fix: resolve templruntime imported and not used (#841), fixes #834

Co-authored-by: Adrian Hesketh <[email protected]>

.version

@@ -1 +1 @@
-0.2.749
+0.2.753

generator/generator.go

@@ -125,6 +125,9 @@ func (g *generator) generate() (err error) {
 	if err = g.writeTemplateNodes(); err != nil {
 		return
 	}
+	if err = g.writeBlankAssignmentForRuntimeImport(); err != nil {
+		return
+	}
 	return err
 }
 
@@ -1482,6 +1485,17 @@ func (g *generator) writeScript(t parser.ScriptTemplate) error {
 	return nil
 }
 
+// writeBlankAssignmentForRuntimeImport writes out a blank identifier assignment.
+// This ensures that even if the github.com/a-h/templ/runtime package is not used in the generated code,
+// the Go compiler will not complain about the unused import.
+func (g *generator) writeBlankAssignmentForRuntimeImport() error {
+	var err error
+	if _, err = g.w.Write("var _ = templruntime.GeneratedTemplate"); err != nil {
+		return err
+	}
+	return nil
+}
+
 func functionName(name string, body string) string {
 	h := sha256.New()
 	h.Write([]byte(body))

generator/test-only-scripts/expected.html

@@ -0,0 +1,7 @@
+<script type="text/javascript">
+  function __templ_withParameters_1056(a, b, c){console.log(a, b, c);
+}
+</script>
+<script type="text/javascript">
+  __templ_withParameters_1056("hello","world",42069)
+</script>

generator/test-only-scripts/render_test.go

@@ -0,0 +1,23 @@
+package onlyscripts
+
+import (
+	_ "embed"
+	"testing"
+
+	"github.com/a-h/templ/generator/htmldiff"
+)
+
+//go:embed expected.html
+var expected string
+
+func Test(t *testing.T) {
+	script := withParameters("hello", "world", 42069)
+
+	diff, err := htmldiff.Diff(script, expected)
+	if err != nil {
+		t.Fatal(err)
+	}
+	if diff != "" {
+		t.Error(diff)
+	}
+}

generator/test-only-scripts/template.templ

@@ -0,0 +1,5 @@
+package onlyscripts
+
+script withParameters(a string, b string, c int) {
+	console.log(a, b, c);
+}