Deprecate legacy action APIs

The asm, compile, cover, and pack actions on go_context are no longer
used by rules_go itself and not covered by any tests. Unless there is
a very strong use case for them in our user base and someone steps up
to contribute test coverage, these are marked for removal in version
0.36.0.

This commit `print`s a warning if any of the deprecated actions is
invoked.

Note: `cover` has already been removed in 0.32.0.

go/private/actions/asm.bzl

@@ -16,13 +16,22 @@ load(
     "//go/private:mode.bzl",
     "link_mode_args",
 )
+load(
+    "//go/private/actions:deprecation.bzl",
+    "LEGACY_ACTIONS_DEPRECATION_NOTICE",
+)
 
 def emit_asm(
         go,
         source = None,
         hdrs = []):
     """See go/toolchains.rst#asm for full documentation."""
 
+    print(LEGACY_ACTIONS_DEPRECATION_NOTICE.format(
+        old = "go_context.asm",
+        new = "go_context.archive",
+    ))
+
     if source == None:
         fail("source is a required parameter")
 

go/private/actions/compile.bzl

@@ -16,6 +16,10 @@ load(
     "//go/private:mode.bzl",
     "link_mode_args",
 )
+load(
+    "//go/private/actions:deprecation.bzl",
+    "LEGACY_ACTIONS_DEPRECATION_NOTICE",
+)
 
 def _archive(v):
     importpaths = [v.data.importpath]
@@ -38,6 +42,11 @@ def emit_compile(
         asmhdr = None):
     """See go/toolchains.rst#compile for full documentation."""
 
+    print(LEGACY_ACTIONS_DEPRECATION_NOTICE.format(
+        old = "go_context.compile",
+        new = "go_context.archive",
+    ))
+
     if sources == None:
         fail("sources is a required parameter")
     if out_lib == None:

go/private/actions/deprecation.bzl

@@ -0,0 +1,15 @@
+# Copyright 2022 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.
+
+LEGACY_ACTIONS_DEPRECATION_NOTICE = "The rules_go team intends to remove '{old}' in version 0.36.0 as it is no longer used by the ruleset itself and entirely untested. Consider using '{new}' instead. If that should not be possible for you, please comment on https://github.com/bazelbuild/rules_go/issues/3168."

go/private/actions/pack.bzl

@@ -12,6 +12,11 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
+load(
+    "//go/private/actions:deprecation.bzl",
+    "LEGACY_ACTIONS_DEPRECATION_NOTICE",
+)
+
 def emit_pack(
         go,
         in_lib = None,
@@ -20,6 +25,11 @@ def emit_pack(
         archives = []):
     """See go/toolchains.rst#pack for full documentation."""
 
+    print(LEGACY_ACTIONS_DEPRECATION_NOTICE.format(
+        old = "go_context.asm",
+        new = "go_context.archive",
+    ))
+
     if in_lib == None:
         fail("in_lib is a required parameter")
     if out_lib == None:

go/toolchains.rst

@@ -585,6 +585,9 @@ It returns a GoArchive_.
 asm
 +++
 
+**Deprecated:** Planned to be removed in rules_go version 0.36.0. Please use `archive` instead and
+comment on https://github.com/bazelbuild/rules_go/issues/3168 if should not be possible.
+
 The asm function adds an action that runs ``go tool asm`` on a source file to
 produce an object, and returns the File of that object.
 
@@ -655,6 +658,9 @@ a ``runfiles`` object.
 compile
 +++++++
 
+**Deprecated:** Planned to be removed in rules_go version 0.36.0. Please use `archive` instead and
+comment on https://github.com/bazelbuild/rules_go/issues/3168 if should not be possible.
+
 The compile function adds an action that compiles a list of source files into
 a package archive (.a file).
 
@@ -716,6 +722,9 @@ It does not return anything.
 cover
 +++++
 
+**Removed in rules_go 0.32.0:** Please comment on https://github.com/bazelbuild/rules_go/issues/3168
+if you still use this feature and cannot rely on `archive` instead.
+
 The cover function adds an action that runs ``go tool cover`` on a set of source
 files to produce copies with cover instrumentation.
 
@@ -782,6 +791,9 @@ It does not return anything.
 pack
 ++++
 
+**Deprecated:** Planned to be removed in rules_go version 0.36.0. Please use `archive` instead and
+comment on https://github.com/bazelbuild/rules_go/issues/3168 if should not be possible.
+
 The pack function adds an action that produces an archive from a base archive
 and a collection of additional object files.