Introduce --ignore-whitespace-changes flag

Fixes: #222

Introduce flag to ignore leading and trailing whitespaces in strings.

assets/issues/issue-222/from.yml

@@ -0,0 +1,3 @@
+---
+foo: |
+  bar

assets/issues/issue-222/to.yml

@@ -0,0 +1,3 @@
+---
+foo: |+
+  bar

internal/cmd/between.go

@@ -86,6 +86,7 @@ types are: YAML (http://yaml.org/) and JSON (http://json.org/).
 
 		report, err := dyff.CompareInputFiles(from, to,
 			dyff.IgnoreOrderChanges(reportOptions.ignoreOrderChanges),
+			dyff.IgnoreWhitespaceChanges(reportOptions.ignoreWhitespaceChanges),
 			dyff.KubernetesEntityDetection(reportOptions.kubernetesEntityDetection),
 			dyff.AdditionalIdentifiers(reportOptions.additionalIdentifiers...),
 		)

internal/cmd/cmds_test.go

@@ -580,6 +580,17 @@ spec.replicas  (apps/v1/Deployment/test)
 			Expect(err).ToNot(HaveOccurred())
 			Expect(out).To(BeEquivalentTo("\n"))
 		})
+
+		It("should ignore the 'whitespace only' changes", func() {
+			out, err := dyff("between",
+				"--omit-header",
+				"--ignore-whitespace-changes",
+				assets("issues", "issue-222", "from.yml"),
+				assets("issues", "issue-222", "to.yml"))
+
+			Expect(err).ToNot(HaveOccurred())
+			Expect(out).To(BeEquivalentTo("\n"))
+		})
 	})
 
 	Context("last-applied command", func() {

internal/cmd/common.go

@@ -40,6 +40,7 @@ import (
 type reportConfig struct {
 	style                     string
 	ignoreOrderChanges        bool
+	ignoreWhitespaceChanges   bool
 	kubernetesEntityDetection bool
 	noTableStyle              bool
 	doNotInspectCerts         bool
@@ -58,6 +59,7 @@ type reportConfig struct {
 var defaults = reportConfig{
 	style:                     "human",
 	ignoreOrderChanges:        false,
+	ignoreWhitespaceChanges:   false,
 	kubernetesEntityDetection: true,
 	noTableStyle:              false,
 	doNotInspectCerts:         false,
@@ -78,6 +80,7 @@ var reportOptions reportConfig
 func applyReportOptionsFlags(cmd *cobra.Command) {
 	// Compare options
 	cmd.Flags().BoolVarP(&reportOptions.ignoreOrderChanges, "ignore-order-changes", "i", defaults.ignoreOrderChanges, "ignore order changes in lists")
+	cmd.Flags().BoolVar(&reportOptions.ignoreWhitespaceChanges, "ignore-whitespace-changes", defaults.ignoreWhitespaceChanges, "ignore leading or trailing whitespace changes")
 	cmd.Flags().BoolVarP(&reportOptions.kubernetesEntityDetection, "detect-kubernetes", "", defaults.kubernetesEntityDetection, "detect kubernetes entities")
 	cmd.Flags().StringArrayVar(&reportOptions.additionalIdentifiers, "additional-identifier", defaults.additionalIdentifiers, "use additional identifier candidates in named entry lists")
 	cmd.Flags().StringSliceVar(&reportOptions.filters, "filter", defaults.filters, "filter reports to a subset of differences based on supplied arguments")

pkg/dyff/core.go

@@ -38,6 +38,7 @@ type CompareOption func(*compareSettings)
 type compareSettings struct {
 	NonStandardIdentifierGuessCountThreshold int
 	IgnoreOrderChanges                       bool
+	IgnoreWhitespaceChanges                  bool
 	KubernetesEntityDetection                bool
 	AdditionalIdentifiers                    []string
 }
@@ -71,6 +72,13 @@ func IgnoreOrderChanges(value bool) CompareOption {
 	}
 }
 
+// IgnoreWhitespaceChanges disables the detection for whitespace only changes
+func IgnoreWhitespaceChanges(value bool) CompareOption {
+	return func(settings *compareSettings) {
+		settings.IgnoreWhitespaceChanges = value
+	}
+}
+
 // KubernetesEntityDetection enabled detecting entity identifiers from Kubernetes "kind:" and "metadata:" fields.
 func KubernetesEntityDetection(value bool) CompareOption {
 	return func(settings *compareSettings) {
@@ -595,19 +603,24 @@ func (compare *compare) namedEntryLists(path ytbx.Path, identifier listItemIdent
 }
 
 func (compare *compare) nodeValues(path ytbx.Path, from *yamlv3.Node, to *yamlv3.Node) ([]Diff, error) {
-	result := make([]Diff, 0)
 	if strings.Compare(from.Value, to.Value) != 0 {
-		result = append(result, Diff{
+		// leave and don't report any differences if ignore whitespaces changes is
+		// configured and it is really only a whitespace only change between the strings
+		if compare.settings.IgnoreWhitespaceChanges && isWhitespaceOnlyChange(from.Value, to.Value) {
+			return nil, nil
+		}
+
+		return []Diff{{
 			&path,
 			[]Detail{{
 				Kind: MODIFICATION,
 				From: from,
 				To:   to,
 			}},
-		})
+		}}, nil
 	}
 
-	return result, nil
+	return nil, nil
 }
 
 func (compare *compare) boolValues(path ytbx.Path, from *yamlv3.Node, to *yamlv3.Node) ([]Diff, error) {
@@ -1135,3 +1148,7 @@ func grab(node *yamlv3.Node, pathString string) (*yamlv3.Node, error) {
 		pathString,
 	)
 }
+
+func isWhitespaceOnlyChange(from string, to string) bool {
+	return strings.Trim(from, " \n") == strings.Trim(to, " \n")
+}

pkg/dyff/output_human.go

@@ -632,10 +632,6 @@ func isMultiLine(from string, to string) bool {
 	return strings.Contains(from, "\n") || strings.Contains(to, "\n")
 }
 
-func isWhitespaceOnlyChange(from string, to string) bool {
-	return strings.Trim(from, " \n") == strings.Trim(to, " \n")
-}
-
 func showWhitespaceCharacters(text string) string {
 	return strings.Replace(strings.Replace(text, "\n", bold("↵\n"), -1), " ", bold("·"), -1)
 }