From 3ade70ef1bcb7269c573156cb0c2bfa9e87fee4e Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Daniel=20Mart=C3=AD?= <mvdan@mvdan.cc>
Date: Tue, 17 Sep 2024 16:42:38 +0100
Subject: [PATCH] pkg: generate register.go automatically as well
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

Resolves a TODO, and avoids us having to maintain the file manually.

Signed-off-by: Daniel Martí <mvdan@mvdan.cc>
Change-Id: I79d852f1822fedb89a63b810115b5dd8fbee4c78
Reviewed-on: https://review.gerrithub.io/c/cue-lang/cue/+/1201391
TryBot-Result: CUEcueckoo <cueckoo@cuelang.org>
Reviewed-by: Roger Peppe <rogpeppe@gmail.com>
Unity-Result: CUE porcuepine <cue.porcuepine@gmail.com>
---
 pkg/gen.go      | 27 +++++++++++++++++----------
 pkg/register.go | 14 +-------------
 2 files changed, 18 insertions(+), 23 deletions(-)

diff --git a/pkg/gen.go b/pkg/gen.go
index 35cb57c551d..f229e416ec5 100644
--- a/pkg/gen.go
+++ b/pkg/gen.go
@@ -28,8 +28,6 @@
 // Be sure to also update an entry in pkg/pkg.go, if so desired.
 package main
 
-// TODO generate ../register.go too.
-
 import (
 	"bytes"
 	_ "embed"
@@ -55,8 +53,6 @@ import (
 	"cuelang.org/go/internal"
 )
 
-const genFile = "pkg.go"
-
 type headerParams struct {
 	GoPkg  string
 	CUEPkg string
@@ -104,23 +100,34 @@ func main() {
 	if packages.PrintErrors(pkgs) > 0 {
 		os.Exit(1)
 	}
+	regBuf := new(bytes.Buffer)
+	fmt.Fprintf(regBuf, "// Code generated by cuelang.org/go/pkg/gen. DO NOT EDIT.\n\n")
+	fmt.Fprintf(regBuf, "package pkg\n\n")
+	fmt.Fprintf(regBuf, "import (\n")
 	for _, pkg := range pkgs {
 		switch {
 		case pkg.PkgPath == pkgParent:
 			// The pkg package itself should not be generated.
 		case strings.Contains(pkg.PkgPath, "/internal"):
 			// Internal packages are not for public use.
-		case pkg.PkgPath == "cuelang.org/go/pkg/path":
-			// TODO remove this special case. Currently the path
-			// pkg.go file cannot be generated automatically but that
-			// will be possible when we can attach arbitrary signatures
-			// to builtin functions.
 		default:
+			fmt.Fprintf(regBuf, "\t_ %q\n", pkg.PkgPath)
+			if pkg.PkgPath == "cuelang.org/go/pkg/path" {
+				// TODO remove this special case. Currently the path
+				// pkg.go file cannot be generated automatically but that
+				// will be possible when we can attach arbitrary signatures
+				// to builtin functions.
+				break
+			}
 			if err := generate(pkg); err != nil {
 				log.Fatalf("%s: %v", pkg, err)
 			}
 		}
 	}
+	fmt.Fprintf(regBuf, ")\n")
+	if err := os.WriteFile("register.go", regBuf.Bytes(), 0o666); err != nil {
+		log.Fatal(err)
+	}
 }
 
 type generator struct {
@@ -190,7 +197,7 @@ func generate(pkg *packages.Package) error {
 		b = g.w.Bytes() // write the unformatted source
 	}
 
-	filename := filepath.Join(pkgDir, genFile)
+	filename := filepath.Join(pkgDir, "pkg.go")
 
 	if err := os.WriteFile(filename, b, 0666); err != nil {
 		return err
diff --git a/pkg/register.go b/pkg/register.go
index 6718dbd3fa3..5c318155866 100644
--- a/pkg/register.go
+++ b/pkg/register.go
@@ -1,16 +1,4 @@
-// Copyright 2020 CUE Authors
-//
-// Licensed under the Apache License, Version 2.0 (the "License");
-// you may not use this file except in compliance with the License.
-// You may obtain a copy of the License at
-//
-//     http://www.apache.org/licenses/LICENSE-2.0
-//
-// Unless required by applicable law or agreed to in writing, software
-// distributed under the License is distributed on an "AS IS" BASIS,
-// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
-// See the License for the specific language governing permissions and
-// limitations under the License.
+// Code generated by cuelang.org/go/pkg/gen. DO NOT EDIT.
 
 package pkg