Add go_deps.config(env = ...) as a replacement for `gazelle_depende…

…ncies(go_env = ...)` (#1748)

With this PR, `go_deps.config(go_env = {...})` can be used to specify environment variables for go_repository, replacing gazelle_dependencies(go_env = ...). They are exported in a way that makes them usable for `@rules_go//go`, which will be done in a follow-up change to rules_go.

Work towards bazel-contrib/rules_go#3814

MODULE.bazel

@@ -56,7 +56,6 @@ use_repo(
 bazel_dep(name = "bazel_skylib_gazelle_plugin", version = "1.4.1", dev_dependency = True)
 bazel_dep(name = "stardoc", version = "0.6.2", dev_dependency = True, repo_name = "io_bazel_stardoc")
 
-
 go_sdk_dev = use_extension("@io_bazel_rules_go//go:extensions.bzl", "go_sdk", dev_dependency = True)
 
 # Known to exist since it is instantiated by rules_go itself.

internal/bzlmod/go_deps.bzl

@@ -175,6 +175,9 @@ def _is_dev_dependency(module_ctx, tag):
     # not available.
     return module_ctx.is_dev_dependency(tag) if hasattr(module_ctx, "is_dev_dependency") else False
 
+def _intersperse_newlines(tags):
+    return [tag for p in zip(tags, len(tags) * ["\n"]) for tag in p]
+
 # This function processes the gazelle_default_attributes tag for a given module and returns a struct
 # containing the attributes from _GAZELLE_ATTRS that are defined in the tag.
 def _process_gazelle_default_attributes(module_ctx):
@@ -260,14 +263,19 @@ def _go_repository_config_impl(ctx):
         ))
 
     ctx.file("WORKSPACE", "\n".join(repos))
-    ctx.file("BUILD.bazel", "exports_files(['WORKSPACE'])")
+    ctx.file("BUILD.bazel", "exports_files(['WORKSPACE', 'config.json'])")
+    ctx.file("go_env.bzl", content = "GO_ENV = " + repr(ctx.attr.go_env))
+
+    # For use by @rules_go//go.
+    ctx.file("config.json", content = json.encode_indent(ctx.attr.go_env))
 
 _go_repository_config = repository_rule(
     implementation = _go_repository_config_impl,
     attrs = {
         "importpaths": attr.string_dict(mandatory = True),
         "module_names": attr.string_dict(mandatory = True),
         "build_naming_conventions": attr.string_dict(mandatory = True),
+        "go_env": attr.string_dict(mandatory = True),
     },
 )
 
@@ -301,11 +309,19 @@ def _go_deps_impl(module_ctx):
     root_module_direct_deps = {}
     root_module_direct_dev_deps = {}
 
-    if module_ctx.modules[0].name == "gazelle":
+    first_module = module_ctx.modules[0]
+    if first_module.is_root and first_module.name in ["gazelle", "rules_go"]:
         root_module_direct_deps["bazel_gazelle_go_repository_config"] = None
 
     outdated_direct_dep_printer = print
+    go_env = {}
     for module in module_ctx.modules:
+        if len(module.tags.config) > 1:
+            fail(
+                "Multiple \"go_deps.config\" tags defined in module \"{}\":\n".format(module.name),
+                *_intersperse_newlines(module.tags.config)
+            )
+
         # Parse the go_deps.config tag of the root module only.
         for mod_config in module.tags.config:
             if not module.is_root:
@@ -317,6 +333,7 @@ def _go_deps_impl(module_ctx):
                 outdated_direct_dep_printer = print
             elif check_direct_deps == "error":
                 outdated_direct_dep_printer = fail
+            go_env = mod_config.go_env
 
         _process_overrides(module_ctx, module, "gazelle_override", gazelle_overrides, _process_gazelle_override)
         _process_overrides(module_ctx, module, "module_override", module_overrides, _process_module_override, archive_overrides)
@@ -533,6 +550,7 @@ def _go_deps_impl(module_ctx):
             )
             for path, module in module_resolutions.items()
         }),
+        go_env = go_env,
     )
 
     return _extension_metadata(
@@ -572,6 +590,9 @@ _config_tag = tag_class(
         "check_direct_dependencies": attr.string(
             values = ["off", "warning", "error"],
         ),
+        "go_env": attr.string_dict(
+            doc = "The environment variables to use when fetching Go dependencies or running the `@rules_go//go` tool.",
+        ),
     },
 )
 

internal/bzlmod/non_module_deps.bzl

@@ -28,6 +28,10 @@ load(
     "@go_host_compatible_sdk_label//:defs.bzl",
     "HOST_COMPATIBLE_SDK",
 )
+load(
+    "@bazel_gazelle_go_repository_config//:go_env.bzl",
+    "GO_ENV",
+)
 
 visibility("//")
 
@@ -36,7 +40,7 @@ def _non_module_deps_impl(_):
         name = "bazel_gazelle_go_repository_cache",
         # Label.workspace_name is always a canonical name, so use a canonical label.
         go_sdk_name = "@" + HOST_COMPATIBLE_SDK.workspace_name,
-        go_env = {},
+        go_env = GO_ENV,
     )
     go_repository_tools(
         name = "bazel_gazelle_go_repository_tools",

tests/bcr/MODULE.bazel

@@ -18,11 +18,18 @@ bazel_dep(name = "protobuf", version = "23.1", repo_name = "my_protobuf")
 bazel_dep(name = "rules_go", version = "0.42.0", repo_name = "my_rules_go")
 bazel_dep(name = "rules_proto", version = "6.0.0-rc2", repo_name = "my_rules_proto")
 
+go_sdk = use_extension("@my_rules_go//go:extensions.bzl", "go_sdk")
+
 # This bazel_dep provides the Go dependency github.com/cloudflare/circl, which requires custom
 # patches beyond what Gazelle can generate.
 bazel_dep(name = "circl", version = "1.3.7")
 
 go_deps = use_extension("@gazelle//:extensions.bzl", "go_deps")
+go_deps.config(
+    go_env = {
+        "GOPRIVATE": "example.com/*",
+    },
+)
 
 # Validate a go.mod replace directive works.
 go_deps.from_file(go_mod = "//:go.mod")