Remove some fields from Go context (#4034)

**What type of PR is this?**
Starlark cleanup

**What does this PR do? Why is it needed?**
All of these are either unused or can easily be retrieved from another
context field.
We were already retrieving them from both so this change makes things
more consistent.

**Which issues(s) does this PR fix?**

Fixes #

**Other notes for review**

extras/gomock.bzl

@@ -32,7 +32,7 @@ _MOCKGEN_TOOL = Label("//extras/gomock:mockgen")
 _MOCKGEN_MODEL_LIB = Label("//extras/gomock:mockgen_model")
 
 def _gomock_source_impl(ctx):
-    go_ctx = go_context(ctx)
+    go = go_context(ctx, include_deprecated_properties = False)
 
     # In Source mode, it's not necessary to pass through a library, as the only thing we use it for is setting up
     # the relative file locations. Forcing users to pass a library makes it difficult in the case where a mock should
@@ -73,8 +73,10 @@ def _gomock_source_impl(ctx):
             needed_files.append(aux)
         args += ["-aux_files", ",".join(aux_files)]
 
+    sdk = go.sdk
+
     inputs_direct = needed_files + [source]
-    inputs_transitive = [go_ctx.sdk.tools, go_ctx.sdk.headers, go_ctx.sdk.srcs]
+    inputs_transitive = [sdk.tools, sdk.headers, sdk.srcs]
 
     # We can use the go binary from the stdlib for most of the environment
     # variables, but our GOPATH is specific to the library target we were given.
@@ -83,7 +85,7 @@ def _gomock_source_impl(ctx):
         inputs = depset(inputs_direct, transitive = inputs_transitive),
         tools = [
             ctx.file.mockgen_tool,
-            go_ctx.go,
+            sdk.go,
         ],
         toolchain = GO_TOOLCHAIN_LABEL,
         command = """
@@ -92,7 +94,7 @@ def _gomock_source_impl(ctx):
             {cmd} {args} > {out}
         """.format(
             gopath = gopath,
-            goroot = go_ctx.sdk.root_file.dirname,
+            goroot = sdk.root_file.dirname,
             cmd = "$(pwd)/" + ctx.file.mockgen_tool.path,
             args = " ".join(args),
             out = ctx.outputs.out.path,

go/private/actions/compilepkg.bzl

@@ -122,7 +122,7 @@ def emit_compilepkg(
         else:
             cover_mode = "set"
         args.add("-cover_mode", cover_mode)
-        args.add("-cover_format", go.cover_format)
+        args.add("-cover_format", go.mode.cover_format)
         args.add_all(cover, before_each = "-cover")
     args.add_all(archives, before_each = "-arc", map_each = _archive)
     if recompile_internal_deps:
@@ -133,7 +133,7 @@ def emit_compilepkg(
         args.add("-importpath", go.label.name)
     if importmap:
         args.add("-p", importmap)
-    args.add("-package_list", go.package_list)
+    args.add("-package_list", sdk.package_list)
 
     args.add("-lo", out_lib)
     args.add("-o", out_export)
@@ -237,10 +237,12 @@ def _run_nogo(
         out_validation,
         nogo):
     """Runs nogo on Go source files, including those generated by cgo."""
-    inputs_direct = (sources + [nogo, go.package_list] +
+    sdk = go.sdk
+
+    inputs_direct = (sources + [nogo, sdk.package_list] +
                      [archive.data.facts_file for archive in archives if archive.data.facts_file] +
                      [archive.data.export_file for archive in archives])
-    inputs_transitive = [go.sdk.tools, go.sdk.headers, go.stdlib.libs]
+    inputs_transitive = [sdk.tools, sdk.headers, go.stdlib.libs]
     outputs = [out_facts, out_log]
 
     args = go.builder_args(go, "nogo", use_path_mapping = True)
@@ -259,7 +261,7 @@ def _run_nogo(
         args.add("-importpath", go.label.name)
     if importmap:
         args.add("-p", importmap)
-    args.add("-package_list", go.package_list)
+    args.add("-package_list", sdk.package_list)
 
     args.add_all(archives, before_each = "-facts", map_each = _facts)
     args.add("-out_facts", out_facts)

go/private/actions/link.bzl

@@ -136,7 +136,7 @@ def emit_link(
         not any([arc.importmap == go.coverdata.data.importmap for arc in arcs])):
         arcs.append(go.coverdata.data)
     builder_args.add_all(arcs, before_each = "-arc", map_each = _format_archive)
-    builder_args.add("-package_list", go.package_list)
+    builder_args.add("-package_list", go.sdk.package_list)
 
