Add test case for tabs in multi-line strings

Author: thockin

kyaml/kyaml.go

@@ -278,6 +278,15 @@ func (ky *Encoder) renderScalar(node *yaml.Node, indent int, flags flagMask, out
 
 const kyamlFoldStr = "\\\n"
 
+var regularEscapeMap = map[rune]string{
+	'\n': "\\n" + kyamlFoldStr, // use YAML's line folding to make the output more readable
+	'\t': "\t",                 // literal tab
+}
+var compactEscapeMap = map[rune]string{
+	'\n': "\\n",
+	'\t': "\\t",
+}
+
 // renderString processes a string (either single-line or multi-line),
 // rendering it to the output.  This DOES NOT render a trailing newline.
 func (ky *Encoder) renderString(val string, indent int, flags flagMask, out io.Writer) error {
@@ -290,11 +299,10 @@ func (ky *Encoder) renderString(val string, indent int, flags flagMask, out io.W
 		return nil
 	}
 
-	// What to print when we find a newline in the input.
-	newline := "\\n"
-	if !compact {
-		// We use YAML's line folding to make the output more readable.
-		newline += kyamlFoldStr
+	// Special cases for certain input.
+	escapeOverrides := regularEscapeMap
+	if compact {
+		escapeOverrides = compactEscapeMap
 	}
 
 	//
@@ -325,7 +333,7 @@ func (ky *Encoder) renderString(val string, indent int, flags flagMask, out io.W
 			fmt.Fprintf(buf, "%02x", s[0])
 			continue
 		}
-		ky.appendEscapedRune(r, indent, newline, buf)
+		ky.appendEscapedRune(r, indent, escapeOverrides, buf)
 	}
 
 	// closing quote
@@ -485,7 +493,7 @@ func parseTimestamp(s string) (time.Time, bool) {
 }
 
 // We use a buffer here so we can peek backwards.
-func (ky *Encoder) appendEscapedRune(r rune, indent int, newline string, buf *bytes.Buffer) {
+func (ky *Encoder) appendEscapedRune(r rune, indent int, escapeOverrides map[rune]string, buf *bytes.Buffer) {
 	afterNewline := buf.Bytes()[len(buf.Bytes())-1] == '\n'
 
 	if afterNewline {
@@ -504,6 +512,10 @@ func (ky *Encoder) appendEscapedRune(r rune, indent int, newline string, buf *by
 			buf.WriteRune(' ')
 		}
 	}
+	if s, found := escapeOverrides[r]; found {
+		buf.WriteString(s)
+		return
+	}
 	if r == '"' || r == '\\' { // always escaped
 		buf.WriteRune('\\')
 		buf.WriteRune(r)
@@ -521,7 +533,7 @@ func (ky *Encoder) appendEscapedRune(r rune, indent int, newline string, buf *by
 	case '\f':
 		buf.WriteString(`\f`)
 	case '\n':
-		buf.WriteString(newline)
+		buf.WriteString(`\n`)
 	case '\r':
 		buf.WriteString(`\r`)
 	case '\t':

kyaml/kyaml_test.go

@@ -1870,10 +1870,14 @@ func TestKYAMLFromYAML(t *testing.T) {
 				simple: |
 				  This is a multi-line string.
 				  It has multiple lines.
-				leading_space: |
+				leading_spaces: |
 				  This is a multi-line string.
 				    It can
-				      retain indentation.
+				      retain space indentation.
+				leading_tabs: |
+				  This is a multi-line string.
+				  	It can
+				  		retain tab indentation.
 				blank_lines: |
 				  This is a multi-line string.
 
@@ -1886,10 +1890,15 @@ func TestKYAMLFromYAML(t *testing.T) {
 				     This is a multi-line string.\n\
 				     It has multiple lines.\n\
 				    ",
-				  leading_space: "\
+				  leading_spaces: "\
 				     This is a multi-line string.\n\
 				    \  It can\n\
-				    \    retain indentation.\n\
+				    \    retain space indentation.\n\
+				    ",
+				  leading_tabs: "\
+				     This is a multi-line string.\n\
+				    \	It can\n\
+				    \		retain tab indentation.\n\
 				    ",
 				  blank_lines: "\
 				     This is a multi-line string.\n\
@@ -1904,7 +1913,8 @@ func TestKYAMLFromYAML(t *testing.T) {
 			name: "multi-line strings dquoted",
 			input: `
 				simple: "This is a multi-line string.\nIt has multiple lines.\n"
-				eading_space: "This is a multi-line string.\n  It can\n    retain indentation.\n"
+				leading_spaces: "This is a multi-line string.\n  It can\n    retain space indentation.\n"
+				leading_tabs: "This is a multi-line string.\n\tIt can\n\t\tretain tab indentation.\n"
 				blank_lines: "This is a multi-line string.\n\nIt can retain blank lines.\n"
 				`,
 			expected: `
@@ -1914,10 +1924,15 @@ func TestKYAMLFromYAML(t *testing.T) {
 				     This is a multi-line string.\n\
 				     It has multiple lines.\n\
 				    ",
-				  leading_space: "\
+				  leading_spaces: "\
 				     This is a multi-line string.\n\
 				    \  It can\n\
-				    \    retain indentation.\n\
+				    \    retain space indentation.\n\
+				    ",
+				  leading_tabs: "\
+				     This is a multi-line string.\n\
+				    \	It can\n\
+				    \		retain tab indentation.\n\
 				    ",
 				  blank_lines: "\
 				     This is a multi-line string.\n\
@@ -2419,7 +2434,7 @@ func TestRenderStringEscapes(t *testing.T) {
 	}, {
 		name:   "tab",
 		input:  '\t',
-		expect: `"\t"`,
+		expect: "\"\t\"",
 	}, {
 		name:   "vtab",
 		input:  '\v',