Client-side apply has a pathological case with deeply nested identical objects #698
Description
Test case
- Strip the description fields from https://raw.githubusercontent.com/kubernetes-sigs/kubebuilder/master/docs/book/src/multiversion-tutorial/testdata/project/config/crd/bases/batch.tutorial.kubebuilder.io_cronjobs.yaml (to make it fit in an annotation)
- kubectl apply -f the above
- kubectl apply -f the above again
Underlying issue
Deeply nested (e.g. validation for podspec) identical issues hit a pathological case in the json-patch library's merge patch generator, which recursively traverses every sub-tree to check if two json trees are identical
Evidence
You can attach an execution trace and use go tool trace to see this for yourself
(that's me stopping the attempt after 30s, not it taking 30s total)
runtime trace call patch
diff --git a/cmd/kubectl/kubectl.go b/cmd/kubectl/kubectl.go
index 53934ac2b0..fab992ad95 100644
--- a/cmd/kubectl/kubectl.go
+++ b/cmd/kubectl/kubectl.go
@@ -21,6 +21,9 @@ import (
"math/rand"
"os"
"time"
+ "runtime/trace"
+ "os/signal"
+ "syscall"
"github.com/spf13/pflag"
@@ -33,6 +36,16 @@ import (
)
func main() {
+ traceOut, err := os.Create("/tmp/kubectl.trace")
+ if err != nil {
+ panic(err)
+ }
+ defer traceOut.Close()
+ if err := trace.Start(traceOut); err != nil {
+ panic(err)
+ }
+ defer trace.Stop()
+
rand.Seed(time.Now().UnixNano())
command := cmd.NewDefaultKubectlCommand()
@@ -46,7 +59,17 @@ func main() {
logs.InitLogs()
defer logs.FlushLogs()
+ sigCh := make(chan os.Signal)
+ go func() {
+ <-sigCh
+ trace.Stop()
+ traceOut.Close()
+ panic("at the disco!")
+ }()
+ signal.Notify(sigCh, syscall.SIGINT, syscall.SIGTERM)
+
if err := command.Execute(); err != nil {
- os.Exit(1)
+ //os.Exit(1)
+ return
}
}Potential fixes
EDIT: See below -- moving around some conditions in the jsonpatch library seems to fix things.
Also, this may be kind-of moot, since we'll be getting server-side apply, which doesn't suffer from this particular issue.