fix: seed parent.Values via MergeValues in regression tests

Populate parent.Values with MergeValues(parent, nil) to simulate the
state after processImportValues, so tests exercise the
childChartMergeTrue code path that was the actual source of the #32093
regression. Rename partial-override test to avoid duplication with
existing TestCoalesceValuesSubchartNilCleanedWhenUserPartiallyOverrides.

Signed-off-by: yxxhero <aiopsclub@163.com>

pkg/chart/common/util/coalesce_test.go

@@ -932,7 +932,11 @@ func TestCoalesceValuesSubchartNilCleanedWhenUserPartiallyOverrides(t *testing.T
 // TestCoalesceValuesSubchartDefaultNilsCleanedWithUnrelatedUserValues tests that
 // nil values in subchart defaults are cleaned even when the parent provides an
 // unrelated user value under that subchart's namespace.
-// Regression test for issue #32093.
+//
+// This simulates the state after processImportValues (merge=true) populates
+// parent.Values with merged child defaults including nils, then CoalesceValues
+// is called with user values that touch the child namespace. The bug in #32093
+// was that childChartMergeTrue shadowed the merge flag, skipping cleanNilValues.
 func TestCoalesceValuesSubchartDefaultNilsCleanedWithUnrelatedUserValues(t *testing.T) {
 	is := assert.New(t)
 
@@ -953,6 +957,12 @@ func TestCoalesceValuesSubchartDefaultNilsCleanedWithUnrelatedUserValues(t *test
 		Values:   map[string]any{},
 	}, subchart)
 
+	// Simulate the state after processImportValues has populated parent.Values
+	// with merged defaults (including nils from child chart defaults).
+	mergedDefaults, err := MergeValues(parent, nil)
+	is.NoError(err)
+	parent.Values = mergedDefaults
+
 	vals := map[string]any{
 		"child": map[string]any{
 			"someOtherKey": "value",
@@ -976,11 +986,15 @@ func TestCoalesceValuesSubchartDefaultNilsCleanedWithUnrelatedUserValues(t *test
 	is.False(ok, "Expected ingress.configureCertmanager (nil from chart defaults) to be removed when parent sets unrelated child value")
 }
 
-// TestCoalesceValuesSubchartDefaultNilsCleanedWithPartialOverrideSameMap tests
-// that nil values in subchart defaults are cleaned even when the user overrides
-// a sibling key within the same map.
-// Regression test for issue #32093.
-func TestCoalesceValuesSubchartDefaultNilsCleanedWithPartialOverrideSameMap(t *testing.T) {
+// TestCoalesceValuesSubchartDefaultNilsCleanedWithPartialOverrideSameMapMerged
+// tests that nil values in subchart defaults are cleaned even when the user
+// overrides a sibling key within the same map, after the parent chart's Values
+// have been populated by a prior merge step.
+//
+// Unlike TestCoalesceValuesSubchartNilCleanedWhenUserPartiallyOverrides which
+// tests coalescing from scratch, this test seeds parent.Values via MergeValues
+// to exercise the childChartMergeTrue code path described in issue #32093.
+func TestCoalesceValuesSubchartDefaultNilsCleanedWithPartialOverrideSameMapMerged(t *testing.T) {
 	is := assert.New(t)
 
 	subchart := &chart.Chart{
@@ -998,6 +1012,12 @@ func TestCoalesceValuesSubchartDefaultNilsCleanedWithPartialOverrideSameMap(t *t
 		Values:   map[string]any{},
 	}, subchart)
 
+	// Simulate the state after processImportValues has populated parent.Values
+	// with merged defaults (including nils from child chart defaults).
+	mergedDefaults, err := MergeValues(parent, nil)
+	is.NoError(err)
+	parent.Values = mergedDefaults
+
 	vals := map[string]any{
 		"child": map[string]any{
 			"keyMapping": map[string]any{