fix(fmt): incorrect conversion from single to double quotes, fixes #380

.version

@@ -1 +1 @@
-0.2.508
+0.2.513

README.md

@@ -78,18 +78,20 @@ Run Go tests.
 # Create test profile directories.
 mkdir -p coverage/fmt
 mkdir -p coverage/generate
+mkdir -p coverage/version
 mkdir -p coverage/unit
 # Build the test binary.
 go build -cover -o ./coverage/templ-cover ./cmd/templ
 # Run the covered generate command.
 GOCOVERDIR=coverage/fmt ./coverage/templ-cover fmt .
 GOCOVERDIR=coverage/generate ./coverage/templ-cover generate -include-version=false
+GOCOVERDIR=coverage/version ./coverage/templ-cover version
 # Run the unit tests.
 go test -cover ./... -args -test.gocoverdir="$PWD/coverage/unit"
 # Display the combined percentage.
-go tool covdata percent -i=./coverage/fmt,./coverage/generate,./coverage/unit
+go tool covdata percent -i=./coverage/fmt,./coverage/generate,./coverage/version,./coverage/unit
 # Generate a text coverage profile for tooling to use.
-go tool covdata textfmt -i=./coverage/fmt,./coverage/generate,./coverage/unit -o coverage.out
+go tool covdata textfmt -i=./coverage/fmt,./coverage/generate,./coverage/version,./coverage/unit -o coverage.out
 # Print total
 go tool cover -func coverage.out | grep total
 ```

generator/test-attribute-escaping/expected.html

@@ -1,3 +1,6 @@
 <div>
 	<a href="about:invalid#TemplFailedSanitizationURL">text</a>
 </div>
+<div>
+	<button hx-post="/click" hx-trigger="click" hx-vals='{"val":"Value"}'>Click</button>
+</div>

generator/test-attribute-escaping/template.templ

@@ -4,4 +4,11 @@ templ BasicTemplate(url string) {
 	<div>
 		<a href={ templ.URL(url) }>text</a>
 	</div>
+	<div>
+		<button
+			hx-post="/click"
+			hx-trigger="click"
+			hx-vals='{"val":"Value"}'
+		>Click</button>
+	</div>
 }

parser/v2/elementparser.go

@@ -131,6 +131,7 @@ var (
 		if result.B.OK {
 			valueParser = attributeConstantValueSingleQuoteParser
 			closeParser = parse.String(`'`)
+			attr.SingleQuote = true
 		}
 
 		// Attribute value.
@@ -140,6 +141,10 @@ var (
 		}
 
 		attr.Value = html.UnescapeString(attr.Value)
+		// Only use single quotes if actually required, due to double quote in the value (prefer double quotes).
+		if attr.SingleQuote && !strings.Contains(attr.Value, "\"") {
+			attr.SingleQuote = false
+		}
 
 		// " - closing quote.
 		if _, ok, err = closeParser.Parse(pi); err != nil || !ok {

parser/v2/elementparser_test.go

@@ -271,12 +271,23 @@ if test {
 			},
 		},
 		{
-			name:   "single quote constant attribute",
+			name:   "single quote not required constant attribute",
+			input:  ` href='no double quote in value'`,
+			parser: StripType(constantAttributeParser),
+			expected: ConstantAttribute{
+				Name:        "href",
+				Value:       `no double quote in value`,
+				SingleQuote: false,
+			},
+		},
+		{
+			name:   "single quote required constant attribute",
 			input:  ` href='"test"'`,
 			parser: StripType(constantAttributeParser),
 			expected: ConstantAttribute{
-				Name:  "href",
-				Value: `"test"`,
+				Name:        "href",
+				Value:       `"test"`,
+				SingleQuote: true,
 			},
 		},
 		{

parser/v2/templelementparser_test.go

@@ -108,7 +108,10 @@ func TestTemplElementExpressionParser(t *testing.T) {
 				Children: []Node{
 					Whitespace{Value: "\n\t\t\t"},
 					Element{Name: "a", Attributes: []Attribute{
-						ConstantAttribute{"href", "someurl"},
+						ConstantAttribute{
+							Name:  "href",
+							Value: "someurl",
+						},
 					},
 						TrailingSpace: SpaceVertical,
 					},

parser/v2/types.go

@@ -690,12 +690,17 @@ func (bca BoolConstantAttribute) Write(w io.Writer, indent int) error {
 
 // href=""
 type ConstantAttribute struct {
-	Name  string
-	Value string
+	Name        string
+	Value       string
+	SingleQuote bool
 }
 
 func (ca ConstantAttribute) String() string {
-	return ca.Name + `="` + ca.Value + `"`
+	quote := `"`
+	if ca.SingleQuote {
+		quote = `'`
+	}
+	return ca.Name + `=` + quote + ca.Value + quote
 }
 
 func (ca ConstantAttribute) Write(w io.Writer, indent int) error {

parser/v2/types_test.go

@@ -236,6 +236,28 @@ package test
 templ nested() {
 	<div>{ "the" }<div>{ "other" }</div></div>
 }
+`,
+		},
+		{
+			name: "constant attributes prerfer double quotes, but use single quotes if required",
+			input: ` // first line removed to make indentation clear in Go code
+package test
+
+templ nested() {
+	<div class="double">double</div>
+	<div class='single-not-required'>single-not-required</div>
+	<div data-value='{"data":"value"}'>single-required</div>
+}
+
+`,
+			expected: `// first line removed to make indentation clear in Go code
+package test
+
+templ nested() {
+	<div class="double">double</div>
+	<div class="single-not-required">single-not-required</div>
+	<div data-value='{"data":"value"}'>single-required</div>
+}
 `,
 		},
 		{