ssa: add DriftIgnoreRules to ApplyOptions for field-level ignore on apply

ssa/go.mod

@@ -5,6 +5,7 @@ go 1.25.0
 require (
 	github.com/evanphx/json-patch/v5 v5.9.11
 	github.com/fluxcd/cli-utils v0.37.2-flux.1
+	github.com/go-openapi/jsonpointer v0.21.1
 	github.com/google/go-cmp v0.7.0
 	github.com/onsi/gomega v1.39.0
 	github.com/wI2L/jsondiff v0.6.1
@@ -34,7 +35,6 @@ require (
 	github.com/fxamacker/cbor/v2 v2.9.0 // indirect
 	github.com/go-errors/errors v1.5.1 // indirect
 	github.com/go-logr/logr v1.4.3 // indirect
-	github.com/go-openapi/jsonpointer v0.21.1 // indirect
 	github.com/go-openapi/jsonreference v0.21.0 // indirect
 	github.com/go-openapi/swag v0.23.1 // indirect
 	github.com/google/btree v1.1.3 // indirect

ssa/jsondiff/patch.go

@@ -38,6 +38,26 @@ func GenerateRemovePatch(paths ...string) jsondiff.Patch {
 	return patch
 }
 
+// ReplaceOp describes a single JSON Patch replace operation.
+type ReplaceOp struct {
+	Path  string
+	Value any
+}
+
+// GenerateReplacePatch generates a JSON patch that replaces the values at the
+// given JSON pointer paths.
+func GenerateReplacePatch(ops ...ReplaceOp) jsondiff.Patch {
+	var patch jsondiff.Patch
+	for _, op := range ops {
+		patch = append(patch, jsondiff.Operation{
+			Type:  jsondiff.OperationReplace,
+			Path:  op.Path,
+			Value: op.Value,
+		})
+	}
+	return patch
+}
+
 // ApplyPatchToUnstructured applies the given JSON patch to the given
 // unstructured object. The patch is applied in-place.
 // It permits the patch to contain "remove" operations that target non-existing

ssa/jsondiff/unstructured.go

@@ -44,6 +44,23 @@ type IgnoreRule struct {
 	Selector *Selector
 }
 
+// CompiledIgnoreRules is a set of IgnoreRule with compiled selectors.
+type CompiledIgnoreRules map[*SelectorRegex][]string
+
+// CompileIgnoreRules compiles the selectors in the given IgnoreRule slice
+// and returns a CompiledIgnoreRules.
+func CompileIgnoreRules(rules []IgnoreRule) (CompiledIgnoreRules, error) {
+	compiled := make(CompiledIgnoreRules, len(rules))
+	for _, rule := range rules {
+		sr, err := NewSelectorRegex(rule.Selector)
+		if err != nil {
+			return nil, fmt.Errorf("failed to create ignore rule selector: %w", err)
+		}
+		compiled[sr] = rule.Paths
+	}
+	return compiled, nil
+}
+
 // UnstructuredList runs a dry-run patch for a list of Kubernetes resources
 // against a Kubernetes cluster and compares the result against the original
 // objects. It returns a DiffSet, which contains differences between the
@@ -59,13 +76,9 @@ func UnstructuredList(ctx context.Context, c client.Client, objs []*unstructured
 	o := &ListOptions{}
 	o.ApplyOptions(opts)
 
-	var sm = make(map[*SelectorRegex][]string, len(o.IgnoreRules))
-	for _, ips := range o.IgnoreRules {
-		sr, err := NewSelectorRegex(ips.Selector)
-		if err != nil {
-			return nil, fmt.Errorf("failed to create ignore rule selector: %w", err)
-		}
-		sm[sr] = ips.Paths
+	sm, err := CompileIgnoreRules(o.IgnoreRules)
+	if err != nil {
+		return nil, err
 	}
 
 	var resOpts []ResourceOption