     # Build a list of rpaths for dynamic libraries we need to find.
     # rpaths are relative paths from the binary to directories where libraries
@@ -156,7 +156,7 @@ def emit_link(
     stamp_x_defs_stable = False
     for k, v in archive.x_defs.items():
         builder_args.add("-X", "%s=%s" % (k, v))
-        if go.stamp:
+        if go.mode.stamp:
             stable_vars_count = (count_group_matches(v, "{STABLE_", "}") +
                                  v.count("{BUILD_EMBED_LABEL}") +
                                  v.count("{BUILD_USER}") +

go/private/context.bzl

@@ -158,10 +158,6 @@ def _declare_file(go, path = "", ext = "", name = ""):
 def _declare_directory(go, path = "", ext = "", name = ""):
     return go.actions.declare_directory(_child_name(go, path, ext, name))
 
-def _new_args(go):
-    # TODO(jayconrod): print warning.
-    return go.builder_args(go)
-
 def _dirname(file):
     return file.dirname
 
@@ -171,21 +167,22 @@ def _builder_args(go, command = None, use_path_mapping = False):
     args.set_param_file_format("shell")
     if command:
         args.add(command)
-    args.add("-sdk", go.sdk.root_file.dirname)
+    sdk_root_file = go.sdk.root_file
+    args.add("-sdk", sdk_root_file.dirname)
 
     # Path mapping can't map the values of environment variables, so we need to pass GOROOT to the
     # action via an argument instead.
     if use_path_mapping:
         if go.stdlib:
             goroot_file = go.stdlib.root_file
         else:
-            goroot_file = go.sdk_root
+            goroot_file = sdk_root_file
 
         # Use a file rather than goroot as the latter is just a string and thus
         # not subject to path mapping.
         args.add_all("-goroot", [goroot_file], map_each = _dirname, expand_directories = False)
     args.add("-installsuffix", installsuffix(go.mode))
-    args.add_joined("-tags", go.tags, join_with = ",")
+    args.add_joined("-tags", go.mode.tags, join_with = ",")
     return args
 
 def _tool_args(go):
@@ -437,7 +434,7 @@ def get_nogo(go):
     else:
         return None
 
-def go_context(ctx, attr = None):
+def go_context(ctx, attr = None, include_deprecated_properties = True):
     """Returns an API used to build Go code.
 
     See /go/toolchains.rst#go-context
@@ -468,8 +465,6 @@ def go_context(ctx, attr = None):
         stdlib = _flatten_possibly_transitioned_attr(attr._stdlib)[GoStdLib]
 
     mode = get_mode(ctx, toolchain, cgo_context_info, go_config_info)
-    tags = mode.tags
-    binary = toolchain.sdk.go
 
     if stdlib:
         goroot = stdlib.root_file.dirname
@@ -528,19 +523,29 @@ def go_context(ctx, attr = None):
     importpath, importmap, pathtype = _infer_importpath(ctx, attr)
     importpath_aliases = tuple(getattr(attr, "importpath_aliases", ()))
 
+    if include_deprecated_properties:
+        deprecated_properties = {
+            "root": goroot,
+            "go": toolchain.sdk.go,
+            "sdk_root": toolchain.sdk.root_file,
+            "sdk_tools": toolchain.sdk.tools,
+            "package_list": toolchain.sdk.package_list,
+            "tags": mode.tags,
+            "stamp": mode.stamp,
+            "cover_format": mode.cover_format,
+            "pgoprofile": mode.pgoprofile,
+        }
+    else:
+        deprecated_properties = {}
+
     return struct(
         # Fields
         toolchain = toolchain,
         sdk = toolchain.sdk,
         mode = mode,
-        root = goroot,
-        go = binary,
         stdlib = stdlib,
-        sdk_root = toolchain.sdk.root_file,
-        sdk_tools = toolchain.sdk.tools,
         actions = ctx.actions,
         cc_toolchain_files = cc_toolchain_files,
-        package_list = toolchain.sdk.package_list,
         importpath = importpath,
         importmap = importmap,
         importpath_aliases = importpath_aliases,
@@ -552,18 +557,14 @@ def go_context(ctx, attr = None):
         coverage_instrumented = ctx.coverage_instrumented(),
         env = env,
         env_for_path_mapping = env_for_path_mapping,
-        tags = tags,
-        stamp = mode.stamp,
         label = ctx.label,
-        cover_format = mode.cover_format,
-        pgoprofile = mode.pgoprofile,
+
         # Action generators
         archive = toolchain.actions.archive,
         binary = toolchain.actions.binary,
         link = toolchain.actions.link,
 
