[POC] go.mod replace with ModulePath

.bazelci/presubmit.yml

@@ -4,6 +4,9 @@ matrix:
     - ubuntu2204
     - macos
   bazel: [6.x, 7.x]
+  bcr_variant:
+    - tests/bcr/go_work
+    - tests/bcr/go_mod
 tasks:
   ubuntu2204:
     name: Ubuntu 22.04 with WORKSPACE
@@ -39,11 +42,12 @@ tasks:
     name: BCR test module
     platform: ${{ platform }}
     bazel: ${{ bazel }}
-    working_directory: tests/bcr
+    working_directory: ${{ bcr_variant }}
     shell_commands:
     # Regenerate the BUILD files for the test module using Gazelle.
     # Also verify -repo_config are generated correctly in gazelle.bash
     - rm pkg/BUILD.bazel proto/BUILD.bazel
+    - touch pkg/BUILD.bazel proto/BUILD.bazel
     - bazel run //:gazelle -- update pkg proto
     - bazel run //:gazelle -- pkg proto
     build_targets:
@@ -59,7 +63,7 @@ tasks:
     name: BCR test on Windows
     platform: windows
     bazel: ${{ bazel }}
-    working_directory: tests/bcr
+    working_directory: ${{ bcr_variant }}
     shell_commands:
     # Regenerate the BUILD file for the test module using Gazelle.
     # Also verify -repo_config are generated correctly in gazelle.bash

.bcr/presubmit.yml

@@ -1,5 +1,5 @@
 bcr_test_module:
-  module_path: tests/bcr
+  module_path: tests/bcr/go_mod
   matrix:
     platform:
       - debian10

.gitignore

@@ -2,11 +2,11 @@
 /bazel-bin
 /bazel-out
 /bazel-testlogs
-/tests/bcr/bazel-bcr
-/tests/bcr/bazel-bin
-/tests/bcr/bazel-out
-/tests/bcr/bazel-testlogs
-/tests/bcr/MODULE.bazel.lock
+/tests/bcr/*/bazel-go_*
+/tests/bcr/*/bazel-bin
+/tests/bcr/*/bazel-out
+/tests/bcr/*/bazel-testlogs
+/tests/bcr/*/MODULE.bazel.lock
 MODULE.bazel.lock
 .DS_STORE
 .ijwb/

cmd/fetch_repo/BUILD.bazel

@@ -7,6 +7,7 @@ go_library(
         "fetch_repo.go",
         "go_mod_download.go",
         "module.go",
+        "path.go",
         "vcs.go",
     ],
     importpath = "github.com/bazelbuild/bazel-gazelle/cmd/fetch_repo",
@@ -40,6 +41,7 @@ filegroup(
         "fetch_repo_test.go",
         "go_mod_download.go",
         "module.go",
+        "path.go",
         "vcs.go",
     ],
     visibility = ["//visibility:public"],

cmd/fetch_repo/fetch_repo.go

@@ -34,6 +34,7 @@ import (
 var (
 	// Common flags
 	importpath = flag.String("importpath", "", "Go importpath to the repository fetch")
+	path       = flag.String("path", "", "absolute or relative path to a local go module")
 	dest       = flag.String("dest", "", "destination directory")
 
 	// Repository flags
@@ -54,17 +55,41 @@ func main() {
 	log.SetPrefix("fetch_repo: ")
 
 	flag.Parse()
-	if *importpath == "" {
-		log.Fatal("-importpath must be set")
+
+	if *importpath == "" && *path == "" {
+		log.Fatal("-importpath or -path must be set")
 	}
+
 	if *dest == "" {
 		log.Fatal("-dest must be set")
 	}
 	if flag.NArg() != 0 {
 		log.Fatal("fetch_repo does not accept positional arguments")
 	}
 
