r.buf = r.buf[:len(r.buf)-1]
	}
	return r.buf, r.err
}

// readGoInfo expects a Go file as input and reads the file up to and including the import section.
// It records what it learned in *info.
// If info.fset is non-nil, readGoInfo parses the file and sets info.parsed, info.parseErr,
// info.imports and info.embeds.
//

		r.buf = r.buf[:len(r.buf)-1]
	}
	return r.buf, r.err
}

// readGoInfo expects a Go file as input and reads the file up to and including the import section.
// It records what it learned in *info.
// If info.fset is non-nil, readGoInfo parses the file and sets info.parsed, info.parseErr,
// info.imports and info.embeds.
//

			continue
		}
		info := fileInfo{
			name: filepath.Join(dir, name),
			fset: fset,
		}
		f, err := os.Open(info.name)
		if err != nil {
			return nil, err
		}
		err = readGoInfo(f, &info)
		f.Close()
		if err != nil {
			return nil, fmt.Errorf("reading %v: %v", name, err)
		}
		if info.parsed.Name.Name == "main" {
			continue
		}
		if bytes.Contains(info.header, buildIgnore) {

		return nil, err
	}

	// TODO(matloob) should we decide whether to ignore binary only here or earlier
	// when we create the index file?
	var ignoreBinaryOnly bool
	if strings.HasSuffix(name, ".go") {
		err = readGoInfo(f, info)
		if strings.HasSuffix(name, "_test.go") {
			ignoreBinaryOnly = true // ignore //go:binary-only-package comments in _test.go files
		}
	} else {
		info.header, err = readComments(f)
	}
	f.Close()

		// binary, no reading
		return info, nil
	}

	f, err := ctxt.openFile(info.name)
	if err != nil {
		return nil, err
	}

	if strings.HasSuffix(name, ".go") {
		err = readGoInfo(f, info)
		if strings.HasSuffix(name, "_test.go") {
			binaryOnly = nil // ignore //go:binary-only-package comments in _test.go files
		}
	} else {