0.01s)
        --- PASS: TestCostEstimation/extended_library_replace/calc_maxLength (0.01s)
        --- PASS: TestCostEstimation/extended_library_replace/set_maxLength (0.00s)
PASS
ok      k8s.io/apiextensions-apiserver/pkg/apiserver/schema/cel 0.032s
[root@raji-workspace2 kubernetes]#

[k8s-ci-robot]

LGTM label has been added.

Git tree hash: 034969ae302920a6d5004b023ad04c8d0cc7e373

[dims]

/retest
/approve
/lgtm

[liggitt]

/lgtm
/approve

[k8s-ci-robot]

LGTM label has been added.

Git tree hash: e1cec82593af66156924a3036926ff32d41653a8

[k8s-ci-robot]

[APPROVALNOTIFIER] This PR is APPROVED

This pull-request has been approved by: dims, jpbetz, liggitt

The full list of commands accepted by this bot can be found here.

The pull request process is described here

Needs approval from an approver in each of these files:

• staging/src/k8s.io/apiextensions-apiserver/OWNERS [dims,jpbetz,liggitt]
• staging/src/k8s.io/apiserver/pkg/cel/OWNERS [dims,jpbetz,liggitt]

Approvers can indicate their approval by writing /approve in a comment
Approvers can cancel approval by writing /approve cancel in a comment

[liggitt]

once merged, update the cherry-pick PRs (https://github.com/kubernetes/kubernetes/pulls?q=is%3Apr+-base%3Amaster+119800) to include this commit

[jpbetz]

/hold cancel

[jpbetz]

/retest

[alexzielenski]

/triage accepted

[jpbetz]

/retest

[BenTheElder]

When you see a flaking unit test, please file an issue or add a reference to the existing issue, unit tests should NOT be flaking : (

I don't see one so I filed #120112

[sftim]

Changelog suggestion

-Fix CEL estimated cost of replace() to handle a zero length replacement string correctly.
-Previously this would cause the estimated cost to be higher than it should be.
+Fixed CEL estimated cost of `replace()` to handle a zero length replacement string correctly.
+Previously this would cause the estimated cost to be higher than it should be.

[jpbetz]

Changelog suggestion

Applied. Thanks!