[Feature] go.mod & go.work FilePath ReplaceDirective support

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", "", "path to a local go module")
 	dest       = flag.String("dest", "", "destination directory")
 
 	// Repository flags
@@ -54,17 +55,43 @@ func main() {
 	log.SetPrefix("fetch_repo: ")
 
 	flag.Parse()
-	if *importpath == "" {
+
+	if *importpath == "" && *path == "" {
 		log.Fatal("-importpath 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")
+		}
+		log.Printf("module from\n from: %s,\n to: %s", *path, *dest)
+
+		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 +1,47 @@
+/* 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 (
+	"bytes"
+	"fmt"
+	"os/exec"
+	"strings"
+)
+
+func moduleFromPath(from string, dest string) error {
+	err := copyTree(dest, from)
+	if err != nil {
+		return err
+	}
+
+	cmd := exec.Command(findGoPath(), "mod", "download", "-json")
+	cmd.Dir = dest
+	cmd.Args = append(cmd.Args, "-modcacherw")
+
+	buf := &bytes.Buffer{}
+	bufErr := &bytes.Buffer{}
+	cmd.Stdout = buf
+	cmd.Stderr = bufErr
+	fmt.Printf("Running: %s %s\n", cmd.Path, strings.Join(cmd.Args, " "))
+	// TODO: handle errors
+	cmd.Run()
+
+	// if _, ok := dlErr.(*exec.ExitError); !ok {
+	// 	return fmt.Errorf("error running 'go mod download': %v", dlErr)
+	// }
+	return nil
+}

internal/bzlmod/go_deps.bzl

@@ -13,7 +13,7 @@
 # limitations under the License.
 
 load("//internal:go_repository.bzl", "go_repository")
-load(":go_mod.bzl", "deps_from_go_mod", "parse_go_work", "sums_from_go_mod", "sums_from_go_work")
+load(":go_mod.bzl", "deps_from_go_mod", "go_work_from_label", "sums_from_go_mod", "sums_from_go_work")
 load(
     ":default_gazelle_overrides.bzl",
     "DEFAULT_BUILD_EXTRA_ARGS_BY_PATH",
@@ -83,12 +83,6 @@ _GAZELLE_ATTRS = {
     ),
 }
 
-def go_work_from_label(module_ctx, go_work_label):
-    """Loads deps from a go.work file"""
-    go_work_path = module_ctx.path(go_work_label)
-    go_work_content = module_ctx.read(go_work_path)
-    return parse_go_work(go_work_content, go_work_label)
-
 def _fail_on_non_root_overrides(module_ctx, module, tag_class):
     if module.is_root:
         return
@@ -299,6 +293,10 @@ def check_for_version_conflict(version, previous, module_tag, module_name_to_go_
         # version is the same, skip because we won't error
         return
 
+    if hasattr(module_tag, "file_path"):
+        # overrides are not considered for version conflicts
+        return
+
     # When using go.work, duplicate dependency versions are possible.
     # This can cause issues, so we fail with a hopefully actionable error.
     current_label = module_tag._parent_label
@@ -432,7 +430,10 @@ def _go_deps_impl(module_ctx):
             ]
 
             if module.is_root or getattr(module_ctx, "is_isolated", False):
-                replace_map.update(go_mod_replace_map)
+                # for the replace_map, first in wins
+                for mod_path, mod in go_mod_replace_map.items():
+                    if not mod_path in replace_map:
+                        replace_map[mod_path] = mod
             else:
                 # Register this Bazel module as providing the specified Go module. It participates
                 # in version resolution using its registry version, which uses a relaxed variant of
@@ -487,7 +488,7 @@ def _go_deps_impl(module_ctx):
             # for direct dependencies. For manually specified go_deps.module
             # tags, we always report version upgrades unless users override with
             # the "indirect" attribute.
-            if module.is_root and not module_tag.indirect:
+            if module.is_root and not module_tag.indirect:  # and not module_tag.file_path:
                 root_versions[module_tag.path] = raw_version
                 if _is_dev_dependency(module_ctx, module_tag):
                     root_module_direct_dev_deps[_repo_name(module_tag.path)] = None
@@ -504,10 +505,21 @@ def _go_deps_impl(module_ctx):
             paths[module_tag.path] = struct(version = version, module_tag = module_tag)
 
             if module_tag.path not in module_resolutions or version > module_resolutions[module_tag.path].version:
+                to_path = None
+                file_path = None
+
+                if module_tag.path in replace_map:
+                    replacement = replace_map[module_tag.path]
+
+                    to_path = replacement.to_path
+                    file_path = replacement.file_path
+
                 module_resolutions[module_tag.path] = struct(
                     repo_name = _repo_name(module_tag.path),
                     version = version,
                     raw_version = raw_version,
+                    to_path = to_path,
+                    file_path = file_path,
                 )
 
     _fail_on_unmatched_overrides(archive_overrides.keys(), module_resolutions, "archive_overrides")
@@ -533,6 +545,7 @@ def _go_deps_impl(module_ctx):
                 version = new_version,
                 raw_version = replace.version,
             )
+
             if path in root_versions:
                 if replace != replace.to_path:
                     # If the root module replaces a Go module with a completely different one, do
@@ -542,7 +555,6 @@ def _go_deps_impl(module_ctx):
                     root_versions[path] = replace.version
 
     for path, bazel_dep in bazel_deps.items():
-        # We can't apply overrides to Bazel dependencies and thus fall back to using the Go module.
         if path in archive_overrides or path in gazelle_overrides or path in module_overrides or path in replace_map:
             continue
 
@@ -582,7 +594,6 @@ def _go_deps_impl(module_ctx):
             # Do not create a go_repository for a dep shared with the non-isolated instance of
             # go_deps.
             continue
-
         go_repository_args = {
             "name": module.repo_name,
             "importpath": path,
@@ -602,6 +613,12 @@ def _go_deps_impl(module_ctx):
                 "patches": _get_patches(path, archive_overrides),
                 "patch_args": _get_patch_args(path, archive_overrides),
             })
+        elif module.file_path:
+            go_repository_args.update({
+                # the version is now meaningless
+                "version": None,
+                "file_path": module.file_path,
+            })
         else:
             go_repository_args.update({
                 "sum": _get_sum_from_module(path, module, sums),
@@ -656,7 +673,12 @@ def _get_sum_from_module(path, module, sums):
         entry = (module.replace, module.raw_version)
 
     if entry not in sums:
-        fail("No sum for {}@{} found. You may need to run: bazel run @rules_go//go -- mod tidy".format(path, module.raw_version))
+        if module.raw_version == "{":
+            # replacement have no sums, so we can skip this
+            return None
+        elif module.file_path == None:
+            # TODO: this error likely needs to convey where to run go mod tidy, as it may be in a subdir
+            fail("No sum for {}@{} from {} found. You may need to run: bazel run @rules_go//go -- mod tidy".format(path, module.raw_version, "parent-label-todo"))  #module.parent_label))
 
     return sums[entry]
 
@@ -703,6 +725,10 @@ _module_tag = tag_class(
         ),
         "build_naming_convention": attr.string(doc = """Removed, do not use""", default = ""),
         "build_file_proto_mode": attr.string(doc = """Removed, do not use""", default = ""),
+        "file_path": attr.string(
+            doc = """For when a module is replaced by one residing in a local directory path """,
+            mandatory = False,
+        ),
     },
 )