func TestLeadAndLineComments(t *testing.T) {
f, err := ParseFile(fset, "", `
package p
type T struct {
/* F1 lead comment */
//
F1 int /* F1 */ // line comment
// F2 lead
// comment
F2 int // F2 line comment
// f3 lead comment
f3 int // f3 line comment
}
`, ParseComments)
if err != nil {
t.Fatal(err)
}
checkFieldComments(t, f, "T.F1", "/* F1 lead comment *///", "/* F1 */// line comment")
checkFieldComments(t, f, "T.F2", "// F2 lead// comment", "// F2 line comment")
checkFieldComments(t, f, "T.f3", "// f3 lead comment", "// f3 line comment")
ast.FileExports(f)
checkFieldComments(t, f, "T.F1", "/* F1 lead comment *///", "/* F1 */// line comment")
checkFieldComments(t, f, "T.F2", "// F2 lead// comment", "// F2 line comment")
if getField(f, "T.f3") != nil {
t.Error("not expected to find T.f3")
}
}
// format parses src, prints the corresponding AST, verifies the resulting
// src is syntactically correct, and returns the resulting src or an error
// if any.
func format(src []byte, mode checkMode) ([]byte, error) {
// parse src
f, err := parser.ParseFile(fset, "", src, parser.ParseComments)
if err != nil {
return nil, fmt.Errorf("parse: %s\n%s", err, src)
}
// filter exports if necessary
if mode&export != 0 {
ast.FileExports(f) // ignore result
f.Comments = nil // don't print comments that are not in AST
}
// determine printer configuration
cfg := Config{Tabwidth: tabwidth}
if mode&rawFormat != 0 {
cfg.Mode |= RawFormat
}
// print AST
var buf bytes.Buffer
if err := cfg.Fprint(&buf, fset, f); err != nil {
return nil, fmt.Errorf("print: %s", err)
}
// make sure formated output is syntactically correct
res := buf.Bytes()
if _, err := parser.ParseFile(fset, "", res, 0); err != nil {
return nil, fmt.Errorf("re-parse: %s\n%s", err, buf.Bytes())
}
return res, nil
}
// packageExports is a local implementation of ast.PackageExports
// which correctly updates each package file's comment list.
// (The ast.PackageExports signature is frozen, hence the local
// implementation).
//
func packageExports(fset *token.FileSet, pkg *ast.Package) {
for _, src := range pkg.Files {
cmap := ast.NewCommentMap(fset, src, src.Comments)
ast.FileExports(src)
src.Comments = cmap.Filter(src).Comments()
}
}