         # Helpers
-        args = _new_args,  # deprecated
         builder_args = _builder_args,
         tool_args = _tool_args,
         new_library = _new_library,
@@ -574,6 +575,9 @@ def go_context(ctx, attr = None):
         # Private
         # TODO: All uses of this should be removed
         _ctx = ctx,
+
+        # Deprecated
+        **deprecated_properties
     )
 
 def _go_context_data_impl(ctx):

go/private/rules/binary.bzl

@@ -96,7 +96,7 @@ def new_cc_import(
 
 def _go_binary_impl(ctx):
     """go_binary_impl emits actions for compiling and linking a go executable."""
-    go = go_context(ctx)
+    go = go_context(ctx, include_deprecated_properties = False)
 
     is_main = go.mode.link not in (LINKMODE_SHARED, LINKMODE_PLUGIN)
     library = go.new_library(go, importable = False, is_main = is_main)

go/private/rules/library.bzl

@@ -34,7 +34,7 @@ load(
 
 def _go_library_impl(ctx):
     """Implements the go_library() rule."""
-    go = go_context(ctx)
+    go = go_context(ctx, include_deprecated_properties = False)
     library = go.new_library(go)
     source = go.library_to_source(go, ctx.attr, library, ctx.coverage_instrumented())
     archive = go.archive(go, source)

go/private/rules/nogo.bzl

@@ -38,7 +38,7 @@ def _nogo_impl(ctx):
         return None
 
     # Generate the source for the nogo binary.
-    go = go_context(ctx)
+    go = go_context(ctx, include_deprecated_properties = False)
     nogo_main = go.declare_file(go, path = "nogo_main.go")
     nogo_args = ctx.actions.args()
     nogo_args.add("gennogomain")

go/private/rules/source.bzl

@@ -27,7 +27,7 @@ load(
 
 def _go_source_impl(ctx):
     """Implements the go_source() rule."""
-    go = go_context(ctx)
+    go = go_context(ctx, include_deprecated_properties = False)
     library = go.new_library(go)
     source = go.library_to_source(go, ctx.attr, library, ctx.coverage_instrumented())
     return [

go/private/rules/stdlib.bzl

@@ -30,7 +30,7 @@ load(
 )
 
 def _stdlib_impl(ctx):
-    go = go_context(ctx)
+    go = go_context(ctx, include_deprecated_properties = False)
     return go.toolchain.actions.stdlib(go)
 
 stdlib = rule(

go/private/rules/test.bzl

@@ -56,7 +56,7 @@ def _go_test_impl(ctx):
     It emits an action to run the test generator, and then compiles the
     test into a binary."""
 
-    go = go_context(ctx)
+    go = go_context(ctx, include_deprecated_properties = False)
 
     # Compile the library to test with internal white box tests
     internal_library = go.new_library(go, testfilter = "exclude")
@@ -100,7 +100,7 @@ def _go_test_impl(ctx):
             arguments.add("-cover_mode", "atomic")
         else:
             arguments.add("-cover_mode", "set")
-        arguments.add("-cover_format", go.cover_format)
+        arguments.add("-cover_format", go.mode.cover_format)
     arguments.add(
         # the l is the alias for the package under test, the l_test must be the
         # same with the test suffix

