fix(pruner): ensure enforcedConfigLevel is always defaulted and DeepCopy is correct

[infernus01]

Changes

• Fix enforcedConfigLevel silently vanishing from the pruner global config
  when a user provides a partial global-config (e.g. only ttlSecondsAfterFinished)
• Fix DeepCopyInto shallow copy bug that prevented the defaulting webhook
  from detecting changes made by SetDefaults

Problem

When a user provides any global-config field without explicitly setting
enforcedConfigLevel, the v0.79.1 SetDefaults skips defaulting entirely
because GlobalConfig is non-nil. Combined with omitempty struct tags in
the vendored pruner, enforcedConfigLevel is omitted from the ConfigMap.
The pruner controller then falls back to the internal default (resource
level), which never consults namespace-level ConfigMaps — all selector-based
pruning rules silently stop working.

On top of this, DeepCopyInto for TektonPrunerConfig does *out = *in,
which copies the *GlobalConfig pointer instead of the struct. The Knative
defaulting webhook deep-copies the object before calling SetDefaults, then
compares it with the original to generate a patch. Because both copies share
the same pointer, the webhook always sees no difference (PatchBytes: null)
and never applies the defaults.

Root Cause

Commit 774867c changed GlobalConfig from a value type to a pointer and
guarded SetDefaults() with if p.GlobalConfig == nil to prevent
historyLimit from resetting to 100 when set to null. The side effect was
that enforcedConfigLevel was never filled in for partial configs. The
existing DeepCopyInto was not updated for the pointer type change.

Fix

tektonpruner_defaults.go: Always fill in enforcedConfigLevel when
nil, without touching other fields:

if p.GlobalConfig == nil {
    p.GlobalConfig = &config.GlobalConfig{}
    p.GlobalConfig.SetDefaults()
} else if p.GlobalConfig.EnforcedConfigLevel == nil {
    v := config.EnforcedConfigLevelGlobal
    p.GlobalConfig.EnforcedConfigLevel = &v
}

tektonpruner_types.go: Deep-copy the GlobalConfig pointer:

func (in *TektonPrunerConfig) DeepCopyInto(out *TektonPrunerConfig) {
    *out = *in
    if in.GlobalConfig != nil {
        out.GlobalConfig = new(config.GlobalConfig)
        *out.GlobalConfig = *in.GlobalConfig
    }
}

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Release Notes

NONE

[infernus01]

/cc @pramodbindal @anithapriyanatarajan

[codecov-commenter]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 24.48%. Comparing base (6ce06ca) to head (f718bcf).
⚠️ Report is 1 commits behind head on main.

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #3688      +/-   ##
==========================================
- Coverage   24.49%   24.48%   -0.01%     
==========================================
  Files         470      470              
  Lines       24919    24924       +5     
==========================================
- Hits         6103     6102       -1     
- Misses      18122    18126       +4     
- Partials      694      696       +2     

Flag	Coverage Δ
unit-tests	24.48% <ø> (-0.01%)	⬇️

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[infernus01]

/retest

[anithapriyanatarajan]

@infernus01 did we verify the impact on upgrade due to this change?

[infernus01]

@anithapriyanatarajan There can be 4 cases for the upgrade scenario:
Case 1: User explicitly set enforcedConfigLevel: namespace
The else if p.GlobalConfig.EnforcedConfigLevel == nil is false — their value is non-nil. Nothing changes. No impact.

Case 2: User explicitly set enforcedConfigLevel: global
Same — non-nil, skipped. No impact.

Case 3: User never set enforcedConfigLevel, but old operator (<=v0.78.1) filled it in
On versions <=v0.78.1, SetDefaults always ran and set global. The field already exists. This fix skips it. No impact.

Case 4: User never set enforcedConfigLevel, running v0.79.1+ where it was silently dropped
This is the only case where behavior changes. Let's say, enforcedConfigLevel is missing from the ConfigMap(which can, without this fix). A user sets per-namespace overrides in their global config:

  tektonpruner:
    global-config:
      ttlSecondsAfterFinished: 60
      namespaces:
        dev:
          ttlSecondsAfterFinished: 30

Without explicitly setting enforcedConfigLevel. The broken SetDefaults never filled it in, so it's missing from the ConfigMap. The pruner's fallback is resource level, which happens to check globalSpec.Namespaces["dev"] and finds TTL=30. And this I haven't yet verified will work or not. But after this fix, enforcedConfigLevel: global is filled in and at global level, the pruner only uses root-level settings. The namespaces: section is skipped. The dev namespace override will not work.
So this case is technically possible but unlikely in practice.

[anithapriyanatarajan]

/lgtm

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