-	if *version != "" {
+	if *path != "" {
+		if *importpath != "" {
+			log.Fatal("-importpath must not be set")
+		}
+		if *remote != "" {
+			log.Fatal("-remote must not be set in module path mode")
+		}
+		if *cmd != "" {
+			log.Fatal("-vcs must not be set in module path mode")
+		}
+		if *rev != "" {
+			log.Fatal("-rev must not be set in module path mode")
+		}
+		if *version != "" {
+			log.Fatal("-version must not be set in module path mode")
+		}
+		if *sum != "" {
+			log.Fatal("-sum must not be set in module path mode")
+		}
+		if err := moduleFromPath(*path, *dest); err != nil {
+			log.Fatal(err)
+		}
+	} else if *version != "" {
 		if *remote != "" {
 			log.Fatal("-remote must not be set in module mode")
 		}

cmd/fetch_repo/module.go

@@ -17,8 +17,9 @@ package main
 
 import (
 	"fmt"
-	"golang.org/x/mod/sumdb/dirhash"
 	"os"
+
+	"golang.org/x/mod/sumdb/dirhash"
 )
 
 func fetchModule(dest, importpath, version, sum string) error {
@@ -33,7 +34,6 @@ func fetchModule(dest, importpath, version, sum string) error {
 	// so we create a dummy module in the current directory (which should be
 	// empty).
 	w, err := os.OpenFile("go.mod", os.O_WRONLY|os.O_CREATE|os.O_EXCL, 0o666)
-
 	if err != nil {
 		return fmt.Errorf("error creating temporary go.mod: %v", err)
 	}
@@ -46,7 +46,7 @@ func fetchModule(dest, importpath, version, sum string) error {
 		return fmt.Errorf("error closing temporary go.mod: %v", err)
 	}
 
-	var dl = GoModDownloadResult{}
+	dl := GoModDownloadResult{}
 	err = runGoModDownload(&dl, dest, importpath, version)
 	os.Remove("go.mod")
 	if err != nil {

cmd/fetch_repo/path.go

@@ -0,0 +1,37 @@
+/* Copyright 2019 The Bazel Authors. All rights reserved.
+
+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 main
+
+import (
+	"fmt"
+	"os/exec"
+)
+
+func moduleFromPath(from string, dest string) error {
+	err := copyTree(dest, from)
+	if err != nil {
+		return err
+	}
+
+	cmd := exec.Command(findGoPath(), "mod", "download", "-json", "-modcacherw")
+	cmd.Dir = dest
+
+	output, err := cmd.CombinedOutput()
+	if err != nil {
+		return fmt.Errorf("error running '%v': %v in %s. Output: %s", cmd.Args, err, dest, string(output))
+	}
+	return nil
+}

def.bzl

@@ -12,13 +12,17 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
+load(
+    "@bazel_gazelle_is_bazel_module//:defs.bzl",
+    "GAZELLE_IS_BAZEL_MODULE",
+)
 load(
     "@bazel_skylib//lib:shell.bzl",
     "shell",
 )
 load(
-    "@bazel_gazelle_is_bazel_module//:defs.bzl",
-    "GAZELLE_IS_BAZEL_MODULE",
+    "//internal:gazelle_binary.bzl",
+    _gazelle_binary = "gazelle_binary_wrapper",
 )
 load(
     "//internal:go_repository.bzl",
@@ -29,10 +33,6 @@ load(
     _git_repository = "git_repository",
     _http_archive = "http_archive",
 )
-load(
-    "//internal:gazelle_binary.bzl",
-    _gazelle_binary = "gazelle_binary_wrapper",
-)
 load(
     "//internal/generationtest:generationtest.bzl",
     _gazelle_generation_test = "gazelle_generation_test",

docs/BUILD.bazel

@@ -5,8 +5,8 @@ resulting documentation markdown files, to prevent users trying to load()
 the stardoc repository, which is not a dependency users should install.
 """
 
-load("@bazel_skylib//rules:write_file.bzl", "write_file")
 load("@bazel_skylib//rules:diff_test.bzl", "diff_test")
+load("@bazel_skylib//rules:write_file.bzl", "write_file")
 load("@io_bazel_stardoc//stardoc:stardoc.bzl", "stardoc")
 
 # gazelle:ignore

internal/bzlmod/BUILD.bazel

@@ -30,6 +30,9 @@ bzl_library(
     name = "go_mod",
     srcs = ["go_mod.bzl"],
     visibility = ["//:__subpackages__"],
+    deps = [
+        ":semver",
+    ],
 )
 
 bzl_library(