go/toolchains.rst

@@ -570,16 +570,6 @@ Fields
 | Controls the compilation setup affecting things like enabling profilers and sanitizers.          |
 | See `compilation modes`_ for more information about the allowed values.                          |
 +--------------------------------+-----------------------------------------------------------------+
-| :param:`root`                  | :type:`string`                                                  |
-+--------------------------------+-----------------------------------------------------------------+
-| Path of the effective GOROOT. If :param:`stdlib` is set, this is the same                        |
-| as ``go.stdlib.root_file.dirname``. Otherwise, this is the same as                               |
-| ``go.sdk.root_file.dirname``.                                                                    |
-+--------------------------------+-----------------------------------------------------------------+
-| :param:`go`                    | :type:`File`                                                    |
-+--------------------------------+-----------------------------------------------------------------+
-| The main "go" binary used to run go sdk tools.                                                   |
-+--------------------------------+-----------------------------------------------------------------+
 | :param:`stdlib`                | :type:`GoStdLib`                                                |
 +--------------------------------+-----------------------------------------------------------------+
 | The standard library and tools to use in this build mode. This may be the                        |
@@ -595,18 +585,36 @@ Fields
 +--------------------------------+-----------------------------------------------------------------+
 | The files you need to add to the inputs of an action in order to use the cc toolchain.           |
 +--------------------------------+-----------------------------------------------------------------+
-| :param:`package_list`          | :type:`File`                                                    |
-+--------------------------------+-----------------------------------------------------------------+
-| A file that contains the package list of the standard library.                                   |
-+--------------------------------+-----------------------------------------------------------------+
 | :param:`env`                   | :type:`dict of string to string`                                |
 +--------------------------------+-----------------------------------------------------------------+
 | Environment variables to pass to actions. Includes ``GOARCH``, ``GOOS``,                         |
 | ``GOROOT``, ``GOROOT_FINAL``, ``CGO_ENABLED``, and ``PATH``.                                     |
 +--------------------------------+-----------------------------------------------------------------+
+
+Deprecated Fields
+^^^^^^
+
++--------------------------------+-----------------------------------------------------------------+
+| **Name**                       | **Type**                                                        |
++--------------------------------+-----------------------------------------------------------------+
++--------------------------------+-----------------------------------------------------------------+
+| :param:`root`                  | :type:`string`                                                  |
++--------------------------------+-----------------------------------------------------------------+
+| Prefer `go.env["GOROOT"]`. Path of the effective GOROOT. If :param:`stdlib` is set,              |
+| this is the same as ``go.stdlib.root_file.dirname``. Otherwise, this is the same as              |
+| ``go.sdk.root_file.dirname``.                                                                    |
++--------------------------------+-----------------------------------------------------------------+
+| :param:`go`                    | :type:`File`                                                    |
++--------------------------------+-----------------------------------------------------------------+
+| Prefer `go.sdk.go`. The main "go" binary used to run go sdk tools.                               |
++--------------------------------+-----------------------------------------------------------------+
+| :param:`package_list`          | :type:`File`                                                    |
++--------------------------------+-----------------------------------------------------------------+
+| Prefer `go.sdk.package_list`. A file that contains the package list of the standard library.     |
++--------------------------------+-----------------------------------------------------------------+
 | :param:`tags`                  | :type:`list of string`                                          |
 +--------------------------------+-----------------------------------------------------------------+
-| List of build tags used to filter source files.                                                  |
+| Prefer `go.mode.tags`. List of build tags used to filter source files.                           |
 +--------------------------------+-----------------------------------------------------------------+
 
 Methods

proto/compiler.bzl

@@ -182,7 +182,7 @@ def proto_path(src, proto):
     return src.path[len(prefix):]
 
 def _go_proto_compiler_impl(ctx):
-    go = go_context(ctx)
+    go = go_context(ctx, include_deprecated_properties = False)
     library = go.new_library(go)
     source = go.library_to_source(go, ctx.attr, library, ctx.coverage_instrumented())
     proto_toolchain = proto_toolchains.find_toolchain(

proto/def.bzl

@@ -67,7 +67,7 @@ def get_imports(attr, importpath):
     return depset(direct = direct.keys(), transitive = transitive)
 
 def _go_proto_aspect_impl(_target, ctx):
-    go = go_context(ctx, ctx.rule.attr)
+    go = go_context(ctx, ctx.rule.attr, include_deprecated_properties = False)
     imports = get_imports(ctx.rule.attr, go.importpath)
     return [GoProtoImports(imports = imports)]
 
@@ -90,7 +90,7 @@ def _proto_library_to_source(_go, attr, source, merge):
             merge(source, compiler[GoSource])
 
 def _go_proto_library_impl(ctx):
-    go = go_context(ctx)
+    go = go_context(ctx, include_deprecated_properties = False)
     if ctx.attr.compiler:
         #TODO: print("DEPRECATED: compiler attribute on {}, use compilers instead".format(ctx.label))
         compilers = [ctx.attr.compiler]