Brad Fitzpatrick 6fb316f5ed feature/buildfeatures: split const bools out of the featuretags package, add Has prefix
This renames the package+symbols in the earlier 17ffa8013835d4 to be
in their own package ("buildfeatures") and start with the word "Has"
like "if buildfeatures.HasFoo {".

Updates #12614

Change-Id: I510e5f65993e5b76a0e163e3aa4543755213cbf6
Signed-off-by: Brad Fitzpatrick <bradfitz@tailscale.com>
2025-09-15 10:33:51 -07:00

50 lines
1.4 KiB
Go

// Copyright (c) Tailscale Inc & AUTHORS
// SPDX-License-Identifier: BSD-3-Clause
//go:build ignore
// The gens.go program generates the feature_<feature>_enabled.go
// and feature_<feature>_disabled.go files for each feature tag.
package main
import (
"cmp"
"fmt"
"os"
"strings"
"tailscale.com/feature/featuretags"
"tailscale.com/util/must"
)
const header = `// Copyright (c) Tailscale Inc & AUTHORS
// SPDX-License-Identifier: BSD-3-Clause
// Code g|e|n|e|r|a|t|e|d by gen.go; D|O N|OT E|D|I|T.
`
func main() {
header := strings.ReplaceAll(header, "|", "") // to avoid this file being marked as generated
for k, m := range featuretags.Features {
if !k.IsOmittable() {
continue
}
sym := "Has" + cmp.Or(m.Sym, strings.ToUpper(string(k)[:1])+string(k)[1:])
for _, suf := range []string{"enabled", "disabled"} {
bang := ""
if suf == "enabled" {
bang = "!" // !ts_omit_...
}
must.Do(os.WriteFile("feature_"+string(k)+"_"+suf+".go",
fmt.Appendf(nil, "%s//go:build %s%s\n\npackage buildfeatures\n\n"+
"// %s is whether the binary was built with support for modular feature %q.\n"+
"// Specifically, it's whether the binary was NOT built with the %q build tag.\n"+
"// It's a const so it can be used for dead code elimination.\n"+
"const %s = %t\n",
header, bang, k.OmitTag(), sym, m.Desc, k.OmitTag(), sym, suf == "enabled"), 0644))
}
}
}