fix: Allow patches with empty files with multiple newlines or comments (#5771)

* fix: Add test, when an empty patch file is given, it should not fail

* fix: Add code so there's no error given if an empty file is given as a patch

* chore: Generate plugin with pluginator

* chore: fix tests

Signed-off-by: Julio Chana <julio.chana@lokalise.com>

* Add t.helper() at start of test function

Signed-off-by: Julio Chana <julio.chana@lokalise.com>

---------

Signed-off-by: Julio Chana <julio.chana@lokalise.com>

plugin/builtin/patchtransformer/PatchTransformer.go

@@ -59,8 +59,9 @@ func (p *plugin) Config(h *resmap.PluginHelpers, c []byte) error {
 	patchesSM, errSM := h.ResmapFactory().RF().SliceFromBytes([]byte(p.patchText))
 	patchesJson, errJson := jsonPatchFromBytes([]byte(p.patchText))
 
-	if (errSM == nil && errJson == nil) ||
-		(patchesSM != nil && patchesJson != nil) {
+	if ((errSM == nil && errJson == nil) ||
+		(patchesSM != nil && patchesJson != nil)) &&
+		(len(patchesSM) > 0 && len(patchesJson) > 0) {
 		return fmt.Errorf(
 			"illegally qualifies as both an SM and JSON patch: %s",
 			p.patchSource)

plugin/builtin/patchtransformer/PatchTransformer_test.go

@@ -1108,3 +1108,54 @@ spec:
         name: test-deployment
 `)
 }
+
+func TestPatchTransformerPatchEmpty(t *testing.T) {
+	th := kusttest_test.MakeEnhancedHarness(t).
+		PrepBuiltin("PatchTransformer")
+	defer th.Reset()
+
+	th.WriteF("patch.yaml", `
+  `)
+
+	th.RunTransformerAndCheckError(`
+apiVersion: builtin
+kind: PatchTransformer
+metadata:
+  name: notImportantHere
+path: patch.yaml
+target:
+  name: myDeploy
+`, someDeploymentResources, func(t *testing.T, err error) {
+		t.Helper()
+		if err != nil {
+			t.Fatalf("unexpected error")
+		}
+	})
+}
+
+func TestPatchTransformerPatchEmptyOnlyComments(t *testing.T) {
+	th := kusttest_test.MakeEnhancedHarness(t).
+		PrepBuiltin("PatchTransformer")
+	defer th.Reset()
+
+	th.WriteF("patch.yaml", `
+# File with only comments
+
+# Is a virtually empty yaml
+`)
+
+	th.RunTransformerAndCheckError(`
+apiVersion: builtin
+kind: PatchTransformer
+metadata:
+  name: notImportantHere
+path: patch.yaml
+target:
+  name: myDeploy
+`, someDeploymentResources, func(t *testing.T, err error) {
+		t.Helper()
+		if err != nil {
+			t.Fatalf("unexpected error")
+		}
+	})
+}