Add buf migrate MVP

TODO.txt

@@ -20,6 +20,27 @@
 - document behavior of file searching, config override
 - fix tamper-proofing
 - go through all todos
+- `buf mod init` should create a v2 buf.yaml.
+- Is `buf build` supposed to call the API when there is already a buf.lock? On the same
+  directory, the released version (main) doesn't make that API call but `bufmod` calls
+  `buf.registry.module.v1beta1.CommitService/GetCommitNodes`. Is it for computing digest? Or is it because the buf.lock is in v1?
+
+- Migrate buf.work.yaml, buf.yaml and buf.lock
+  - It would be nice if the bufconfig.File exposes a Path() method. Or a path() method and
+    I can move bufmigrate into bufconfig.
+  - A strategy to resolve dependencies for buf.lock
+  - A strategy to resolve dependencies declared. i.e. foo depends on common:commit_1,
+    bar depends on common:commit_2 and baz depends on common (without pinning a commit).
+  - Refine migration behavior and flags.
+  - Relative paths in lint/breaking ignore rules (and similar fields requiring paths), what
+    are they relative to? Their module root or the workspace root?
+  - Group lint rules, right now lint rules are expanded to a list of individual rules.
+    - Going from v1beta1 there are many changes to the rules.
+    - Going from v1 to v2, the only change is that PACKAGE_NO_IMPORT_CYCLE is added to MINIMAL, BASIC, DEFAULT.
+  - Breaking rules:
+    - FIELD_SAME_TYPE from v1beta1 is split into 3 rules in v1: FIELD_SAME_TYPE,
+      FIELD_WIRE_COMPATIBLE_TYPE, FIELD_WIRE_JSON_COMPATIBLE_TYPE.
+    - Rule `FILE_SAME_PACKAGE` has been added to PACKAGE, WIRE and WIRE_JSON in v1.
 - Un-skip relevant tests in generate_test.go and generate_unix_test.go, when
   - the behavior of --path and --exclude-path is updated to match what's on main
 - Debug the skipped test with proto file ref in generate_test.go

private/buf/bufmigrate/bufmigrate.go

@@ -0,0 +1,134 @@
+// Copyright 2020-2023 Buf Technologies, Inc.
+//
+// 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.
+
+package bufmigrate
+
+import (
+	"context"
+	"errors"
+	"fmt"
+	"io"
+	"path/filepath"
+
+	"buf.build/gen/go/bufbuild/registry/connectrpc/go/buf/registry/module/v1beta1/modulev1beta1connect"
+	"github.com/bufbuild/buf/private/pkg/slicesext"
+	"github.com/bufbuild/buf/private/pkg/storage/storageos"
+)
+
+// Migrate migrate buf configuration files.
+func Migrate(
+	ctx context.Context,
+	storageProvider storageos.Provider,
+	commitService modulev1beta1connect.CommitServiceClient,
+	options ...MigrateOption,
+) (retErr error) {
+	migrateOptions := newMigrateOptions()
+	for _, option := range options {
+		option(migrateOptions)
+	}
+	if migrateOptions.bufWorkYAMLFilePath == "" && len(migrateOptions.bufYAMLFilePaths) == 0 {
+		return errors.New("unimplmented")
+	}
+	// TODO: decide on behavior for where to write this file
+	destinationDir := "."
+	// Alternatively, we could do the following: (but "." is probably better, since we want users to
+	// have buf.yaml v2 at their repository root and they are likely running this command from there)
+	//
+	// if migrateOptions.bufWorkYAMLFilePath != "" {
+	// 	destinationDir = filepath.Base(migrateOptions.bufWorkYAMLFilePath)
+	// } else if len(migrateOptions.bufYAMLFilePaths) == 1 {
+	// 	// TODO: maybe use "." (or maybe add --dest flag)
+	// 	destinationDir = filepath.Base(migrateOptions.bufYAMLFilePaths[0])
+	// } else {
+	// 	destinationDir = "."
+	// }
+	bucket, err := storageProvider.NewReadWriteBucket(
+		".",
+		storageos.ReadWriteBucketWithSymlinksIfSupported(),
+	)
+	if err != nil {
+		return err
+	}
+	migrator := newMigrator(
+		bucket,
+		destinationDir,
+	)
+	if migrateOptions.bufWorkYAMLFilePath != "" {
+		if err := migrator.addWorkspaceDirectory(
+			ctx,
+			filepath.Dir(migrateOptions.bufWorkYAMLFilePath),
+		); err != nil {
+			return err
+		}
+	}
+	for _, bufYAMLPath := range migrateOptions.bufYAMLFilePaths {
+		// TODO: read upwards to make sure it's not in a workspace
+		// i.e. for ./foo/bar/buf.yaml, check none of "./foo", ".", "../", "../..", and etc. is a workspace.
+		if err := migrator.addModuleDirectory(
+			ctx,
+			filepath.Dir(bufYAMLPath),
+		); err != nil {
+			return err
+		}
+	}
+	if migrateOptions.dryRun {
+		return migrator.migrateAsDryRun(migrateOptions.dryRunWriter)
+	}
+	return migrator.migrate(ctx)
+}
+
+// MigrateOption is a migrate option.
+type MigrateOption func(*migrateOptions)
+
+// MigrateAsDryRun write to the writer the summary of the changes to be made, without writing to the disk.
+func MigrateAsDryRun(writer io.Writer) MigrateOption {
+	return func(migrateOptions *migrateOptions) {
+		migrateOptions.dryRun = true
+		migrateOptions.dryRunWriter = writer
+	}
+}
+
+// MigrateBufWorkYAMLFile migrates a v1 buf.work.yaml.
+func MigrateBufWorkYAMLFile(path string) (MigrateOption, error) {
+	// TODO: Looking at IsLocal's doc, it seems to validate for what we want: relative and does not jump context.
+	if !filepath.IsLocal(path) {
+		return nil, fmt.Errorf("%s is not a relative path", path)
+	}
+	return func(migrateOptions *migrateOptions) {
+		migrateOptions.bufWorkYAMLFilePath = filepath.Clean(path)
+	}, nil
+}
+
+// MigrateBufYAMLFile migrates buf.yaml files.
+func MigrateBufYAMLFile(paths []string) (MigrateOption, error) {
+	for _, path := range paths {
+		if !filepath.IsLocal(path) {
+			return nil, fmt.Errorf("%s is not a relative path", path)
+		}
+	}
+	return func(migrateOptions *migrateOptions) {
+		migrateOptions.bufYAMLFilePaths = slicesext.Map(paths, filepath.Clean)
+	}, nil
+}
+
+type migrateOptions struct {
+	dryRun              bool
+	dryRunWriter        io.Writer
+	bufWorkYAMLFilePath string
+	bufYAMLFilePaths    []string
+}
+
+func newMigrateOptions() *migrateOptions {
+	return &migrateOptions{}
+}

private/buf/bufmigrate/bufmigrate_test.go

@@ -0,0 +1,22 @@
+// Copyright 2020-2023 Buf Technologies, Inc.
+//
+// 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.
+
+package bufmigrate
+
+import "testing"
+
+func TestMigrate(t *testing.T) {
+	// TODO
+	t.Parallel()
+}